WO2019151433A1 - Opened tow of protein filament and method for manufacturing same - Google Patents

Opened tow of protein filament and method for manufacturing same Download PDF

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WO2019151433A1
WO2019151433A1 PCT/JP2019/003470 JP2019003470W WO2019151433A1 WO 2019151433 A1 WO2019151433 A1 WO 2019151433A1 JP 2019003470 W JP2019003470 W JP 2019003470W WO 2019151433 A1 WO2019151433 A1 WO 2019151433A1
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seq
amino acid
sequence
acid sequence
protein
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PCT/JP2019/003470
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French (fr)
Japanese (ja)
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皓斗 佐藤
池田　敦
翔太 冨樫
佑之介 安部
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Ｓｐｉｂｅｒ株式会社
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Publication of WO2019151433A1 publication Critical patent/WO2019151433A1/en

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    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F4/00—Monocomponent artificial filaments or the like of proteins; Manufacture thereof
    • D01F4/02—Monocomponent artificial filaments or the like of proteins; Manufacture thereof from fibroin
    • D—TEXTILES; PAPER
    • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
    • D02J—FINISHING OR DRESSING OF FILAMENTS, YARNS, THREADS, CORDS, ROPES OR THE LIKE
    • D02J1/00—Modifying the structure or properties resulting from a particular structure; Modifying, retaining, or restoring the physical form or cross-sectional shape, e.g. by use of dies or squeeze rollers
    • D02J1/18—Separating or spreading
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K14/00—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof
    • C07K14/435—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans

Definitions

  • the present invention relates to a protein filament opening tow and a method for producing the same.
  • Protein fibers include filaments (long fibers) such as silk and staples (short fibers) such as wool, the former has a supple texture, and the latter has a soft feeling and heat retaining properties. It has characteristics. These protein fibers, unlike synthetic fibers, are all biodegradable and have low production and processing energy. Increase in demand is expected.
  • Cited Document 1 discloses a method of opening a bundle of natural silk filaments having crimps to obtain silk wisteria that is highly opened compared to the opened tow.
  • the present invention has been made in view of the above problems, and provides a protein filament opening tow and a method for producing the same, which can easily produce an extremely thick yarn.
  • the present invention relates to the following inventions, for example.
  • a tow of a protein filament wherein the protein filament comprises a modified fibroin and has crimps.
  • the modified fibroin is SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 32, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 40, or the amino acid sequence shown by SEQ ID NO: 41, or SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 32, SEQ ID NO: 33, sequence The open sequence according to [1] or [2], which has an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 40, or SEQ ID NO: 41.
  • a method for producing a spread tow of protein filaments comprising: crimping a bundle of protein filaments; and opening the bundle of crimped protein filaments to obtain a spread tow And the protein filament comprises a modified fibroin.
  • the crimping step includes mechanically crimping the bundle of protein filaments, or contacting the bundle of protein filaments with an aqueous medium. Production method.
  • the modified fibroin is SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 32, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 40, or the amino acid sequence shown by SEQ ID NO: 41, or SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 32, SEQ ID NO: 33, sequence Any one of [4] to [8], which has an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 40, or SEQ ID NO: 41
  • the opened tow produced by the method according to the present invention includes a protein filament that can be obtained by spinning to have an arbitrary length (for example, longer than 1500 m), so that it is possible to easily produce a very thick yarn. It becomes.
  • FIG. 2 is a photograph of a bundle of crimped protein filaments in Example 1.
  • FIG. 2 is a photograph of the opened tow in Example 1.
  • 4 is a photograph of the opened tow in Example 2.
  • One embodiment of the present invention relates to a protein filament opening tow.
  • the opened tow is a fiber bundle obtained by collecting a plurality of spun yarns.
  • the protein filament contains modified fibroin as a main component.
  • the modified fibroin according to the present embodiment has a domain sequence represented by Formula 1: [(A) n motif-REP] m or Formula 2: [(A) n motif-REP] m- (A) n motif. It is a protein containing.
  • an amino acid sequence (N-terminal sequence and C-terminal sequence) may be further added to either one or both of the N-terminal side and the C-terminal side of the domain sequence.
  • the N-terminal sequence and the C-terminal sequence are not limited to these, but are typically regions having no amino acid motif repeat characteristic of fibroin and consisting of about 100 amino acids.
  • modified fibroin means an artificially produced fibroin (artificial fibroin).
  • the modified fibroin may be a fibroin whose domain sequence is different from the amino acid sequence of naturally occurring fibroin or may be the same as the amino acid sequence of naturally occurring fibroin.
  • Natural fibroin as used herein is also represented by Formula 1: [(A) n motif-REP] m or Formula 2: [(A) n motif-REP] m- (A) n motif.
  • a protein comprising a domain sequence to be processed.
  • the amino acid sequence of naturally-occurring fibroin may be used as it is, and it depends on the amino acid sequence of naturally-occurring fibroin.
  • the amino acid sequence may be modified (for example, the amino acid sequence may be modified by modifying the gene sequence of a naturally-derived fibroin that has been cloned), or it may be artificially designed without relying on the naturally-occurring fibroin. And those synthesized (for example, those having a desired amino acid sequence by chemically synthesizing a nucleic acid encoding the designed amino acid sequence).
  • domain sequence refers to a fibroin-specific crystal region (typically corresponding to the (A) n motif in the amino acid sequence) and an amorphous region (typically in the REP of the amino acid sequence).
  • (A) n motif represents an amino acid sequence mainly composed of alanine residues, and the number of amino acid residues is 2 to 27.
  • the number of amino acid residues of the n motif may be an integer of 2 to 20, 4 to 27, 4 to 20, 8 to 20, 10 to 20, 4 to 16, 8 to 16, or 10 to 16 .
  • the ratio of the number of alanine residues to the total number of amino acid residues in the (A) n motif may be 40% or more, such as 60% or more, 70% or more, 80% or more, 83% or more, 85% or more, It may be 86% or more, 90% or more, 95% or more, or 100% (meaning that it is composed only of alanine residues).
  • a plurality of (A) n motifs present in the domain sequence may be composed of at least seven alanine residues alone.
  • REP indicates an amino acid sequence composed of 2 to 200 amino acid residues.
  • REP may be an amino acid sequence composed of 10 to 200 amino acid residues.
  • m represents an integer of 2 to 300, and may be an integer of 10 to 300.
  • a plurality of (A) n motifs may have the same amino acid sequence or different amino acid sequences.
  • Plural REPs may have the same amino acid sequence or different amino acid sequences.
  • the modified fibroin is, for example, a modification of the amino acid sequence corresponding to, for example, substitution, deletion, insertion and / or addition of one or more amino acid residues to the cloned natural fibroin gene sequence. Can be obtained at Substitution, deletion, insertion and / or addition of amino acid residues can be carried out by methods well known to those skilled in the art such as partial-directed mutagenesis. Specifically, Nucleic Acid Res. 10, 6487 (1982), Methods in Enzymology, 100, 448 (1983), and the like.
  • Naturally-derived fibroin is a protein containing a domain sequence represented by Formula 1: [(A) n motif-REP] m or Formula 2: [(A) n motif-REP] m- (A) n motif.
  • Specific examples include fibroin produced by insects or spiders.
  • fibroin produced by insects include, for example, Bombyx mori, Kwako (Bombyx mandaraina), Tengea (Antheraea yamanai), ⁇ ⁇ (Antereaperanii), ⁇ ⁇ (Eriothyraminey) ), Silkworms produced by silkworms, such as Samia cythia, chestnut worms (Caligula japonica), Chuser moth (Antherea mylitta), Antheraea assama, and vespax (Vespaxia spp.) Hornet silk protein.
  • fibroin produced by insects include silkworm fibroin L chain (GenBank accession number M76430 (base sequence) and AAA27840.1 (amino acid sequence)).
  • Fibroin produced by spiders includes, for example, spiders belonging to the genus spider (Araneus spp.) Such as the spider spider, the spider spider, the red spider spider, and the bean spider, the genus spiders of the genus Araneus, the spider spider spider, the spider spider genus e Spiders, spiders such as spiders, spiders belonging to the genus Spider, spiders belonging to the genus Pronos, spiders belonging to the genus Trinofunda, such as Torinofundamas (genus Cyrtarachne) Spiders belonging to the genus (Gasteracantha), spiders belonging to the genus Spider (Ordgarius genus), such as the spiders, the spiders, and the spiders belonging to the genus Ordgarius Spiders belonging to the genus Argiope, such as the genus Argiope, spiders belonging to the genus Arachnura, such as the white-tailed spider, spiders belonging to the
  • Spiders belonging to the genus Azumigumi (Menosira), spiders belonging to the genus Dyschiriognatha (genus Dyschiriognatha) such as the common spider spider, the black spider spider, the genus Spider genus belonging to the genus Spider belonging to the genus (L) and the genus Spider belonging to the genus Usd Produced by spiders belonging to the family Tetragnathidae such as spiders belonging to the genus Prostenops
  • Examples include spider silk protein.
  • the spider silk protein include dragline proteins such as MaSp (MaSp1 and MaSp2) and ADF (ADF3 and ADF4), MiSp (MiSp1 and MiSp2), and the like.
  • spider silk proteins produced by spiders include, for example, fibroin-3 (adf-3) [derived from Araneus diadematus] (GenBank accession numbers AAC47010 (amino acid sequence), U47855 (base sequence)), fibroin-4 (adf-4) [derived from Araneus diadematus] (GenBank accession number AAC47011 (amino acid sequence), U47856 (base sequence)), dragline silk protein spiroin 1 [derived from Nephila clavipes] (GenBank accession number 4) ), U37520 (base sequence)), major ampulate spidro n 1 [derived from Latroductus hesperus] (GenBank accession number ABR68856 (amino acid sequence), EF595246 (base sequence)), dragline silk protein spidolin 2 [derived from Nephila clavata (GenBank accession number AAL32 base sequence 44 AAL32 base sequence amino acid 44, amino acid sequence 44 AAL47)
  • Naturally derived fibroin include fibroin whose sequence information is registered in NCBI GenBank.
  • sequence information is registered in NCBI GenBank.
  • spidin, sample, fibroin, “silk and polypeptide”, or “silk and protein” is described as a keyword in DEFINITION from sequences including INV as DIVISION among the sequence information registered in NCBI GenBank. It can be confirmed by extracting a character string of a specific product from the sequence, CDS, and a sequence in which the specific character string is described from SOURCE to TISSUE TYPE.
  • the modified fibroin may be modified silk fibroin (modified silk protein amino acid sequence produced by silkworm), modified spider silk fibroin (modified spider silk protein amino acid sequence produced by spiders) Thing). Among them, modified spider silk fibroin is preferably used.
  • modified fibroin examples include a modified fibroin derived from a large sphincter bookmark silk protein produced in a spider large bottle gland, a modified fibroin with a reduced content of glycine residues, (A) an n motif Modified fibroin with reduced content, content of glycine residue, and (A) modified fibroin with reduced content of n motif.
  • Examples of the modified fibroin derived from the large sphincter bookmark silk protein produced in the spider large bottle gland include a protein containing a domain sequence represented by Formula 1: [(A) n motif-REP] m .
  • (A) the number of amino acid residues of the n motif is preferably an integer of 3 to 20, more preferably an integer of 4 to 20
  • an integer of 8 to 20 is more preferable, an integer of 10 to 20 is still more preferable, an integer of 4 to 16 is still more preferable, an integer of 8 to 16 is particularly preferable, and an integer of 10 to 16 is most preferable.
  • the number of amino acid residues constituting REP is preferably 10 to 200 residues. More preferably, it is ⁇ 150 residues, more preferably 20-100 residues, and even more preferably 20-75 residues.
  • a modified fibroin derived from the large sphincter bookmark silk protein produced in the spider large bottle gland is a glycine residue contained in the amino acid sequence represented by Formula 1: [(A) n motif-REP] m ,
  • the total number of residues of serine residues and alanine residues is preferably 40% or more, more preferably 60% or more, still more preferably 70% or more based on the total number of amino acid residues. .
  • the modified fibroin derived from the large sphincter bookmark silk protein produced in the spider large bottle gland comprises a unit of an amino acid sequence represented by the formula 1: [(A) n motif-REP] m and has a C-terminal. It may be a polypeptide whose sequence is an amino acid sequence shown in any of SEQ ID NOs: 14 to 16 or an amino acid sequence having 90% or more homology with the amino acid sequence shown in any of SEQ ID NOs: 14 to 16.
  • the amino acid sequence shown in SEQ ID NO: 14 is the same as the amino acid sequence consisting of 50 amino acids at the C-terminal of the amino acid sequence of ADF3 (GI: 1263287, NCBI), and the amino acid sequence shown in SEQ ID NO: 15 is the sequence
  • the amino acid sequence shown in SEQ ID NO: 14 is identical to the amino acid sequence obtained by removing 20 residues from the C-terminus, and the amino acid sequence shown in SEQ ID NO: 16 is 29 residues removed from the C-terminus of the amino acid sequence shown in SEQ ID NO: 14. It is identical to the amino acid sequence.
  • modified fibroin derived from a large sphincter bookmark silk protein produced in the spider large bottle-like gland
  • amino acid sequence represented by SEQ ID NO: 17, or (1-ii) sequence Mention may be made of modified fibroin comprising an amino acid sequence having a sequence identity of 90% or more with the amino acid sequence indicated by number 17. The sequence identity is preferably 95% or more.
  • the amino acid sequence represented by SEQ ID NO: 17 is an amino acid sequence of ADF3 in which an amino acid sequence (SEQ ID NO: 18) consisting of a start codon, His10 tag and an HRV3C protease (Human rhinovirus 3C protease) recognition site is added to the N-terminus.
  • the 13th repeat region was increased to approximately double, and the translation was mutated to terminate at the 1154th amino acid residue.
  • the C-terminal amino acid sequence of the amino acid sequence shown in SEQ ID NO: 17 is identical to the amino acid sequence shown in SEQ ID NO: 16.
  • the modified fibroin (1-i) may be composed of the amino acid sequence represented by SEQ ID NO: 17.
  • the modified fibroin with a reduced content of glycine residues has an amino acid sequence with a reduced content of glycine residues in the domain sequence compared to naturally occurring fibroin. It can be said that the modified fibroin has an amino acid sequence corresponding to at least one or more glycine residues in REP substituted with another amino acid residue as compared with naturally occurring fibroin.
  • Modified fibroin with a reduced content of glycine residues has a domain sequence of GGX and GPGXX in REP (where G is a glycine residue, P is a proline residue, X Is an amino acid residue other than glycine.)
  • G is a glycine residue
  • P is a proline residue
  • X is an amino acid residue other than glycine.
  • this corresponds to substitution of one glycine residue in at least one or more of the motif sequences with another amino acid residue. It may have an amino acid sequence.
  • the ratio of the motif sequence in which the above glycine residue is replaced with another amino acid residue may be 10% or more with respect to the total motif sequence.
  • the modified fibroin with a reduced content of glycine residues includes a domain sequence represented by Formula 1: [(A) n motif-REP] m , and is located on the most C-terminal side from the domain sequence (A )
  • the number of alanine residues relative to the total number of amino acid residues in the n motif may be 83% or more, preferably 86% or more, more preferably 90% or more, and 95% or more. More preferably, it is 100% (meaning that it is composed only of alanine residues).
  • the modified fibroin in which the content of glycine residues is reduced is that the content ratio of the amino acid sequence consisting of XGX is increased by substituting one glycine residue of the GGX motif with another amino acid residue. preferable.
  • the content ratio of the amino acid sequence consisting of GGX in the domain sequence is preferably 30% or less, more preferably 20% or less, and more preferably 10% or less. More preferably, it is 6% or less, still more preferably 4% or less, still more preferably 2% or less.
  • the content ratio of the amino acid sequence consisting of GGX in the domain sequence can be calculated by the same method as the method for calculating the content ratio (z / w) of the amino acid sequence consisting of XGX below.
  • a fibroin modified fibroin or naturally-occurring fibroin containing a domain sequence represented by Formula 1: [(A) n motif-REP] m , (A) n located closest to the C-terminal side from the domain sequence
  • An amino acid sequence consisting of XGX is extracted from all REPs included in the sequence excluding the sequence from the motif to the C-terminal of the domain sequence.
  • z / w (%) can be calculated by dividing z by w.
  • z / w is preferably 50.9% or more, more preferably 56.1% or more, and 58.7% or more. Is more preferably 70% or more, still more preferably 80% or more. Although there is no restriction
  • a modified fibroin with a reduced content of glycine residues encodes another amino acid residue by substituting at least a part of the base sequence encoding the glycine residue from the cloned gene sequence of naturally occurring fibroin. It can obtain by modifying so that. At this time, one glycine residue in GGX motif and GPGXX motif may be selected as a glycine residue to be modified, or substitution may be performed so that z / w is 50.9% or more.
  • an amino acid sequence satisfying the above-described aspect can be designed from the amino acid sequence of naturally derived fibroin, and a nucleic acid encoding the designed amino acid sequence can be obtained by chemical synthesis.
  • one or more amino acid residues are further substituted or deleted.
  • the amino acid sequence corresponding to the insertion and / or addition may be modified.
  • the other amino acid residue is not particularly limited as long as it is an amino acid residue other than glycine residue, but valine (V) residue, leucine (L) residue, isoleucine (I) residue, methionine ( M) hydrophobic amino acid residues such as proline (P) residue, phenylalanine (F) residue and tryptophan (W) residue, glutamine (Q) residue, asparagine (N) residue, serine (S ) Residues, lysine (K) residues and glutamic acid (E) residues are preferred, and valine (V) residues, leucine (L) residues, isoleucine (I) residues and glutamine ( Q) residue is more preferable, and glutamine (Q) residue is more preferable.
  • modified fibroin with a reduced content of glycine residues (2-i) the amino acid sequence represented by SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 10 or SEQ ID NO: 12, or (2- ii)
  • SEQ ID NO: 3 amino acid sequence represented by SEQ ID NO: 4, SEQ ID NO: 10 or SEQ ID NO: 12, or
  • 2- ii A modified fibroin containing an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 10 or SEQ ID NO: 12 can be mentioned.
  • the modified fibroin (2-i) will be described.
  • the amino acid sequence represented by SEQ ID NO: 3 is obtained by substituting GQX for all GGX in the REP of the amino acid sequence represented by SEQ ID NO: 1 corresponding to naturally occurring fibroin.
  • the amino acid sequence represented by SEQ ID NO: 4 is the amino acid sequence represented by SEQ ID NO: 3, in which every two (A) n motifs are deleted from the N-terminal side to the C-terminal side, and further before the C-terminal sequence.
  • One [(A) n motif-REP] is inserted into the.
  • the amino acid sequence shown in SEQ ID NO: 10 has two alanine residues inserted in the C-terminal side of each (A) n motif of the amino acid sequence shown in SEQ ID NO: 4, and a part of glutamine (Q) residues. Substituted with a serine (S) residue and a part of the amino acid at the N-terminal side is deleted so as to be almost the same as the molecular weight of SEQ ID NO: 4.
  • the amino acid sequence represented by SEQ ID NO: 12 is a region of 20 domain sequences present in the amino acid sequence represented by SEQ ID NO: 4 (however, several amino acid residues on the C-terminal side of the region are substituted). Is a sequence in which a His tag is added to the C-terminal of the sequence repeated four times.
  • the value of z / w in the amino acid sequence represented by SEQ ID NO: 1 is 46.8%.
  • the z / w values in the amino acid sequence shown in SEQ ID NO: 3, the amino acid sequence shown in SEQ ID NO: 4, the amino acid sequence shown in SEQ ID NO: 10, and the amino acid sequence shown in SEQ ID NO: 12 are 58.7%, 70.1%, 66.1% and 70.0%.
  • the value of x / y at the ratio of the amino acid sequence shown by SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 10 and SEQ ID NO: 12 (described later) 1: 1.8 to 11.3 is: 15.0%, 15.0%, 93.4%, 92.7% and 89.3%, respectively.
  • the modified fibroin (2-i) may be composed of the amino acid sequence represented by SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 10 or SEQ ID NO: 12.
  • the modified fibroin (2-ii) includes an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 10 or SEQ ID NO: 12.
  • the modified fibroin of (2-ii) is also a protein containing a domain sequence represented by Formula 1: [(A) n motif-REP] m .
  • the sequence identity is preferably 95% or more.
  • the modified fibroin of (2-ii) has a sequence identity of 90% or more with the amino acid sequence represented by SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 10 or SEQ ID NO: 12, and is contained in REP (XGX ( Where X is an amino acid residue other than glycine.) Z / w where z is the total number of amino acid residues of the amino acid sequence consisting of z and w is the total number of amino acid residues of REP in the domain sequence. Is preferably 50.9% or more.
  • modified fibroin may contain a tag sequence at one or both of the N-terminal and C-terminal. This makes it possible to isolate, immobilize, detect and visualize the modified fibroin.
  • tag sequences include affinity tags that use specific affinity (binding property, affinity) with other molecules.
  • affinity tag include a histidine tag (His tag).
  • His tag is a short peptide with about 4 to 10 histidine residues, and has the property of binding specifically to metal ions such as nickel. Therefore, the isolation of modified fibroin by metal chelating chromatography (chelating metal chromatography) Can be used.
  • Specific examples of the tag sequence include the amino acid sequence represented by SEQ ID NO: 5 (amino acid sequence including a His tag sequence and a hinge sequence).
  • GST glutathione-S-transferase
  • MBP maltose-binding protein
  • an “epitope tag” using an antigen-antibody reaction can also be used.
  • a peptide (epitope) exhibiting antigenicity as a tag sequence, an antibody against the epitope can be bound.
  • HA peptide sequence of hemagglutinin of influenza virus
  • myc tag peptide sequence of hemagglutinin of influenza virus
  • FLAG tag peptide sequence of hemagglutinin of influenza virus
  • a tag sequence that can be separated with a specific protease can also be used.
  • the modified fibroin from which the tag sequence has been separated can also be recovered.
  • modified fibroin containing a tag sequence (2-iii) SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 11 or SEQ ID NO: 13, or (2-iv) SEQ ID NO: 8,
  • a modified fibroin containing an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 9, SEQ ID NO: 11 or SEQ ID NO: 13 can be mentioned.
  • amino acid sequences represented by SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 11 and SEQ ID NO: 13 are SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 10, respectively.
  • amino acid sequence represented by SEQ ID NO: 5 (including His tag sequence and hinge sequence) is added to the N-terminus of the amino acid sequence represented by SEQ ID NO: 12.
  • the modified fibroin may be composed of the amino acid sequence represented by SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 11 or SEQ ID NO: 13.
  • the modified fibroin (2-iv) includes an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 11 or SEQ ID NO: 13.
  • the modified fibroin of (2-iv) is also a protein containing a domain sequence represented by Formula 1: [(A) n motif-REP] m .
  • the sequence identity is preferably 95% or more.
  • the modified fibroin (2-iv) has an amino acid sequence represented by SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 11 or SEQ ID NO: 13 with a sequence identity of 90% or more, and is contained in XREP ( Where X is an amino acid residue other than glycine.) Z / w where z is the total number of amino acid residues of the amino acid sequence consisting of z and w is the total number of amino acid residues of REP in the domain sequence. Is preferably 50.9% or more.
  • the aforementioned modified fibroin may contain a secretion signal for releasing the protein produced in the recombinant protein production system to the outside of the host.
  • the sequence of the secretion signal can be appropriately set according to the type of host.
  • (A) modified fibroin content of n motifs has been reduced, the domain sequence is compared to the naturally occurring fibroin, having an amino acid sequence reduced the content of (A) n motif. It can be said that the domain sequence of the modified fibroin has an amino acid sequence corresponding to the deletion of at least one or more (A) n motifs as compared to naturally occurring fibroin.
  • the modified fibroin in which the content of n motif is reduced may have an amino acid sequence corresponding to 10% to 40% deletion of (A) n motif from naturally occurring fibroin.
  • the modified fibroin with a reduced content of n motif has 1 to 3 (A) n motifs in which the domain sequence is at least from the N-terminal side to the C-terminal side compared to naturally occurring fibroin. Each may have an amino acid sequence corresponding to the deletion of one (A) n motif.
  • the domain sequence of the modified fibroin is at least two consecutive from the N-terminal side to the C-terminal side compared to the naturally derived fibroin (A) n motif And an amino acid sequence corresponding to the deletion of one (A) n motif repeated in this order.
  • (A) modified fibroin content of n motifs has been reduced, the domain sequence, amino acids corresponding to at least the N-terminal side 2 every other towards the C-terminal side (A) n motifs lacking It may have a sequence.
  • a modified fibroin with a reduced content of n- motif contains a domain sequence represented by Formula 1: [(A) n- motif-REP] m , and is adjacent to the C-terminal side from the N-terminal side.
  • the number of alanine residues relative to the total number of amino acid residues in the n motif may be 83% or more, preferably 86% or more, more preferably 90% or more, and 95% or more. More preferably, it is 100% (meaning that it is composed only of alanine residues).
  • FIG. 1 shows a domain sequence obtained by removing the N-terminal sequence and the C-terminal sequence from the modified fibroin.
  • the domain sequence is from the N-terminal side (left side): (A) n motif-first REP (50 amino acid residues)-(A) n motif-second REP (100 amino acid residues)-(A) n Motif-third REP (10 amino acid residues)-(A) n motif-fourth REP (20 amino acid residues)-(A) n motif-fifth REP (30 amino acid residues)-(A) It has a sequence called n motif.
  • FIG. 1 includes pattern 1 (comparison between the first REP and the second REP, and comparison between the third REP and the fourth REP), pattern 2 (comparison between the first REP and the second REP, and 4th REP and 5th REP), pattern 3 (2nd REP and 3rd REP comparison, 4th REP and 5th REP comparison), pattern 4 (first REP and Comparison of the second REP).
  • pattern 1 compare between the first REP and the second REP, and comparison between the third REP and the fourth REP
  • pattern 2 comparison between the first REP and the second REP, and 4th REP and 5th REP
  • pattern 3 (2nd REP and 3rd REP comparison, 4th REP and 5th REP comparison
  • pattern 4 first REP and Comparison of the second REP
  • the number of amino acid residues of each REP in the two adjacent [(A) n motif-REP] units selected is compared.
  • each pattern the number of all amino acid residues of two adjacent [(A) n motif-REP] units indicated by solid lines is added (not only REP but also (A) the number of amino acid residues of the n motif. is there.). Then, the total value added is compared, and the total value (maximum value of the total value) of the pattern having the maximum total value is set as x. In the example shown in FIG. 1, the total value of pattern 1 is the maximum.
  • x / y (%) can be calculated by dividing x by the total number of amino acid residues y of the domain sequence.
  • x / y is preferably 50% or more, more preferably 60% or more, still more preferably 65% or more, It is still more preferably 70% or more, still more preferably 75% or more, and particularly preferably 80% or more.
  • x / y is preferably 50% or more, more preferably 60% or more, still more preferably 65% or more, It is still more preferably 70% or more, still more preferably 75% or more, and particularly preferably 80% or more.
  • x / y is preferably 89.6% or more, and when the jagged ratio is 1: 1.8 to 3.4, x / y / Y is preferably 77.1% or more, and when the jagged ratio is 1: 1.9 to 8.4, x / y is preferably 75.9% or more, and the jagged ratio is 1 In the case of 1.9 to 4.1, x / y is preferably 64.2% or more.
  • x / y is 46.4% or more, preferably 50% or more, more preferably 55% or more, still more preferably 60% or more, and 70% or more. Even more preferable, 80% or more is particularly preferable.
  • x / y is 46.4% or more, preferably 50% or more, more preferably 55% or more, still more preferably 60% or more, and 70% or more. Even more preferable, 80% or more is particularly preferable.
  • x / y is 46.4% or more, preferably 50% or more, more preferably 55% or more, still more preferably 60% or more, and 70% or more. Even more preferable, 80% or more is particularly preferable.
  • (A) modified fibroin content of n motif is reduced, for example, encoding a cloned naturally occurring fibroin gene sequences, as x / y is more than 64.2% of the (A) n motif It can be obtained by deleting one or more of the sequences.
  • an amino acid sequence corresponding to the deletion of one or more (A) n motifs is designed so that x / y is 64.2% or more from the amino acid sequence of naturally occurring fibroin. It can also be obtained by chemically synthesizing a nucleic acid encoding the amino acid sequence.
  • one or more amino acid residues are further substituted, deleted, inserted and / or added.
  • the amino acid sequence corresponding to this may be modified.
  • the modified fibroin (3-i) will be described.
  • the amino acid sequence represented by SEQ ID NO: 2 has the amino acid sequence represented by SEQ ID NO: 1 corresponding to naturally occurring fibroin deleted from the N-terminal side to the C-terminal side every two (A) n motifs Furthermore, one [(A) n motif-REP] is inserted in front of the C-terminal sequence.
  • the amino acid sequence shown in SEQ ID NO: 4 is obtained by substituting all GGX in REP of the amino acid sequence shown in SEQ ID NO: 2 with GQX.
  • the amino acid sequence shown in SEQ ID NO: 10 has two alanine residues inserted in the C-terminal side of each (A) n motif of the amino acid sequence shown in SEQ ID NO: 4, and a part of glutamine (Q) residues. Substituted with a serine (S) residue and a part of the amino acid at the N-terminal side is deleted so as to be almost the same as the molecular weight of SEQ ID NO: 4.
  • the amino acid sequence represented by SEQ ID NO: 12 is a region of 20 domain sequences present in the amino acid sequence represented by SEQ ID NO: 9 (however, several amino acid residues on the C-terminal side of the region are substituted). Is a sequence in which a His tag is added to the C-terminal of the sequence repeated four times.
  • the value of x / y of the amino acid sequence represented by SEQ ID NO: 1 (corresponding to naturally-occurring fibroin) at a jagged ratio of 1: 1.8 to 11.3 is 15.0%.
  • the value of x / y in the amino acid sequence represented by SEQ ID NO: 2 and the amino acid sequence represented by SEQ ID NO: 4 is 93.4%.
  • the value of x / y in the amino acid sequence represented by SEQ ID NO: 10 is 92.7%.
  • the value of x / y in the amino acid sequence represented by SEQ ID NO: 12 is 89.3%.
  • the z / w values in the amino acid sequences represented by SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 10 and SEQ ID NO: 12 are 46.8%, 56.2%, 70.1% and 66. respectively. 1% and 70.0%.
  • the modified fibroin (3-i) may be composed of the amino acid sequence represented by SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 10 or SEQ ID NO: 12.
  • the modified fibroin (3-ii) includes an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 10 or SEQ ID NO: 12.
  • the modified fibroin of (3-ii) is also a protein containing a domain sequence represented by Formula 1: [(A) n motif-REP] m .
  • the sequence identity is preferably 95% or more.
  • the modified fibroin of (3-ii) has 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 10 or SEQ ID NO: 12, and from the N-terminal side to the C-terminal side
  • the number of amino acid residues of REP of two adjacent [(A) n motif-REP] units is sequentially compared, and the number of amino acid residues of REP having a small number of amino acid residues is 1, the other
  • x / y is 64.2% or more, where x is the maximum total value of the total number of bases and y is the total number of amino acid residues in the domain sequence.
  • the above-described modified fibroin may contain the above-described tag sequence at one or both of the N-terminal and C-terminal.
  • modified fibroin containing a tag sequence As more specific examples of modified fibroin containing a tag sequence, (3-iii) SEQ ID NO: 7, SEQ ID NO: 9, SEQ ID NO: 11 or SEQ ID NO: 13, or (3-iv) SEQ ID NO: 7, A modified fibroin containing an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 9, SEQ ID NO: 11 or SEQ ID NO: 13 can be mentioned.
  • amino acid sequences represented by SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 11 and SEQ ID NO: 13 are SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 10, respectively.
  • amino acid sequence represented by SEQ ID NO: 5 (including His tag sequence and hinge sequence) is added to the N-terminus of the amino acid sequence represented by SEQ ID NO: 12.
  • the modified fibroin may be composed of the amino acid sequence represented by SEQ ID NO: 7, SEQ ID NO: 9, SEQ ID NO: 11 or SEQ ID NO: 13.
  • the modified fibroin (3-iv) includes an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 7, SEQ ID NO: 9, SEQ ID NO: 11 or SEQ ID NO: 13.
  • the modified fibroin of (3-iv) is also a protein containing a domain sequence represented by Formula 1: [(A) n motif-REP] m .
  • the sequence identity is preferably 95% or more.
  • the modified fibroin (3-iv) has 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 7, SEQ ID NO: 9, SEQ ID NO: 11 or SEQ ID NO: 13, and from the N-terminal side to the C-terminal side.
  • the other X is the maximum total value of the total number of amino acid residues of two adjacent [(A) n motif-REP] units with a ratio of the number of amino acid residues of REP of 1.8 to 11.3.
  • x / y is preferably 64.2% or more.
  • the aforementioned modified fibroin may contain a secretion signal for releasing the protein produced in the recombinant protein production system to the outside of the host.
  • the sequence of the secretion signal can be appropriately set according to the type of host.
  • the domain sequence of the modified fibroin is different from that of naturally occurring fibroin in addition to at least one or more glycine residues in REP. It can be said to have an amino acid sequence corresponding to substitution with an amino acid residue.
  • it is a modified fibroin having the characteristics of the modified fibroin in which the content of the glycine residue is reduced and (A) the modified fibroin in which the content of the n motif is reduced.
  • Specific embodiments and the like are as described in the modified fibroin in which the content of glycine residues is reduced and (A) the modified fibroin in which the content of n motif is reduced.
  • modified fibroin with reduced glycine residue content and (A) n- motif content (4-i) the amino acid represented by SEQ ID NO: 4, SEQ ID NO: 10 or SEQ ID NO: 12
  • modified fibroin comprising a sequence or (4-ii) an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 4, SEQ ID NO: 10 or SEQ ID NO: 12.
  • Specific embodiments of the modified fibroin comprising the amino acid sequence represented by SEQ ID NO: 4, SEQ ID NO: 10 or SEQ ID NO: 12 are as described above.
  • the modified fibroin according to another embodiment has a domain sequence in which one or more amino acid residues in REP are replaced with amino acid residues having a large hydrophobicity index as compared to naturally occurring fibroin, and It may have an amino acid sequence including a region having a large hydrophobic index locally, corresponding to the insertion of one or more amino acid residues having a large hydrophobic index in REP.
  • the region where the hydrophobic index is locally large is preferably composed of 2 to 4 amino acid residues.
  • the amino acid residue having a large hydrophobicity index is an amino acid selected from isoleucine (I), valine (V), leucine (L), phenylalanine (F), cysteine (C), methionine (M) and alanine (A). More preferably, it is a residue.
  • the modified fibroin according to the present embodiment has one or more amino acid residues in REP substituted with amino acid residues having a large hydrophobicity index and / or 1 in REP compared to naturally occurring fibroin.
  • one or more amino acid residues are substituted, deleted, inserted and / or compared with naturally occurring fibroin.
  • the modified fibroin according to the present embodiment for example, hydrophobicizes one or more hydrophilic amino acid residues (for example, amino acid residues having a negative hydrophobicity index) in REP from the gene sequence of naturally-derived fibroin that has been cloned. It can be obtained by substituting amino acid residues (for example, amino acid residues having a positive hydrophobicity index) and / or inserting one or more hydrophobic amino acid residues in REP.
  • hydrophilic amino acid residues for example, amino acid residues having a negative hydrophobicity index
  • one or more hydrophilic amino acid residues in REP are substituted with hydrophobic amino acid residues from the amino acid sequence of naturally occurring fibroin, and / or one or more hydrophobic amino acid residues in REP It can also be obtained by designing an amino acid sequence corresponding to insertion of, and chemically synthesizing a nucleic acid encoding the designed amino acid sequence.
  • one or more hydrophilic amino acid residues in REP have been replaced with hydrophobic amino acid residues from the amino acid sequence of naturally occurring fibroin and / or one or more hydrophobic amino acids in REP
  • the amino acid sequence corresponding to the substitution, deletion, insertion and / or addition of one or more amino acid residues may be further modified.
  • the modified fibroin according to another embodiment includes a domain sequence represented by Formula 1: [(A) n motif-REP] m , and (A) located at the most C-terminal side of the domain sequence from the n motif.
  • P, and (A) where the total number of amino acid residues contained in the sequence excluding the sequence from the n motif to the C terminus of the domain sequence from the domain sequence is q / Q may have an amino acid sequence of 6.2% or more.
  • hydrophobicity index of amino acid residues As for the hydrophobicity index of amino acid residues, a known index (Hydropathy index: Kyte J, & Doolittle R (1982) “A simple method for displaying the hydropathic character of bio.p. 7”. 105-132). Specifically, the hydrophobicity index (hydropathic index, hereinafter also referred to as “HI”) of each amino acid is as shown in Table 1 below.
  • a sequence obtained by removing the sequence from the domain sequence represented by Formula 1: [(A) n motif-REP] m to the most C-terminal side from the domain (A) n motif to the C terminus of the domain sequence. (Hereinafter referred to as “array A”).
  • array A the average value of the hydrophobicity index of four consecutive amino acid residues is calculated.
  • the average value of the hydrophobicity index is obtained by dividing the total HI of each amino acid residue contained in the four consecutive amino acid residues by 4 (number of amino acid residues).
  • the average value of the hydrophobicity index is obtained for all four consecutive amino acid residues (each amino acid residue is used for calculating the average value 1 to 4 times). Next, a region where the average value of the hydrophobicity index of four consecutive amino acid residues is 2.6 or more is specified. Even if a certain amino acid residue corresponds to a plurality of “four consecutive amino acid residues whose average value of hydrophobicity index is 2.6 or more”, it should be included as one amino acid residue in the region. become.
  • the total number of amino acid residues contained in the region is p.
  • the total number of amino acid residues contained in sequence A is q.
  • the average value of the hydrophobicity index of four consecutive amino acid residues is 2
  • p / q is preferably 6.2% or more, more preferably 7% or more, further preferably 10% or more, and 20% or more. Even more preferably, it is still more preferably 30% or more.
  • the upper limit of p / q is not particularly limited, but may be 45% or less, for example.
  • the modified fibroin according to this embodiment includes, for example, one or a plurality of hydrophilic amino acid residues (for example, hydrophobicity) in the REP so that the amino acid sequence of the naturally-derived fibroin thus cloned satisfies the above p / q condition.
  • hydrophilic amino acid residues for example, hydrophobicity
  • Substituting a hydrophobic amino acid residue (for example, an amino acid residue having a positive hydrophobicity index) and / or one or more hydrophobic amino acid residues during REP Can be obtained by locally modifying the amino acid sequence to include a region having a large hydrophobicity index.
  • an amino acid sequence satisfying the above p / q conditions can be designed from the amino acid sequence of naturally derived fibroin, and a nucleic acid encoding the designed amino acid sequence can be obtained by chemical synthesis.
  • one or more amino acid residues in REP were replaced with amino acid residues having a higher hydrophobicity index and / or one or more amino acid residues in REP.
  • modifications corresponding to substitution, deletion, insertion and / or addition of one or more amino acid residues may be performed. .
  • the amino acid residue having a large hydrophobicity index is not particularly limited, but isoleucine (I), valine (V), leucine (L), phenylalanine (F), cysteine (C), methionine (M) and alanine (A ) are preferred, and valine (V), leucine (L) and isoleucine (I) are more preferred.
  • modified fibroin (5-i) the amino acid sequence represented by SEQ ID NO: 20, SEQ ID NO: 22 or SEQ ID NO: 23, or (5-ii) SEQ ID NO: 20, SEQ ID NO: 22 or SEQ ID NO: 23 And a modified fibroin comprising an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by
  • the modified fibroin (5-i) will be described.
  • the amino acid sequence shown in SEQ ID NO: 19 is an amino acid sequence in which the alanine residues in the (A) n motif of (A) naturally derived fibroin are deleted so that the number of consecutive alanine residues is five.
  • the amino acid sequence represented by SEQ ID NO: 20 is inserted into the amino acid sequence represented by SEQ ID NO: 19 by two amino acid sequences (VLI) each consisting of 3 amino acid residues every other REP, and represented by SEQ ID NO: 19. A part of amino acids on the C-terminal side are deleted so that the molecular weight of the amino acid sequence is almost the same.
  • the amino acid sequence represented by SEQ ID NO: 21 is obtained by inserting two alanine residues at the C-terminal side of each (A) n motif with respect to the amino acid sequence represented by SEQ ID NO: 19, and further adding some glutamine (Q) residues. A group is substituted with a serine (S) residue, and a part of amino acids on the C-terminal side is deleted so as to be approximately the same as the molecular weight of the amino acid sequence represented by SEQ ID NO: 19.
  • the amino acid sequence represented by SEQ ID NO: 22 is obtained by inserting one amino acid sequence (VLI) consisting of 3 amino acid residues at every other REP to the amino acid sequence represented by SEQ ID NO: 21.
  • the amino acid sequence shown in SEQ ID NO: 23 is obtained by inserting two amino acid sequences (VLI) each consisting of 3 amino acid residues into the amino acid sequence shown in SEQ ID NO: 21 every other REP.
  • the modified fibroin (5-i) may be composed of the amino acid sequence represented by SEQ ID NO: 20, SEQ ID NO: 22 or SEQ ID NO: 23.
  • the modified fibroin (5-ii) includes an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 20, SEQ ID NO: 22 or SEQ ID NO: 23.
  • the modified fibroin of (5-ii) is also a protein containing a domain sequence represented by Formula 1: [(A) n motif-REP] m .
  • the sequence identity is preferably 95% or more.
  • the modified fibroin of (5-ii) has a sequence identity of 90% or more with the amino acid sequence represented by SEQ ID NO: 20, SEQ ID NO: 22 or SEQ ID NO: 23, and is located at the most C-terminal side (A) n
  • the amino acids included in the region where the average value of the hydrophobicity index of 4 consecutive amino acid residues is 2.6 or more P is the total number of residues
  • P / q is preferably 6.2% or more.
  • the above-mentioned modified fibroin may contain a tag sequence at one or both of the N-terminal and C-terminal.
  • modified fibroin comprising a tag sequence
  • 5-iii the amino acid sequence represented by SEQ ID NO: 24, SEQ ID NO: 25 or SEQ ID NO: 26, or (5-iv) SEQ ID NO: 24, SEQ ID NO: 25 or Mention may be made of modified fibroin comprising an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 26.
  • amino acid sequences represented by SEQ ID NO: 24, SEQ ID NO: 25, and SEQ ID NO: 26 are the amino acid sequences represented by SEQ ID NO: 5 at the N-terminus of the amino acid sequences represented by SEQ ID NO: 20, SEQ ID NO: 22 and SEQ ID NO: 23, respectively (His tag). Including a sequence and a hinge sequence).
  • the modified fibroin may consist of the amino acid sequence represented by SEQ ID NO: 24, SEQ ID NO: 25 or SEQ ID NO: 26.
  • the modified fibroin (5-iv) includes an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 24, SEQ ID NO: 25 or SEQ ID NO: 26.
  • the modified fibroin of (5-iv) is also a protein containing a domain sequence represented by Formula 1: [(A) n motif-REP] m .
  • the sequence identity is preferably 95% or more.
  • the modified fibroin (5-iv) has 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 24, SEQ ID NO: 25 or SEQ ID NO: 26, and is located at the most C-terminal side (A) n
  • the amino acids included in the region where the average value of the hydrophobicity index of 4 consecutive amino acid residues is 2.6 or more P is the total number of residues
  • P / q is preferably 6.2% or more.
  • the aforementioned modified fibroin may contain a secretion signal for releasing the protein produced in the recombinant protein production system to the outside of the host.
  • the sequence of the secretion signal can be appropriately set according to the type of host.
  • the modified fibroin according to still another embodiment has an amino acid sequence in which the content of glutamine residues is reduced as compared with naturally occurring fibroin.
  • the modified fibroin according to this embodiment preferably includes at least one motif selected from a GGX motif and a GPGXX motif in the amino acid sequence of REP.
  • the content ratio of the GPGXX motif is usually 1% or more, may be 5% or more, and is preferably 10% or more.
  • the upper limit of GPGXX motif content rate 50% or less may be sufficient and 30% or less may be sufficient.
  • GPGXX motif content is a value calculated by the following method.
  • Formula 1 [(A) n motif-REP] m
  • Formula 2 [(A) n motif-REP] m- (A) fibroin (modified fibroin or naturally derived) containing a domain sequence represented by the n motif In fibroin), the number of GPGXX motifs contained in the region in all REPs contained in the sequence excluding the sequence from the domain sequence (A) n motif located at the most C-terminal side to the C-terminus of the domain sequence.
  • the number obtained by multiplying the total number by three is s, and is located at the most C-terminal side.
  • the sequence from the n motif to the C-terminal of the domain sequence is determined from the domain sequence.
  • the content ratio of the GPGXX motif is calculated as s / t, where t is the total number of amino acid residues of all REPs excluding the n motif. It is.
  • “A sequence located at the most C-terminal side (A) excluding the sequence from the n motif to the C-terminal of the domain sequence from the domain sequence” (A)
  • the sequence from the n motif to the C terminus of the domain sequence ”(sequence corresponding to REP) may include a sequence that is not highly correlated with the sequence characteristic of fibroin, and m is small In this case (that is, when the domain sequence is short), the calculation result of the content ratio of the GPGXX motif is affected, so this influence is excluded.
  • the “GPGXX motif” is located at the C-terminus of REP, even if “XX” is, for example, “AA”, it is treated as “GPGXX motif”.
  • FIG. 3 is a schematic diagram showing the domain sequence of the modified fibroin.
  • the modified fibroin according to this embodiment preferably has a glutamine residue content of 9% or less, more preferably 7% or less, still more preferably 4% or less, and preferably 0%. Particularly preferred.
  • the “glutamine residue content” is a value calculated by the following method.
  • Formula 1 [(A) n motif-REP] m
  • Formula 2 [(A) n motif-REP] m-
  • the total number of glutamine residues contained in the region is u
  • the sequence from the (A) n motif located at the most C-terminal side to the C-terminus of the domain sequence is excluded from the domain sequence
  • (A) n The glutamine residue content is calculated as u / t, where t is the total number of amino acid residues in all REPs excluding the motif.
  • the reason why "A sequence located at the most C-terminal side (A) excluding the sequence from the n motif to the C-terminus of the domain sequence from the domain sequence" is the reason described above. It is the same.
  • the domain sequence has one or more glutamine residues in REP deleted or substituted with other amino acid residues as compared to naturally occurring fibroin. It may have a corresponding amino acid sequence.
  • the “other amino acid residue” may be an amino acid residue other than a glutamine residue, but is preferably an amino acid residue having a larger hydrophobicity index than the glutamine residue. Table 1 shows the hydrophobicity index of amino acid residues.
  • amino acid residues having a larger hydrophobicity index than glutamine residues include isoleucine (I), valine (V), leucine (L), phenylalanine (F), cysteine (C), methionine (M ) Amino acid residues selected from alanine (A), glycine (G), threonine (T), serine (S), tryptophan (W), tyrosine (Y), proline (P) and histidine (H). it can.
  • an amino acid residue selected from isoleucine (I), valine (V), leucine (L), phenylalanine (F), cysteine (C), methionine (M) and alanine (A) is more preferable. More preferred is an amino acid residue selected from among isoleucine (I), valine (V), leucine (L) and phenylalanine (F).
  • the hydrophobicity of REP is preferably ⁇ 0.8 or more, more preferably ⁇ 0.7 or more, still more preferably 0 or more, and It is still more preferable that it is 3 or more, and it is especially preferable that it is 0.4 or more.
  • the “hydrophobicity of REP” is a value calculated by the following method.
  • Formula 1 [(A) n motif-REP] m
  • Formula 2 [(A) n motif-REP] m-
  • the sum of the hydrophobicity index of each amino acid residue in the region is represented by v, and the sequence from the (A) n motif located at the most C-terminal side to the C-terminus of the domain sequence is excluded from the domain sequence, and ( A) The hydrophobicity of REP is calculated as v / t, where t is the total number of amino acid residues of all REPs excluding the n motif.
  • t is the total number of amino acid residues of all REPs excluding the n motif.
  • the modified fibroin according to the present embodiment has a domain sequence in which one or more glutamine residues in REP are deleted compared to naturally-occurring fibroin and / or one or more glutamine in REP.
  • modifications corresponding to substitution of residues with other amino acid residues there are further alterations in amino acid sequence corresponding to substitution, deletion, insertion and / or addition of one or more amino acid residues. Also good.
  • the modified fibroin according to the present embodiment includes, for example, deletion of one or more glutamine residues in REP from the cloned gene sequence of natural fibroin and / or one or more glutamine residues in REP. Can be obtained by substituting with other amino acid residues.
  • one or more glutamine residues in REP are deleted from the amino acid sequence of naturally occurring fibroin, and / or one or more glutamine residues in REP are replaced with other amino acid residues.
  • it can also be obtained by designing a corresponding amino acid sequence and chemically synthesizing a nucleic acid encoding the designed amino acid sequence.
  • modified fibroin As more specific examples of the modified fibroin according to the present invention, (6-i) the amino acid represented by SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 38 or SEQ ID NO: 39 90% or more of the modified fibroin containing the sequence, or (6-ii) the amino acid sequence represented by SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 38 or SEQ ID NO: 39 Mention may be made of modified fibroin comprising amino acid sequences having sequence identity.
  • the (6-i) modified fibroin will be described.
  • Amino acid sequence shown in SEQ ID NO: 4 is a fibroin naturally occurring Nephila clavipes (GenBank accession number: P46804.1, GI: 1174415) based on the nucleotide sequence and amino acid sequence of, (A) n
  • the amino acid sequence in which the alanine residue in the motif is continued is modified with an amino acid to improve productivity, such as the number of consecutive alanine residues is five.
  • Met-PRT410 since Met-PRT410 has not altered the glutamine residue (Q), the glutamine residue content is comparable to the glutamine residue content of naturally occurring fibroin.
  • the amino acid sequence represented by SEQ ID NO: 27 (M_PRT888) is obtained by replacing all QQs in Met-PRT410 (SEQ ID NO: 4) with VL.
  • the amino acid sequence represented by SEQ ID NO: 28 (M_PRT965) is obtained by substituting all QQs in Met-PRT410 (SEQ ID NO: 4) with TS and substituting the remaining Q with A.
  • the amino acid sequence (M_PRT889) represented by SEQ ID NO: 29 is obtained by replacing all QQs in Met-PRT410 (SEQ ID NO: 4) with VL and replacing the remaining Q with I.
  • the amino acid sequence (M_PRT916) represented by SEQ ID NO: 30 is obtained by substituting all QQs in Met-PRT410 (SEQ ID NO: 4) with VI and replacing the remaining Q with L.
  • the amino acid sequence represented by SEQ ID NO: 31 is obtained by replacing all QQs in Met-PRT410 (SEQ ID NO: 4) with VF and replacing the remaining Q with I.
  • the amino acid sequence (M_PRT525) represented by SEQ ID NO: 37 is obtained by inserting two alanine residues into a region (A 5 ) where alanine residues are continuous with respect to Met-PRT410 (SEQ ID NO: 4).
  • the two C-terminal domain sequences were deleted and 13 glutamine residues (Q) were replaced with serine residues (S) or proline residues (P) so that they were almost the same as those in FIG.
  • the amino acid sequence represented by SEQ ID NO: 38 (M_PRT699) is obtained by substituting VL for all QQs in M_PRT525 (SEQ ID NO: 37).
  • the amino acid sequence represented by SEQ ID NO: 39 is obtained by replacing all QQs in M_PRT525 (SEQ ID NO: 37) with VL and replacing the remaining Q with I.
  • amino acid sequences represented by SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 38, and SEQ ID NO: 39 all have a glutamine residue content of 9% or less (Table 2). ).
  • the modified fibroin (6-i) may be composed of the amino acid sequence represented by SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 38 or SEQ ID NO: 39. .
  • the modified fibroin of (6-ii) has a sequence identity of 90% or more with the amino acid sequence represented by SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 38 or SEQ ID NO: 39.
  • the amino acid sequence having The modified fibroin of (6-ii) is also represented by the formula 1: [(A) n motif-REP] m or the formula 2: [(A) n motif-REP] m- (A) n motif.
  • the sequence identity is preferably 95% or more.
  • the modified fibroin (6-ii) preferably has a glutamine residue content of 9% or less.
  • the modified fibroin (6-ii) preferably has a GPGXX motif content of 10% or more.
  • modified fibroin may contain a tag sequence at one or both of the N-terminal and C-terminal. This makes it possible to isolate, immobilize, detect and visualize the modified fibroin.
  • modified fibroin containing a tag sequence (6-iii) amino acids represented by SEQ ID NO: 32, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 40 or SEQ ID NO: 41 90% or more of the modified fibroin containing the sequence, or (6-iv) SEQ ID NO: 32, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 40 or SEQ ID NO: 41 Mention may be made of modified fibroin comprising amino acid sequences having sequence identity.
  • amino acid sequences shown by SEQ ID NO: 32, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 40 and SEQ ID NO: 41 are SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, respectively.
  • the amino acid sequence represented by SEQ ID NO: 5 (including His tag sequence and hinge sequence) is added to the N-terminus of the amino acid sequence represented by SEQ ID NO: 31, SEQ ID NO: 38 and SEQ ID NO: 39.
  • the modified fibroin of (6-iii) may be composed of the amino acid sequence represented by SEQ ID NO: 32, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 40 or SEQ ID NO: 41. .
  • the modified fibroin (6-iv) has a sequence identity of 90% or more with the amino acid sequence represented by SEQ ID NO: 32, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 40 or SEQ ID NO: 41.
  • the amino acid sequence having The modified fibroin of (6-iv) is also a domain represented by Formula 1: [(A) n motif-REP] m or Formula 2: [(A) n motif-REP] m- (A) n motif.
  • the sequence identity is preferably 95% or more.
  • the modified fibroin (6-iv) preferably has a glutamine residue content of 9% or less.
  • the modified fibroin (6-iv) preferably has a GPGXX motif content of 10% or more.
  • the aforementioned modified fibroin may contain a secretion signal for releasing the protein produced in the recombinant protein production system to the outside of the host.
  • the sequence of the secretion signal can be appropriately set according to the type of host.
  • modified fibroin protein
  • the modified fibroin (protein) is transformed with, for example, an expression vector having a nucleic acid sequence encoding the protein and one or more regulatory sequences operably linked to the nucleic acid sequence. It can be produced by expressing the nucleic acid using a host.
  • the method for producing the nucleic acid encoding the modified fibroin is not particularly limited.
  • the nucleic acid is produced by a method such as amplification by polymerase chain reaction (PCR), cloning, modification by genetic engineering techniques, or chemical synthesis. can do.
  • the method for chemically synthesizing nucleic acids is not particularly limited.
  • AKTA oligopilot plus 10/100 (GE Healthcare Japan Co., Ltd.) is used based on the amino acid sequence information of proteins obtained from the NCBI web database.
  • a gene can be chemically synthesized by a method of linking oligonucleotides that are synthesized automatically by PCR or the like.
  • a nucleic acid encoding the modified fibroin consisting of an amino acid sequence in which an amino acid sequence consisting of a start codon and a His10 tag is added to the N terminus of the above amino acid sequence is synthesized. May be.
  • Regulatory sequences are sequences that control the expression of modified fibroin in the host (for example, promoters, enhancers, ribosome binding sequences, transcription termination sequences, etc.), and can be appropriately selected depending on the type of host.
  • an inducible promoter that functions in the host cell and can induce expression of the modified fibroin may be used.
  • An inducible promoter is a promoter that can control transcription by the presence of an inducer (expression inducer), absence of a repressor molecule, or physical factors such as an increase or decrease in temperature, osmotic pressure or pH value.
  • the type of expression vector can be appropriately selected according to the type of host, such as a plasmid vector, virus vector, cosmid vector, fosmid vector, artificial chromosome vector, and the like.
  • a vector that can replicate autonomously in a host cell or can be integrated into a host chromosome and contains a promoter at a position where a nucleic acid encoding a modified fibroin can be transcribed is preferably used.
  • any of prokaryotes and eukaryotes such as yeast, filamentous fungi, insect cells, animal cells and plant cells can be preferably used.
  • prokaryotic hosts include bacteria belonging to the genus Escherichia, Brevibacillus, Serratia, Bacillus, Microbacterium, Brevibacterium, Corynebacterium, Pseudomonas and the like.
  • microorganisms belonging to the genus Escherichia include Escherichia coli.
  • microorganisms belonging to the genus Brevibacillus include Brevibacillus agri and the like.
  • microorganisms belonging to the genus Serratia include Serratia liqufaciens and the like.
  • microorganisms belonging to the genus Bacillus include Bacillus subtilis.
  • microorganisms belonging to the genus Microbacterium include microbacterium / ammonia film.
  • microorganisms belonging to the genus Brevibacterium include Brevibacterium divaricatam.
  • microorganisms belonging to the genus Corynebacterium include Corynebacterium ammoniagenes.
  • microorganisms belonging to the genus Pseudomonas include Pseudomonas putida.
  • a prokaryotic host is used as a vector for introducing a nucleic acid encoding a modified fibroin
  • a prokaryotic host for example, pBTrp2 (manufactured by Boehringer Mannheim), pGEX (manufactured by Pharmacia), pUC18, pBluescript II, pSupex, pET22b, pCold, pUB110, pNCO2 (Japanese Patent Laid-Open No. 2002-238696) and the like can be mentioned.
  • Examples of eukaryotic hosts include yeast and filamentous fungi (molds, etc.).
  • yeast include yeasts belonging to the genus Saccharomyces, Pichia, Schizosaccharomyces and the like.
  • Examples of the filamentous fungi include filamentous fungi belonging to the genus Aspergillus, the genus Penicillium, the genus Trichoderma and the like.
  • examples of a vector into which a nucleic acid encoding a modified fibroin is introduced include YEp13 (ATCC37115) and YEp24 (ATCC37051).
  • a method for introducing the expression vector into the host cell any method can be used as long as it is a method for introducing DNA into the host cell.
  • a method using calcium ions [Proc. Natl. Acad. Sci. USA, 69, 2110 (1972)]
  • electroporation method electroporation method
  • spheroplast method protoplast method
  • lithium acetate method competent method, and the like.
  • a method for expressing a nucleic acid by a host transformed with an expression vector in addition to direct expression, secretory production, fusion protein expression, etc. can be performed according to the method described in Molecular Cloning 2nd edition, etc. .
  • the modified fibroin can be produced, for example, by culturing a host transformed with an expression vector in a culture medium, producing and accumulating the protein in the culture medium, and collecting the protein from the culture medium.
  • the method for culturing a host in a culture medium can be performed according to a method usually used for culturing a host.
  • the culture medium contains a carbon source, nitrogen source, inorganic salts, etc. that can be assimilated by the host, and can efficiently culture the host. If so, either a natural medium or a synthetic medium may be used.
  • Any carbon source may be used as long as it can be assimilated by the above-mentioned transformed microorganism.
  • Examples thereof include glucose, fructose, sucrose, and carbohydrates such as molasses, starch and starch hydrolyzate, acetic acid and propionic acid, etc.
  • Organic acids and alcohols such as ethanol and propanol can be used.
  • the nitrogen source examples include ammonium salts of inorganic acids or organic acids such as ammonia, ammonium chloride, ammonium sulfate, ammonium acetate, and ammonium phosphate, other nitrogen-containing compounds, and peptone, meat extract, yeast extract, corn steep liquor, Casein hydrolyzate, soybean meal and soybean meal hydrolyzate, various fermented cells and digested products thereof can be used.
  • inorganic salts for example, monopotassium phosphate, dipotassium phosphate, magnesium phosphate, magnesium sulfate, sodium chloride, ferrous sulfate, manganese sulfate, copper sulfate and calcium carbonate can be used.
  • Cultivation of prokaryotes such as E. coli or eukaryotes such as yeast can be performed under aerobic conditions such as shaking culture or deep aeration and agitation culture.
  • the culture temperature is, for example, 15 to 40 ° C.
  • the culture time is usually 16 hours to 7 days.
  • the pH of the culture medium during the culture is preferably maintained at 3.0 to 9.0.
  • the pH of the culture medium can be adjusted using an inorganic acid, an organic acid, an alkaline solution, urea, calcium carbonate, ammonia, or the like.
  • antibiotics such as ampicillin and tetracycline may be added to the culture medium as necessary.
  • an inducer may be added to the medium as necessary.
  • isopropyl- ⁇ -D-thiogalactopyranoside is used when cultivating a microorganism transformed with an expression vector using the lac promoter
  • indole acrylic is used when culturing a microorganism transformed with an expression vector using the trp promoter.
  • An acid or the like may be added to the medium.
  • Isolation and purification of the expressed modified fibroin can be performed by a commonly used method.
  • the host cell is recovered by centrifugation after culturing, suspended in an aqueous buffer, and then subjected to an ultrasonic crusher, a French press, a Manton Gaurin.
  • the host cells are disrupted with a homogenizer, dynomill, or the like to obtain a cell-free extract.
  • a method usually used for protein isolation and purification that is, a solvent extraction method, a salting-out method using ammonium sulfate, a desalting method, an organic solvent, etc.
  • Precipitation method anion exchange chromatography method using resin such as diethylaminoethyl (DEAE) -Sepharose, DIAION HPA-75 (manufactured by Mitsubishi Kasei), positive using resin such as S-Sepharose FF (manufactured by Pharmacia)
  • Electrophoresis methods such as ion exchange chromatography, hydrophobic chromatography using resins such as butyl sepharose and phenyl sepharose, gel filtration using molecular sieve, affinity chromatography, chromatofocusing, isoelectric focusing Using methods such as these alone or in combination, purification It is possible to obtain the goods.
  • the modified fibroin when expressed by forming an insoluble substance in the cell, the host cell is similarly collected, crushed, and centrifuged to collect the modified fibroin insoluble substance as a precipitate fraction.
  • the recovered insoluble form of modified fibroin can be solubilized with a protein denaturant.
  • a purified preparation of modified fibroin can be obtained by the same isolation and purification method as described above.
  • the protein when secreted extracellularly, the protein can be recovered from the culture supernatant. That is, a culture supernatant is obtained by treating the culture with a technique such as centrifugation, and a purified preparation can be obtained from the culture supernatant by using the same isolation and purification method as described above.
  • the protein filament can be produced by a known spinning method. That is, for example, when a protein filament containing modified fibroin as a main component is produced, first, the modified fibroin produced according to the above-described method is converted into dimethyl sulfoxide (DMSO), N, N-dimethylformamide (DMF), formic acid. Or a solvent such as hexafluoroisopropanol (HFIP), together with an inorganic salt as a dissolution accelerator, if necessary, and dissolved to prepare a dope solution. Next, using this dope solution, a protein filament can be obtained by spinning by a known spinning method such as wet spinning, dry spinning, dry wet spinning or melt spinning. Preferred spinning methods include wet spinning or dry wet spinning.
  • FIG. 4 is an explanatory view schematically showing an example of a spinning device for producing protein filaments.
  • a spinning device 10 shown in FIG. 4 is an example of a spinning device for dry and wet spinning, and includes an extrusion device 1, an undrawn yarn production device 2, a wet heat drawing device 3, and a drying device 4.
  • the dope solution 6 stored in the storage tank 7 is pushed out from the base 9 by the gear pump 8.
  • the dope solution may be filled into a cylinder and extruded from a nozzle using a syringe pump.
  • the extruded dope liquid 6 is supplied into the coagulating liquid 11 in the coagulating liquid tank 20 through the air gap 19, the solvent is removed, the modified fibroin is coagulated, and a fibrous coagulated body is formed.
  • the fibrous solidified body is supplied into the hot water 12 in the drawing bath 21 and drawn.
  • the draw ratio is determined by the speed ratio between the supply nip roller 13 and the take-up nip roller 14.
  • the stretched fibrous solidified body is supplied to the drying device 4 and dried in the yarn path 22 to obtain the protein filament 36 as the wound body 5.
  • Reference numerals 18a to 18g denote thread guides.
  • the coagulation liquid 11 may be any solvent that can be desolvated, and examples thereof include lower alcohols having 1 to 5 carbon atoms such as methanol, ethanol and 2-propanol, and acetone.
  • the coagulation liquid 11 may appropriately contain water.
  • the temperature of the coagulation liquid 11 is preferably 0 to 30 ° C.
  • the extrusion speed is preferably 0.2 to 6.0 mL / hour per hole, and 1.4 to 4.0 mL / hour More preferably it is time.
  • the distance through which the coagulated modified fibroin passes through the coagulating liquid 11 may be long enough to efficiently remove the solvent. 500 mm.
  • the take-up speed of the undrawn yarn may be, for example, 1 to 20 m / min, and preferably 1 to 3 m / min.
  • the residence time in the coagulating liquid 11 may be, for example, 0.01 to 3 minutes, and preferably 0.05 to 0.15 minutes.
  • stretching pre-stretching
  • the coagulating liquid tank 20 may be provided in multiple stages, and the stretching may be performed in each stage or a specific stage as necessary.
  • the stretching performed when obtaining the protein filament for example, the pre-stretching performed in the coagulating liquid tank 20 and the wet heat stretching performed in the stretching bath 21 are used, and dry heat stretching is also employed.
  • Wet heat stretching can be performed in warm water, in a solution obtained by adding an organic solvent or the like to warm water, or in steam heating.
  • the temperature may be, for example, 50 to 90 ° C., and preferably 75 to 85 ° C.
  • undrawn yarn or predrawn yarn
  • Dry heat stretching can be performed using an electric tubular furnace, a dry heat plate, or the like.
  • the temperature may be, for example, 140 ° C. to 270 ° C., and preferably 160 ° C. to 230 ° C.
  • an undrawn yarn or predrawn yarn
  • an undrawn yarn can be drawn, for example, 0.5 to 8 times, and preferably 1 to 4 times.
  • Wet heat stretching and dry heat stretching may be performed independently, or may be performed in multiple stages or in combination. That is, the first stage stretching is performed by wet heat stretching, the second stage stretching is performed by dry heat stretching, or the first stage stretching is performed by wet heat stretching, the second stage stretching is performed by wet heat stretching, and the third stage stretching is performed by dry heat stretching.
  • wet heat stretching and dry heat stretching can be appropriately combined.
  • the final draw ratio of the lower limit of the undrawn yarn (or predrawn yarn) is preferably more than 1 time, 2 times or more, 3 times or more, 4 times or more, 5 times or more, 6 times. Above, 7 times or more, 8 times or more, 9 times or more, and upper limit is preferably 40 times or less, 30 times or less, 20 times or less, 15 times or less, 14 times or less, 13 times or less 12 times or less, 11 times or less, and 10 times or less.
  • the length of the protein filament obtained by the above method can be appropriately adjusted depending on the spinning conditions, and preferably exceeds 1500 m, and may be 10,000 m or more, 15000 m or more, or 20000 m or more.
  • the protein filament has a shrinkage ratio (shrinkage ratio after drying) of more than 7%, 15% or more, 25% or more, 32% or more, 40% or more when brought into contact with an aqueous medium described later after spinning and then dried. 48% or more, 56% or more, 64% or more, or 72% or more.
  • the shrinkage after drying is usually 80% or less.
  • the protein filament has a shrinkage ratio (shrinkage ratio when wet) of, for example, 2% or more when it is wetted by contacting with an aqueous medium (for example, water having a boiling point below) after spinning. It may be 2.5% or more, 3% or more, 3.5% or more, 4% or more, 4.5% or more, 5% or more, 5.5% or more, or 6% or more. Also good.
  • the upper limit of the shrinkage rate when wet is not particularly limited, but 80% or less, 60% or less, 40% or less, 20% or less, 10% or less, 7% or less, 6% or less, 5% or less, 4% or less, or 3 % Or less.
  • the spread tow according to the present invention obtains a spread tow by crimping a bundle of protein filaments obtained by the above-described method (crimping step) and opening the bundle of crimped protein filaments. And a process (opening process). Moreover, you may implement the process (oil agent adhesion process) of attaching an oil agent to the bundle
  • the number of protein filaments constituting the bundle of protein filaments is not limited and may be one or more, 100 or more, 192 or more, 1000 or more, 4800 or more, 5000 or more, 10,000 or more, 48000. There may be more than 100,000, more than 1,000, or more than one million. There is no upper limit to the number of protein filaments constituting the bundle of protein filaments, but it is preferably 10 million or less from the viewpoint of productivity.
  • the open tow finally obtained by the crimping process has a better soft feeling.
  • the bundle of protein filaments may be crimped by conventional mechanical crimping or may be crimped by contact with an aqueous medium. Moreover, these processing methods can also be used together.
  • the protein filament bundle may be crimped mechanically and then contacted with an aqueous medium to impart crimps to the protein filament bundle. Examples of the mechanical crimping method include a false twisting method, an indentation method, a rubbing method, an air injection method (high pressure air jet method), and a shaping method.
  • a bundle of protein filaments is pushed into a stuffer box with a roller that rotates at a high speed, thereby crimping the bundle of protein filaments and fixing the crimp with heat (heat setting).
  • the aqueous medium is a liquid or gas (steam) medium containing water (including water vapor).
  • the aqueous medium may be water or a mixed solution of water and a hydrophilic solvent.
  • a hydrophilic solvent it is also possible to use volatile solvents, such as ethanol and methanol, or its vapor
  • the aqueous medium is preferably a mixed solution of water and ethanol.
  • the ratio of water to the volatile solvent or the vapor thereof is not particularly limited.
  • the water: volatile solvent or the vapor thereof may be 10:90 to 90:10 by mass ratio.
  • a known oil agent such as an oil for process passage (for example, antistatic) or a finishing agent may be dispersed in the aqueous medium.
  • an oil agent such as an oil for process passage (for example, antistatic) or a finishing agent.
  • the amount of the oil agent is not particularly limited, and may be, for example, 1 to 10% by mass or 2 to 5% by mass with respect to the total amount of the aqueous medium.
  • the temperature of the aqueous medium may be 10 ° C or higher, 25 ° C or higher, 40 ° C or higher, 60 ° C or higher, or 100 ° C or higher, and 230 ° C or lower, 120 ° C or lower, or 100 ° C or lower. More specifically, when the aqueous medium is a gas (steam), the temperature of the aqueous medium is preferably from 100 to 230 ° C, more preferably from 100 to 120 ° C. When the steam of the aqueous medium is 230 ° C. or lower, heat denaturation of the protein filament can be prevented. When the aqueous medium is a liquid, the temperature of the aqueous medium is preferably 10 ° C. or higher, 25 ° C.
  • the time for contacting the aqueous medium with the bundle of protein filaments is not particularly limited, but may be 30 seconds or more, 1 minute or more, or 2 minutes or more, and is preferably 10 minutes or less from the viewpoint of productivity. Contact of the aqueous medium with the bundle of protein filaments may be performed under normal pressure or under reduced pressure (for example, vacuum).
  • Examples of the method of bringing an aqueous medium into contact with the bundle of protein filaments include a method of immersing the bundle of protein filaments in water, a method of spraying aqueous medium steam on the bundle of protein filaments, and an environment filled with steam of the aqueous medium. Examples include a method of exposing a bundle of protein filaments. When the aqueous medium is steam, the aqueous medium can be contacted with the bundle of protein filaments using a conventional steam setting apparatus.
  • the steam setting device include devices such as product name: FMSA type steam setter (manufactured by Fukushin Kogyo Co., Ltd.) and product name: EPS-400 (manufactured by Sakurai Dyeing Machinery Co., Ltd.).
  • a method of crimping a bundle of protein filaments with steam of an aqueous medium a bundle of protein filaments is accommodated in a predetermined storage chamber, while steam of the aqueous medium is introduced into the storage chamber, The steam may be brought into contact with a bundle of protein filaments while adjusting the temperature to the predetermined temperature (for example, 100 ° C. to 230 ° C.).
  • the crimping step of the bundle of protein filaments by contact with the aqueous medium is preferably in a state where no tensile force is applied to the bundle of protein filaments (no tension is applied in the direction of the fiber axis) or a predetermined size. It is carried out in the state of being added (strained by a predetermined amount in the fiber axis direction). In this case, the degree of crimping can be controlled by adjusting the tensile force applied to the bundle of protein filaments.
  • a method of adjusting the tensile force applied to the bundle of protein filaments for example, a method of adjusting a load applied to the bundle of protein filaments by suspending weights of various weights on the bundle of protein filaments, A method of fixing both ends in a state in which a bundle of protein filaments is loosened and variously changing the amount of looseness, winding a bundle of protein filaments around a wound body such as a paper tube or a bobbin, and winding force at that time Examples thereof include a method of appropriately changing (clamping force to the paper tube or bobbin).
  • the protein filament bundle may be dried after the aqueous medium is brought into contact with the bundle of protein filaments.
  • the drying method is not particularly limited, natural drying may be used, and the protein filament bundle may be forcibly dried using a drying facility. Crimping with an aqueous medium and subsequent drying can be carried out continuously. Specifically, for example, the protein filament bundle can be dipped in an aqueous medium while being sent out from a bobbin, and then dried by blowing hot air or sending it on a hot roller.
  • the drying temperature is not particularly limited, and may be, for example, 20 to 150 ° C., preferably 40 to 120 ° C., and more preferably 60 to 100 ° C.
  • the bundle of protein filaments crimped by the above method has crimps.
  • the degree of crimp is not limited, and the number of crimps may be, for example, 10 to 100 pieces / 40 mm, or 20 to 40 pieces / 40 mm.
  • the oil agent is attached to the bundle of protein filaments, and various properties can be imparted to the protein filament.
  • the oil agent attaching step can be performed at any stage in the production method.
  • the oil agent attaching step may be performed before the crimping step, simultaneously with the crimping step, or after the crimping step and before the fiber opening step.
  • the oil agent is not particularly limited, and can be selected from known oil agents according to the properties imparted to the bundle of protein filaments.
  • the oil agent may be one that imparts characteristics for smoothly performing each process such as antistatic property, lubricity, convergence, heat resistance, etc. (that is, for passing through the process), and is finally obtained. It may be one that imparts desired characteristics such as flexibility and antistatic properties to the opened tow (ie, for finishing).
  • a bundle of crimped protein filaments is opened to obtain a opened tow.
  • the method of opening is not particularly limited, and a conventionally known method can be used.
  • the protein filament bundle may be opened by scratching the bundle of protein filaments in the fiber axis direction using a hand card or by using a rotating opening roller.
  • the bundle of protein filaments can be opened by jetting an air jet in the direction of the fiber axis of the bundle of protein filaments.
  • the opened tow according to the present invention manufactured by the above method it is not necessary to join a large number of opened tows in order to produce an extremely thick yarn, and thus an extremely thick yarn can be easily manufactured.
  • a finished product (chunky knit sweater, blanket, etc.) having no joints or few joints can be obtained.
  • the opened tow according to the present invention is composed of a bundle of filaments and does not require a step of spinning staples in its manufacture, it can be manufactured with high productivity.
  • the opened tow according to the present invention can have desired characteristics such as characteristics similar to wool, characteristics not obtainable with natural silk and regenerated silk, by design of the modified fibroin.
  • ⁇ Manufacture of modified spider silk fibroin> (1) Preparation of plasmid expression strain Based on the nucleotide sequence and amino acid sequence of fibroin (GenBank accession numbers: P46804.1, GI: 1174415) derived from Nephila clavipes, the amino acid sequence represented by SEQ ID NO: 13 A modified fibroin (hereinafter also referred to as “PRT799”) was designed.
  • the amino acid sequence represented by SEQ ID NO: 13 has an amino acid sequence in which substitution, insertion, and deletion of amino acid residues are performed for the purpose of improving productivity with respect to the amino acid sequence of fibroin derived from Nephila clavipes.
  • an amino acid sequence (tag sequence and hinge sequence) represented by SEQ ID NO: 5 is added to the N-terminus.
  • nucleic acid encoding PRT799 was synthesized.
  • the nucleic acid was added with an NdeI site at the 5 'end and an EcoRI site downstream of the stop codon.
  • the nucleic acid was cloned into a cloning vector (pUC118). Thereafter, the nucleic acid was cleaved by restriction enzyme treatment with NdeI and EcoRI, and then recombined with the protein expression vector pET-22b (+) to obtain an expression vector.
  • the seed culture was added to a jar fermenter to which 500 mL of production medium (Table 5) was added so that the OD 600 was 0.05.
  • the culture solution temperature was maintained at 37 ° C., and the culture was performed at a constant pH of 6.9. Further, the dissolved oxygen concentration in the culture solution was maintained at 20% of the dissolved oxygen saturation concentration.
  • a feed solution (glucose 455 g / 1 L, Yeast Extract 120 g / 1 L) was added at a rate of 1 mL / min.
  • the culture solution temperature was maintained at 37 ° C., and the culture was performed at a constant pH of 6.9.
  • the dissolved oxygen concentration in the culture solution was maintained at 20% of the dissolved oxygen saturation concentration, and cultured for 20 hours.
  • 1M isopropyl- ⁇ -thiogalactopyranoside (IPTG) was added to the culture solution to a final concentration of 1 mM to induce expression of the modified fibroin.
  • the culture solution was centrifuged, and the cells were collected. Perform SDS-PAGE using cells prepared from the culture solution before and after IPTG addition, and confirm the expression of the desired modified fibroin by the appearance of the desired modified fibroin size band depending on the addition of IPTG did.
  • the washed precipitate is suspended in 8 M guanidine buffer (8 M guanidine hydrochloride, 10 mM sodium dihydrogen phosphate, 20 mM NaCl, 1 mM Tris-HCl, pH 7.0) to a concentration of 100 mg / mL, and 30 ° C. at 30 ° C. Stir with a stirrer for minutes to dissolve.
  • dialysis was performed with water using a dialysis tube (cellulose tube 36/32 manufactured by Sanko Junyaku Co., Ltd.).
  • the white aggregated protein obtained after dialysis was collected by centrifugation, water was removed with a freeze dryer, and the lyophilized powder was collected to obtain a modified spider silk fibroin “PRT799”.
  • Example 1 The protein filaments obtained as described above were combined with 25 bobbins to form a bundle and immersed in water at 20 ° C. to shrink the protein filament, thereby crimping the protein filament bundle. Next, the bundle of protein filaments was dried at 40 ° C. for 18 hours to obtain a bundle of crimped protein filaments shown in FIG. At this time, the shrinkage ratio of the protein filament was 50% by mass. After sufficiently drying the bundle of protein filaments, the bundle of protein filaments was scratched in the direction of the fiber axis with a hand card to obtain an open tow as shown in FIG. The fineness of the spread tow was about 20,000 denier and had an excellent soft feeling.
  • Example 2 As in Example 1, protein filaments were combined into 25 bobbins and bundled. This was crimped by the indentation method. Subsequently, the bundle of protein filaments was crimped again by immersing in 20 ° C. water in which an antistatic oil agent was dispersed at a concentration of 20% by mass for 1 minute. Next, the bundle of protein filaments was dried at 40 ° C. for 18 hours to obtain a bundle of crimped protein filaments. After sufficiently drying the bundle of protein filaments, the bundle of protein filaments was scratched in the fiber axis direction with a hand card to obtain a spread tow as shown in FIG. The fineness of the spread tow was about 20,000 denier and had an excellent soft feeling.

Abstract

The purpose of the present invention is to provide an opened tow of a protein filament with which it is possible to easily manufacture an extra-thick yarn, and a method for manufacturing the opened tow. In the opened tow of a protein filament according to the present invention, the protein filament includes modified fibroin and is crimped.

Description

タンパク質フィラメントの開繊トウ及びその製造方法Opening tow of protein filament and method for producing the same
　本発明は、タンパク質フィラメントの開繊トウ及びその製造方法に関する。 The present invention relates to a protein filament opening tow and a method for producing the same.
　タンパク質繊維には、シルク等のフィラメント（長繊維）とウール等のステープル（短繊維）があり、前者はしなやかな風合いを有し、また後者はソフト感や保温性を有する等、それぞれが独自の特性を備えている。このようなタンパク質繊維は、いずれも合成繊維とは異なって、生分解性を有し、生産や加工のエネルギーが小さいこと等から、近年の環境保全意識の高まりに応じて、様々な分野への需要の増大が見込まれている。 Protein fibers include filaments (long fibers) such as silk and staples (short fibers) such as wool, the former has a supple texture, and the latter has a soft feeling and heat retaining properties. It has characteristics. These protein fibers, unlike synthetic fibers, are all biodegradable and have low production and processing energy. Increase in demand is expected.
　ところで、近年、そのようなタンパク質繊維からなる編物の一種として、チャンキーニットセーターやチャンキーニットブラケット等、いわゆる極太毛糸の編成物が流行している。ところが、毛糸はウール等のステープルで構成されているため、チャンキーニットセーターやチャンキーニットブラケット等の編成に用いられる長尺で極太の毛糸を製造するには、例えば、フィラメントを用いて極太の糸を製造する場合に比して工数がかさむといった不具合があった。ここで、タンパク質フィラメントから極太糸を得るには、例えば、シルクの捲縮フィラメントの束を開繊した、いわゆる開繊トウを用いることが考えられる。引用文献１には、捲縮を有する天然シルクのフィラメントの束を開繊して、開繊トウよりも高度に開繊されたシルクわたを得る方法が開示されている。 By the way, in recent years, knitted fabrics of so-called extra-thick wool such as chunky knit sweaters and chunky knit brackets have become popular as a kind of knitted fabric made of such protein fibers. However, since the yarn is composed of staples such as wool, in order to produce a long and very thick yarn used for knitting such as a chunky knit sweater or a chunky knit bracket, for example, using a filament, There was a problem that man-hours were increased as compared with the case of producing yarn. Here, in order to obtain a very thick yarn from a protein filament, for example, it is conceivable to use a so-called opened tow obtained by opening a bundle of silk crimped filaments. Cited Document 1 discloses a method of opening a bundle of natural silk filaments having crimps to obtain silk wisteria that is highly opened compared to the opened tow.
特開２０１０－１３３０４０号公報JP 2010-1333040 A
　しかしながら、天然のシルクは、１本の長さがせいぜい１５００ｍ程度であるため、編物を編成する際に、開繊トウを多数つなぎ合わせる作業が必要であった。それ故、極太毛糸の代替として、天然シルクの開繊トウを用いる場合にあっても、編み物編成用の極太糸の製造に余分な工数がかかるといった問題が内在していた。 However, since natural silk has a length of about 1500 m at most, it is necessary to join a large number of spread tows when knitting a knitted fabric. Therefore, even when natural silk spread tow is used as an alternative to extra-thick yarn, there is an inherent problem that extra man-hours are required to produce extra-thick yarn for knitting.
　本発明は上記課題に鑑みてなされたものであり、極太糸を容易に製造可能な、タンパク質フィラメントの開繊トウ及びその製造方法を提供する。 The present invention has been made in view of the above problems, and provides a protein filament opening tow and a method for producing the same, which can easily produce an extremely thick yarn.
　本発明は、例えば、以下の各発明に関する。
［１］
　タンパク質フィラメントの開繊トウであって、上記タンパク質フィラメントは、改変フィブロインを含み、かつ、捲縮を有する、開繊トウ。
［２］
　上記改変フィブロインが、改変クモ糸フィブロインである、［１］に記載の開繊トウ。
［３］
　上記改変フィブロインが、配列番号９、配列番号１１、配列番号１３、配列番号２４、配列番号２５、配列番号２６、配列番号３２、配列番号３３、配列番号３４、配列番号３５、配列番号３６、配列番号４０、若しくは配列番号４１で示されるアミノ酸配列を有する、又は、配列番号９、配列番号１１、配列番号１３、配列番号２４、配列番号２５、配列番号２６、配列番号３２、配列番号３３、配列番号３４、配列番号３５、配列番号３６、配列番号４０、若しくは配列番号４１で示されるアミノ酸配列と９０％以上の配列同一性を有するアミノ酸配列を有する、［１］又は［２］に記載の開繊トウ。
［４］
　タンパク質フィラメントの開繊トウを製造する方法であって、タンパク質フィラメントの束を捲縮させる工程と、捲縮された上記タンパク質フィラメントの上記束を開繊して、開繊トウを得る工程と、を備え、上記タンパク質フィラメントは改変フィブロインを含む、製造方法。
［５］
　上記改変フィブロインが、改変クモ糸フィブロインである、［４］に記載の製造方法。［６］
　上記捲縮させる工程が、上記タンパク質フィラメントの上記束を機械的に捲縮させること、又は、上記タンパク質フィラメントの上記束を水性媒体に接触させることを含む、［４］又は［５］に記載の製造方法。
［７］
　上記捲縮させる工程が、上記タンパク質フィラメントの上記束を機械的に捲縮させ、次いで水性媒体に接触させることを含む、［６］に記載の製造方法。
［８］
　上記水性媒体の温度が、１０～２３０℃である、［６］又は［７］に記載の製造方法。
［９］
　上記改変フィブロインが、配列番号９、配列番号１１、配列番号１３、配列番号２４、配列番号２５、配列番号２６、配列番号３２、配列番号３３、配列番号３４、配列番号３５、配列番号３６、配列番号４０、若しくは配列番号４１で示されるアミノ酸配列を有する、又は、配列番号９、配列番号１１、配列番号１３、配列番号２４、配列番号２５、配列番号２６、配列番号３２、配列番号３３、配列番号３４、配列番号３５、配列番号３６、配列番号４０、若しくは配列番号４１で示されるアミノ酸配列と９０％以上の配列同一性を有するアミノ酸配列を有する、［４］～［８］のいずれかに記載の製造方法。 The present invention relates to the following inventions, for example.
[1]
A tow of a protein filament, wherein the protein filament comprises a modified fibroin and has crimps.
[2]
The opened tow according to [1], wherein the modified fibroin is a modified spider silk fibroin.
[3]
The modified fibroin is SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 32, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 40, or the amino acid sequence shown by SEQ ID NO: 41, or SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 32, SEQ ID NO: 33, sequence The open sequence according to [1] or [2], which has an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 40, or SEQ ID NO: 41. Fine tow.
[4]
A method for producing a spread tow of protein filaments, comprising: crimping a bundle of protein filaments; and opening the bundle of crimped protein filaments to obtain a spread tow And the protein filament comprises a modified fibroin.
[5]
The production method according to [4], wherein the modified fibroin is a modified spider silk fibroin. [6]
[4] or [5], wherein the crimping step includes mechanically crimping the bundle of protein filaments, or contacting the bundle of protein filaments with an aqueous medium. Production method.
[7]
The production method according to [6], wherein the crimping step includes mechanically crimping the bundle of the protein filaments and then contacting the bundle with an aqueous medium.
[8]
The production method according to [6] or [7], wherein the temperature of the aqueous medium is 10 to 230 ° C.
[9]
The modified fibroin is SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 32, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 40, or the amino acid sequence shown by SEQ ID NO: 41, or SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 32, SEQ ID NO: 33, sequence Any one of [4] to [8], which has an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 40, or SEQ ID NO: 41 The manufacturing method as described.
　本発明に係る方法により製造される開繊トウによれば、紡糸により任意の長さ（例えば、１５００ｍを超える長尺）が得られるタンパク質フィラメントを含むため、極太糸を容易に製造することが可能となる。 According to the opened tow produced by the method according to the present invention, it includes a protein filament that can be obtained by spinning to have an arbitrary length (for example, longer than 1500 m), so that it is possible to easily produce a very thick yarn. It becomes.
改変フィブロインのドメイン配列の一例を示す模式図である。It is a schematic diagram which shows an example of the domain arrangement | sequence of a modified fibroin. 改変フィブロインのドメイン配列の一例を示す模式図である。It is a schematic diagram which shows an example of the domain arrangement | sequence of a modified fibroin. 改変フィブロインのドメイン配列の一例を示す模式図である。It is a schematic diagram which shows an example of the domain arrangement | sequence of a modified fibroin. タンパク質フィラメントを製造するための紡糸装置の一例を概略的に示す説明図である。It is explanatory drawing which shows roughly an example of the spinning apparatus for manufacturing a protein filament. 実施例１における捲縮されたタンパク質フィラメントの束の写真である。2 is a photograph of a bundle of crimped protein filaments in Example 1. FIG. 実施例１における開繊トウの写真である。2 is a photograph of the opened tow in Example 1. 実施例２における開繊トウの写真である。4 is a photograph of the opened tow in Example 2.
　本発明の一形態は、タンパク質フィラメントの開繊トウに関する。開繊トウとは、紡糸された糸を複数集めた繊維束を開繊したものである。タンパク質フィラメントは、改変フィブロインを主成分として含む。 One embodiment of the present invention relates to a protein filament opening tow. The opened tow is a fiber bundle obtained by collecting a plurality of spun yarns. The protein filament contains modified fibroin as a main component.
　＜改変フィブロイン＞
　本実施形態に係る改変フィブロインは、式１：［（Ａ）ｎモチーフ－ＲＥＰ］ｍ、又は式２：［（Ａ）ｎモチーフ－ＲＥＰ］ｍ－（Ａ）ｎモチーフで表されるドメイン配列を含むタンパク質である。改変フィブロインは、ドメイン配列のＮ末端側及びＣ末端側のいずれか一方又は両方に更にアミノ酸配列（Ｎ末端配列及びＣ末端配列）が付加されていてもよい。Ｎ末端配列及びＣ末端配列は、これに限定されるものではないが、典型的には、フィブロインに特徴的なアミノ酸モチーフの反復を有さない領域であり、１００残基程度のアミノ酸からなる。 <Modified fibroin>
The modified fibroin according to the present embodiment has a domain sequence represented by Formula 1: [(A) n motif-REP] m or Formula 2: [(A) n motif-REP] m- (A) n motif. It is a protein containing. In the modified fibroin, an amino acid sequence (N-terminal sequence and C-terminal sequence) may be further added to either one or both of the N-terminal side and the C-terminal side of the domain sequence. The N-terminal sequence and the C-terminal sequence are not limited to these, but are typically regions having no amino acid motif repeat characteristic of fibroin and consisting of about 100 amino acids.
　本明細書において「改変フィブロイン」とは、人為的に製造されたフィブロイン（人造フィブロイン）を意味する。改変フィブロインは、そのドメイン配列が、天然由来のフィブロインのアミノ酸配列とは異なるフィブロインであってもよく、天然由来のフィブロインのアミノ酸配列と同一であるフィブロインであってもよい。本明細書でいう「天然由来のフィブロイン」もまた、式１：［（Ａ）ｎモチーフ－ＲＥＰ］ｍ、又は式２：［（Ａ）ｎモチーフ－ＲＥＰ］ｍ－（Ａ）ｎモチーフで表されるドメイン配列を含むタンパク質である。 As used herein, “modified fibroin” means an artificially produced fibroin (artificial fibroin). The modified fibroin may be a fibroin whose domain sequence is different from the amino acid sequence of naturally occurring fibroin or may be the same as the amino acid sequence of naturally occurring fibroin. “Natural fibroin” as used herein is also represented by Formula 1: [(A) n motif-REP] m or Formula 2: [(A) n motif-REP] m- (A) n motif. A protein comprising a domain sequence to be processed.
　「改変フィブロイン」は、本実施形態で特定されるアミノ酸配列を有するものであれば、天然由来のフィブロインのアミノ酸配列をそのまま利用したものであってもよく、天然由来のフィブロインのアミノ酸配列に依拠してそのアミノ酸配列を改変したもの（例えば、クローニングした天然由来のフィブロインの遺伝子配列を改変することによりアミノ酸配列を改変したもの）であってもよく、また天然由来のフィブロインに依らず人工的に設計及び合成したもの（例えば、設計したアミノ酸配列をコードする核酸を化学合成することにより所望のアミノ酸配列を有するもの）であってもよい。 As long as the “modified fibroin” has the amino acid sequence specified in the present embodiment, the amino acid sequence of naturally-occurring fibroin may be used as it is, and it depends on the amino acid sequence of naturally-occurring fibroin. The amino acid sequence may be modified (for example, the amino acid sequence may be modified by modifying the gene sequence of a naturally-derived fibroin that has been cloned), or it may be artificially designed without relying on the naturally-occurring fibroin. And those synthesized (for example, those having a desired amino acid sequence by chemically synthesizing a nucleic acid encoding the designed amino acid sequence).
　本明細書において「ドメイン配列」とは、フィブロイン特有の結晶領域（典型的には、アミノ酸配列の（Ａ）ｎモチーフに相当する。）と非晶領域（典型的には、アミノ酸配列のＲＥＰに相当する。）を生じるアミノ酸配列であり、式１：［（Ａ）ｎモチーフ－ＲＥＰ］ｍ、又は式２：［（Ａ）ｎモチーフ－ＲＥＰ］ｍ－（Ａ）ｎモチーフで表されるアミノ酸配列を意味する。ここで、（Ａ）ｎモチーフは、アラニン残基を主とするアミノ酸配列を示し、アミノ酸残基数は２～２７である。（Ａ）ｎモチーフのアミノ酸残基数は、２～２０、４～２７、４～２０、８～２０、１０～２０、４～１６、８～１６、又は１０～１６の整数であってよい。また、（Ａ）ｎモチーフ中の全アミノ酸残基数に対するアラニン残基数の割合は４０％以上であればよく、６０％以上、７０％以上、８０％以上、８３％以上、８５％以上、８６％以上、９０％以上、９５％以上、又は１００％（アラニン残基のみで構成されることを意味する。）であってもよい。ドメイン配列中に複数存在する（Ａ）ｎモチーフは、少なくとも７つがアラニン残基のみで構成されてもよい。ＲＥＰは２～２００アミノ酸残基から構成されるアミノ酸配列を示す。ＲＥＰは、１０～２００アミノ酸残基から構成されるアミノ酸配列であってもよい。ｍは２～３００の整数を示し、１０～３００の整数であってもよい。複数存在する（Ａ）ｎモチーフは、互いに同一のアミノ酸配列でもよく、異なるアミノ酸配列でもよい。複数存在するＲＥＰは、互いに同一のアミノ酸配列でもよく、異なるアミノ酸配列でもよい。 In the present specification, the “domain sequence” refers to a fibroin-specific crystal region (typically corresponding to the (A) n motif in the amino acid sequence) and an amorphous region (typically in the REP of the amino acid sequence). Amino acid sequence that gives rise to the following formula: Formula 1: [(A) n motif-REP] m or Formula 2: [(A) n motif-REP] m- (A) amino acid represented by n motif Means an array. Here, (A) n motif represents an amino acid sequence mainly composed of alanine residues, and the number of amino acid residues is 2 to 27. (A) The number of amino acid residues of the n motif may be an integer of 2 to 20, 4 to 27, 4 to 20, 8 to 20, 10 to 20, 4 to 16, 8 to 16, or 10 to 16 . In addition, the ratio of the number of alanine residues to the total number of amino acid residues in the (A) n motif may be 40% or more, such as 60% or more, 70% or more, 80% or more, 83% or more, 85% or more, It may be 86% or more, 90% or more, 95% or more, or 100% (meaning that it is composed only of alanine residues). A plurality of (A) n motifs present in the domain sequence may be composed of at least seven alanine residues alone. REP indicates an amino acid sequence composed of 2 to 200 amino acid residues. REP may be an amino acid sequence composed of 10 to 200 amino acid residues. m represents an integer of 2 to 300, and may be an integer of 10 to 300. A plurality of (A) n motifs may have the same amino acid sequence or different amino acid sequences. Plural REPs may have the same amino acid sequence or different amino acid sequences.
　改変フィブロインは、例えば、クローニングした天然由来のフィブロインの遺伝子配列に対し、例えば、１又は複数のアミノ酸残基を置換、欠失、挿入及び／又は付加したことに相当するアミノ酸配列の改変を行うことで得ることができる。アミノ酸残基の置換、欠失、挿入及び／又は付加は、部分特異的突然変異誘発法等の当業者に周知の方法により行うことができる。具体的には、Ｎｕｃｌｅｉｃ　Ａｃｉｄ　Ｒｅｓ．１０，６４８７（１９８２）、Ｍｅｔｈｏｄｓ　ｉｎ　Ｅｎｚｙｍｏｌｏｇｙ，１００，４４８（１９８３）等の文献に記載されている方法に準じて行うことができる。 The modified fibroin is, for example, a modification of the amino acid sequence corresponding to, for example, substitution, deletion, insertion and / or addition of one or more amino acid residues to the cloned natural fibroin gene sequence. Can be obtained at Substitution, deletion, insertion and / or addition of amino acid residues can be carried out by methods well known to those skilled in the art such as partial-directed mutagenesis. Specifically, Nucleic Acid Res. 10, 6487 (1982), Methods in Enzymology, 100, 448 (1983), and the like.
　天然由来のフィブロインは、式１：［（Ａ）ｎモチーフ－ＲＥＰ］ｍ、又は式２：［（Ａ）ｎモチーフ－ＲＥＰ］ｍ－（Ａ）ｎモチーフで表されるドメイン配列を含むタンパク質であり、具体的には、例えば、昆虫又はクモ類が産生するフィブロインが挙げられる。 Naturally-derived fibroin is a protein containing a domain sequence represented by Formula 1: [(A) n motif-REP] m or Formula 2: [(A) n motif-REP] m- (A) n motif. Specific examples include fibroin produced by insects or spiders.
　昆虫が産生するフィブロインとしては、例えば、ボンビックス・モリ（Ｂｏｍｂｙｘ　ｍｏｒｉ）、クワコ（Ｂｏｍｂｙｘ　ｍａｎｄａｒｉｎａ）、天蚕（Ａｎｔｈｅｒａｅａ　ｙａｍａｍａｉ）、柞蚕（Ａｎｔｅｒａｅａ　ｐｅｒｎｙｉ）、楓蚕（Ｅｒｉｏｇｙｎａ　ｐｙｒｅｔｏｒｕｍ）、蓖蚕（Ｐｉｌｏｓａｍｉａ　Ｃｙｎｔｈｉａ　ｒｉｃｉｎｉ）、樗蚕（Ｓａｍｉａ　ｃｙｎｔｈｉａ）、栗虫（Ｃａｌｉｇｕｒａ　ｊａｐｏｎｉｃａ）、チュッサー蚕（Ａｎｔｈｅｒａｅａ　ｍｙｌｉｔｔａ）、ムガ蚕（Ａｎｔｈｅｒａｅａ　ａｓｓａｍａ）等のカイコが産生する絹タンパク質、及びスズメバチ（Ｖｅｓｐａ　ｓｉｍｉｌｌｉｍａ　ｘａｎｔｈｏｐｔｅｒａ）の幼虫が吐出するホーネットシルクタンパク質が挙げられる。 Examples of fibroin produced by insects include, for example, Bombyx mori, Kwako (Bombyx mandaraina), Tengea (Antheraea yamanai), 柞 蚕 (Antereaperanii), 楓 蚕 (Eriothyraminey) ), Silkworms produced by silkworms, such as Samia cythia, chestnut worms (Caligula japonica), Chuser moth (Antherea mylitta), Antheraea assama, and vespax (Vespaxia spp.) Hornet silk protein.
　昆虫が産生するフィブロインのより具体的な例としては、例えば、カイコ・フィブロインＬ鎖（ＧｅｎＢａｎｋアクセッション番号Ｍ７６４３０（塩基配列）、及びＡＡＡ２７８４０．１（アミノ酸配列））が挙げられる。 More specific examples of fibroin produced by insects include silkworm fibroin L chain (GenBank accession number M76430 (base sequence) and AAA27840.1 (amino acid sequence)).
　クモ類が産生するフィブロインとしては、例えば、オニグモ、ニワオニグモ、アカオニグモ、アオオニグモ及びマメオニグモ等のオニグモ属（Ａｒａｎｅｕｓ属）に属するクモ、ヤマシロオニグモ、イエオニグモ、ドヨウオニグモ及びサツマノミダマシ等のヒメオニグモ属（Ｎｅｏｓｃｏｎａ属）に属するクモ、コオニグモモドキ等のコオニグモモドキ属（Ｐｒｏｎｕｓ属）に属するクモ、トリノフンダマシ及びオオトリノフンダマシ等のトリノフンダマシ属（Ｃｙｒｔａｒａｃｈｎｅ属）に属するクモ、トゲグモ及びチブサトゲグモ等のトゲグモ属（Ｇａｓｔｅｒａｃａｎｔｈａ属）に属するクモ、マメイタイセキグモ及びムツトゲイセキグモ等のイセキグモ属（Ｏｒｄｇａｒｉｕｓ属）に属するクモ、コガネグモ、コガタコガネグモ及びナガコガネグモ等のコガネグモ属（Ａｒｇｉｏｐｅ属）に属するクモ、キジロオヒキグモ等のオヒキグモ属（Ａｒａｃｈｎｕｒａ属）に属するクモ、ハツリグモ等のハツリグモ属（Ａｃｕｓｉｌａｓ属）に属するクモ、スズミグモ、キヌアミグモ及びハラビロスズミグモ等のスズミグモ属（Ｃｙｔｏｐｈｏｒａ属）に属するクモ、ゲホウグモ等のゲホウグモ属（Ｐｏｌｔｙｓ属）に属するクモ、ゴミグモ、ヨツデゴミグモ、マルゴミグモ及びカラスゴミグモ等のゴミグモ属（Ｃｙｃｌｏｓａ属）に属するクモ、及びヤマトカナエグモ等のカナエグモ属（Ｃｈｏｒｉｚｏｐｅｓ属）に属するクモが産生するスパイダーシルクタンパク質、並びにアシナガグモ、ヤサガタアシナガグモ、ハラビロアシダカグモ及びウロコアシナガグモ等のアシナガグモ属（Ｔｅｔｒａｇｎａｔｈａ属）に属するクモ、オオシロカネグモ、チュウガタシロカネグモ及びコシロカネグモ等のシロカネグモ属（Ｌｅｕｃａｕｇｅ属）に属するクモ、ジョロウグモ及びオオジョロウグモ等のジョロウグモ属（Ｎｅｐｈｉｌａ属）に属するクモ、キンヨウグモ等のアズミグモ属（Ｍｅｎｏｓｉｒａ属）に属するクモ、ヒメアシナガグモ等のヒメアシナガグモ属（Ｄｙｓｃｈｉｒｉｏｇｎａｔｈａ属）に属するクモ、クロゴケグモ、セアカゴケグモ、ハイイロゴケグモ及びジュウサンボシゴケグモ等のゴケグモ属（Ｌａｔｒｏｄｅｃｔｕｓ属）に属するクモ、及びユープロステノプス属（Ｅｕｐｒｏｓｔｈｅｎｏｐｓ属）に属するクモ等のアシナガグモ科（Ｔｅｔｒａｇｎａｔｈｉｄａｅ科）に属するクモが産生するスパイダーシルクタンパク質が挙げられる。スパイダーシルクタンパク質としては、例えば、ＭａＳｐ（ＭａＳｐ１及びＭａＳｐ２）、ＡＤＦ（ＡＤＦ３及びＡＤＦ４）等の牽引糸タンパク質、ＭｉＳｐ（ＭｉＳｐ１及びＭｉＳｐ２）等が挙げられる。 Fibroin produced by spiders includes, for example, spiders belonging to the genus spider (Araneus spp.) Such as the spider spider, the spider spider, the red spider spider, and the bean spider, the genus spiders of the genus Araneus, the spider spider spider, the spider spider genus e Spiders, spiders such as spiders, spiders belonging to the genus Spider, spiders belonging to the genus Pronos, spiders belonging to the genus Trinofunda, such as Torinofundamas (genus Cyrtarachne) Spiders belonging to the genus (Gasteracantha), spiders belonging to the genus Spider (Ordgarius genus), such as the spiders, the spiders, and the spiders belonging to the genus Ordgarius Spiders belonging to the genus Argiope, such as the genus Argiope, spiders belonging to the genus Arachnura, such as the white-tailed spider, spiders belonging to the genus Acusilas such as the common spider, the spider belonging to the genus Acusilas, and the genus Spider Spiders belonging to (genus Cytophora), spiders belonging to the genus Spider belonging to the genus Spider (genus Poltys) such as spiders, genus Spider, spiders belonging to the genus Spider belonging to the genus Cyclosa (genus Cyclosa), and spiders belonging to the genus Cyclosa (genus Cyclosa) Spider silk proteins produced by spiders belonging to the genus Chorizopes), and Asina, such as Asagaaga spider, Yasagata Asaga spider, Harabiro Ashida spider and Urokoa Asaga spider Spiders belonging to the genus Tetragnata, spiders belonging to the genus Spider genus (Leucage sp.) Such as the white spider spider and the white spider spider, the spider genus belonging to the spider spider genus (Nephila spp. Spiders belonging to the genus Azumigumi (Menosira), spiders belonging to the genus Dyschiriognatha (genus Dyschiriognatha) such as the common spider spider, the black spider spider, the genus Spider genus belonging to the genus Spider belonging to the genus (L) and the genus Spider belonging to the genus Usd Produced by spiders belonging to the family Tetragnathidae such as spiders belonging to the genus Prostenops Examples include spider silk protein. Examples of the spider silk protein include dragline proteins such as MaSp (MaSp1 and MaSp2) and ADF (ADF3 and ADF4), MiSp (MiSp1 and MiSp2), and the like.
　クモ類が産生するスパイダーシルクタンパク質のより具体的な例としては、例えば、ｆｉｂｒｏｉｎ－３（ａｄｆ－３）［Ａｒａｎｅｕｓ　ｄｉａｄｅｍａｔｕｓ由来］（ＧｅｎＢａｎｋアクセッション番号ＡＡＣ４７０１０（アミノ酸配列）、Ｕ４７８５５（塩基配列））、ｆｉｂｒｏｉｎ－４（ａｄｆ－４）［Ａｒａｎｅｕｓ　ｄｉａｄｅｍａｔｕｓ由来］（ＧｅｎＢａｎｋアクセッション番号ＡＡＣ４７０１１（アミノ酸配列）、Ｕ４７８５６（塩基配列））、ｄｒａｇｌｉｎｅ　ｓｉｌｋ　ｐｒｏｔｅｉｎ　ｓｐｉｄｒｏｉｎ　１［Ｎｅｐｈｉｌａ　ｃｌａｖｉｐｅｓ由来］（ＧｅｎＢａｎｋアクセッション番号ＡＡＣ０４５０４（アミノ酸配列）、Ｕ３７５２０（塩基配列））、ｍａｊｏｒ　ａｍｐｕｌｌａｔｅ　ｓｐｉｄｒｏｉｎ　１［Ｌａｔｒｏｄｅｃｔｕｓ　ｈｅｓｐｅｒｕｓ由来］（ＧｅｎＢａｎｋアクセッション番号ＡＢＲ６８８５６（アミノ酸配列）、ＥＦ５９５２４６（塩基配列））、ｄｒａｇｌｉｎｅ　ｓｉｌｋ　ｐｒｏｔｅｉｎ　ｓｐｉｄｒｏｉｎ　２［Ｎｅｐｈｉｌａ　ｃｌａｖａｔａ由来］（ＧｅｎＢａｎｋアクセッション番号ＡＡＬ３２４７２（アミノ酸配列）、ＡＦ４４１２４５（塩基配列））、ｍａｊｏｒ　ａｍｐｕｌｌａｔｅ　ｓｐｉｄｒｏｉｎ　１［Ｅｕｐｒｏｓｔｈｅｎｏｐｓ　ａｕｓｔｒａｌｉｓ由来］（ＧｅｎＢａｎｋアクセッション番号ＣＡＪ００４２８（アミノ酸配列）、ＡＪ９７３１５５（塩基配列））、及びｍａｊｏｒ　ａｍｐｕｌｌａｔｅ　ｓｐｉｄｒｏｉｎ　２［Ｅｕｐｒｏｓｔｈｅｎｏｐｓ　ａｕｓｔｒａｌｉｓ］（ＧｅｎＢａｎｋアクセッション番号ＣＡＭ３２２４９．１（アミノ酸配列）、ＡＭ４９０１６９（塩基配列））、ｍｉｎｏｒ　ａｍｐｕｌｌａｔｅ　ｓｉｌｋ　ｐｒｏｔｅｉｎ　１［Ｎｅｐｈｉｌａ　ｃｌａｖｉｐｅｓ］（ＧｅｎＢａｎｋアクセッション番号ＡＡＣ１４５８９．１（アミノ酸配列））、ｍｉｎｏｒ　ａｍｐｕｌｌａｔｅ　ｓｉｌｋ　ｐｒｏｔｅｉｎ　２［Ｎｅｐｈｉｌａ　ｃｌａｖｉｐｅｓ］（ＧｅｎＢａｎｋアクセッション番号ＡＡＣ１４５９１．１（アミノ酸配列））、ｍｉｎｏｒ　ａｍｐｕｌｌａｔｅ　ｓｐｉｄｒｏｉｎ－ｌｉｋｅ　ｐｒｏｔｅｉｎ［Ｎｅｐｈｉｌｅｎｇｙｓ　ｃｒｕｅｎｔａｔａ］（ＧｅｎＢａｎｋアクセッション番号ＡＢＲ３７２７８．１（アミノ酸配列）等が挙げられる。 More specific examples of spider silk proteins produced by spiders include, for example, fibroin-3 (adf-3) [derived from Araneus diadematus] (GenBank accession numbers AAC47010 (amino acid sequence), U47855 (base sequence)), fibroin-4 (adf-4) [derived from Araneus diadematus] (GenBank accession number AAC47011 (amino acid sequence), U47856 (base sequence)), dragline silk protein spiroin 1 [derived from Nephila clavipes] (GenBank accession number 4) ), U37520 (base sequence)), major ampulate spidro n 1 [derived from Latroductus hesperus] (GenBank accession number ABR68856 (amino acid sequence), EF595246 (base sequence)), dragline silk protein spidolin 2 [derived from Nephila clavata (GenBank accession number AAL32 base sequence 44 AAL32 base sequence amino acid 44, amino acid sequence 44 AAL47) )), Major ampulerate spiroin 1 [from Euprosthenops australis] (GenBank accession numbers CAJ00428 (amino acid sequence), AJ973155 (base sequence)), and major amplospiroid 2 [Euprostenaplas ] (GenBank accession number CAM322249.1 (amino acid sequence), AM490169 (base sequence)), minor sample silk protein 1 [Nephila clubs] (GenBank accession number AAC145891 (amino acid sequence)), minor sample 2 Nephila clavies] (GenBank accession number AAC14591.1 (amino acid sequence)), minor sample spirodin-like protein [Nephilegenes cruentata] (GenBank accession number ABR37278.1 (amino acid sequence), etc.
　天然由来のフィブロインのより具体的な例としては、更に、ＮＣＢＩ　ＧｅｎＢａｎｋに配列情報が登録されているフィブロインを挙げることができる。例えば、ＮＣＢＩ　ＧｅｎＢａｎｋに登録されている配列情報のうちＤＩＶＩＳＩＯＮとしてＩＮＶを含む配列の中から、ＤＥＦＩＮＩＴＩＯＮにｓｐｉｄｒｏｉｎ、ａｍｐｕｌｌａｔｅ、ｆｉｂｒｏｉｎ、「ｓｉｌｋ及びｐｏｌｙｐｅｐｔｉｄｅ」、又は「ｓｉｌｋ及びｐｒｏｔｅｉｎ」がキーワードとして記載されている配列、ＣＤＳから特定のｐｒｏｄｕｃｔの文字列、ＳＯＵＲＣＥからＴＩＳＳＵＥ　ＴＹＰＥに特定の文字列の記載された配列を抽出することにより確認することができる。 More specific examples of naturally derived fibroin include fibroin whose sequence information is registered in NCBI GenBank. For example, spidin, sample, fibroin, “silk and polypeptide”, or “silk and protein” is described as a keyword in DEFINITION from sequences including INV as DIVISION among the sequence information registered in NCBI GenBank. It can be confirmed by extracting a character string of a specific product from the sequence, CDS, and a sequence in which the specific character string is described from SOURCE to TISSUE TYPE.
　改変フィブロインは、改変絹（シルク）フィブロイン（カイコが産生する絹タンパク質のアミノ酸配列を改変したもの）であってもよく、改変クモ糸フィブロイン（クモ類が産生するスパイダーシルクタンパク質のアミノ酸配列を改変したもの）であってもよい。それらのうちでも改変クモ糸フィブロインが、好適に用いられる。 The modified fibroin may be modified silk fibroin (modified silk protein amino acid sequence produced by silkworm), modified spider silk fibroin (modified spider silk protein amino acid sequence produced by spiders) Thing). Among them, modified spider silk fibroin is preferably used.
　改変フィブロインの具体的な例として、クモの大瓶状腺で産生される大吐糸管しおり糸タンパク質に由来する改変フィブロイン、グリシン残基の含有量が低減された改変フィブロイン、（Ａ）ｎモチーフの含有量が低減された改変フィブロイン、グリシン残基の含有量、及び（Ａ）ｎモチーフの含有量が低減された改変フィブロインが挙げられる。 Specific examples of the modified fibroin include a modified fibroin derived from a large sphincter bookmark silk protein produced in a spider large bottle gland, a modified fibroin with a reduced content of glycine residues, (A) an n motif Modified fibroin with reduced content, content of glycine residue, and (A) modified fibroin with reduced content of n motif.
　クモの大瓶状腺で産生される大吐糸管しおり糸タンパク質に由来する改変フィブロインとしては、式１：［（Ａ）ｎモチーフ－ＲＥＰ］ｍで表されるドメイン配列を含むタンパク質が挙げられる。クモの大瓶状腺で産生される大吐糸管しおり糸タンパク質に由来する改変フィブロインにおいて、（Ａ）ｎモチーフのアミノ酸残基数は、３～２０の整数が好ましく、４～２０の整数がより好ましく、８～２０の整数が更に好ましく、１０～２０の整数が更により好ましく、４～１６の整数が更によりまた好ましく、８～１６の整数が特に好ましく、１０～１６の整数が最も好ましい。クモの大瓶状腺で産生される大吐糸管しおり糸タンパク質に由来する改変フィブロインは、式１中、ＲＥＰを構成するアミノ酸残基の数は、１０～２００残基であることが好ましく、１０～１５０残基であることがより好ましく、２０～１００残基であることが更に好ましく、２０～７５残基であることが更により好ましい。クモの大瓶状腺で産生される大吐糸管しおり糸タンパク質に由来する改変フィブロインは、式１：［（Ａ）ｎモチーフ－ＲＥＰ］ｍで表されるアミノ酸配列中に含まれるグリシン残基、セリン残基及びアラニン残基の合計残基数がアミノ酸残基数全体に対して、４０％以上であることが好ましく、６０％以上であることがより好ましく、７０％以上であることが更に好ましい。 Examples of the modified fibroin derived from the large sphincter bookmark silk protein produced in the spider large bottle gland include a protein containing a domain sequence represented by Formula 1: [(A) n motif-REP] m . In the modified fibroin derived from the large sphincter bookmark silkworm protein produced in the large spider gland, (A) the number of amino acid residues of the n motif is preferably an integer of 3 to 20, more preferably an integer of 4 to 20 Preferably, an integer of 8 to 20 is more preferable, an integer of 10 to 20 is still more preferable, an integer of 4 to 16 is still more preferable, an integer of 8 to 16 is particularly preferable, and an integer of 10 to 16 is most preferable. In the modified fibroin derived from the large sphincter bookmark silk protein produced in the spider large bottle-like gland, in Formula 1, the number of amino acid residues constituting REP is preferably 10 to 200 residues. More preferably, it is ˜150 residues, more preferably 20-100 residues, and even more preferably 20-75 residues. A modified fibroin derived from the large sphincter bookmark silk protein produced in the spider large bottle gland is a glycine residue contained in the amino acid sequence represented by Formula 1: [(A) n motif-REP] m , The total number of residues of serine residues and alanine residues is preferably 40% or more, more preferably 60% or more, still more preferably 70% or more based on the total number of amino acid residues. .
　クモの大瓶状腺で産生される大吐糸管しおり糸タンパク質に由来する改変フィブロインは、式１：［（Ａ）ｎモチーフ－ＲＥＰ］ｍで表されるアミノ酸配列の単位を含み、かつＣ末端配列が配列番号１４～１６のいずれかに示されるアミノ酸配列又は配列番号１４～１６のいずれかに示されるアミノ酸配列と９０％以上の相同性を有するアミノ酸配列であるポリペプチドであってもよい。 The modified fibroin derived from the large sphincter bookmark silk protein produced in the spider large bottle gland comprises a unit of an amino acid sequence represented by the formula 1: [(A) n motif-REP] m and has a C-terminal. It may be a polypeptide whose sequence is an amino acid sequence shown in any of SEQ ID NOs: 14 to 16 or an amino acid sequence having 90% or more homology with the amino acid sequence shown in any of SEQ ID NOs: 14 to 16.
　配列番号１４に示されるアミノ酸配列は、ＡＤＦ３（ＧＩ：１２６３２８７、ＮＣＢＩ）のアミノ酸配列のＣ末端の５０残基のアミノ酸からなるアミノ酸配列と同一であり、配列番号１５に示されるアミノ酸配列は、配列番号１４に示されるアミノ酸配列のＣ末端から２０残基取り除いたアミノ酸配列と同一であり、配列番号１６に示されるアミノ酸配列は、配列番号１４に示されるアミノ酸配列のＣ末端から２９残基取り除いたアミノ酸配列と同一である。 The amino acid sequence shown in SEQ ID NO: 14 is the same as the amino acid sequence consisting of 50 amino acids at the C-terminal of the amino acid sequence of ADF3 (GI: 1263287, NCBI), and the amino acid sequence shown in SEQ ID NO: 15 is the sequence The amino acid sequence shown in SEQ ID NO: 14 is identical to the amino acid sequence obtained by removing 20 residues from the C-terminus, and the amino acid sequence shown in SEQ ID NO: 16 is 29 residues removed from the C-terminus of the amino acid sequence shown in SEQ ID NO: 14. It is identical to the amino acid sequence.
　クモの大瓶状腺で産生される大吐糸管しおり糸タンパク質に由来する改変フィブロインのより具体的な例として、（１－ｉ）配列番号１７で示されるアミノ酸配列、又は（１－ｉｉ）配列番号１７で示されるアミノ酸配列と９０％以上の配列同一性を有するアミノ酸配列を含む、改変フィブロインを挙げることができる。配列同一性は、９５％以上であることが好ましい。 As a more specific example of a modified fibroin derived from a large sphincter bookmark silk protein produced in the spider large bottle-like gland, (1-i) the amino acid sequence represented by SEQ ID NO: 17, or (1-ii) sequence Mention may be made of modified fibroin comprising an amino acid sequence having a sequence identity of 90% or more with the amino acid sequence indicated by number 17. The sequence identity is preferably 95% or more.
　配列番号１７で示されるアミノ酸配列は、Ｎ末端に開始コドン、Ｈｉｓ１０タグ及びＨＲＶ３Ｃプロテアーゼ（Ｈｕｍａｎ　ｒｈｉｎｏｖｉｒｕｓ　３Ｃプロテアーゼ）認識サイトからなるアミノ酸配列（配列番号１８）を付加したＡＤＦ３のアミノ酸配列において、第１～１３番目の反復領域をおよそ２倍になるように増やすとともに、翻訳が第１１５４番目アミノ酸残基で終止するように変異させたものである。配列番号１７で示されるアミノ酸配列のＣ末端のアミノ酸配列は、配列番号１６で示されるアミノ酸配列と同一である。 The amino acid sequence represented by SEQ ID NO: 17 is an amino acid sequence of ADF3 in which an amino acid sequence (SEQ ID NO: 18) consisting of a start codon, His10 tag and an HRV3C protease (Human rhinovirus 3C protease) recognition site is added to the N-terminus. The 13th repeat region was increased to approximately double, and the translation was mutated to terminate at the 1154th amino acid residue. The C-terminal amino acid sequence of the amino acid sequence shown in SEQ ID NO: 17 is identical to the amino acid sequence shown in SEQ ID NO: 16.
　（１－ｉ）の改変フィブロインは、配列番号１７で示されるアミノ酸配列からなるものであってもよい。 The modified fibroin (1-i) may be composed of the amino acid sequence represented by SEQ ID NO: 17.
　グリシン残基の含有量が低減された改変フィブロインは、そのドメイン配列が、天然由来のフィブロインと比較して、グリシン残基の含有量が低減されたアミノ酸配列を有する。当該改変フィブロインは、天然由来のフィブロインと比較して、少なくともＲＥＰ中の１又は複数のグリシン残基が別のアミノ酸残基に置換されたことに相当するアミノ酸配列を有するものということができる。 The modified fibroin with a reduced content of glycine residues has an amino acid sequence with a reduced content of glycine residues in the domain sequence compared to naturally occurring fibroin. It can be said that the modified fibroin has an amino acid sequence corresponding to at least one or more glycine residues in REP substituted with another amino acid residue as compared with naturally occurring fibroin.
　グリシン残基の含有量が低減された改変フィブロインは、そのドメイン配列が、天然由来のフィブロインと比較して、ＲＥＰ中のＧＧＸ及びＧＰＧＸＸ（但し、Ｇはグリシン残基、Ｐはプロリン残基、Ｘはグリシン以外のアミノ酸残基を示す。）から選ばれる少なくとも一つのモチーフ配列において、少なくとも１又は複数の当該モチーフ配列中の１つのグリシン残基が別のアミノ酸残基に置換されたことに相当するアミノ酸配列を有するものであってもよい。 Modified fibroin with a reduced content of glycine residues has a domain sequence of GGX and GPGXX in REP (where G is a glycine residue, P is a proline residue, X Is an amino acid residue other than glycine.) In at least one motif sequence selected from (1), this corresponds to substitution of one glycine residue in at least one or more of the motif sequences with another amino acid residue. It may have an amino acid sequence.
　グリシン残基の含有量が低減された改変フィブロインは、上述のグリシン残基が別のアミノ酸残基に置換されたモチーフ配列の割合が、全モチーフ配列に対して、１０％以上であってもよい。 In the modified fibroin with a reduced content of glycine residues, the ratio of the motif sequence in which the above glycine residue is replaced with another amino acid residue may be 10% or more with respect to the total motif sequence. .
　グリシン残基の含有量が低減された改変フィブロインは、式１：［（Ａ）ｎモチーフ－ＲＥＰ］ｍで表されるドメイン配列を含み、上記ドメイン配列から、最もＣ末端側に位置する（Ａ）ｎモチーフから上記ドメイン配列のＣ末端までの配列を除いた配列中の全ＲＥＰに含まれるＸＧＸ（但し、Ｘはグリシン以外のアミノ酸残基を示す。）からなるアミノ酸配列の総アミノ酸残基数をｚとし、上記ドメイン配列から、最もＣ末端側に位置する（Ａ）ｎモチーフから上記ドメイン配列のＣ末端までの配列を除いた配列中の総アミノ酸残基数をｗとしたときに、ｚ／ｗが３０％以上、４０％以上、５０％以上又は５０．９％以上であるアミノ酸配列を有するものであってもよい。（Ａ）ｎモチーフ中の全アミノ酸残基数に対するアラニン残基数は８３％以上であってよいが、８６％以上であることが好ましく、９０％以上であることがより好ましく、９５％以上であることが更に好ましく、１００％であること（アラニン残基のみで構成されることを意味する）が更により好ましい。 The modified fibroin with a reduced content of glycine residues includes a domain sequence represented by Formula 1: [(A) n motif-REP] m , and is located on the most C-terminal side from the domain sequence (A ) The total number of amino acid residues in the amino acid sequence consisting of XGX (where X represents an amino acid residue other than glycine) contained in all REPs in the sequence excluding the sequence from the n motif to the C-terminal of the domain sequence Z, and when the total number of amino acid residues in the sequence excluding the sequence from the domain sequence located at the most C-terminal side (A) from the n motif to the C-terminal of the domain sequence is w, z It may have an amino acid sequence in which / w is 30% or more, 40% or more, 50% or more, or 50.9% or more. (A) The number of alanine residues relative to the total number of amino acid residues in the n motif may be 83% or more, preferably 86% or more, more preferably 90% or more, and 95% or more. More preferably, it is 100% (meaning that it is composed only of alanine residues).
　グリシン残基の含有量が低減された改変フィブロインは、ＧＧＸモチーフの１つのグリシン残基を別のアミノ酸残基に置換することにより、ＸＧＸからなるアミノ酸配列の含有割合を高めたものであることが好ましい。グリシン残基の含有量が低減された改変フィブロインは、ドメイン配列中のＧＧＸからなるアミノ酸配列の含有割合が３０％以下であることが好ましく、２０％以下であることがより好ましく、１０％以下であることが更に好ましく、６％以下であることが更により好ましく、４％以下であることが更によりまた好ましく、２％以下であることが特に好ましい。ドメイン配列中のＧＧＸからなるアミノ酸配列の含有割合は、下記ＸＧＸからなるアミノ酸配列の含有割合（ｚ／ｗ）の算出方法と同様の方法で算出することができる。 The modified fibroin in which the content of glycine residues is reduced is that the content ratio of the amino acid sequence consisting of XGX is increased by substituting one glycine residue of the GGX motif with another amino acid residue. preferable. In the modified fibroin in which the content of glycine residues is reduced, the content ratio of the amino acid sequence consisting of GGX in the domain sequence is preferably 30% or less, more preferably 20% or less, and more preferably 10% or less. More preferably, it is 6% or less, still more preferably 4% or less, still more preferably 2% or less. The content ratio of the amino acid sequence consisting of GGX in the domain sequence can be calculated by the same method as the method for calculating the content ratio (z / w) of the amino acid sequence consisting of XGX below.
　ｚ／ｗの算出方法を更に詳細に説明する。まず、式１：［（Ａ）ｎモチーフ－ＲＥＰ］ｍで表されるドメイン配列を含むフィブロイン（改変フィブロイン又は天然由来のフィブロイン）において、ドメイン配列から、最もＣ末端側に位置する（Ａ）ｎモチーフからドメイン配列のＣ末端までの配列を除いた配列に含まれる全てのＲＥＰから、ＸＧＸからなるアミノ酸配列を抽出する。ＸＧＸを構成するアミノ酸残基の総数がｚである。例えば、ＸＧＸからなるアミノ酸配列が５０個抽出された場合（重複はなし）、ｚは５０×３＝１５０である。また、例えば、ＸＧＸＧＸからなるアミノ酸配列の場合のように２つのＸＧＸに含まれるＸ（中央のＸ）が存在する場合は、重複分を控除して計算する（ＸＧＸＧＸの場合は５アミノ酸残基である）。ｗは、ドメイン配列から、最もＣ末端側に位置する（Ａ）ｎモチーフからドメイン配列のＣ末端までの配列を除いた配列に含まれる総アミノ酸残基数である。例えば、図１に示したドメイン配列の場合、ｗは４＋５０＋４＋１００＋４＋１０＋４＋２０＋４＋３０＝２３０である（最もＣ末端側に位置する（Ａ）ｎモチーフは除いている。）。次に、ｚをｗで除すことによって、ｚ／ｗ（％）を算出することができる。 The method for calculating z / w will be described in more detail. First, in a fibroin (modified fibroin or naturally-occurring fibroin) containing a domain sequence represented by Formula 1: [(A) n motif-REP] m , (A) n located closest to the C-terminal side from the domain sequence An amino acid sequence consisting of XGX is extracted from all REPs included in the sequence excluding the sequence from the motif to the C-terminal of the domain sequence. The total number of amino acid residues constituting XGX is z. For example, when 50 amino acid sequences consisting of XGX are extracted (no duplication), z is 50 × 3 = 150. Also, for example, when there is an X (center X) included in two XGXs as in the case of an amino acid sequence consisting of XGXGX, the calculation is performed by subtracting the overlap (in the case of XGXGX, it is 5 amino acid residues). is there). w is the total number of amino acid residues contained in the sequence excluding the sequence from the domain sequence to the most C-terminal (A) n motif to the C-terminus of the domain sequence. For example, in the case of the domain sequence shown in FIG. 1, w is 4 + 50 + 4 + 100 + 4 + 10 + 4 + 20 + 4 + 30 = 230 (excluding the (A) n motif located closest to the C-terminal side). Next, z / w (%) can be calculated by dividing z by w.
　グリシン残基の含有量が低減された改変フィブロインにおいて、ｚ／ｗは、５０．９％以上であることが好ましく、５６．１％以上であることがより好ましく、５８．７％以上であることが更に好ましく、７０％以上であることが更により好ましく、８０％以上であることが更によりまた好ましい。ｚ／ｗの上限に特に制限はないが、例えば、９５％以下であってもよい。 In the modified fibroin with a reduced content of glycine residues, z / w is preferably 50.9% or more, more preferably 56.1% or more, and 58.7% or more. Is more preferably 70% or more, still more preferably 80% or more. Although there is no restriction | limiting in particular in the upper limit of z / w, For example, 95% or less may be sufficient.
　グリシン残基の含有量が低減された改変フィブロインは、例えば、クローニングした天然由来のフィブロインの遺伝子配列から、グリシン残基をコードする塩基配列の少なくとも一部を置換して別のアミノ酸残基をコードするように改変することにより得ることができる。このとき、改変するグリシン残基として、ＧＧＸモチーフ及びＧＰＧＸＸモチーフにおける１つのグリシン残基を選択してもよいし、またｚ／ｗが５０．９％以上になるように置換してもよい。また、例えば、天然由来のフィブロインのアミノ酸配列から上記態様を満たすアミノ酸配列を設計し、設計したアミノ酸配列をコードする核酸を化学合成することにより得ることもできる。いずれの場合においても、天然由来のフィブロインのアミノ酸配列からＲＥＰ中のグリシン残基を別のアミノ酸残基に置換したことに相当する改変に加え、更に１又は複数のアミノ酸残基を置換、欠失、挿入及び／又は付加したことに相当するアミノ酸配列の改変を行ってもよい。 A modified fibroin with a reduced content of glycine residues, for example, encodes another amino acid residue by substituting at least a part of the base sequence encoding the glycine residue from the cloned gene sequence of naturally occurring fibroin. It can obtain by modifying so that. At this time, one glycine residue in GGX motif and GPGXX motif may be selected as a glycine residue to be modified, or substitution may be performed so that z / w is 50.9% or more. In addition, for example, an amino acid sequence satisfying the above-described aspect can be designed from the amino acid sequence of naturally derived fibroin, and a nucleic acid encoding the designed amino acid sequence can be obtained by chemical synthesis. In any case, in addition to the modification corresponding to the substitution of the glycine residue in REP with another amino acid residue from the amino acid sequence of naturally occurring fibroin, one or more amino acid residues are further substituted or deleted. The amino acid sequence corresponding to the insertion and / or addition may be modified.
　上記の別のアミノ酸残基としては、グリシン残基以外のアミノ酸残基であれば特に制限はないが、バリン（Ｖ）残基、ロイシン（Ｌ）残基、イソロイシン（Ｉ）残基、メチオニン（Ｍ）残基、プロリン（Ｐ）残基、フェニルアラニン（Ｆ）残基及びトリプトファン（Ｗ）残基等の疎水性アミノ酸残基、グルタミン（Ｑ）残基、アスパラギン（Ｎ）残基、セリン（Ｓ）残基、リシン（Ｋ）残基及びグルタミン酸（Ｅ）残基等の親水性アミノ酸残基が好ましく、バリン（Ｖ）残基、ロイシン（Ｌ）残基、イソロイシン（Ｉ）残基及びグルタミン（Ｑ）残基がより好ましく、グルタミン（Ｑ）残基が更に好ましい。 The other amino acid residue is not particularly limited as long as it is an amino acid residue other than glycine residue, but valine (V) residue, leucine (L) residue, isoleucine (I) residue, methionine ( M) hydrophobic amino acid residues such as proline (P) residue, phenylalanine (F) residue and tryptophan (W) residue, glutamine (Q) residue, asparagine (N) residue, serine (S ) Residues, lysine (K) residues and glutamic acid (E) residues are preferred, and valine (V) residues, leucine (L) residues, isoleucine (I) residues and glutamine ( Q) residue is more preferable, and glutamine (Q) residue is more preferable.
　グリシン残基の含有量が低減された改変フィブロインのより具体的な例として、（２－ｉ）配列番号３、配列番号４、配列番号１０若しくは配列番号１２で示されるアミノ酸配列、又は（２－ｉｉ）配列番号３、配列番号４、配列番号１０若しくは配列番号１２で示されるアミノ酸配列と９０％以上の配列同一性を有するアミノ酸配列を含む、改変フィブロインを挙げることができる。 As more specific examples of modified fibroin with a reduced content of glycine residues, (2-i) the amino acid sequence represented by SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 10 or SEQ ID NO: 12, or (2- ii) A modified fibroin containing an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 10 or SEQ ID NO: 12 can be mentioned.
　（２－ｉ）の改変フィブロインについて説明する。配列番号３で示されるアミノ酸配列は、天然由来のフィブロインに相当する配列番号１で示されるアミノ酸配列のＲＥＰ中の全てのＧＧＸをＧＱＸに置換したものである。配列番号４で示されるアミノ酸配列は、配列番号３で示されるアミノ酸配列から、Ｎ末端側からＣ末端側に向かって２つおきに（Ａ）ｎモチーフを欠失させ、更にＣ末端配列の手前に［（Ａ）ｎモチーフ－ＲＥＰ］を１つ挿入したものである。配列番号１０で示されるアミノ酸配列は、配列番号４で示されるアミノ酸配列の各（Ａ）ｎモチーフのＣ末端側に２つのアラニン残基を挿入し、更に一部のグルタミン（Ｑ）残基をセリン（Ｓ）残基に置換し、配列番号４の分子量とほぼ同じとなるようにＮ末端側の一部のアミノ酸を欠失させたものである。配列番号１２で示されるアミノ酸配列は、配列番号４で示されるアミノ酸配列中に存在する２０個のドメイン配列の領域（但し、当該領域のＣ末端側の数アミノ酸残基が置換されている。）を４回繰り返した配列のＣ末端にＨｉｓタグが付加されたものである。 The modified fibroin (2-i) will be described. The amino acid sequence represented by SEQ ID NO: 3 is obtained by substituting GQX for all GGX in the REP of the amino acid sequence represented by SEQ ID NO: 1 corresponding to naturally occurring fibroin. The amino acid sequence represented by SEQ ID NO: 4 is the amino acid sequence represented by SEQ ID NO: 3, in which every two (A) n motifs are deleted from the N-terminal side to the C-terminal side, and further before the C-terminal sequence. One [(A) n motif-REP] is inserted into the. The amino acid sequence shown in SEQ ID NO: 10 has two alanine residues inserted in the C-terminal side of each (A) n motif of the amino acid sequence shown in SEQ ID NO: 4, and a part of glutamine (Q) residues. Substituted with a serine (S) residue and a part of the amino acid at the N-terminal side is deleted so as to be almost the same as the molecular weight of SEQ ID NO: 4. The amino acid sequence represented by SEQ ID NO: 12 is a region of 20 domain sequences present in the amino acid sequence represented by SEQ ID NO: 4 (however, several amino acid residues on the C-terminal side of the region are substituted). Is a sequence in which a His tag is added to the C-terminal of the sequence repeated four times.
　配列番号１で示されるアミノ酸配列（天然由来のフィブロインに相当）におけるｚ／ｗの値は、４６．８％である。配列番号３で示されるアミノ酸配列、配列番号４で示されるアミノ酸配列、配列番号１０で示されるアミノ酸配列、及び配列番号１２で示されるアミノ酸配列におけるｚ／ｗの値は、それぞれ５８．７％、７０．１％、６６．１％及び７０．０％である。また、配列番号１、配列番号３、配列番号４、配列番号１０及び配列番号１２で示されるアミノ酸配列のギザ比率（後述する）１：１．８～１１．３におけるｘ／ｙの値は、それぞれ１５．０％、１５．０％、９３．４％、９２．７％及び８９．３％である。 The value of z / w in the amino acid sequence represented by SEQ ID NO: 1 (corresponding to naturally occurring fibroin) is 46.8%. The z / w values in the amino acid sequence shown in SEQ ID NO: 3, the amino acid sequence shown in SEQ ID NO: 4, the amino acid sequence shown in SEQ ID NO: 10, and the amino acid sequence shown in SEQ ID NO: 12 are 58.7%, 70.1%, 66.1% and 70.0%. In addition, the value of x / y at the ratio of the amino acid sequence shown by SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 10 and SEQ ID NO: 12 (described later) 1: 1.8 to 11.3 is: 15.0%, 15.0%, 93.4%, 92.7% and 89.3%, respectively.
　（２－ｉ）の改変フィブロインは、配列番号３、配列番号４、配列番号１０又は配列番号１２で示されるアミノ酸配列からなるものであってもよい。 The modified fibroin (2-i) may be composed of the amino acid sequence represented by SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 10 or SEQ ID NO: 12.
　（２－ｉｉ）の改変フィブロインは、配列番号３、配列番号４、配列番号１０又は配列番号１２で示されるアミノ酸配列と９０％以上の配列同一性を有するアミノ酸配列を含むものである。（２－ｉｉ）の改変フィブロインもまた、式１：［（Ａ）ｎモチーフ－ＲＥＰ］ｍで表されるドメイン配列を含むタンパク質である。上記配列同一性は、９５％以上であることが好ましい。 The modified fibroin (2-ii) includes an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 10 or SEQ ID NO: 12. The modified fibroin of (2-ii) is also a protein containing a domain sequence represented by Formula 1: [(A) n motif-REP] m . The sequence identity is preferably 95% or more.
　（２－ｉｉ）の改変フィブロインは、配列番号３、配列番号４、配列番号１０又は配列番号１２で示されるアミノ酸配列と９０％以上の配列同一性を有し、かつＲＥＰ中に含まれるＸＧＸ（但し、Ｘはグリシン以外のアミノ酸残基を示す。）からなるアミノ酸配列の総アミノ酸残基数をｚとし、上記ドメイン配列中のＲＥＰの総アミノ酸残基数をｗとしたときに、ｚ／ｗが５０．９％以上であることが好ましい。 The modified fibroin of (2-ii) has a sequence identity of 90% or more with the amino acid sequence represented by SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 10 or SEQ ID NO: 12, and is contained in REP (XGX ( Where X is an amino acid residue other than glycine.) Z / w where z is the total number of amino acid residues of the amino acid sequence consisting of z and w is the total number of amino acid residues of REP in the domain sequence. Is preferably 50.9% or more.
　上述の改変フィブロインは、Ｎ末端及びＣ末端のいずれか一方又は両方にタグ配列を含んでいてもよい。これにより、改変フィブロインの単離、固定化、検出及び可視化等が可能となる。 The above-mentioned modified fibroin may contain a tag sequence at one or both of the N-terminal and C-terminal. This makes it possible to isolate, immobilize, detect and visualize the modified fibroin.
　タグ配列として、例えば、他の分子との特異的親和性（結合性、アフィニティ）を利用したアフィニティタグを挙げることができる。アフィニティタグの具体例として、ヒスチジンタグ（Ｈｉｓタグ）を挙げることができる。Ｈｉｓタグは、ヒスチジン残基が４から１０個程度並んだ短いペプチドで、ニッケル等の金属イオンと特異的に結合する性質があるため、金属キレートクロマトグラフィー（ｃｈｅｌａｔｉｎｇ　ｍｅｔａｌ　ｃｈｒｏｍａｔｏｇｒａｐｈｙ）による改変フィブロインの単離に利用することができる。タグ配列の具体例として、例えば、配列番号５で示されるアミノ酸配列（Ｈｉｓタグ配列及びヒンジ配列を含むアミノ酸配列）が挙げられる。 Examples of tag sequences include affinity tags that use specific affinity (binding property, affinity) with other molecules. Specific examples of the affinity tag include a histidine tag (His tag). The His tag is a short peptide with about 4 to 10 histidine residues, and has the property of binding specifically to metal ions such as nickel. Therefore, the isolation of modified fibroin by metal chelating chromatography (chelating metal chromatography) Can be used. Specific examples of the tag sequence include the amino acid sequence represented by SEQ ID NO: 5 (amino acid sequence including a His tag sequence and a hinge sequence).
　また、グルタチオンに特異的に結合するグルタチオン－Ｓ－トランスフェラーゼ（ＧＳＴ）、マルトースに特異的に結合するマルトース結合タンパク質（ＭＢＰ）等のタグ配列を利用することもできる。 Tag sequences such as glutathione-S-transferase (GST) that specifically binds to glutathione and maltose-binding protein (MBP) that specifically binds to maltose can also be used.
　さらに、抗原抗体反応を利用した「エピトープタグ」を利用することもできる。抗原性を示すペプチド（エピトープ）をタグ配列として付加することにより、当該エピトープに対する抗体を結合させることができる。エピトープタグとして、ＨＡ（インフルエンザウイルスのヘマグルチニンのペプチド配列）タグ、ｍｙｃタグ、ＦＬＡＧタグ等を挙げることができる。エピトープタグを利用することにより、高い特異性で容易に改変フィブロインを精製することができる。 Furthermore, an “epitope tag” using an antigen-antibody reaction can also be used. By adding a peptide (epitope) exhibiting antigenicity as a tag sequence, an antibody against the epitope can be bound. As the epitope tag, HA (peptide sequence of hemagglutinin of influenza virus) tag, myc tag, FLAG tag and the like can be mentioned. By using the epitope tag, the modified fibroin can be easily purified with high specificity.
　さらにタグ配列を特定のプロテアーゼで切り離せるようにしたものも使用することができる。当該タグ配列を介して吸着したタンパク質をプロテアーゼ処理することにより、タグ配列を切り離した改変フィブロインを回収することもできる。 Furthermore, a tag sequence that can be separated with a specific protease can also be used. By treating the protein adsorbed via the tag sequence with protease, the modified fibroin from which the tag sequence has been separated can also be recovered.
　タグ配列を含む改変フィブロインのより具体的な例として、（２－ｉｉｉ）配列番号８、配列番号９、配列番号１１若しくは配列番号１３で示されるアミノ酸配列、又は（２－ｉｖ）配列番号８、配列番号９、配列番号１１若しくは配列番号１３で示されるアミノ酸配列と９０％以上の配列同一性を有するアミノ酸配列を含む、改変フィブロインを挙げることができる。 As more specific examples of modified fibroin containing a tag sequence, (2-iii) SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 11 or SEQ ID NO: 13, or (2-iv) SEQ ID NO: 8, A modified fibroin containing an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 9, SEQ ID NO: 11 or SEQ ID NO: 13 can be mentioned.
　配列番号６、配列番号７、配列番号８、配列番号９、配列番号１１及び配列番号１３で示されるアミノ酸配列は、それぞれ配列番号１、配列番号２、配列番号３、配列番号４、配列番号１０及び配列番号１２で示されるアミノ酸配列のＮ末端に配列番号５で示されるアミノ酸配列（Ｈｉｓタグ配列及びヒンジ配列を含む）を付加したものである。 The amino acid sequences represented by SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 11 and SEQ ID NO: 13 are SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 10, respectively. And the amino acid sequence represented by SEQ ID NO: 5 (including His tag sequence and hinge sequence) is added to the N-terminus of the amino acid sequence represented by SEQ ID NO: 12.
　（２－ｉｉｉ）の改変フィブロインは、配列番号８、配列番号９、配列番号１１又は配列番号１３で示されるアミノ酸配列からなるものであってもよい。 (2-iii) The modified fibroin may be composed of the amino acid sequence represented by SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 11 or SEQ ID NO: 13.
　（２－ｉｖ）の改変フィブロインは、配列番号８、配列番号９、配列番号１１又は配列番号１３で示されるアミノ酸配列と９０％以上の配列同一性を有するアミノ酸配列を含むものである。（２－ｉｖ）の改変フィブロインもまた、式１：［（Ａ）ｎモチーフ－ＲＥＰ］ｍで表されるドメイン配列を含むタンパク質である。上記配列同一性は、９５％以上であることが好ましい。 The modified fibroin (2-iv) includes an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 11 or SEQ ID NO: 13. The modified fibroin of (2-iv) is also a protein containing a domain sequence represented by Formula 1: [(A) n motif-REP] m . The sequence identity is preferably 95% or more.
　（２－ｉｖ）の改変フィブロインは、配列番号８、配列番号９、配列番号１１又は配列番号１３で示されるアミノ酸配列と９０％以上の配列同一性を有し、かつＲＥＰ中に含まれるＸＧＸ（但し、Ｘはグリシン以外のアミノ酸残基を示す。）からなるアミノ酸配列の総アミノ酸残基数をｚとし、上記ドメイン配列中のＲＥＰの総アミノ酸残基数をｗとしたときに、ｚ／ｗが５０．９％以上であることが好ましい。 The modified fibroin (2-iv) has an amino acid sequence represented by SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 11 or SEQ ID NO: 13 with a sequence identity of 90% or more, and is contained in XREP ( Where X is an amino acid residue other than glycine.) Z / w where z is the total number of amino acid residues of the amino acid sequence consisting of z and w is the total number of amino acid residues of REP in the domain sequence. Is preferably 50.9% or more.
　上述の改変フィブロインは、組換えタンパク質生産系において生産されたタンパク質を宿主の外部に放出するための分泌シグナルを含んでいてもよい。分泌シグナルの配列は、宿主の種類に応じて適宜設定することができる。 The aforementioned modified fibroin may contain a secretion signal for releasing the protein produced in the recombinant protein production system to the outside of the host. The sequence of the secretion signal can be appropriately set according to the type of host.
　（Ａ）ｎモチーフの含有量が低減された改変フィブロインは、そのドメイン配列が、天然由来のフィブロインと比較して、（Ａ）ｎモチーフの含有量が低減されたアミノ酸配列を有する。当該改変フィブロインのドメイン配列は、天然由来のフィブロインと比較して、少なくとも１又は複数の（Ａ）ｎモチーフが欠失したことに相当するアミノ酸配列を有するものということができる。 (A) modified fibroin content of n motifs has been reduced, the domain sequence is compared to the naturally occurring fibroin, having an amino acid sequence reduced the content of (A) n motif. It can be said that the domain sequence of the modified fibroin has an amino acid sequence corresponding to the deletion of at least one or more (A) n motifs as compared to naturally occurring fibroin.
　（Ａ）ｎモチーフの含有量が低減された改変フィブロインは、天然由来のフィブロインから（Ａ）ｎモチーフを１０～４０％欠失させたことに相当するアミノ酸配列を有するものであってもよい。 (A) The modified fibroin in which the content of n motif is reduced may have an amino acid sequence corresponding to 10% to 40% deletion of (A) n motif from naturally occurring fibroin.
　（Ａ）ｎモチーフの含有量が低減された改変フィブロインは、そのドメイン配列が、天然由来のフィブロインと比較して、少なくともＮ末端側からＣ末端側に向かって１～３つの（Ａ）ｎモチーフ毎に１つの（Ａ）ｎモチーフが欠失したことに相当するアミノ酸配列を有するものであってもよい。 (A) The modified fibroin with a reduced content of n motif has 1 to 3 (A) n motifs in which the domain sequence is at least from the N-terminal side to the C-terminal side compared to naturally occurring fibroin. Each may have an amino acid sequence corresponding to the deletion of one (A) n motif.
　（Ａ）ｎモチーフの含有量が低減された改変フィブロインは、そのドメイン配列が、天然由来のフィブロインと比較して、少なくともＮ末端側からＣ末端側に向かって２つ連続した（Ａ）ｎモチーフの欠失、及び１つの（Ａ）ｎモチーフの欠失がこの順に繰り返されたことに相当するアミノ酸配列を有するものであってもよい。 (A) The modified fibroin in which the content of the n motif is reduced, the domain sequence of the modified fibroin is at least two consecutive from the N-terminal side to the C-terminal side compared to the naturally derived fibroin (A) n motif And an amino acid sequence corresponding to the deletion of one (A) n motif repeated in this order.
　（Ａ）ｎモチーフの含有量が低減された改変フィブロインは、そのドメイン配列が、少なくともＮ末端側からＣ末端側に向かって２つおきに（Ａ）ｎモチーフが欠失したことに相当するアミノ酸配列を有するものであってもよい。 (A) modified fibroin content of n motifs has been reduced, the domain sequence, amino acids corresponding to at least the N-terminal side 2 every other towards the C-terminal side (A) n motifs lacking It may have a sequence.
　（Ａ）ｎモチーフの含有量が低減された改変フィブロインは、式１：［（Ａ）ｎモチーフ－ＲＥＰ］ｍで表されるドメイン配列を含み、Ｎ末端側からＣ末端側に向かって、隣合う２つの［（Ａ）ｎモチーフ－ＲＥＰ］ユニットのＲＥＰのアミノ酸残基数を順次比較して、アミノ酸残基数が少ないＲＥＰのアミノ酸残基数を１としたとき、他方のＲＥＰのアミノ酸残基数の比が１．８～１１．３となる隣合う２つの［（Ａ）ｎモチーフ－ＲＥＰ］ユニットのアミノ酸残基数を足し合わせた合計値の最大値をｘとし、ドメイン配列の総アミノ酸残基数をｙとしたときに、ｘ／ｙが２０％以上、３０％以上、４０％以上又は５０％以上であるアミノ酸配列を有するものであってもよい。（Ａ）ｎモチーフ中の全アミノ酸残基数に対するアラニン残基数は８３％以上であってよいが、８６％以上であることが好ましく、９０％以上であることがより好ましく、９５％以上であることが更に好ましく、１００％であること（アラニン残基のみで構成されることを意味する）が更により好ましい。 (A) A modified fibroin with a reduced content of n- motif contains a domain sequence represented by Formula 1: [(A) n- motif-REP] m , and is adjacent to the C-terminal side from the N-terminal side. By sequentially comparing the number of amino acid residues in the REP of the two matching [(A) n motif-REP] units, when the number of amino acid residues in the REP with a small number of amino acid residues is 1, the amino acid residue of the other REP The maximum total value of the sum of the number of amino acid residues of two adjacent [(A) n motif-REP] units with a cardinal ratio of 1.8 to 11.3 is x, and the total domain sequence It may have an amino acid sequence in which x / y is 20% or more, 30% or more, 40% or more, or 50% or more, where y is the number of amino acid residues. (A) The number of alanine residues relative to the total number of amino acid residues in the n motif may be 83% or more, preferably 86% or more, more preferably 90% or more, and 95% or more. More preferably, it is 100% (meaning that it is composed only of alanine residues).
　ｘ／ｙの算出方法を図１を参照しながら更に詳細に説明する。図１には、改変フィブロインからＮ末端配列及びＣ末端配列を除いたドメイン配列を示す。当該ドメイン配列は、Ｎ末端側（左側）から（Ａ）ｎモチーフ－第１のＲＥＰ（５０アミノ酸残基）－（Ａ）ｎモチーフ－第２のＲＥＰ（１００アミノ酸残基）－（Ａ）ｎモチーフ－第３のＲＥＰ（１０アミノ酸残基）－（Ａ）ｎモチーフ－第４のＲＥＰ（２０アミノ酸残基）－（Ａ）ｎモチーフ－第５のＲＥＰ（３０アミノ酸残基）－（Ａ）ｎモチーフという配列を有する。 The method for calculating x / y will be described in more detail with reference to FIG. FIG. 1 shows a domain sequence obtained by removing the N-terminal sequence and the C-terminal sequence from the modified fibroin. The domain sequence is from the N-terminal side (left side): (A) n motif-first REP (50 amino acid residues)-(A) n motif-second REP (100 amino acid residues)-(A) n Motif-third REP (10 amino acid residues)-(A) n motif-fourth REP (20 amino acid residues)-(A) n motif-fifth REP (30 amino acid residues)-(A) It has a sequence called n motif.
　隣合う２つの［（Ａ）ｎモチーフ－ＲＥＰ］ユニットは、重複がないように、Ｎ末端側からＣ末端側に向かって、順次選択する。このとき、選択されない［（Ａ）ｎモチーフ－ＲＥＰ］ユニットが存在してもよい。図１には、パターン１（第１のＲＥＰと第２のＲＥＰの比較、及び第３のＲＥＰと第４のＲＥＰの比較）、パターン２（第１のＲＥＰと第２のＲＥＰの比較、及び第４のＲＥＰと第５のＲＥＰの比較）、パターン３（第２のＲＥＰと第３のＲＥＰの比較、及び第４のＲＥＰと第５のＲＥＰの比較）、パターン４（第１のＲＥＰと第２のＲＥＰの比較）を示した。なお、これ以外にも選択方法は存在する。 Two adjacent [(A) n motif-REP] units are sequentially selected from the N-terminal side to the C-terminal side so as not to overlap. At this time, an unselected [(A) n motif-REP] unit may exist. FIG. 1 includes pattern 1 (comparison between the first REP and the second REP, and comparison between the third REP and the fourth REP), pattern 2 (comparison between the first REP and the second REP, and 4th REP and 5th REP), pattern 3 (2nd REP and 3rd REP comparison, 4th REP and 5th REP comparison), pattern 4 (first REP and Comparison of the second REP). There are other selection methods.
　次に各パターンについて、選択した隣合う２つの［（Ａ）ｎモチーフ－ＲＥＰ］ユニット中の各ＲＥＰのアミノ酸残基数を比較する。比較は、よりアミノ酸残基数の少ない方を１としたときの、他方のアミノ酸残基数の比を求めることによって行う。例えば、第１のＲＥＰ（５０アミノ酸残基）と第２のＲＥＰ（１００アミノ酸残基）の比較の場合、よりアミノ酸残基数の少ない第１のＲＥＰを１としたとき、第２のＲＥＰのアミノ酸残基数の比は、１００／５０＝２である。同様に、第４のＲＥＰ（２０アミノ酸残基）と第５のＲＥＰ（３０アミノ酸残基）の比較の場合、よりアミノ酸残基数の少ない第４のＲＥＰを１としたとき、第５のＲＥＰのアミノ酸残基数の比は、３０／２０＝１．５である。 Next, for each pattern, the number of amino acid residues of each REP in the two adjacent [(A) n motif-REP] units selected is compared. The comparison is performed by determining the ratio of the number of amino acid residues on the other side when the smaller number of amino acid residues is 1. For example, in the comparison of the first REP (50 amino acid residues) and the second REP (100 amino acid residues), when the first REP having a smaller number of amino acid residues is 1, the second REP The ratio of the number of amino acid residues is 100/50 = 2. Similarly, in the comparison of the fourth REP (20 amino acid residues) and the fifth REP (30 amino acid residues), when the fourth REP having a smaller number of amino acid residues is 1, the fifth REP The ratio of the number of amino acid residues is 30/20 = 1.5.
　図１中、よりアミノ酸残基数の少ない方を１としたときに、他方のアミノ酸残基数の比が１．８～１１．３となる［（Ａ）ｎモチーフ－ＲＥＰ］ユニットの組を実線で示した。以下このような比をギザ比率と呼ぶ。よりアミノ酸残基数の少ない方を１としたときに、他方のアミノ酸残基数の比が１．８未満又は１１．３超となる［（Ａ）ｎモチーフ－ＲＥＰ］ユニットの組は破線で示した。 In FIG. 1, when the smaller number of amino acid residues is 1, the ratio of the number of other amino acid residues is 1.8 to 11.3 [(A) n motif-REP] unit pairs Shown in solid line. Hereinafter, such a ratio is referred to as a jagged ratio. When the smaller number of amino acid residues is 1, the ratio of the number of other amino acid residues is less than 1.8 or more than 11.3. [(A) n motif-REP] unit pairs are indicated by broken lines. Indicated.
　各パターンにおいて、実線で示した隣合う２つの［（Ａ）ｎモチーフ－ＲＥＰ］ユニットの全てのアミノ酸残基数を足し合わせる（ＲＥＰのみではなく、（Ａ）ｎモチーフのアミノ酸残基数もである。）。そして、足し合わせた合計値を比較して、当該合計値が最大となるパターンの合計値（合計値の最大値）をｘとする。図１に示した例では、パターン１の合計値が最大である。 In each pattern, the number of all amino acid residues of two adjacent [(A) n motif-REP] units indicated by solid lines is added (not only REP but also (A) the number of amino acid residues of the n motif. is there.). Then, the total value added is compared, and the total value (maximum value of the total value) of the pattern having the maximum total value is set as x. In the example shown in FIG. 1, the total value of pattern 1 is the maximum.
　次に、ｘをドメイン配列の総アミノ酸残基数ｙで除すことによって、ｘ／ｙ（％）を算出することができる。 Next, x / y (%) can be calculated by dividing x by the total number of amino acid residues y of the domain sequence.
　（Ａ）ｎモチーフの含有量が低減された改変フィブロインにおいて、ｘ／ｙは、５０％以上であることが好ましく、６０％以上であることがより好ましく、６５％以上であることが更に好ましく、７０％以上であることが更により好ましく、７５％以上であることが更によりまた好ましく、８０％以上であることが特に好ましい。ｘ／ｙの上限に特に制限はなく、例えば、１００％以下であってよい。ギザ比率が１：１．９～１１．３の場合には、ｘ／ｙは８９．６％以上であることが好ましく、ギザ比率が１：１．８～３．４の場合には、ｘ／ｙは７７．１％以上であることが好ましく、ギザ比率が１：１．９～８．４の場合には、ｘ／ｙは７５．９％以上であることが好ましく、ギザ比率が１：１．９～４．１の場合には、ｘ／ｙは６４．２％以上であることが好ましい。 (A) In the modified fibroin in which the content of the n motif is reduced, x / y is preferably 50% or more, more preferably 60% or more, still more preferably 65% or more, It is still more preferably 70% or more, still more preferably 75% or more, and particularly preferably 80% or more. There is no restriction | limiting in particular in the upper limit of x / y, For example, you may be 100% or less. When the jagged ratio is 1: 1.9 to 11.3, x / y is preferably 89.6% or more, and when the jagged ratio is 1: 1.8 to 3.4, x / y / Y is preferably 77.1% or more, and when the jagged ratio is 1: 1.9 to 8.4, x / y is preferably 75.9% or more, and the jagged ratio is 1 In the case of 1.9 to 4.1, x / y is preferably 64.2% or more.
　（Ａ）ｎモチーフの含有量が低減された改変フィブロインが、ドメイン配列中に複数存在する（Ａ）ｎモチーフの少なくとも７つがアラニン残基のみで構成される改変フィブロインである場合、ｘ／ｙは、４６．４％以上であることが好ましく、５０％以上であることがより好ましく、５５％以上であることが更に好ましく、６０％以上であることが更により好ましく、７０％以上であることが更によりまた好ましく、８０％以上であることが特に好ましい。ｘ／ｙの上限に特に制限はなく、１００％以下であればよい。 (A) A plurality of modified fibroin in which the content of n motif is reduced is present in the domain sequence. (A) When at least 7 of n motifs are modified fibroin composed only of alanine residues, x / y is 46.4% or more, preferably 50% or more, more preferably 55% or more, still more preferably 60% or more, and 70% or more. Even more preferable, 80% or more is particularly preferable. There is no restriction | limiting in particular in the upper limit of x / y, and what is necessary is just 100% or less.
　（Ａ）ｎモチーフの含有量が低減された改変フィブロインは、例えば、クローニングした天然由来のフィブロインの遺伝子配列から、ｘ／ｙが６４．２％以上になるように（Ａ）ｎモチーフをコードする配列の１又は複数を欠失させることにより得ることができる。また、例えば、天然由来のフィブロインのアミノ酸配列から、ｘ／ｙが６４．２％以上になるように１又は複数の（Ａ）ｎモチーフが欠失したことに相当するアミノ酸配列を設計し、設計したアミノ酸配列をコードする核酸を化学合成することにより得ることもできる。いずれの場合においても、天然由来のフィブロインのアミノ酸配列から（Ａ）ｎモチーフが欠失したことに相当する改変に加え、更に１又は複数のアミノ酸残基を置換、欠失、挿入及び／又は付加したことに相当するアミノ酸配列の改変を行ってもよい。 (A) modified fibroin content of n motif is reduced, for example, encoding a cloned naturally occurring fibroin gene sequences, as x / y is more than 64.2% of the (A) n motif It can be obtained by deleting one or more of the sequences. In addition, for example, an amino acid sequence corresponding to the deletion of one or more (A) n motifs is designed so that x / y is 64.2% or more from the amino acid sequence of naturally occurring fibroin. It can also be obtained by chemically synthesizing a nucleic acid encoding the amino acid sequence. In any case, in addition to the modification corresponding to the deletion of the (A) n motif from the amino acid sequence of naturally occurring fibroin, one or more amino acid residues are further substituted, deleted, inserted and / or added. The amino acid sequence corresponding to this may be modified.
　（Ａ）ｎモチーフの含有量が低減された改変フィブロインのより具体的な例として、（３－ｉ）配列番号２、配列番号４、配列番号１０若しくは配列番号１２で示されるアミノ酸配列、又は（３－ｉｉ）配列番号２、配列番号４、配列番号１０若しくは配列番号１２で示されるアミノ酸配列と９０％以上の配列同一性を有するアミノ酸配列を含む、改変フィブロインを挙げることができる。 (A) As a more specific example of a modified fibroin with a reduced content of n motif, (3-i) an amino acid sequence represented by SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 10 or SEQ ID NO: 12, or ( 3-ii) A modified fibroin comprising an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 10 or SEQ ID NO: 12 can be mentioned.
　（３－ｉ）の改変フィブロインについて説明する。配列番号２で示されるアミノ酸配列は、天然由来のフィブロインに相当する配列番号１で示されるアミノ酸配列から、Ｎ末端側からＣ末端側に向かって２つおきに（Ａ）ｎモチーフを欠失させ、更にＣ末端配列の手前に［（Ａ）ｎモチーフ－ＲＥＰ］を１つ挿入したものである。配列番号４で示されるアミノ酸配列は、配列番号２で示されるアミノ酸配列のＲＥＰ中の全てのＧＧＸをＧＱＸに置換したものである。配列番号１０で示されるアミノ酸配列は、配列番号４で示されるアミノ酸配列の各（Ａ）ｎモチーフのＣ末端側に２つのアラニン残基を挿入し、更に一部のグルタミン（Ｑ）残基をセリン（Ｓ）残基に置換し、配列番号４の分子量とほぼ同じとなるようにＮ末端側の一部のアミノ酸を欠失させたものである。配列番号１２で示されるアミノ酸配列は、配列番号９で示されるアミノ酸配列中に存在する２０個のドメイン配列の領域（但し、当該領域のＣ末端側の数アミノ酸残基が置換されている。）を４回繰り返した配列のＣ末端にＨｉｓタグが付加されたものである。 The modified fibroin (3-i) will be described. The amino acid sequence represented by SEQ ID NO: 2 has the amino acid sequence represented by SEQ ID NO: 1 corresponding to naturally occurring fibroin deleted from the N-terminal side to the C-terminal side every two (A) n motifs Furthermore, one [(A) n motif-REP] is inserted in front of the C-terminal sequence. The amino acid sequence shown in SEQ ID NO: 4 is obtained by substituting all GGX in REP of the amino acid sequence shown in SEQ ID NO: 2 with GQX. The amino acid sequence shown in SEQ ID NO: 10 has two alanine residues inserted in the C-terminal side of each (A) n motif of the amino acid sequence shown in SEQ ID NO: 4, and a part of glutamine (Q) residues. Substituted with a serine (S) residue and a part of the amino acid at the N-terminal side is deleted so as to be almost the same as the molecular weight of SEQ ID NO: 4. The amino acid sequence represented by SEQ ID NO: 12 is a region of 20 domain sequences present in the amino acid sequence represented by SEQ ID NO: 9 (however, several amino acid residues on the C-terminal side of the region are substituted). Is a sequence in which a His tag is added to the C-terminal of the sequence repeated four times.
　配列番号１で示されるアミノ酸配列（天然由来のフィブロインに相当）のギザ比率１：１．８～１１．３におけるｘ／ｙの値は１５．０％である。配列番号２で示されるアミノ酸配列、及び配列番号４で示されるアミノ酸配列におけるｘ／ｙの値は、いずれも９３．４％である。配列番号１０で示されるアミノ酸配列におけるｘ／ｙの値は、９２．７％である。配列番号１２で示されるアミノ酸配列におけるｘ／ｙの値は、８９．３％である。配列番号１、配列番号２、配列番号４、配列番号１０及び配列番号１２で示されるアミノ酸配列におけるｚ／ｗの値は、それぞれ４６．８％、５６．２％、７０．１％、６６．１％及び７０．０％である。 The value of x / y of the amino acid sequence represented by SEQ ID NO: 1 (corresponding to naturally-occurring fibroin) at a jagged ratio of 1: 1.8 to 11.3 is 15.0%. The value of x / y in the amino acid sequence represented by SEQ ID NO: 2 and the amino acid sequence represented by SEQ ID NO: 4 is 93.4%. The value of x / y in the amino acid sequence represented by SEQ ID NO: 10 is 92.7%. The value of x / y in the amino acid sequence represented by SEQ ID NO: 12 is 89.3%. The z / w values in the amino acid sequences represented by SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 10 and SEQ ID NO: 12 are 46.8%, 56.2%, 70.1% and 66. respectively. 1% and 70.0%.
　（３－ｉ）の改変フィブロインは、配列番号２、配列番号４、配列番号１０又は配列番号１２で示されるアミノ酸配列からなるものであってもよい。 The modified fibroin (3-i) may be composed of the amino acid sequence represented by SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 10 or SEQ ID NO: 12.
　（３－ｉｉ）の改変フィブロインは、配列番号２、配列番号４、配列番号１０又は配列番号１２で示されるアミノ酸配列と９０％以上の配列同一性を有するアミノ酸配列を含むものである。（３－ｉｉ）の改変フィブロインもまた、式１：［（Ａ）ｎモチーフ－ＲＥＰ］ｍで表されるドメイン配列を含むタンパク質である。上記配列同一性は、９５％以上であることが好ましい。 The modified fibroin (3-ii) includes an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 10 or SEQ ID NO: 12. The modified fibroin of (3-ii) is also a protein containing a domain sequence represented by Formula 1: [(A) n motif-REP] m . The sequence identity is preferably 95% or more.
　（３－ｉｉ）の改変フィブロインは、配列番号２、配列番号４、配列番号１０又は配列番号１２で示されるアミノ酸配列と９０％以上の配列同一性を有し、かつＮ末端側からＣ末端側に向かって、隣合う２つの［（Ａ）ｎモチーフ－ＲＥＰ］ユニットのＲＥＰのアミノ酸残基数を順次比較して、アミノ酸残基数が少ないＲＥＰのアミノ酸残基数を１としたとき、他方のＲＥＰのアミノ酸残基数の比が１．８～１１．３（ギザ比率が１：１．８～１１．３）となる隣合う２つの［（Ａ）ｎモチーフ－ＲＥＰ］ユニットのアミノ酸残基数を足し合わせた合計値の最大値をｘとし、ドメイン配列の総アミノ酸残基数をｙとしたときに、ｘ／ｙが６４．２％以上であることが好ましい。 The modified fibroin of (3-ii) has 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 10 or SEQ ID NO: 12, and from the N-terminal side to the C-terminal side When the number of amino acid residues of REP of two adjacent [(A) n motif-REP] units is sequentially compared, and the number of amino acid residues of REP having a small number of amino acid residues is 1, the other The amino acid residues of two adjacent [(A) n motif-REP] units with a ratio of the number of amino acid residues of REP of 1.8 to 11.3 (giza ratio is 1: 1.8 to 11.3) It is preferable that x / y is 64.2% or more, where x is the maximum total value of the total number of bases and y is the total number of amino acid residues in the domain sequence.
　上述の改変フィブロインは、Ｎ末端及びＣ末端のいずれか一方又は両方に上述したタグ配列を含んでいてもよい。 The above-described modified fibroin may contain the above-described tag sequence at one or both of the N-terminal and C-terminal.
　タグ配列を含む改変フィブロインのより具体的な例として、（３－ｉｉｉ）配列番号７、配列番号９、配列番号１１若しくは配列番号１３で示されるアミノ酸配列、又は（３－ｉｖ）配列番号７、配列番号９、配列番号１１若しくは配列番号１３で示されるアミノ酸配列と９０％以上の配列同一性を有するアミノ酸配列を含む、改変フィブロインを挙げることができる。 As more specific examples of modified fibroin containing a tag sequence, (3-iii) SEQ ID NO: 7, SEQ ID NO: 9, SEQ ID NO: 11 or SEQ ID NO: 13, or (3-iv) SEQ ID NO: 7, A modified fibroin containing an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 9, SEQ ID NO: 11 or SEQ ID NO: 13 can be mentioned.
　配列番号６、配列番号７、配列番号８、配列番号９、配列番号１１及び配列番号１３で示されるアミノ酸配列は、それぞれ配列番号１、配列番号２、配列番号３、配列番号４、配列番号１０及び配列番号１２で示されるアミノ酸配列のＮ末端に配列番号５で示されるアミノ酸配列（Ｈｉｓタグ配列及びヒンジ配列を含む）を付加したものである。 The amino acid sequences represented by SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 11 and SEQ ID NO: 13 are SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 10, respectively. And the amino acid sequence represented by SEQ ID NO: 5 (including His tag sequence and hinge sequence) is added to the N-terminus of the amino acid sequence represented by SEQ ID NO: 12.
　（３－ｉｉｉ）の改変フィブロインは、配列番号７、配列番号９、配列番号１１又は配列番号１３で示されるアミノ酸配列からなるものであってもよい。 (3-iii) The modified fibroin may be composed of the amino acid sequence represented by SEQ ID NO: 7, SEQ ID NO: 9, SEQ ID NO: 11 or SEQ ID NO: 13.
　（３－ｉｖ）の改変フィブロインは、配列番号７、配列番号９、配列番号１１又は配列番号１３で示されるアミノ酸配列と９０％以上の配列同一性を有するアミノ酸配列を含むものである。（３－ｉｖ）の改変フィブロインもまた、式１：［（Ａ）ｎモチーフ－ＲＥＰ］ｍで表されるドメイン配列を含むタンパク質である。上記配列同一性は、９５％以上であることが好ましい。 The modified fibroin (3-iv) includes an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 7, SEQ ID NO: 9, SEQ ID NO: 11 or SEQ ID NO: 13. The modified fibroin of (3-iv) is also a protein containing a domain sequence represented by Formula 1: [(A) n motif-REP] m . The sequence identity is preferably 95% or more.
　（３－ｉｖ）の改変フィブロインは、配列番号７、配列番号９、配列番号１１又は配列番号１３で示されるアミノ酸配列と９０％以上の配列同一性を有し、かつＮ末端側からＣ末端側に向かって、隣合う２つの［（Ａ）ｎモチーフ－ＲＥＰ］ユニットのＲＥＰのアミノ酸残基数を順次比較して、アミノ酸残基数が少ないＲＥＰのアミノ酸残基数を１としたとき、他方のＲＥＰのアミノ酸残基数の比が１．８～１１．３となる隣合う２つの［（Ａ）ｎモチーフ－ＲＥＰ］ユニットのアミノ酸残基数を足し合わせた合計値の最大値をｘとし、ドメイン配列の総アミノ酸残基数をｙとしたときに、ｘ／ｙが６４．２％以上であることが好ましい。 The modified fibroin (3-iv) has 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 7, SEQ ID NO: 9, SEQ ID NO: 11 or SEQ ID NO: 13, and from the N-terminal side to the C-terminal side. When the number of amino acid residues of REP of two adjacent [(A) n motif-REP] units is sequentially compared, and the number of amino acid residues of REP having a small number of amino acid residues is 1, the other X is the maximum total value of the total number of amino acid residues of two adjacent [(A) n motif-REP] units with a ratio of the number of amino acid residues of REP of 1.8 to 11.3. When the total number of amino acid residues of the domain sequence is y, x / y is preferably 64.2% or more.
　上述の改変フィブロインは、組換えタンパク質生産系において生産されたタンパク質を宿主の外部に放出するための分泌シグナルを含んでいてもよい。分泌シグナルの配列は、宿主の種類に応じて適宜設定することができる。 The aforementioned modified fibroin may contain a secretion signal for releasing the protein produced in the recombinant protein production system to the outside of the host. The sequence of the secretion signal can be appropriately set according to the type of host.
　グリシン残基の含有量、及び（Ａ）ｎモチーフの含有量が低減された改変フィブロインは、そのドメイン配列が、天然由来のフィブロインと比較して、（Ａ）ｎモチーフの含有量が低減されたことに加え、グリシン残基の含有量が低減されたアミノ酸配列を有するものである。当該改変フィブロインのドメイン配列は、天然由来のフィブロインと比較して、少なくとも１又は複数の（Ａ）ｎモチーフが欠失したことに加え、更に少なくともＲＥＰ中の１又は複数のグリシン残基が別のアミノ酸残基に置換されたことに相当するアミノ酸配列を有するものということができる。すなわち、上述したグリシン残基の含有量が低減された改変フィブロインと、（Ａ）ｎモチーフの含有量が低減された改変フィブロインの特徴を併せ持つ改変フィブロインである。具体的な態様等は、グリシン残基の含有量が低減された改変フィブロイン、及び、（Ａ）ｎモチーフの含有量が低減された改変フィブロインで説明したとおりである。 The modified fibroin in which the content of glycine residue and (A) the content of n motif is reduced, the domain sequence thereof is (A) the content of n motif is reduced compared to naturally occurring fibroin. In addition, it has an amino acid sequence with a reduced content of glycine residues. In addition to the deletion of at least one or more (A) n motifs, the domain sequence of the modified fibroin is different from that of naturally occurring fibroin in addition to at least one or more glycine residues in REP. It can be said to have an amino acid sequence corresponding to substitution with an amino acid residue. That is, it is a modified fibroin having the characteristics of the modified fibroin in which the content of the glycine residue is reduced and (A) the modified fibroin in which the content of the n motif is reduced. Specific embodiments and the like are as described in the modified fibroin in which the content of glycine residues is reduced and (A) the modified fibroin in which the content of n motif is reduced.
　グリシン残基の含有量、及び（Ａ）ｎモチーフの含有量が低減された改変フィブロインのより具体的な例として、（４－ｉ）配列番号４、配列番号１０若しくは配列番号１２で示されるアミノ酸配列、又は（４－ｉｉ）配列番号４、配列番号１０若しくは配列番号１２で示されるアミノ酸配列と９０％以上の配列同一性を有するアミノ酸配列を含む、改変フィブロインを挙げることができる。配列番号４、配列番号１０若しくは配列番号１２で示されるアミノ酸配列を含む改変フィブロインの具体的な態様は上述のとおりである。 As a more specific example of a modified fibroin with reduced glycine residue content and (A) n- motif content, (4-i) the amino acid represented by SEQ ID NO: 4, SEQ ID NO: 10 or SEQ ID NO: 12 Mention may be made of modified fibroin comprising a sequence or (4-ii) an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 4, SEQ ID NO: 10 or SEQ ID NO: 12. Specific embodiments of the modified fibroin comprising the amino acid sequence represented by SEQ ID NO: 4, SEQ ID NO: 10 or SEQ ID NO: 12 are as described above.
　他の実施形態に係る改変フィブロインは、そのドメイン配列が、天然由来のフィブロインと比較して、ＲＥＰ中の１又は複数のアミノ酸残基が疎水性指標の大きいアミノ酸残基に置換されたこと、及び／又はＲＥＰ中に１又は複数の疎水性指標の大きいアミノ酸残基が挿入されたことに相当する、局所的に疎水性指標の大きい領域を含むアミノ酸配列を有するものであってよい。 The modified fibroin according to another embodiment has a domain sequence in which one or more amino acid residues in REP are replaced with amino acid residues having a large hydrophobicity index as compared to naturally occurring fibroin, and It may have an amino acid sequence including a region having a large hydrophobic index locally, corresponding to the insertion of one or more amino acid residues having a large hydrophobic index in REP.
　局所的に疎水性指標の大きい領域は、連続する２～４アミノ酸残基で構成されていることが好ましい。 The region where the hydrophobic index is locally large is preferably composed of 2 to 4 amino acid residues.
　上述の疎水性指標の大きいアミノ酸残基は、イソロイシン（Ｉ）、バリン（Ｖ）、ロイシン（Ｌ）、フェニルアラニン（Ｆ）、システイン（Ｃ）、メチオニン（Ｍ）及びアラニン（Ａ）から選ばれるアミノ酸残基であることがより好ましい。 The amino acid residue having a large hydrophobicity index is an amino acid selected from isoleucine (I), valine (V), leucine (L), phenylalanine (F), cysteine (C), methionine (M) and alanine (A). More preferably, it is a residue.
　本実施形態に係る改変フィブロインは、天然由来のフィブロインと比較して、ＲＥＰ中の１又は複数のアミノ酸残基が疎水性指標の大きいアミノ酸残基に置換されたこと、及び／又はＲＥＰ中に１又は複数の疎水性指標の大きいアミノ酸残基が挿入されたことに相当する改変に加え、更に、天然由来のフィブロインと比較して、１又は複数のアミノ酸残基を置換、欠失、挿入及び／又は付加したことに相当するアミノ酸配列の改変があってもよい。 The modified fibroin according to the present embodiment has one or more amino acid residues in REP substituted with amino acid residues having a large hydrophobicity index and / or 1 in REP compared to naturally occurring fibroin. Alternatively, in addition to the modification corresponding to the insertion of a plurality of amino acid residues having a large hydrophobicity index, one or more amino acid residues are substituted, deleted, inserted and / or compared with naturally occurring fibroin. Alternatively, there may be an amino acid sequence modification corresponding to the addition.
　本実施形態に係る改変フィブロインは、例えば、クローニングした天然由来のフィブロインの遺伝子配列からＲＥＰ中の１又は複数の親水性アミノ酸残基（例えば、疎水性指標がマイナスであるアミノ酸残基）を疎水性アミノ酸残基（例えば、疎水性指標がプラスであるアミノ酸残基）に置換すること、及び／又はＲＥＰ中に１又は複数の疎水性アミノ酸残基を挿入することにより得ることができる。また、例えば、天然由来のフィブロインのアミノ酸配列からＲＥＰ中の１又は複数の親水性アミノ酸残基を疎水性アミノ酸残基に置換したこと、及び／又はＲＥＰ中に１又は複数の疎水性アミノ酸残基を挿入したことに相当するアミノ酸配列を設計し、設計したアミノ酸配列をコードする核酸を化学合成することにより得ることもできる。いずれの場合においても、天然由来のフィブロインのアミノ酸配列からＲＥＰ中の１又は複数の親水性アミノ酸残基を疎水性アミノ酸残基に置換したこと、及び／又はＲＥＰ中に１又は複数の疎水性アミノ酸残基を挿入したことに相当する改変に加え、更に１又は複数のアミノ酸残基を置換、欠失、挿入及び／又は付加したことに相当するアミノ酸配列の改変を行ってもよい。 The modified fibroin according to the present embodiment, for example, hydrophobicizes one or more hydrophilic amino acid residues (for example, amino acid residues having a negative hydrophobicity index) in REP from the gene sequence of naturally-derived fibroin that has been cloned. It can be obtained by substituting amino acid residues (for example, amino acid residues having a positive hydrophobicity index) and / or inserting one or more hydrophobic amino acid residues in REP. In addition, for example, one or more hydrophilic amino acid residues in REP are substituted with hydrophobic amino acid residues from the amino acid sequence of naturally occurring fibroin, and / or one or more hydrophobic amino acid residues in REP It can also be obtained by designing an amino acid sequence corresponding to insertion of, and chemically synthesizing a nucleic acid encoding the designed amino acid sequence. In any case, one or more hydrophilic amino acid residues in REP have been replaced with hydrophobic amino acid residues from the amino acid sequence of naturally occurring fibroin and / or one or more hydrophobic amino acids in REP In addition to the modification corresponding to the insertion of a residue, the amino acid sequence corresponding to the substitution, deletion, insertion and / or addition of one or more amino acid residues may be further modified.
　さらに他の実施形態に係る改変フィブロインは、式１：［（Ａ）ｎモチーフ－ＲＥＰ］ｍで表されるドメイン配列を含み、最もＣ末端側に位置する（Ａ）ｎモチーフから上記ドメイン配列のＣ末端までの配列を上記ドメイン配列から除いた配列に含まれる全てのＲＥＰにおいて、連続する４アミノ酸残基の疎水性指標の平均値が２．６以上となる領域に含まれるアミノ酸残基の総数をｐとし、最もＣ末端側に位置する（Ａ）ｎモチーフから上記ドメイン配列のＣ末端までの配列を上記ドメイン配列から除いた配列に含まれるアミノ酸残基の総数をｑとしたときに、ｐ／ｑが６．２％以上であるアミノ酸配列を有してもよい。 Furthermore, the modified fibroin according to another embodiment includes a domain sequence represented by Formula 1: [(A) n motif-REP] m , and (A) located at the most C-terminal side of the domain sequence from the n motif. The total number of amino acid residues contained in the region where the average value of the hydrophobicity index of four consecutive amino acid residues is 2.6 or more in all REPs contained in the sequence obtained by removing the sequence up to the C-terminal from the domain sequence. P, and (A) where the total number of amino acid residues contained in the sequence excluding the sequence from the n motif to the C terminus of the domain sequence from the domain sequence is q / Q may have an amino acid sequence of 6.2% or more.
　アミノ酸残基の疎水性指標については、公知の指標（Ｈｙｄｒｏｐａｔｈｙ　ｉｎｄｅｘ：Ｋｙｔｅ　Ｊ，＆Ｄｏｏｌｉｔｔｌｅ　Ｒ（１９８２）“Ａ　ｓｉｍｐｌｅ　ｍｅｔｈｏｄ　ｆｏｒ　ｄｉｓｐｌａｙｉｎｇ　ｔｈｅ　ｈｙｄｒｏｐａｔｈｉｃ　ｃｈａｒａｃｔｅｒ　ｏｆ　ａ　ｐｒｏｔｅｉｎ”，Ｊ．Ｍｏｌ．Ｂｉｏｌ．，１５７，ｐｐ．１０５－１３２）を使用する。具体的には、各アミノ酸の疎水性指標（ハイドロパシー・インデックス、以下「ＨＩ」とも記す。）は、下記表１に示すとおりである。 As for the hydrophobicity index of amino acid residues, a known index (Hydropathy index: Kyte J, & Doolittle R (1982) “A simple method for displaying the hydropathic character of bio.p. 7”. 105-132). Specifically, the hydrophobicity index (hydropathic index, hereinafter also referred to as “HI”) of each amino acid is as shown in Table 1 below.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　ｐ／ｑの算出方法を更に詳細に説明する。算出には、式１：［（Ａ）ｎモチーフ－ＲＥＰ］ｍで表されるドメイン配列から、最もＣ末端側に位置する（Ａ）ｎモチーフからドメイン配列のＣ末端までの配列を除いた配列（以下、「配列Ａ」とする）を用いる。まず、配列Ａに含まれる全てのＲＥＰにおいて、連続する４アミノ酸残基の疎水性指標の平均値を算出する。疎水性指標の平均値は、連続する４アミノ酸残基に含まれる各アミノ酸残基のＨＩの総和を４（アミノ酸残基数）で除して求める。疎水性指標の平均値は、全ての連続する４アミノ酸残基について求める（各アミノ酸残基は、１～４回平均値の算出に用いられる。）。次いで、連続する４アミノ酸残基の疎水性指標の平均値が２．６以上となる領域を特定する。あるアミノ酸残基が、複数の「疎水性指標の平均値が２．６以上となる連続する４アミノ酸残基」に該当する場合であっても、領域中には１アミノ酸残基として含まれることになる。そして、当該領域に含まれるアミノ酸残基の総数がｐである。また、配列Ａに含まれるアミノ酸残基の総数がｑである。 The method for calculating p / q will be described in more detail. For the calculation, a sequence obtained by removing the sequence from the domain sequence represented by Formula 1: [(A) n motif-REP] m to the most C-terminal side from the domain (A) n motif to the C terminus of the domain sequence. (Hereinafter referred to as “array A”). First, in all REPs included in the sequence A, the average value of the hydrophobicity index of four consecutive amino acid residues is calculated. The average value of the hydrophobicity index is obtained by dividing the total HI of each amino acid residue contained in the four consecutive amino acid residues by 4 (number of amino acid residues). The average value of the hydrophobicity index is obtained for all four consecutive amino acid residues (each amino acid residue is used for calculating the average value 1 to 4 times). Next, a region where the average value of the hydrophobicity index of four consecutive amino acid residues is 2.6 or more is specified. Even if a certain amino acid residue corresponds to a plurality of “four consecutive amino acid residues whose average value of hydrophobicity index is 2.6 or more”, it should be included as one amino acid residue in the region. become. The total number of amino acid residues contained in the region is p. The total number of amino acid residues contained in sequence A is q.
　例えば、「疎水性指標の平均値が２．６以上となる連続する４アミノ酸残基」が２０カ所抽出された場合（重複はなし）、連続する４アミノ酸残基の疎水性指標の平均値が２．６以上となる領域には、連続する４アミノ酸残基（重複はなし）が２０含まれることになり、ｐは２０×４＝８０である。また、例えば、２つの「疎水性指標の平均値が２．６以上となる連続する４アミノ酸残基」が１アミノ酸残基だけ重複して存在する場合、連続する４アミノ酸残基の疎水性指標の平均値が２．６以上となる領域には、７アミノ酸残基含まれることになる（ｐ＝２×４－１＝７。「－１」は重複分の控除である。）。例えば、図２に示したドメイン配列の場合、「疎水性指標の平均値が２．６以上となる連続する４アミノ酸残基」が重複せずに７つ存在するため、ｐは７×４＝２８となる。また、例えば、図２に示したドメイン配列の場合、ｑは４＋５０＋４＋４０＋４＋１０＋４＋２０＋４＋３０＝１７０である（Ｃ末端側の最後に存在する（Ａ）ｎモチーフは含めない）。次に、ｐをｑで除すことによって、ｐ／ｑ（％）を算出することができる。図２の場合２８／１７０＝１６．４７％となる。 For example, when 20 “four consecutive amino acid residues with an average value of hydrophobicity index of 2.6 or more” are extracted (no overlap), the average value of the hydrophobicity index of four consecutive amino acid residues is 2 The region of .6 or more contains 20 consecutive 4 amino acid residues (no overlap), and p is 20 × 4 = 80. In addition, for example, when two “four consecutive amino acid residues having an average value of hydrophobicity index of 2.6 or more” overlap by one amino acid residue, the hydrophobicity index of four consecutive amino acid residues In the region where the average value of is 2.6 or more, 7 amino acid residues are included (p = 2 × 4-1 = 7, where “−1” is a deduction of duplicates). For example, in the case of the domain sequence shown in FIG. 2, there are 7 “4 consecutive amino acid residues with an average value of hydrophobicity index of 2.6 or more” without duplication, and therefore p is 7 × 4 = 28. For example, in the case of the domain sequence shown in FIG. 2, q is 4 + 50 + 4 + 40 + 4 + 10 + 4 + 20 + 4 + 30 = 170 (the (A) n motif present at the end on the C-terminal side is not included). Next, p / q (%) can be calculated by dividing p by q. In the case of FIG. 2, 28/170 = 16.47%.
　本実施形態に係る改変フィブロインにおいて、ｐ／ｑは、６．２％以上であることが好ましく、７％以上であることがより好ましく、１０％以上であることが更に好ましく、２０％以上であることが更により好ましく、３０％以上であることが更によりまた好ましい。ｐ／ｑの上限は、特に制限されないが、例えば、４５％以下であってもよい。 In the modified fibroin according to this embodiment, p / q is preferably 6.2% or more, more preferably 7% or more, further preferably 10% or more, and 20% or more. Even more preferably, it is still more preferably 30% or more. The upper limit of p / q is not particularly limited, but may be 45% or less, for example.
　本実施形態に係る改変フィブロインは、例えば、クローニングした天然由来のフィブロインのアミノ酸配列を、上記のｐ／ｑの条件を満たすように、ＲＥＰ中の１又は複数の親水性アミノ酸残基（例えば、疎水性指標がマイナスであるアミノ酸残基）を疎水性アミノ酸残基（例えば、疎水性指標がプラスであるアミノ酸残基）に置換すること、及び／又はＲＥＰ中に１又は複数の疎水性アミノ酸残基を挿入することにより、局所的に疎水性指標の大きい領域を含むアミノ酸配列に改変することにより得ることができる。また、例えば、天然由来のフィブロインのアミノ酸配列から上記のｐ／ｑの条件を満たすアミノ酸配列を設計し、設計したアミノ酸配列をコードする核酸を化学合成することにより得ることもできる。いずれの場合においても、天然由来のフィブロインと比較して、ＲＥＰ中の１又は複数のアミノ酸残基が疎水性指標の大きいアミノ酸残基に置換されたこと、及び／又はＲＥＰ中に１又は複数の疎水性指標の大きいアミノ酸残基が挿入されたことに相当する改変に加え、更に１又は複数のアミノ酸残基を置換、欠失、挿入及び／又は付加したことに相当する改変を行ってもよい。 The modified fibroin according to this embodiment includes, for example, one or a plurality of hydrophilic amino acid residues (for example, hydrophobicity) in the REP so that the amino acid sequence of the naturally-derived fibroin thus cloned satisfies the above p / q condition. Substituting a hydrophobic amino acid residue (for example, an amino acid residue having a positive hydrophobicity index) and / or one or more hydrophobic amino acid residues during REP Can be obtained by locally modifying the amino acid sequence to include a region having a large hydrophobicity index. Alternatively, for example, an amino acid sequence satisfying the above p / q conditions can be designed from the amino acid sequence of naturally derived fibroin, and a nucleic acid encoding the designed amino acid sequence can be obtained by chemical synthesis. In any case, compared to naturally occurring fibroin, one or more amino acid residues in REP were replaced with amino acid residues having a higher hydrophobicity index and / or one or more amino acid residues in REP. In addition to modifications corresponding to insertion of amino acid residues having a large hydrophobicity index, modifications corresponding to substitution, deletion, insertion and / or addition of one or more amino acid residues may be performed. .
　疎水性指標の大きいアミノ酸残基としては、特に制限はないが、イソロイシン（Ｉ）、バリン（Ｖ）、ロイシン（Ｌ）、フェニルアラニン（Ｆ）、システイン（Ｃ）、メチオニン（Ｍ）及びアラニン（Ａ）が好ましく、バリン（Ｖ）、ロイシン（Ｌ）及びイソロイシン（Ｉ）がより好ましい。 The amino acid residue having a large hydrophobicity index is not particularly limited, but isoleucine (I), valine (V), leucine (L), phenylalanine (F), cysteine (C), methionine (M) and alanine (A ) Are preferred, and valine (V), leucine (L) and isoleucine (I) are more preferred.
　改変フィブロインの別の具体的な例として、（５－ｉ）配列番号２０、配列番号２２若しくは配列番号２３で示されるアミノ酸配列、又は（５－ｉｉ）配列番号２０、配列番号２２若しくは配列番号２３で示されるアミノ酸配列と９０％以上の配列同一性を有するアミノ酸配列を含む、改変フィブロインを挙げることができる。 As another specific example of the modified fibroin, (5-i) the amino acid sequence represented by SEQ ID NO: 20, SEQ ID NO: 22 or SEQ ID NO: 23, or (5-ii) SEQ ID NO: 20, SEQ ID NO: 22 or SEQ ID NO: 23 And a modified fibroin comprising an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by
　（５－ｉ）の改変フィブロインについて説明する。配列番号１９で示されるアミノ酸配列は、天然由来のフィブロインの（Ａ）ｎモチーフ中のアラニン残基が連続するアミノ酸配列をアラニン残基が連続する数を５つになるよう欠失したものである。配列番号２０で示されるアミノ酸配列は、配列番号１９で示されるアミノ酸配列に対し、ＲＥＰ一つ置きにそれぞれ３アミノ酸残基からなるアミノ酸配列（ＶＬＩ）を２カ所挿入し、かつ配列番号１９で示されるアミノ酸配列の分子量とほぼ同じとなるようにＣ末端側の一部のアミノ酸を欠失させたものである。配列番号２１で示されるアミノ酸配列は、配列番号１９で示されるアミノ酸配列に対し、各（Ａ）ｎモチーフのＣ末端側に２つのアラニン残基を挿入し、更に一部のグルタミン（Ｑ）残基をセリン（Ｓ）残基に置換し、かつ配列番号１９で示されるアミノ酸配列の分子量とほぼ同じとなるようにＣ末端側の一部のアミノ酸を欠失させたものである。配列番号２２で示されるアミノ酸配列は、配列番号２１で示されるアミノ酸配列に対し、ＲＥＰ一つ置きにそれぞれ３アミノ酸残基からなるアミノ酸配列（ＶＬＩ）を１カ所挿入したものである。配列番号２３で示されるアミノ酸配列は、配列番号２１で示されるアミノ酸配列に対し、ＲＥＰ一つ置きにそれぞれ３アミノ酸残基からなるアミノ酸配列（ＶＬＩ）を２カ所挿入したものである。 The modified fibroin (5-i) will be described. The amino acid sequence shown in SEQ ID NO: 19 is an amino acid sequence in which the alanine residues in the (A) n motif of (A) naturally derived fibroin are deleted so that the number of consecutive alanine residues is five. . The amino acid sequence represented by SEQ ID NO: 20 is inserted into the amino acid sequence represented by SEQ ID NO: 19 by two amino acid sequences (VLI) each consisting of 3 amino acid residues every other REP, and represented by SEQ ID NO: 19. A part of amino acids on the C-terminal side are deleted so that the molecular weight of the amino acid sequence is almost the same. The amino acid sequence represented by SEQ ID NO: 21 is obtained by inserting two alanine residues at the C-terminal side of each (A) n motif with respect to the amino acid sequence represented by SEQ ID NO: 19, and further adding some glutamine (Q) residues. A group is substituted with a serine (S) residue, and a part of amino acids on the C-terminal side is deleted so as to be approximately the same as the molecular weight of the amino acid sequence represented by SEQ ID NO: 19. The amino acid sequence represented by SEQ ID NO: 22 is obtained by inserting one amino acid sequence (VLI) consisting of 3 amino acid residues at every other REP to the amino acid sequence represented by SEQ ID NO: 21. The amino acid sequence shown in SEQ ID NO: 23 is obtained by inserting two amino acid sequences (VLI) each consisting of 3 amino acid residues into the amino acid sequence shown in SEQ ID NO: 21 every other REP.
　（５－ｉ）の改変フィブロインは、配列番号２０、配列番号２２又は配列番号２３で示されるアミノ酸配列からなるものであってもよい。 The modified fibroin (5-i) may be composed of the amino acid sequence represented by SEQ ID NO: 20, SEQ ID NO: 22 or SEQ ID NO: 23.
　（５－ｉｉ）の改変フィブロインは、配列番号２０、配列番号２２又は配列番号２３で示されるアミノ酸配列と９０％以上の配列同一性を有するアミノ酸配列を含むものである。（５－ｉｉ）の改変フィブロインもまた、式１：［（Ａ）ｎモチーフ－ＲＥＰ］ｍで表されるドメイン配列を含むタンパク質である。上記配列同一性は、９５％以上であることが好ましい。 The modified fibroin (5-ii) includes an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 20, SEQ ID NO: 22 or SEQ ID NO: 23. The modified fibroin of (5-ii) is also a protein containing a domain sequence represented by Formula 1: [(A) n motif-REP] m . The sequence identity is preferably 95% or more.
　（５－ｉｉ）の改変フィブロインは、配列番号２０、配列番号２２又は配列番号２３で示されるアミノ酸配列と９０％以上の配列同一性を有し、かつ最もＣ末端側に位置する（Ａ）ｎモチーフからドメイン配列のＣ末端までの配列をドメイン配列から除いた配列に含まれる全てのＲＥＰにおいて、連続する４アミノ酸残基の疎水性指標の平均値が２．６以上となる領域に含まれるアミノ酸残基の総数をｐとし、最もＣ末端側に位置する（Ａ）ｎモチーフからドメイン配列のＣ末端までの配列をドメイン配列から除いた配列に含まれるアミノ酸残基の総数をｑとしたときに、ｐ／ｑが６．２％以上であることが好ましい。 The modified fibroin of (5-ii) has a sequence identity of 90% or more with the amino acid sequence represented by SEQ ID NO: 20, SEQ ID NO: 22 or SEQ ID NO: 23, and is located at the most C-terminal side (A) n In all REPs included in the sequence excluding the sequence from the motif to the C-terminal of the domain sequence, the amino acids included in the region where the average value of the hydrophobicity index of 4 consecutive amino acid residues is 2.6 or more P is the total number of residues, and (A) When the total number of amino acid residues contained in the sequence excluding the sequence from the n motif to the C terminus of the domain sequence from the domain sequence is q , P / q is preferably 6.2% or more.
　上述の改変フィブロインは、Ｎ末端及びＣ末端のいずれか一方又は両方にタグ配列を含んでいてもよい。 The above-mentioned modified fibroin may contain a tag sequence at one or both of the N-terminal and C-terminal.
　タグ配列を含む改変フィブロインのより具体的な例として、（５－ｉｉｉ）配列番号２４、配列番号２５若しくは配列番号２６で示されるアミノ酸配列、又は（５－ｉｖ）配列番号２４、配列番号２５若しくは配列番号２６で示されるアミノ酸配列と９０％以上の配列同一性を有するアミノ酸配列を含む、改変フィブロインを挙げることができる。 As more specific examples of modified fibroin comprising a tag sequence, (5-iii) the amino acid sequence represented by SEQ ID NO: 24, SEQ ID NO: 25 or SEQ ID NO: 26, or (5-iv) SEQ ID NO: 24, SEQ ID NO: 25 or Mention may be made of modified fibroin comprising an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 26.
　配列番号２４、配列番号２５及び配列番号２６で示されるアミノ酸配列は、それぞれ配列番号２０、配列番号２２及び配列番号２３で示されるアミノ酸配列のＮ末端に配列番号５で示されるアミノ酸配列（Ｈｉｓタグ配列及びヒンジ配列を含む）を付加したものである。 The amino acid sequences represented by SEQ ID NO: 24, SEQ ID NO: 25, and SEQ ID NO: 26 are the amino acid sequences represented by SEQ ID NO: 5 at the N-terminus of the amino acid sequences represented by SEQ ID NO: 20, SEQ ID NO: 22 and SEQ ID NO: 23, respectively (His tag). Including a sequence and a hinge sequence).
　（５－ｉｉｉ）の改変フィブロインは、配列番号２４、配列番号２５若しくは配列番号２６で示されるアミノ酸配列からなるものであってもよい。 (5-iii) The modified fibroin may consist of the amino acid sequence represented by SEQ ID NO: 24, SEQ ID NO: 25 or SEQ ID NO: 26.
　（５－ｉｖ）の改変フィブロインは、配列番号２４、配列番号２５若しくは配列番号２６で示されるアミノ酸配列と９０％以上の配列同一性を有するアミノ酸配列を含むものである。（５－ｉｖ）の改変フィブロインもまた、式１：［（Ａ）ｎモチーフ－ＲＥＰ］ｍで表されるドメイン配列を含むタンパク質である。上記配列同一性は、９５％以上であることが好ましい。 The modified fibroin (5-iv) includes an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 24, SEQ ID NO: 25 or SEQ ID NO: 26. The modified fibroin of (5-iv) is also a protein containing a domain sequence represented by Formula 1: [(A) n motif-REP] m . The sequence identity is preferably 95% or more.
　（５－ｉｖ）の改変フィブロインは、配列番号２４、配列番号２５若しくは配列番号２６で示されるアミノ酸配列と９０％以上の配列同一性を有し、かつ最もＣ末端側に位置する（Ａ）ｎモチーフからドメイン配列のＣ末端までの配列をドメイン配列から除いた配列に含まれる全てのＲＥＰにおいて、連続する４アミノ酸残基の疎水性指標の平均値が２．６以上となる領域に含まれるアミノ酸残基の総数をｐとし、最もＣ末端側に位置する（Ａ）ｎモチーフからドメイン配列のＣ末端までの配列をドメイン配列から除いた配列に含まれるアミノ酸残基の総数をｑとしたときに、ｐ／ｑが６．２％以上であることが好ましい。 The modified fibroin (5-iv) has 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 24, SEQ ID NO: 25 or SEQ ID NO: 26, and is located at the most C-terminal side (A) n In all REPs included in the sequence excluding the sequence from the motif to the C-terminal of the domain sequence, the amino acids included in the region where the average value of the hydrophobicity index of 4 consecutive amino acid residues is 2.6 or more P is the total number of residues, and (A) When the total number of amino acid residues contained in the sequence excluding the sequence from the n motif to the C terminus of the domain sequence from the domain sequence is q , P / q is preferably 6.2% or more.
　上述の改変フィブロインは、組換えタンパク質生産系において生産されたタンパク質を宿主の外部に放出するための分泌シグナルを含んでいてもよい。分泌シグナルの配列は、宿主の種類に応じて適宜設定することができる。 The aforementioned modified fibroin may contain a secretion signal for releasing the protein produced in the recombinant protein production system to the outside of the host. The sequence of the secretion signal can be appropriately set according to the type of host.
　さらに他の実施形態に係る改変フィブロインは、天然由来のフィブロインと比較して、グルタミン残基の含有量が低減されたアミノ酸配列を有する。 The modified fibroin according to still another embodiment has an amino acid sequence in which the content of glutamine residues is reduced as compared with naturally occurring fibroin.
　本実施形態に係る改変フィブロインは、ＲＥＰのアミノ酸配列中に、ＧＧＸモチーフ及びＧＰＧＸＸモチーフから選ばれる少なくとも一つのモチーフが含まれていることが好ましい。 The modified fibroin according to this embodiment preferably includes at least one motif selected from a GGX motif and a GPGXX motif in the amino acid sequence of REP.
　本実施形態に係る改変フィブロインが、ＲＥＰ中にＧＰＧＸＸモチーフを含む場合、ＧＰＧＸＸモチーフ含有率は、通常１％以上であり、５％以上であってもよく、１０％以上であるのが好ましい。ＧＰＧＸＸモチーフ含有率の上限に特に制限はなく、５０％以下であってよく、３０％以下であってもよい。 When the modified fibroin according to the present embodiment contains a GPGXX motif in REP, the content ratio of the GPGXX motif is usually 1% or more, may be 5% or more, and is preferably 10% or more. There is no restriction | limiting in particular in the upper limit of GPGXX motif content rate, 50% or less may be sufficient and 30% or less may be sufficient.
　本明細書において、「ＧＰＧＸＸモチーフ含有率」は、以下の方法により算出される値である。
　式１：［（Ａ）ｎモチーフ－ＲＥＰ］ｍ、又は式２：［（Ａ）ｎモチーフ－ＲＥＰ］ｍ－（Ａ）ｎモチーフで表されるドメイン配列を含むフィブロイン（改変フィブロイン又は天然由来のフィブロイン）において、最もＣ末端側に位置する（Ａ）ｎモチーフからドメイン配列のＣ末端までの配列をドメイン配列から除いた配列に含まれる全てのＲＥＰにおいて、その領域に含まれるＧＰＧＸＸモチーフの個数の総数を３倍した数（即ち、ＧＰＧＸＸモチーフ中のＧ及びＰの総数に相当）をｓとし、最もＣ末端側に位置する（Ａ）ｎモチーフからドメイン配列のＣ末端までの配列をドメイン配列から除き、更に（Ａ）ｎモチーフを除いた全ＲＥＰのアミノ酸残基の総数をｔとしたときに、ＧＰＧＸＸモチーフ含有率はｓ／ｔとして算出される。 In the present specification, the “GPGXX motif content” is a value calculated by the following method.
Formula 1: [(A) n motif-REP] m , or Formula 2: [(A) n motif-REP] m- (A) fibroin (modified fibroin or naturally derived) containing a domain sequence represented by the n motif In fibroin), the number of GPGXX motifs contained in the region in all REPs contained in the sequence excluding the sequence from the domain sequence (A) n motif located at the most C-terminal side to the C-terminus of the domain sequence. The number obtained by multiplying the total number by three (ie, corresponding to the total number of G and P in the GPGXX motif) is s, and is located at the most C-terminal side. (A) The sequence from the n motif to the C-terminal of the domain sequence is determined from the domain sequence. (A) The content ratio of the GPGXX motif is calculated as s / t, where t is the total number of amino acid residues of all REPs excluding the n motif. It is.
　ＧＰＧＸＸモチーフ含有率の算出において、「最もＣ末端側に位置する（Ａ）ｎモチーフからドメイン配列のＣ末端までの配列をドメイン配列から除いた配列」を対象としているのは、「最もＣ末端側に位置する（Ａ）ｎモチーフからドメイン配列のＣ末端までの配列」（ＲＥＰに相当する配列）には、フィブロインに特徴的な配列と相関性の低い配列が含まれることがあり、ｍが小さい場合（つまり、ドメイン配列が短い場合）、ＧＰＧＸＸモチーフ含有率の算出結果に影響するので、この影響を排除するためである。なお、ＲＥＰのＣ末端に「ＧＰＧＸＸモチーフ」が位置する場合、「ＸＸ」が例えば「ＡＡ」の場合であっても、「ＧＰＧＸＸモチーフ」として扱う。 In the calculation of the content ratio of the GPGXX motif, “A sequence located at the most C-terminal side (A) excluding the sequence from the n motif to the C-terminal of the domain sequence from the domain sequence” (A) The sequence from the n motif to the C terminus of the domain sequence ”(sequence corresponding to REP) may include a sequence that is not highly correlated with the sequence characteristic of fibroin, and m is small In this case (that is, when the domain sequence is short), the calculation result of the content ratio of the GPGXX motif is affected, so this influence is excluded. When the “GPGXX motif” is located at the C-terminus of REP, even if “XX” is, for example, “AA”, it is treated as “GPGXX motif”.
　図３は、改変フィブロインのドメイン配列を示す模式図である。図３を参照しながらＧＰＧＸＸモチーフ含有率の算出方法を具体的に説明する。まず、図３に示した改変フィブロインのドメイン配列（「［（Ａ）ｎモチーフ－ＲＥＰ］ｍ－（Ａ）ｎモチーフ」タイプである。）では、全てのＲＥＰが「最もＣ末端側に位置する（Ａ）ｎモチーフからドメイン配列のＣ末端までの配列をドメイン配列から除いた配列」（図３中、「領域Ａ」で示した配列。）に含まれているため、ｓを算出するためのＧＰＧＸＸモチーフの個数は７であり、ｓは７×３＝２１となる。同様に、全てのＲＥＰが「最もＣ末端側に位置する（Ａ）ｎモチーフからドメイン配列のＣ末端までの配列をドメイン配列から除いた配列」（図３中、「領域Ａ」で示した配列。）に含まれているため、当該配列から更に（Ａ）ｎモチーフを除いた全ＲＥＰのアミノ酸残基の総数ｔは５０＋４０＋１０＋２０＋３０＝１５０である。次に、ｓをｔで除すことによって、ｓ／ｔ（％）を算出することができ、図３の改変フィブロインの場合２１／１５０＝１４．０％となる。 FIG. 3 is a schematic diagram showing the domain sequence of the modified fibroin. The calculation method of the content ratio of GPGXX motif will be specifically described with reference to FIG. First, in the domain sequence of the modified fibroin shown in FIG. 3 ("[(A) n motif-REP] m- (A) n motif" type), all REPs are "most C-terminally located. (A) Since it is included in the “sequence excluding the sequence from the n motif to the C-terminal of the domain sequence from the domain sequence” (the sequence indicated by “region A” in FIG. 3), The number of GPGXX motifs is 7, and s is 7 × 3 = 21. Similarly, all REPs are “a sequence located at the most C-terminal side (A) The sequence from the n motif to the C-terminal of the domain sequence is excluded from the domain sequence” (the sequence indicated by “region A” in FIG. 3) )), The total number t of amino acid residues of all REPs excluding (A) the n motif from the sequence is 50 + 40 + 10 + 20 + 30 = 150. Next, s / t (%) can be calculated by dividing s by t. In the case of the modified fibroin in FIG. 3, 21/150 = 14.0%.
　本実施形態に係る改変フィブロインは、グルタミン残基含有率が９％以下であることが好ましく、７％以下であることがより好ましく、４％以下であることが更に好ましく、０％であることが特に好ましい。 The modified fibroin according to this embodiment preferably has a glutamine residue content of 9% or less, more preferably 7% or less, still more preferably 4% or less, and preferably 0%. Particularly preferred.
　本明細書において、「グルタミン残基含有率」は、以下の方法により算出される値である。
　式１：［（Ａ）ｎモチーフ－ＲＥＰ］ｍ、又は式２：［（Ａ）ｎモチーフ－ＲＥＰ］ｍ－（Ａ）ｎモチーフで表されるドメイン配列を含むフィブロイン（改変フィブロイン又は天然由来のフィブロイン）において、最もＣ末端側に位置する（Ａ）ｎモチーフからドメイン配列のＣ末端までの配列をドメイン配列から除いた配列（図３の「領域Ａ」に相当する配列。）に含まれる全てのＲＥＰにおいて、その領域に含まれるグルタミン残基の総数をｕとし、最もＣ末端側に位置する（Ａ）ｎモチーフからドメイン配列のＣ末端までの配列をドメイン配列から除き、更に（Ａ）ｎモチーフを除いた全ＲＥＰのアミノ酸残基の総数をｔとしたときに、グルタミン残基含有率はｕ／ｔとして算出される。グルタミン残基含有率の算出において、「最もＣ末端側に位置する（Ａ）ｎモチーフからドメイン配列のＣ末端までの配列をドメイン配列から除いた配列」を対象としている理由は、上述した理由と同様である。 In the present specification, the “glutamine residue content” is a value calculated by the following method.
Formula 1: [(A) n motif-REP] m , or Formula 2: [(A) n motif-REP] m- (A) fibroin (modified fibroin or naturally derived) containing a domain sequence represented by the n motif In fibroin), (A) the sequence from the n- motif to the C-terminus of the domain sequence located on the most C-terminal side (sequence corresponding to “region A” in FIG. 3) excluding the sequence from the domain sequence. In the REP, the total number of glutamine residues contained in the region is u, the sequence from the (A) n motif located at the most C-terminal side to the C-terminus of the domain sequence is excluded from the domain sequence, and (A) n The glutamine residue content is calculated as u / t, where t is the total number of amino acid residues in all REPs excluding the motif. In the calculation of the glutamine residue content rate, the reason why "A sequence located at the most C-terminal side (A) excluding the sequence from the n motif to the C-terminus of the domain sequence from the domain sequence" is the reason described above. It is the same.
　本実施形態に係る改変フィブロインは、そのドメイン配列が、天然由来のフィブロインと比較して、ＲＥＰ中の１又は複数のグルタミン残基を欠失したこと、又は他のアミノ酸残基に置換したことに相当するアミノ酸配列を有するものであってよい。 In the modified fibroin according to the present embodiment, the domain sequence has one or more glutamine residues in REP deleted or substituted with other amino acid residues as compared to naturally occurring fibroin. It may have a corresponding amino acid sequence.
　「他のアミノ酸残基」は、グルタミン残基以外のアミノ酸残基であればよいが、グルタミン残基よりも疎水性指標の大きいアミノ酸残基であることが好ましい。アミノ酸残基の疎水性指標は表１に示すとおりである。 The “other amino acid residue” may be an amino acid residue other than a glutamine residue, but is preferably an amino acid residue having a larger hydrophobicity index than the glutamine residue. Table 1 shows the hydrophobicity index of amino acid residues.
　表１に示すとおり、グルタミン残基よりも疎水性指標の大きいアミノ酸残基としては、イソロイシン（Ｉ）、バリン（Ｖ）、ロイシン（Ｌ）、フェニルアラニン（Ｆ）、システイン（Ｃ）、メチオニン（Ｍ）アラニン（Ａ）、グリシン（Ｇ）、スレオニン（Ｔ）、セリン（Ｓ）、トリプトファン（Ｗ）、チロシン（Ｙ）、プロリン（Ｐ）及びヒスチジン（Ｈ）から選ばれるアミノ酸残基を挙げることができる。これらの中でも、イソロイシン（Ｉ）、バリン（Ｖ）、ロイシン（Ｌ）、フェニルアラニン（Ｆ）、システイン（Ｃ）、メチオニン（Ｍ）及びアラニン（Ａ）から選ばれるアミノ酸残基であることがより好ましく、イソロイシン（Ｉ）、バリン（Ｖ）、ロイシン（Ｌ）及びフェニルアラニン（Ｆ）から選ばれるアミノ酸残基であることが更に好ましい。 As shown in Table 1, amino acid residues having a larger hydrophobicity index than glutamine residues include isoleucine (I), valine (V), leucine (L), phenylalanine (F), cysteine (C), methionine (M ) Amino acid residues selected from alanine (A), glycine (G), threonine (T), serine (S), tryptophan (W), tyrosine (Y), proline (P) and histidine (H). it can. Among these, an amino acid residue selected from isoleucine (I), valine (V), leucine (L), phenylalanine (F), cysteine (C), methionine (M) and alanine (A) is more preferable. More preferred is an amino acid residue selected from among isoleucine (I), valine (V), leucine (L) and phenylalanine (F).
　本実施形態に係る改変フィブロインは、ＲＥＰの疎水性度が、－０．８以上であることが好ましく、－０．７以上であることがより好ましく、０以上であることが更に好ましく、０．３以上であることが更により好ましく、０．４以上であることが特に好ましい。ＲＥＰの疎水性度の上限に特に制限はなく、１．０以下であってよく、０．７以下であってもよい。 In the modified fibroin according to the present embodiment, the hydrophobicity of REP is preferably −0.8 or more, more preferably −0.7 or more, still more preferably 0 or more, and It is still more preferable that it is 3 or more, and it is especially preferable that it is 0.4 or more. There is no restriction | limiting in particular in the upper limit of the hydrophobicity of REP, It may be 1.0 or less and may be 0.7 or less.
　本明細書において、「ＲＥＰの疎水性度」は、以下の方法により算出される値である。
　式１：［（Ａ）ｎモチーフ－ＲＥＰ］ｍ、又は式２：［（Ａ）ｎモチーフ－ＲＥＰ］ｍ－（Ａ）ｎモチーフで表されるドメイン配列を含むフィブロイン（改変フィブロイン又は天然由来のフィブロイン）において、最もＣ末端側に位置する（Ａ）ｎモチーフからドメイン配列のＣ末端までの配列をドメイン配列から除いた配列（図３の「領域Ａ」に相当する配列。）に含まれる全てのＲＥＰにおいて、その領域の各アミノ酸残基の疎水性指標の総和をｖとし、最もＣ末端側に位置する（Ａ）ｎモチーフからドメイン配列のＣ末端までの配列をドメイン配列から除き、更に（Ａ）ｎモチーフを除いた全ＲＥＰのアミノ酸残基の総数をｔとしたときに、ＲＥＰの疎水性度はｖ／ｔとして算出される。ＲＥＰの疎水性度の算出において、「最もＣ末端側に位置する（Ａ）ｎモチーフからドメイン配列のＣ末端までの配列をドメイン配列から除いた配列」を対象としている理由は、上述した理由と同様である。 In the present specification, the “hydrophobicity of REP” is a value calculated by the following method.
Formula 1: [(A) n motif-REP] m , or Formula 2: [(A) n motif-REP] m- (A) fibroin (modified fibroin or naturally derived) containing a domain sequence represented by the n motif In fibroin), (A) the sequence from the n- motif to the C-terminus of the domain sequence located on the most C-terminal side (sequence corresponding to “region A” in FIG. 3) excluding the sequence from the domain sequence. In the REP, the sum of the hydrophobicity index of each amino acid residue in the region is represented by v, and the sequence from the (A) n motif located at the most C-terminal side to the C-terminus of the domain sequence is excluded from the domain sequence, and ( A) The hydrophobicity of REP is calculated as v / t, where t is the total number of amino acid residues of all REPs excluding the n motif. In the calculation of the hydrophobicity of REP, the reason why “A sequence located at the most C-terminal side (A) excluding the sequence from the n motif to the C-terminal of the domain sequence from the domain sequence” is the reason described above. It is the same.
　本実施形態に係る改変フィブロインは、そのドメイン配列が、天然由来のフィブロインと比較して、ＲＥＰ中の１又は複数のグルタミン残基を欠失したこと、及び／又はＲＥＰ中の１又は複数のグルタミン残基を他のアミノ酸残基に置換したことに相当する改変に加え、更に１又は複数のアミノ酸残基を置換、欠失、挿入及び／又は付加したことに相当するアミノ酸配列の改変があってもよい。 The modified fibroin according to the present embodiment has a domain sequence in which one or more glutamine residues in REP are deleted compared to naturally-occurring fibroin and / or one or more glutamine in REP. In addition to modifications corresponding to substitution of residues with other amino acid residues, there are further alterations in amino acid sequence corresponding to substitution, deletion, insertion and / or addition of one or more amino acid residues. Also good.
　本実施形態に係る改変フィブロインは、例えば、クローニングした天然由来のフィブロインの遺伝子配列からＲＥＰ中の１又は複数のグルタミン残基を欠失させること、及び／又はＲＥＰ中の１又は複数のグルタミン残基を他のアミノ酸残基に置換することにより得ることができる。また、例えば、天然由来のフィブロインのアミノ酸配列からＲＥＰ中の１又は複数のグルタミン残基を欠失したこと、及び／又はＲＥＰ中の１又は複数のグルタミン残基を他のアミノ酸残基に置換したことに相当するアミノ酸配列を設計し、設計したアミノ酸配列をコードする核酸を化学合成することにより得ることもできる。 The modified fibroin according to the present embodiment includes, for example, deletion of one or more glutamine residues in REP from the cloned gene sequence of natural fibroin and / or one or more glutamine residues in REP. Can be obtained by substituting with other amino acid residues. In addition, for example, one or more glutamine residues in REP are deleted from the amino acid sequence of naturally occurring fibroin, and / or one or more glutamine residues in REP are replaced with other amino acid residues. In particular, it can also be obtained by designing a corresponding amino acid sequence and chemically synthesizing a nucleic acid encoding the designed amino acid sequence.
　本発明に係る改変フィブロインのより具体的な例として、（６－ｉ）配列番号２７、配列番号２８、配列番号２９、配列番号３０、配列番号３１、配列番号３８若しくは配列番号３９で示されるアミノ酸配列を含む、改変フィブロイン、又は（６－ｉｉ）配列番号２７、配列番号２８、配列番号２９、配列番号３０、配列番号３１、配列番号３８若しくは配列番号３９で示されるアミノ酸配列と９０％以上の配列同一性を有するアミノ酸配列を含む、改変フィブロインを挙げることができる。 As more specific examples of the modified fibroin according to the present invention, (6-i) the amino acid represented by SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 38 or SEQ ID NO: 39 90% or more of the modified fibroin containing the sequence, or (6-ii) the amino acid sequence represented by SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 38 or SEQ ID NO: 39 Mention may be made of modified fibroin comprising amino acid sequences having sequence identity.
　（６－ｉ）の改変フィブロインについて説明する。 The (6-i) modified fibroin will be described.
　配列番号４で示されるアミノ酸配列（Ｍｅｔ－ＰＲＴ４１０）は、天然由来のフィブロインであるＮｅｐｈｉｌａ　ｃｌａｖｉｐｅｓ（ＧｅｎＢａｎｋアクセッション番号：Ｐ４６８０４．１、ＧＩ：１１７４４１５）の塩基配列及びアミノ酸配列に基づき、（Ａ）ｎモチーフ中のアラニン残基が連続するアミノ酸配列をアラニン残基が連続する数を５つにする等の生産性を向上させるためのアミノ酸の改変を行ったものである。一方、Ｍｅｔ－ＰＲＴ４１０は、グルタミン残基（Ｑ）の改変は行っていないため、グルタミン残基含有率は、天然由来のフィブロインのグルタミン残基含有率と同程度である。 Amino acid sequence shown in SEQ ID NO: 4 (Met-PRT410) is a fibroin naturally occurring Nephila clavipes (GenBank accession number: P46804.1, GI: 1174415) based on the nucleotide sequence and amino acid sequence of, (A) n The amino acid sequence in which the alanine residue in the motif is continued is modified with an amino acid to improve productivity, such as the number of consecutive alanine residues is five. On the other hand, since Met-PRT410 has not altered the glutamine residue (Q), the glutamine residue content is comparable to the glutamine residue content of naturally occurring fibroin.
　配列番号２７で示されるアミノ酸配列（Ｍ＿ＰＲＴ８８８）は、Ｍｅｔ－ＰＲＴ４１０（配列番号４）中のＱＱを全てＶＬに置換したものである。 The amino acid sequence represented by SEQ ID NO: 27 (M_PRT888) is obtained by replacing all QQs in Met-PRT410 (SEQ ID NO: 4) with VL.
　配列番号２８で示されるアミノ酸配列（Ｍ＿ＰＲＴ９６５）は、Ｍｅｔ－ＰＲＴ４１０（配列番号４）中のＱＱを全てＴＳに置換し、かつ残りのＱをＡに置換したものである。 The amino acid sequence represented by SEQ ID NO: 28 (M_PRT965) is obtained by substituting all QQs in Met-PRT410 (SEQ ID NO: 4) with TS and substituting the remaining Q with A.
　配列番号２９で示されるアミノ酸配列（Ｍ＿ＰＲＴ８８９）は、Ｍｅｔ－ＰＲＴ４１０（配列番号４）中のＱＱを全てＶＬに置換し、かつ残りのＱをＩに置換したものである。 The amino acid sequence (M_PRT889) represented by SEQ ID NO: 29 is obtained by replacing all QQs in Met-PRT410 (SEQ ID NO: 4) with VL and replacing the remaining Q with I.
　配列番号３０で示されるアミノ酸配列（Ｍ＿ＰＲＴ９１６）は、Ｍｅｔ－ＰＲＴ４１０（配列番号４）中のＱＱを全てＶＩに置換し、かつ残りのＱをＬに置換したものである。 The amino acid sequence (M_PRT916) represented by SEQ ID NO: 30 is obtained by substituting all QQs in Met-PRT410 (SEQ ID NO: 4) with VI and replacing the remaining Q with L.
　配列番号３１で示されるアミノ酸配列（Ｍ＿ＰＲＴ９１８）は、Ｍｅｔ－ＰＲＴ４１０（配列番号４）中のＱＱを全てＶＦに置換し、かつ残りのＱをＩに置換したものである。 The amino acid sequence represented by SEQ ID NO: 31 (M_PRT918) is obtained by replacing all QQs in Met-PRT410 (SEQ ID NO: 4) with VF and replacing the remaining Q with I.
　配列番号３７で示されるアミノ酸配列（Ｍ＿ＰＲＴ５２５）は、Ｍｅｔ－ＰＲＴ４１０（配列番号４）に対し、アラニン残基が連続する領域（Ａ５）に２つのアラニン残基を挿入し、Ｍｅｔ－ＰＲＴ４１０の分子量とほぼ同じになるよう、Ｃ末端側のドメイン配列２つを欠失させ、かつグルタミン残基（Ｑ）１３箇所をセリン残基（Ｓ）又はプロリン残基（Ｐ）に置換したものである。 The amino acid sequence (M_PRT525) represented by SEQ ID NO: 37 is obtained by inserting two alanine residues into a region (A 5 ) where alanine residues are continuous with respect to Met-PRT410 (SEQ ID NO: 4). The two C-terminal domain sequences were deleted and 13 glutamine residues (Q) were replaced with serine residues (S) or proline residues (P) so that they were almost the same as those in FIG.
　配列番号３８で示されるアミノ酸配列（Ｍ＿ＰＲＴ６９９）は、Ｍ＿ＰＲＴ５２５（配列番号３７）中のＱＱを全てＶＬに置換したものである。 The amino acid sequence represented by SEQ ID NO: 38 (M_PRT699) is obtained by substituting VL for all QQs in M_PRT525 (SEQ ID NO: 37).
　配列番号３９で示されるアミノ酸配列（Ｍ＿ＰＲＴ６９８）は、Ｍ＿ＰＲＴ５２５（配列番号３７）中のＱＱを全てＶＬに置換し、かつ残りのＱをＩに置換したものである。 The amino acid sequence represented by SEQ ID NO: 39 (M_PRT698) is obtained by replacing all QQs in M_PRT525 (SEQ ID NO: 37) with VL and replacing the remaining Q with I.
　配列番号２７、配列番号２８、配列番号２９、配列番号３０、配列番号３１、配列番号３８及び配列番号３９で示されるアミノ酸配列は、いずれもグルタミン残基含有率は９％以下である（表２）。 The amino acid sequences represented by SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 38, and SEQ ID NO: 39 all have a glutamine residue content of 9% or less (Table 2). ).
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　（６－ｉ）の改変フィブロインは、配列番号２７、配列番号２８、配列番号２９、配列番号３０、配列番号３１、配列番号３８又は配列番号３９で示されるアミノ酸配列からなるものであってもよい。 The modified fibroin (6-i) may be composed of the amino acid sequence represented by SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 38 or SEQ ID NO: 39. .
　（６－ｉｉ）の改変フィブロインは、配列番号２７、配列番号２８、配列番号２９、配列番号３０、配列番号３１、配列番号３８又は配列番号３９で示されるアミノ酸配列と９０％以上の配列同一性を有するアミノ酸配列を含むものである。（６－ｉｉ）の改変フィブロインもまた、式１：［（Ａ）ｎモチーフ－ＲＥＰ］ｍ、又は式２：［（Ａ）ｎモチーフ－ＲＥＰ］ｍ－（Ａ）ｎモチーフで表されるドメイン配列を含むタンパク質である。上記配列同一性は、９５％以上であることが好ましい。 The modified fibroin of (6-ii) has a sequence identity of 90% or more with the amino acid sequence represented by SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 38 or SEQ ID NO: 39. The amino acid sequence having The modified fibroin of (6-ii) is also represented by the formula 1: [(A) n motif-REP] m or the formula 2: [(A) n motif-REP] m- (A) n motif. A protein containing a sequence. The sequence identity is preferably 95% or more.
　（６－ｉｉ）の改変フィブロインは、グルタミン残基含有率が９％以下であることが好ましい。また、（６－ｉｉ）の改変フィブロインは、ＧＰＧＸＸモチーフ含有率が１０％以上であることが好ましい。 The modified fibroin (6-ii) preferably has a glutamine residue content of 9% or less. The modified fibroin (6-ii) preferably has a GPGXX motif content of 10% or more.
　上述の改変フィブロインは、Ｎ末端及びＣ末端のいずれか一方又は両方にタグ配列を含んでいてもよい。これにより、改変フィブロインの単離、固定化、検出及び可視化等が可能となる。 The above-mentioned modified fibroin may contain a tag sequence at one or both of the N-terminal and C-terminal. This makes it possible to isolate, immobilize, detect and visualize the modified fibroin.
　タグ配列を含む改変フィブロインのより具体的な例として、（６－ｉｉｉ）配列番号３２、配列番号３３、配列番号３４、配列番号３５、配列番号３６、配列番号４０若しくは配列番号４１で示されるアミノ酸配列を含む、改変フィブロイン、又は（６－ｉｖ）配列番号３２、配列番号３３、配列番号３４、配列番号３５、配列番号３６、配列番号４０若しくは配列番号４１で示されるアミノ酸配列と９０％以上の配列同一性を有するアミノ酸配列を含む、改変フィブロインを挙げることができる。 As more specific examples of modified fibroin containing a tag sequence, (6-iii) amino acids represented by SEQ ID NO: 32, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 40 or SEQ ID NO: 41 90% or more of the modified fibroin containing the sequence, or (6-iv) SEQ ID NO: 32, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 40 or SEQ ID NO: 41 Mention may be made of modified fibroin comprising amino acid sequences having sequence identity.
　配列番号３２、配列番号３３、配列番号３４、配列番号３５、配列番号３６、配列番号４０及び配列番号４１で示されるアミノ酸配列は、それぞれ配列番号２７、配列番号２８、配列番号２９、配列番号３０、配列番号３１、配列番号３８及び配列番号３９で示されるアミノ酸配列のＮ末端に配列番号５で示されるアミノ酸配列（Ｈｉｓタグ配列及びヒンジ配列を含む）を付加したものである。Ｎ末端にタグ配列を付加しただけであるため、グルタミン残基含有率に変化はなく、配列番号３２、配列番号３３、配列番号３４、配列番号３５、配列番号３６、配列番号４０及び配列番号４１で示されるアミノ酸配列は、いずれもグルタミン残基含有率が９％以下である（表３）。
Figure JPOXMLDOC01-appb-T000003
 The amino acid sequences shown by SEQ ID NO: 32, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 40 and SEQ ID NO: 41 are SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, respectively. The amino acid sequence represented by SEQ ID NO: 5 (including His tag sequence and hinge sequence) is added to the N-terminus of the amino acid sequence represented by SEQ ID NO: 31, SEQ ID NO: 38 and SEQ ID NO: 39. Since only the tag sequence was added to the N-terminus, there was no change in glutamine residue content, and SEQ ID NO: 32, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 40, and SEQ ID NO: 41. The glutamine residue content is 9% or less in any of the amino acid sequences indicated by (Table 3).
Figure JPOXMLDOC01-appb-T000003
　（６－ｉｉｉ）の改変フィブロインは、配列番号３２、配列番号３３、配列番号３４、配列番号３５、配列番号３６、配列番号４０又は配列番号４１で示されるアミノ酸配列からなるものであってもよい。 The modified fibroin of (6-iii) may be composed of the amino acid sequence represented by SEQ ID NO: 32, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 40 or SEQ ID NO: 41. .
　（６－ｉｖ）の改変フィブロインは、配列番号３２、配列番号３３、配列番号３４、配列番号３５、配列番号３６、配列番号４０又は配列番号４１で示されるアミノ酸配列と９０％以上の配列同一性を有するアミノ酸配列を含むものである。（６－ｉｖ）の改変フィブロインもまた、式１：［（Ａ）ｎモチーフ－ＲＥＰ］ｍ、又は式２：［（Ａ）ｎモチーフ－ＲＥＰ］ｍ－（Ａ）ｎモチーフで表されるドメイン配列を含むタンパク質である。上記配列同一性は、９５％以上であることが好ましい。 The modified fibroin (6-iv) has a sequence identity of 90% or more with the amino acid sequence represented by SEQ ID NO: 32, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 40 or SEQ ID NO: 41. The amino acid sequence having The modified fibroin of (6-iv) is also a domain represented by Formula 1: [(A) n motif-REP] m or Formula 2: [(A) n motif-REP] m- (A) n motif. A protein containing a sequence. The sequence identity is preferably 95% or more.
　（６－ｉｖ）の改変フィブロインは、グルタミン残基含有率が９％以下であることが好ましい。また、（６－ｉｖ）の改変フィブロインは、ＧＰＧＸＸモチーフ含有率が１０％以上であることが好ましい。 The modified fibroin (6-iv) preferably has a glutamine residue content of 9% or less. The modified fibroin (6-iv) preferably has a GPGXX motif content of 10% or more.
　上述の改変フィブロインは、組換えタンパク質生産系において生産されたタンパク質を宿主の外部に放出するための分泌シグナルを含んでいてもよい。分泌シグナルの配列は、宿主の種類に応じて適宜設定することができる。 The aforementioned modified fibroin may contain a secretion signal for releasing the protein produced in the recombinant protein production system to the outside of the host. The sequence of the secretion signal can be appropriately set according to the type of host.
＜改変フィブロインの製造方法＞
　上記いずれの実施形態に係る改変フィブロイン（タンパク質）も、例えば、当該タンパク質をコードする核酸配列と、当該核酸配列に作動可能に連結された１又は複数の調節配列とを有する発現ベクターで形質転換された宿主により、当該核酸を発現させることにより生産することができる。 <Method for producing modified fibroin>
The modified fibroin (protein) according to any of the above embodiments is transformed with, for example, an expression vector having a nucleic acid sequence encoding the protein and one or more regulatory sequences operably linked to the nucleic acid sequence. It can be produced by expressing the nucleic acid using a host.
　改変フィブロインをコードする核酸の製造方法は、特に制限されない。例えば、天然のフィブロインをコードする遺伝子を利用して、ポリメラーゼ連鎖反応（ＰＣＲ）などで増幅しクローニングし、遺伝子工学的手法により改変する方法、又は、化学的に合成する方法によって、当該核酸を製造することができる。核酸の化学的な合成方法も特に制限されず、例えば、ＮＣＢＩのウェブデータベースなどより入手したタンパク質のアミノ酸配列情報をもとに、ＡＫＴＡ　ｏｌｉｇｏｐｉｌｏｔ　ｐｌｕｓ　１０／１００（ＧＥヘルスケア・ジャパン株式会社）などで自動合成したオリゴヌクレオチドをＰＣＲなどで連結する方法によって遺伝子を化学的に合成することができる。この際に、改変フィブロインの精製及び／又は確認を容易にするため、上記のアミノ酸配列のＮ末端に開始コドン及びＨｉｓ１０タグからなるアミノ酸配列を付加したアミノ酸配列からなる改変フィブロインをコードする核酸を合成してもよい。 The method for producing the nucleic acid encoding the modified fibroin is not particularly limited. For example, using the gene encoding natural fibroin, the nucleic acid is produced by a method such as amplification by polymerase chain reaction (PCR), cloning, modification by genetic engineering techniques, or chemical synthesis. can do. The method for chemically synthesizing nucleic acids is not particularly limited. For example, AKTA oligopilot plus 10/100 (GE Healthcare Japan Co., Ltd.) is used based on the amino acid sequence information of proteins obtained from the NCBI web database. A gene can be chemically synthesized by a method of linking oligonucleotides that are synthesized automatically by PCR or the like. At this time, in order to facilitate purification and / or confirmation of the modified fibroin, a nucleic acid encoding the modified fibroin consisting of an amino acid sequence in which an amino acid sequence consisting of a start codon and a His10 tag is added to the N terminus of the above amino acid sequence is synthesized. May be.
　調節配列は、宿主における改変フィブロインの発現を制御する配列（例えば、プロモーター、エンハンサー、リボソーム結合配列、転写終結配列等）であり、宿主の種類に応じて適宜選択することができる。プロモーターとして、宿主細胞中で機能し、改変フィブロインを発現誘導可能な誘導性プロモーターを用いてもよい。誘導性プロモーターは、誘導物質（発現誘導剤）の存在、リプレッサー分子の非存在、又は温度、浸透圧若しくはｐＨ値の上昇若しくは低下等の物理的要因により、転写を制御できるプロモーターである。 Regulatory sequences are sequences that control the expression of modified fibroin in the host (for example, promoters, enhancers, ribosome binding sequences, transcription termination sequences, etc.), and can be appropriately selected depending on the type of host. As the promoter, an inducible promoter that functions in the host cell and can induce expression of the modified fibroin may be used. An inducible promoter is a promoter that can control transcription by the presence of an inducer (expression inducer), absence of a repressor molecule, or physical factors such as an increase or decrease in temperature, osmotic pressure or pH value.
　発現ベクターの種類は、プラスミドベクター、ウイルスベクター、コスミドベクター、フォスミドベクター、人工染色体ベクター等、宿主の種類に応じて適宜選択することができる。発現ベクターとしては、宿主細胞において自立複製が可能、又は宿主の染色体中への組込みが可能で、改変フィブロインをコードする核酸を転写できる位置にプロモーターを含有しているものが好適に用いられる。 The type of expression vector can be appropriately selected according to the type of host, such as a plasmid vector, virus vector, cosmid vector, fosmid vector, artificial chromosome vector, and the like. As the expression vector, a vector that can replicate autonomously in a host cell or can be integrated into a host chromosome and contains a promoter at a position where a nucleic acid encoding a modified fibroin can be transcribed is preferably used.
　宿主として、原核生物、並びに酵母、糸状真菌、昆虫細胞、動物細胞及び植物細胞等の真核生物のいずれも好適に用いることができる。 As the host, any of prokaryotes and eukaryotes such as yeast, filamentous fungi, insect cells, animal cells and plant cells can be preferably used.
　原核生物の宿主の好ましい例として、エシェリヒア属、ブレビバチルス属、セラチア属、バチルス属、ミクロバクテリウム属、ブレビバクテリウム属、コリネバクテリウム属及びシュードモナス属等に属する細菌を挙げることができる。エシェリヒア属に属する微生物として、例えば、エシェリヒア・コリ等を挙げることができる。ブレビバチルス属に属する微生物として、例えば、ブレビバチルス・アグリ等を挙げることができる。セラチア属に属する微生物として、例えば、セラチア・リクエファシエンス等を挙げることができる。バチルス属に属する微生物として、例えば、バチルス・サチラス等を挙げることができる。ミクロバクテリウム属に属する微生物として、例えば、ミクロバクテリウム・アンモニアフィラム等を挙げることができる。ブレビバクテリウム属に属する微生物として、例えば、ブレビバクテリウム・ディバリカタム等を挙げることができる。コリネバクテリウム属に属する微生物として、例えば、コリネバクテリウム・アンモニアゲネス等を挙げることができる。シュードモナス（Ｐｓｅｕｄｏｍｏｎａｓ）属に属する微生物として、例えば、シュードモナス・プチダ等を挙げることができる。 Preferred examples of prokaryotic hosts include bacteria belonging to the genus Escherichia, Brevibacillus, Serratia, Bacillus, Microbacterium, Brevibacterium, Corynebacterium, Pseudomonas and the like. Examples of microorganisms belonging to the genus Escherichia include Escherichia coli. Examples of microorganisms belonging to the genus Brevibacillus include Brevibacillus agri and the like. Examples of microorganisms belonging to the genus Serratia include Serratia liqufaciens and the like. Examples of microorganisms belonging to the genus Bacillus include Bacillus subtilis. Examples of microorganisms belonging to the genus Microbacterium include microbacterium / ammonia film. Examples of microorganisms belonging to the genus Brevibacterium include Brevibacterium divaricatam. Examples of microorganisms belonging to the genus Corynebacterium include Corynebacterium ammoniagenes. Examples of microorganisms belonging to the genus Pseudomonas include Pseudomonas putida.
　原核生物を宿主とする場合、改変フィブロインをコードする核酸を導入するベクターとしては、例えば、ｐＢＴｒｐ２（ベーリンガーマンハイム社製）、ｐＧＥＸ（Ｐｈａｒｍａｃｉａ社製）、ｐＵＣ１８、ｐＢｌｕｅｓｃｒｉｐｔＩＩ、ｐＳｕｐｅｘ、ｐＥＴ２２ｂ、ｐＣｏｌｄ、ｐＵＢ１１０、ｐＮＣＯ２（特開２００２－２３８５６９号公報）等を挙げることができる。 When a prokaryotic host is used as a vector for introducing a nucleic acid encoding a modified fibroin, for example, pBTrp2 (manufactured by Boehringer Mannheim), pGEX (manufactured by Pharmacia), pUC18, pBluescript II, pSupex, pET22b, pCold, pUB110, pNCO2 (Japanese Patent Laid-Open No. 2002-238696) and the like can be mentioned.
　真核生物の宿主としては、例えば、酵母及び糸状真菌（カビ等）を挙げることができる。酵母としては、例えば、サッカロマイセス属、ピキア属、シゾサッカロマイセス属等に属する酵母を挙げることができる。糸状真菌としては、例えば、アスペルギルス属、ペニシリウム属、トリコデルマ（Ｔｒｉｃｈｏｄｅｒｍａ）属等に属する糸状真菌を挙げることができる。 Examples of eukaryotic hosts include yeast and filamentous fungi (molds, etc.). Examples of the yeast include yeasts belonging to the genus Saccharomyces, Pichia, Schizosaccharomyces and the like. Examples of the filamentous fungi include filamentous fungi belonging to the genus Aspergillus, the genus Penicillium, the genus Trichoderma and the like.
　真核生物を宿主とする場合、改変フィブロインをコードする核酸を導入するベクターとしては、例えば、ＹＥｐ１３（ＡＴＣＣ３７１１５）、ＹＥｐ２４（ＡＴＣＣ３７０５１）等を挙げることができる。上記宿主細胞への発現ベクターの導入方法としては、上記宿主細胞へＤＮＡを導入する方法であればいずれも用いることができる。例えば、カルシウムイオンを用いる方法〔Ｐｒｏｃ．　Ｎａｔｌ．　Ａｃａｄ．　Ｓｃｉ．　ＵＳＡ，６９，２１１０（１９７２）〕、エレクトロポレーション法、スフェロプラスト法、プロトプラスト法、酢酸リチウム法、コンピテント法等を挙げることができる。 When a eukaryote is used as a host, examples of a vector into which a nucleic acid encoding a modified fibroin is introduced include YEp13 (ATCC37115) and YEp24 (ATCC37051). As a method for introducing the expression vector into the host cell, any method can be used as long as it is a method for introducing DNA into the host cell. For example, a method using calcium ions [Proc. Natl. Acad. Sci. USA, 69, 2110 (1972)], electroporation method, spheroplast method, protoplast method, lithium acetate method, competent method, and the like.
　発現ベクターで形質転換された宿主による核酸の発現方法としては、直接発現のほか、モレキュラー・クローニング第２版に記載されている方法等に準じて、分泌生産、融合タンパク質発現等を行うことができる。 As a method for expressing a nucleic acid by a host transformed with an expression vector, in addition to direct expression, secretory production, fusion protein expression, etc. can be performed according to the method described in Molecular Cloning 2nd edition, etc. .
　改変フィブロインは、例えば、発現ベクターで形質転換された宿主を培養培地中で培養し、培養培地中に当該タンパク質を生成蓄積させ、該培養培地から採取することにより製造することができる。宿主を培養培地中で培養する方法は、宿主の培養に通常用いられる方法に従って行うことができる。 The modified fibroin can be produced, for example, by culturing a host transformed with an expression vector in a culture medium, producing and accumulating the protein in the culture medium, and collecting the protein from the culture medium. The method for culturing a host in a culture medium can be performed according to a method usually used for culturing a host.
　宿主が、大腸菌等の原核生物又は酵母等の真核生物である場合、培養培地として、宿主が資化し得る炭素源、窒素源及び無機塩類等を含有し、宿主の培養を効率的に行える培地であれば天然培地、合成培地のいずれを用いてもよい。 When the host is a prokaryotic organism such as Escherichia coli or a eukaryotic organism such as yeast, the culture medium contains a carbon source, nitrogen source, inorganic salts, etc. that can be assimilated by the host, and can efficiently culture the host. If so, either a natural medium or a synthetic medium may be used.
　炭素源としては、上記形質転換微生物が資化し得るものであればよく、例えば、グルコース、フラクトース、スクロース、及びこれらを含有する糖蜜、デンプン及びデンプン加水分解物等の炭水化物、酢酸及びプロピオン酸等の有機酸、並びにエタノール及びプロパノール等のアルコール類を用いることができる。窒素源としては、例えば、アンモニア、塩化アンモニウム、硫酸アンモニウム、酢酸アンモニウム及びリン酸アンモニウム等の無機酸又は有機酸のアンモニウム塩、その他の含窒素化合物、並びにペプトン、肉エキス、酵母エキス、コーンスチープリカー、カゼイン加水分解物、大豆粕及び大豆粕加水分解物、各種発酵菌体及びその消化物を用いることができる。無機塩類としては、例えば、リン酸第一カリウム、リン酸第二カリウム、リン酸マグネシウム、硫酸マグネシウム、塩化ナトリウム、硫酸第一鉄、硫酸マンガン、硫酸銅及び炭酸カルシウムを用いることができる。 Any carbon source may be used as long as it can be assimilated by the above-mentioned transformed microorganism. Examples thereof include glucose, fructose, sucrose, and carbohydrates such as molasses, starch and starch hydrolyzate, acetic acid and propionic acid, etc. Organic acids and alcohols such as ethanol and propanol can be used. Examples of the nitrogen source include ammonium salts of inorganic acids or organic acids such as ammonia, ammonium chloride, ammonium sulfate, ammonium acetate, and ammonium phosphate, other nitrogen-containing compounds, and peptone, meat extract, yeast extract, corn steep liquor, Casein hydrolyzate, soybean meal and soybean meal hydrolyzate, various fermented cells and digested products thereof can be used. As inorganic salts, for example, monopotassium phosphate, dipotassium phosphate, magnesium phosphate, magnesium sulfate, sodium chloride, ferrous sulfate, manganese sulfate, copper sulfate and calcium carbonate can be used.
　大腸菌等の原核生物又は酵母等の真核生物の培養は、例えば、振盪培養又は深部通気攪拌培養等の好気的条件下で行うことができる。培養温度は、例えば、１５～４０℃である。培養時間は、通常１６時間～７日間である。培養中の培養培地のｐＨは３．０～９．０に保持することが好ましい。培養培地のｐＨの調整は、無機酸、有機酸、アルカリ溶液、尿素、炭酸カルシウム及びアンモニア等を用いて行うことができる。 Cultivation of prokaryotes such as E. coli or eukaryotes such as yeast can be performed under aerobic conditions such as shaking culture or deep aeration and agitation culture. The culture temperature is, for example, 15 to 40 ° C. The culture time is usually 16 hours to 7 days. The pH of the culture medium during the culture is preferably maintained at 3.0 to 9.0. The pH of the culture medium can be adjusted using an inorganic acid, an organic acid, an alkaline solution, urea, calcium carbonate, ammonia, or the like.
　また、培養中、必要に応じて、アンピシリン及びテトラサイクリン等の抗生物質を培養培地に添加してもよい。プロモーターとして誘導性のプロモーターを用いた発現ベクターで形質転換した微生物を培養するときには、必要に応じてインデューサーを培地に添加してもよい。例えば、ｌａｃプロモーターを用いた発現ベクターで形質転換した微生物を培養するときにはイソプロピル－β－Ｄ－チオガラクトピラノシド等を、ｔｒｐプロモーターを用いた発現ベクターで形質転換した微生物を培養するときにはインドールアクリル酸等を培地に添加してもよい。 Moreover, during the culture, antibiotics such as ampicillin and tetracycline may be added to the culture medium as necessary. When culturing a microorganism transformed with an expression vector using an inducible promoter as a promoter, an inducer may be added to the medium as necessary. For example, isopropyl-β-D-thiogalactopyranoside is used when cultivating a microorganism transformed with an expression vector using the lac promoter, and indole acrylic is used when culturing a microorganism transformed with an expression vector using the trp promoter. An acid or the like may be added to the medium.
　発現させた改変フィブロインの単離、精製は通常用いられている方法で行うことができる。例えば、当該タンパク質が、細胞内に溶解状態で発現した場合には、培養終了後、宿主細胞を遠心分離により回収し、水系緩衝液に懸濁した後、超音波破砕機、フレンチプレス、マントンガウリンホモゲナイザー及びダイノミル等により宿主細胞を破砕し、無細胞抽出液を得る。該無細胞抽出液を遠心分離することにより得られる上清から、タンパク質の単離精製に通常用いられている方法、すなわち、溶媒抽出法、硫安等による塩析法、脱塩法、有機溶媒による沈殿法、ジエチルアミノエチル（ＤＥＡＥ）－セファロース、ＤＩＡＩＯＮ　ＨＰＡ－７５（三菱化成社製）等のレジンを用いた陰イオン交換クロマトグラフィー法、Ｓ－Ｓｅｐｈａｒｏｓｅ　ＦＦ（Ｐｈａｒｍａｃｉａ社製）等のレジンを用いた陽イオン交換クロマトグラフィー法、ブチルセファロース、フェニルセファロース等のレジンを用いた疎水性クロマトグラフィー法、分子篩を用いたゲルろ過法、アフィニティークロマトグラフィー法、クロマトフォーカシング法、等電点電気泳動等の電気泳動法等の方法を単独又は組み合わせて使用し、精製標品を得ることができる。 Isolation and purification of the expressed modified fibroin can be performed by a commonly used method. For example, when the protein is expressed in a dissolved state in the cell, the host cell is recovered by centrifugation after culturing, suspended in an aqueous buffer, and then subjected to an ultrasonic crusher, a French press, a Manton Gaurin. The host cells are disrupted with a homogenizer, dynomill, or the like to obtain a cell-free extract. From the supernatant obtained by centrifuging the cell-free extract, a method usually used for protein isolation and purification, that is, a solvent extraction method, a salting-out method using ammonium sulfate, a desalting method, an organic solvent, etc. Precipitation method, anion exchange chromatography method using resin such as diethylaminoethyl (DEAE) -Sepharose, DIAION HPA-75 (manufactured by Mitsubishi Kasei), positive using resin such as S-Sepharose FF (manufactured by Pharmacia) Electrophoresis methods such as ion exchange chromatography, hydrophobic chromatography using resins such as butyl sepharose and phenyl sepharose, gel filtration using molecular sieve, affinity chromatography, chromatofocusing, isoelectric focusing Using methods such as these alone or in combination, purification It is possible to obtain the goods.
　また、改変フィブロインが細胞内に不溶体を形成して発現した場合は、同様に宿主細胞を回収後、破砕し、遠心分離を行うことにより、沈殿画分として改変フィブロインの不溶体を回収する。回収した改変フィブロインの不溶体はタンパク質変性剤で可溶化することができる。該操作の後、上記と同様の単離精製法により改変フィブロインの精製標品を得ることができる。当該タンパク質が細胞外に分泌された場合には、培養上清から当該タンパク質を回収することができる。すなわち、培養物を遠心分離等の手法により処理することにより培養上清を取得し、その培養上清から、上記と同様の単離精製法を用いることにより、精製標品を得ることができる。 In addition, when the modified fibroin is expressed by forming an insoluble substance in the cell, the host cell is similarly collected, crushed, and centrifuged to collect the modified fibroin insoluble substance as a precipitate fraction. The recovered insoluble form of modified fibroin can be solubilized with a protein denaturant. After the operation, a purified preparation of modified fibroin can be obtained by the same isolation and purification method as described above. When the protein is secreted extracellularly, the protein can be recovered from the culture supernatant. That is, a culture supernatant is obtained by treating the culture with a technique such as centrifugation, and a purified preparation can be obtained from the culture supernatant by using the same isolation and purification method as described above.
＜タンパク質（改変フィブロイン）フィラメントの製造方法＞
　タンパク質フィラメントは、公知の紡糸方法によって製造することができる。すなわち、例えば、改変フィブロインを主成分として含むタンパク質フィラメントを製造する際には、まず、上述した方法に準じて製造した改変フィブロインをジメチルスルホキシド（ＤＭＳＯ）、Ｎ，Ｎ－ジメチルホルムアミド（ＤＭＦ）、ギ酸、又はヘキサフルオロイソプロパノール（ＨＦＩＰ）等の溶媒に、必要に応じて、溶解促進剤としての無機塩と共に添加し、溶解してドープ液を作製する。次いで、このドープ液を用いて、湿式紡糸、乾式紡糸、乾湿式紡糸又は溶融紡糸等の公知の紡糸方法により紡糸して、タンパク質フィラメントを得ることができる。好ましい紡糸方法としては、湿式紡糸又は乾湿式紡糸を挙げることができる。 <Producing method of protein (modified fibroin) filament>
The protein filament can be produced by a known spinning method. That is, for example, when a protein filament containing modified fibroin as a main component is produced, first, the modified fibroin produced according to the above-described method is converted into dimethyl sulfoxide (DMSO), N, N-dimethylformamide (DMF), formic acid. Or a solvent such as hexafluoroisopropanol (HFIP), together with an inorganic salt as a dissolution accelerator, if necessary, and dissolved to prepare a dope solution. Next, using this dope solution, a protein filament can be obtained by spinning by a known spinning method such as wet spinning, dry spinning, dry wet spinning or melt spinning. Preferred spinning methods include wet spinning or dry wet spinning.
　図４は、タンパク質フィラメントを製造するための紡糸装置の一例を概略的に示す説明図である。図４に示す紡糸装置１０は、乾湿式紡糸用の紡糸装置の一例であり、押出し装置１と、未延伸糸製造装置２と、湿熱延伸装置３と、乾燥装置４とを有している。 FIG. 4 is an explanatory view schematically showing an example of a spinning device for producing protein filaments. A spinning device 10 shown in FIG. 4 is an example of a spinning device for dry and wet spinning, and includes an extrusion device 1, an undrawn yarn production device 2, a wet heat drawing device 3, and a drying device 4.
　紡糸装置１０を使用した紡糸方法を説明する。まず、貯槽７に貯蔵されたドープ液６が、ギアポンプ８により口金９から押し出される。ラボスケールにおいては、ドープ液をシリンダーに充填し、シリンジポンプを用いてノズルから押し出してもよい。次いで、押し出されたドープ液６は、エアギャップ１９を経て、凝固液槽２０の凝固液１１内に供給され、溶媒が除去されて、改変フィブロインが凝固し、繊維状凝固体が形成される。次いで、繊維状凝固体が、延伸浴槽２１内の温水１２中に供給されて、延伸される。延伸倍率は供給ニップローラ１３と引き取りニップローラ１４との速度比によって決まる。その後、延伸された繊維状凝固体が、乾燥装置４に供給され、糸道２２内で乾燥されて、タンパク質フィラメント３６が、巻糸体５として得られる。１８ａ～１８ｇは糸ガイドである。 A spinning method using the spinning device 10 will be described. First, the dope solution 6 stored in the storage tank 7 is pushed out from the base 9 by the gear pump 8. In the lab scale, the dope solution may be filled into a cylinder and extruded from a nozzle using a syringe pump. Next, the extruded dope liquid 6 is supplied into the coagulating liquid 11 in the coagulating liquid tank 20 through the air gap 19, the solvent is removed, the modified fibroin is coagulated, and a fibrous coagulated body is formed. Next, the fibrous solidified body is supplied into the hot water 12 in the drawing bath 21 and drawn. The draw ratio is determined by the speed ratio between the supply nip roller 13 and the take-up nip roller 14. Thereafter, the stretched fibrous solidified body is supplied to the drying device 4 and dried in the yarn path 22 to obtain the protein filament 36 as the wound body 5. Reference numerals 18a to 18g denote thread guides.
　凝固液１１としては、脱溶媒できる溶媒であればよく、例えば、メタノール、エタノール及び２－プロパノール等の炭素数１～５の低級アルコール、並びにアセトン等を挙げることができる。凝固液１１は、適宜水を含んでいてもよい。凝固液１１の温度は、０～３０℃であることが好ましい。口金９として、直径０．１～０．６ｍｍのノズルを有するシリンジポンプを使用する場合、押出し速度は１ホール当たり、０．２～６．０ｍＬ／時間が好ましく、１．４～４．０ｍＬ／時間であることがより好ましい。凝固した改変フィブロインが凝固液１１中を通過する距離（実質的には、糸ガイド１８ａから糸ガイド１８ｂまでの距離）は、脱溶媒が効率的に行える長さがあればよく、例えば、２００～５００ｍｍである。未延伸糸の引き取り速度は、例えば、１～２０ｍ／分であってよく、１～３ｍ／分であることが好ましい。凝固液１１中での滞留時間は、例えば、０．０１～３分であってよく、０．０５～０．１５分であることが好ましい。また、凝固液１１中で延伸（前延伸）をしてもよい。凝固液槽２０は多段設けてもよく、また延伸は必要に応じて、各段、又は特定の段で行ってもよい。 The coagulation liquid 11 may be any solvent that can be desolvated, and examples thereof include lower alcohols having 1 to 5 carbon atoms such as methanol, ethanol and 2-propanol, and acetone. The coagulation liquid 11 may appropriately contain water. The temperature of the coagulation liquid 11 is preferably 0 to 30 ° C. When a syringe pump having a nozzle having a diameter of 0.1 to 0.6 mm is used as the base 9, the extrusion speed is preferably 0.2 to 6.0 mL / hour per hole, and 1.4 to 4.0 mL / hour More preferably it is time. The distance through which the coagulated modified fibroin passes through the coagulating liquid 11 (substantially, the distance from the yarn guide 18a to the yarn guide 18b) may be long enough to efficiently remove the solvent. 500 mm. The take-up speed of the undrawn yarn may be, for example, 1 to 20 m / min, and preferably 1 to 3 m / min. The residence time in the coagulating liquid 11 may be, for example, 0.01 to 3 minutes, and preferably 0.05 to 0.15 minutes. Further, stretching (pre-stretching) may be performed in the coagulating liquid 11. The coagulating liquid tank 20 may be provided in multiple stages, and the stretching may be performed in each stage or a specific stage as necessary.
　なお、タンパク質フィラメントを得る際に実施される延伸は、例えば、上記した凝固液槽２０内で行う前延伸、及び延伸浴槽２１内で行う湿熱延伸の他、乾熱延伸も採用される。 In addition, as the stretching performed when obtaining the protein filament, for example, the pre-stretching performed in the coagulating liquid tank 20 and the wet heat stretching performed in the stretching bath 21 are used, and dry heat stretching is also employed.
　湿熱延伸は、温水中、温水に有機溶剤等を加えた溶液中、又はスチーム加熱中で行うことができる。温度としては、例えば、５０～９０℃であってよく、７５～８５℃が好ましい。湿熱延伸では、未延伸糸（又は前延伸糸）を、例えば、１～１０倍延伸することができ、２～８倍延伸することが好ましい。 Wet heat stretching can be performed in warm water, in a solution obtained by adding an organic solvent or the like to warm water, or in steam heating. The temperature may be, for example, 50 to 90 ° C., and preferably 75 to 85 ° C. In wet heat drawing, undrawn yarn (or predrawn yarn) can be drawn, for example, 1 to 10 times, and preferably 2 to 8 times.
　乾熱延伸は、電気管状炉、乾熱板等を使用して行うことができる。温度としては、例えば、１４０℃～２７０℃であってよく、１６０℃～２３０℃が好ましい。乾熱延伸では、未延伸糸（又は前延伸糸）を、例えば、０．５～８倍延伸することができ、１～４倍延伸することが好ましい。 Dry heat stretching can be performed using an electric tubular furnace, a dry heat plate, or the like. The temperature may be, for example, 140 ° C. to 270 ° C., and preferably 160 ° C. to 230 ° C. In dry heat drawing, an undrawn yarn (or predrawn yarn) can be drawn, for example, 0.5 to 8 times, and preferably 1 to 4 times.
　湿熱延伸及び乾熱延伸はそれぞれ単独で行ってもよく、またこれらを多段で、又は組み合わせて行ってもよい。すなわち、一段目延伸を湿熱延伸で行い、二段目延伸を乾熱延伸で行う、又は一段目延伸を湿熱延伸行い、二段目延伸を湿熱延伸行い、更に三段目延伸を乾熱延伸で行う等、湿熱延伸及び乾熱延伸を適宜組み合わせて行うことができる。 Wet heat stretching and dry heat stretching may be performed independently, or may be performed in multiple stages or in combination. That is, the first stage stretching is performed by wet heat stretching, the second stage stretching is performed by dry heat stretching, or the first stage stretching is performed by wet heat stretching, the second stage stretching is performed by wet heat stretching, and the third stage stretching is performed by dry heat stretching. For example, wet heat stretching and dry heat stretching can be appropriately combined.
　最終的な延伸倍率は、その下限値が、未延伸糸（又は前延伸糸）に対して、好ましくは、１倍超、２倍以上、３倍以上、４倍以上、５倍以上、６倍以上、７倍以上、８倍以上、９倍以上のうちのいずれかであり、上限値が、好ましくは４０倍以下、３０倍以下、２０倍以下、１５倍以下、１４倍以下、１３倍以下、１２倍以下、１１倍以下、１０倍以下である。 The final draw ratio of the lower limit of the undrawn yarn (or predrawn yarn) is preferably more than 1 time, 2 times or more, 3 times or more, 4 times or more, 5 times or more, 6 times. Above, 7 times or more, 8 times or more, 9 times or more, and upper limit is preferably 40 times or less, 30 times or less, 20 times or less, 15 times or less, 14 times or less, 13 times or less 12 times or less, 11 times or less, and 10 times or less.
　以上の方法により得られるタンパク質フィラメントの長さは、紡糸の条件により適宜調節することができ、１５００ｍを超えることが好ましく、１００００ｍ以上、１５０００ｍ以上、又は２００００ｍ以上であってもよい。 The length of the protein filament obtained by the above method can be appropriately adjusted depending on the spinning conditions, and preferably exceeds 1500 m, and may be 10,000 m or more, 15000 m or more, or 20000 m or more.
　タンパク質フィラメントは、紡糸後に後述する水性媒体と接触させ、次いで乾燥させた際の収縮率（乾燥後の収縮率）が、７％超、１５％以上、２５％以上、３２％以上、４０％以上、４８％以上、５６％以上、６４％以上、又は７２％以上となるものであってよい。乾燥後の収縮率は、通常、８０％以下である。ここで、タンパク質フィラメントの乾燥後の収縮率は下式で定義される。
　乾燥後の収縮率＝｛１－（水性媒体に接触させ、次いで乾燥させた後のタンパク質フィラメントの長さ／紡糸後、水性媒体に接触させる前のタンパク質フィラメントの長さ）｝×１００（％） The protein filament has a shrinkage ratio (shrinkage ratio after drying) of more than 7%, 15% or more, 25% or more, 32% or more, 40% or more when brought into contact with an aqueous medium described later after spinning and then dried. 48% or more, 56% or more, 64% or more, or 72% or more. The shrinkage after drying is usually 80% or less. Here, the shrinkage ratio after drying of the protein filament is defined by the following equation.
Shrinkage after drying = {1- (length of protein filament after contact with aqueous medium and then dried / length of protein filament after spinning and before contact with aqueous medium)} × 100 (%)
　また、タンパク質フィラメントは、紡糸後に水性媒体（例えば、沸点未満の水等）と接触して湿潤状態とされたときの収縮率（湿潤時収縮率）が、例えば、２％以上となるものであってもよく、２．５％以上、３％以上、３．５％以上、４％以上、４．５％以上、５％以上、５．５％以上、又は６％以上となるものであってもよい。湿潤時収縮率の上限は特に限定されないが、８０％以下、６０％以下、４０％以下、２０％以下、１０％以下、７％以下、６％以下、５％以下、４％以下、又は３％以下であってよい。ここで、タンパク質フィラメントの湿潤時収縮率は下式で定義される。
　湿潤時収縮率＝｛１－（水性媒体に接触させて湿潤状態にしたタンパク質フィラメントの長さ／紡糸後、水性媒体に接触させる前のタンパク質フィラメントの長さ）｝×１００（％） The protein filament has a shrinkage ratio (shrinkage ratio when wet) of, for example, 2% or more when it is wetted by contacting with an aqueous medium (for example, water having a boiling point below) after spinning. It may be 2.5% or more, 3% or more, 3.5% or more, 4% or more, 4.5% or more, 5% or more, 5.5% or more, or 6% or more. Also good. The upper limit of the shrinkage rate when wet is not particularly limited, but 80% or less, 60% or less, 40% or less, 20% or less, 10% or less, 7% or less, 6% or less, 5% or less, 4% or less, or 3 % Or less. Here, the shrinkage ratio when the protein filament is wet is defined by the following equation.
Shrinkage ratio when wet = {1- (length of protein filament wetted by contact with aqueous medium / length of protein filament after spinning and before contact with aqueous medium)} × 100 (%)
　＜開繊トウの製造方法＞
　本発明に係る開繊トウは、上述の方法により得たタンパク質フィラメントの束を捲縮させる工程（捲縮工程）と、捲縮されたタンパク質フィラメントの束を開繊して、開繊トウを得る工程（開繊工程）と、を備える方法により製造することができる。また、製造方法における任意の段階で、タンパク質フィラメントの束に油剤を付着させる工程（油剤付着工程）を実施してもよい。タンパク質フィラメントの束を構成するタンパク質フィラメントの本数は制限されず、１本以上であればよく、１００本以上、１９２本以上、１０００本以上、４８００本以上、５０００本以上、１万本以上、４８０００本以上、１０万本以上、又は１００万本以上であってよい。タンパク質フィラメントの束を構成するタンパク質フィラメントの本数に上限はないが、生産性の観点から、１千万本以下であることが好ましい。 <Manufacturing method of spread tow>
The spread tow according to the present invention obtains a spread tow by crimping a bundle of protein filaments obtained by the above-described method (crimping step) and opening the bundle of crimped protein filaments. And a process (opening process). Moreover, you may implement the process (oil agent adhesion process) of attaching an oil agent to the bundle | flux of protein filaments in the arbitrary steps in a manufacturing method. The number of protein filaments constituting the bundle of protein filaments is not limited and may be one or more, 100 or more, 192 or more, 1000 or more, 4800 or more, 5000 or more, 10,000 or more, 48000. There may be more than 100,000, more than 1,000, or more than one million. There is no upper limit to the number of protein filaments constituting the bundle of protein filaments, but it is preferably 10 million or less from the viewpoint of productivity.
（捲縮工程）
　捲縮工程により、最終的に得られる開繊トウが、より良好なソフト感を有するものとなる。タンパク質フィラメントの束は、従来の機械的捲縮加工により捲縮されてもよいし、水性媒体に接触させることにより捲縮されてもよい。また、これらの加工方法を併用することもできる。例えば、タンパク質フィラメントの束を機械的に捲縮させ、次いで水性媒体に接触させることで、タンパク質フィラメントの束に捲縮（クリンプ）を付与してもよい。機械的捲縮加工方法としては、例えば、仮撚り法、押込み法、擦過法、空気噴射法（高圧エアジェット法）、及び、賦型法が挙げられる。例えば、押込み法では、高速回転するローラーでタンパク質フィラメントの束をスタッファ・ボックス内に押込むことにより、タンパク質フィラメントの束に捲縮を付与し、熱で捲縮を固定（熱セット）する。 (Crimping process)
The open tow finally obtained by the crimping process has a better soft feeling. The bundle of protein filaments may be crimped by conventional mechanical crimping or may be crimped by contact with an aqueous medium. Moreover, these processing methods can also be used together. For example, the protein filament bundle may be crimped mechanically and then contacted with an aqueous medium to impart crimps to the protein filament bundle. Examples of the mechanical crimping method include a false twisting method, an indentation method, a rubbing method, an air injection method (high pressure air jet method), and a shaping method. For example, in the indentation method, a bundle of protein filaments is pushed into a stuffer box with a roller that rotates at a high speed, thereby crimping the bundle of protein filaments and fixing the crimp with heat (heat setting).
　水性媒体に接触させる加工方法によれば、外力によらずに、タンパク質フィラメントの束を捲縮させることができる。水性媒体とは、水（水蒸気を含む。）を含む液体又は気体（スチーム）の媒体である。水性媒体は水であってもよいし、水と親水性溶媒との混合液であってもよい。また、親水性溶媒としては、例えば、エタノール及びメタノール等の揮発性溶媒又はその蒸気を用いることも可能である。水性媒体は、水とエタノールとの混合溶液であることが好ましい。揮発性溶媒又はその蒸気を含む水性媒体を使用することで、タンパク質フィラメントの束が早く乾燥し、よりソフト感のある仕上がりになる。水と揮発性溶媒又はその蒸気との比率は、特に限定されず、例えば、水：揮発性溶媒又はその蒸気は、質量比で１０：９０～９０：１０であってもよい。水性媒体が液体である場合、水性媒体には、例えば、工程通過用（例えば帯電防止用等）又は仕上げ用の油剤等、公知の油剤を分散させてもよい。このような油剤を分散させた水性媒体を用いることによって、捲縮工程とフィラメントへの油剤付着工程とを同時に行うことができ、以って、目的とする開繊トウの製造工程数の削減が有利にはかられ得る。なお、油剤の量は、特に限定されず、例えば、水性媒体全量に対して１～１０質量％であってもよく、或いは２～５質量％であってよい。 According to the processing method in which the aqueous medium is brought into contact, the bundle of protein filaments can be crimped regardless of external force. The aqueous medium is a liquid or gas (steam) medium containing water (including water vapor). The aqueous medium may be water or a mixed solution of water and a hydrophilic solvent. Moreover, as a hydrophilic solvent, it is also possible to use volatile solvents, such as ethanol and methanol, or its vapor | steam, for example. The aqueous medium is preferably a mixed solution of water and ethanol. By using an aqueous medium containing a volatile solvent or its vapor, the bundle of protein filaments dries quickly, resulting in a softer finish. The ratio of water to the volatile solvent or the vapor thereof is not particularly limited. For example, the water: volatile solvent or the vapor thereof may be 10:90 to 90:10 by mass ratio. When the aqueous medium is a liquid, a known oil agent such as an oil for process passage (for example, antistatic) or a finishing agent may be dispersed in the aqueous medium. By using such an aqueous medium in which an oil agent is dispersed, the crimping step and the oil agent attaching step to the filament can be performed at the same time, thereby reducing the number of manufacturing steps of the desired fiber opening tow. It can be advantageously removed. The amount of the oil agent is not particularly limited, and may be, for example, 1 to 10% by mass or 2 to 5% by mass with respect to the total amount of the aqueous medium.
　水性媒体の温度は、１０℃以上、２５℃以上、４０℃以上、６０℃以上、又は１００℃以上であってよく、２３０℃以下、１２０℃以下、又は１００℃以下であってよい。より具体的には、水性媒体が気体（スチーム）である場合、水性媒体の温度は１００～２３０℃が好ましく、１００～１２０℃がより好ましい。水性媒体のスチームが２３０℃以下であると、タンパク質フィラメントの熱変性を防ぐことができる。水性媒体が液体である場合、水性媒体の温度は、効率良く捲縮を付与する観点から、１０℃以上、２５℃以上、又は４０℃以上が好ましく、タンパク質フィラメントの繊維強度を高く保つ観点から、６０℃以下が好ましい。水性媒体をタンパク質フィラメントの束に接触させる時間は、特に制限されないが、３０秒以上、１分以上、又は２分以上であってよく、生産性の観点から１０分以下であることが好ましい。タンパク質フィラメントの束への水性媒体の接触は、常圧下で行ってもよく、減圧下（例えば、真空）で行ってもよい。 The temperature of the aqueous medium may be 10 ° C or higher, 25 ° C or higher, 40 ° C or higher, 60 ° C or higher, or 100 ° C or higher, and 230 ° C or lower, 120 ° C or lower, or 100 ° C or lower. More specifically, when the aqueous medium is a gas (steam), the temperature of the aqueous medium is preferably from 100 to 230 ° C, more preferably from 100 to 120 ° C. When the steam of the aqueous medium is 230 ° C. or lower, heat denaturation of the protein filament can be prevented. When the aqueous medium is a liquid, the temperature of the aqueous medium is preferably 10 ° C. or higher, 25 ° C. or higher, or 40 ° C. or higher from the viewpoint of efficiently imparting crimp, and from the viewpoint of keeping the fiber strength of the protein filament high, 60 degrees C or less is preferable. The time for contacting the aqueous medium with the bundle of protein filaments is not particularly limited, but may be 30 seconds or more, 1 minute or more, or 2 minutes or more, and is preferably 10 minutes or less from the viewpoint of productivity. Contact of the aqueous medium with the bundle of protein filaments may be performed under normal pressure or under reduced pressure (for example, vacuum).
　タンパク質フィラメントの束に水性媒体を接触させる方法としては、タンパク質フィラメントの束を水中に浸漬する方法、タンパク質フィラメントの束に対して水性媒体のスチームを噴霧する方法、水性媒体のスチームが充満した環境にタンパク質フィラメントの束を暴露する方法等が挙げられる。水性媒体がスチームである場合、タンパク質フィラメントの束への水性媒体の接触は、一般的なスチームセット装置を使用して行うことができる。スチームセット装置の具体例としては、製品名：ＦＭＳＡ型スチームセッター（福伸工業株式会社製）、製品名：ＥＰＳ－４００（辻井染機工業株式会社製）等の装置を挙げることができる。水性媒体のスチームによりタンパク質フィラメントの束を捲縮させる方法の具体例としては、所定の収容室内にタンパク質フィラメントの束を収容する一方、収容室内に水性媒体のスチームを導入して、収容室内の温度を上記所定温度（例えば、１００℃～２３０℃）に調整しつつ、タンパク質フィラメントの束にスチームを接触させることが挙げられる。 Examples of the method of bringing an aqueous medium into contact with the bundle of protein filaments include a method of immersing the bundle of protein filaments in water, a method of spraying aqueous medium steam on the bundle of protein filaments, and an environment filled with steam of the aqueous medium. Examples include a method of exposing a bundle of protein filaments. When the aqueous medium is steam, the aqueous medium can be contacted with the bundle of protein filaments using a conventional steam setting apparatus. Specific examples of the steam setting device include devices such as product name: FMSA type steam setter (manufactured by Fukushin Kogyo Co., Ltd.) and product name: EPS-400 (manufactured by Sakurai Dyeing Machinery Co., Ltd.). As a specific example of a method of crimping a bundle of protein filaments with steam of an aqueous medium, a bundle of protein filaments is accommodated in a predetermined storage chamber, while steam of the aqueous medium is introduced into the storage chamber, The steam may be brought into contact with a bundle of protein filaments while adjusting the temperature to the predetermined temperature (for example, 100 ° C. to 230 ° C.).
　なお、水性媒体との接触によるタンパク質フィラメントの束の捲縮工程は好ましくはタンパク質フィラメントの束に対して引張力が何ら加えられない（繊維軸方向に何ら緊張されない）状態、若しくは所定の大きさだけ加えられた（繊維軸方向に所定量だけ緊張させられた）状態で実施される。その際にタンパク質フィラメントの束に加えられる引張力を調整することで、捲縮の程度をコントロールすることが可能となる。タンパク質フィラメントの束に加えられる引張力の調整方法としては、例えば、タンパク質フィラメントの束に様々な重さの重りを吊す等して、タンパク質フィラメントの束に対して負荷される荷重を調整する方法、タンパク質フィラメントの束を弛ませた状態で両末端を固定すると共に、その弛み量を種々変更する方法、タンパク質フィラメントの束を紙管又はボビン等の被巻回体に巻き付けると共に、その際の巻き付け力（紙管やボビンへの締付力）を適宜に変更する方法等が挙げられる。 In addition, the crimping step of the bundle of protein filaments by contact with the aqueous medium is preferably in a state where no tensile force is applied to the bundle of protein filaments (no tension is applied in the direction of the fiber axis) or a predetermined size. It is carried out in the state of being added (strained by a predetermined amount in the fiber axis direction). In this case, the degree of crimping can be controlled by adjusting the tensile force applied to the bundle of protein filaments. As a method of adjusting the tensile force applied to the bundle of protein filaments, for example, a method of adjusting a load applied to the bundle of protein filaments by suspending weights of various weights on the bundle of protein filaments, A method of fixing both ends in a state in which a bundle of protein filaments is loosened and variously changing the amount of looseness, winding a bundle of protein filaments around a wound body such as a paper tube or a bobbin, and winding force at that time Examples thereof include a method of appropriately changing (clamping force to the paper tube or bobbin).
　タンパク質フィラメントの束に水性媒体を接触させた後、タンパク質フィラメントの束を乾燥してもよい。乾燥方法は、特に限定されず、自然乾燥でもよく、乾燥設備を使用して強制的にタンパク質フィラメントの束を乾燥させてもよい。水性媒体による捲縮とその後の乾燥は、連続的に行うことができる。具体的には、例えば、ボビンからタンパク質フィラメントの束を送り出しながら、水性媒体中に浸漬した後、熱風を吹き付けるか、又はホットローラー上に送り出すことで乾燥することができる。乾燥温度としては、特に限定されず、例えば、２０～１５０℃であってよく、４０～１２０℃であることが好ましく、６０～１００℃であることがより好ましい。 The protein filament bundle may be dried after the aqueous medium is brought into contact with the bundle of protein filaments. The drying method is not particularly limited, natural drying may be used, and the protein filament bundle may be forcibly dried using a drying facility. Crimping with an aqueous medium and subsequent drying can be carried out continuously. Specifically, for example, the protein filament bundle can be dipped in an aqueous medium while being sent out from a bobbin, and then dried by blowing hot air or sending it on a hot roller. The drying temperature is not particularly limited, and may be, for example, 20 to 150 ° C., preferably 40 to 120 ° C., and more preferably 60 to 100 ° C.
　以上の方法により捲縮されたタンパク質フィラメントの束は、捲縮（クリンプ）を有する。捲縮の度合いは制限されず、捲縮数は、例えば、１０～１００個／４０ｍｍであってよく、２０～４０個／４０ｍｍであってもよい。 The bundle of protein filaments crimped by the above method has crimps. The degree of crimp is not limited, and the number of crimps may be, for example, 10 to 100 pieces / 40 mm, or 20 to 40 pieces / 40 mm.
（油剤付着工程）
　油剤付着工程では、タンパク質フィラメントの束に油剤を付着させ、タンパク質フィラメントに種々の特性を付与することができる。油剤付着工程は、製造方法における任意の段階で実施することができる。例えば、捲縮工程の前、捲縮工程と同時、又は捲縮工程後であってかつ開繊工程前に油剤付着工程を実施してもよい。油剤は特に限定されず、タンパク質フィラメントの束に付与する特性に応じて、公知の油剤から選択することができる。油剤は、帯電防止性、潤滑性、収束性、耐熱性等、各工程を円滑に実施するための特性を付与するもの（すなわち、工程通過用）であってもよいし、最終的に得られる開繊トウに柔軟性、帯電防止性等の所望の特性を付与するもの（すなわち、仕上げ用）であってもよい。 (Oil agent adhesion process)
In the oil agent attaching step, the oil agent is attached to the bundle of protein filaments, and various properties can be imparted to the protein filament. The oil agent attaching step can be performed at any stage in the production method. For example, the oil agent attaching step may be performed before the crimping step, simultaneously with the crimping step, or after the crimping step and before the fiber opening step. The oil agent is not particularly limited, and can be selected from known oil agents according to the properties imparted to the bundle of protein filaments. The oil agent may be one that imparts characteristics for smoothly performing each process such as antistatic property, lubricity, convergence, heat resistance, etc. (that is, for passing through the process), and is finally obtained. It may be one that imparts desired characteristics such as flexibility and antistatic properties to the opened tow (ie, for finishing).
（開繊工程）
　開繊工程では、捲縮されたタンパク質フィラメントの束を開繊して、開繊トウを得る。開繊させる方法は特に限定されず、従来公知の方法を使用できる。例えば、ハンドカードを用いてタンパク質フィラメントの束を繊維軸方向にひっかくことにより、又は、回転する開繊ローラーを使用することにより、タンパク質フィラメントの束を開繊してもよい。あるいは、タンパク質フィラメントの束の繊維軸方向に向かってエアジェットを噴射することにより、タンパク質フィラメントの束を開繊することもできる。 (Opening process)
In the opening process, a bundle of crimped protein filaments is opened to obtain a opened tow. The method of opening is not particularly limited, and a conventionally known method can be used. For example, the protein filament bundle may be opened by scratching the bundle of protein filaments in the fiber axis direction using a hand card or by using a rotating opening roller. Alternatively, the bundle of protein filaments can be opened by jetting an air jet in the direction of the fiber axis of the bundle of protein filaments.
　以上の方法により製造される、本発明に係る開繊トウによれば、極太糸を製造するために多数の開繊トウをつなぎ合わせる必要がないため、極太糸を容易に製造することができる。また、多数の開繊トウをつなぎ合わせる必要がないため、つなぎ目のない、又はつなぎ目の少ない、見栄えの良い最終製品（チャンキーニットのセーター、ブランケット等）を得ることができる。さらに、本発明に係る開繊トウはフィラメントの束により構成され、その製造にあたってステープルを紡ぐ工程が不要であるため、高い生産性で製造することができる。さらに、本発明に係る開繊トウには、改変フィブロインの設計により、ウールに似た特性、天然シルク及び再生シルクでは得られない特性など、所望の特性をもたせることができる。 According to the opened tow according to the present invention manufactured by the above method, it is not necessary to join a large number of opened tows in order to produce an extremely thick yarn, and thus an extremely thick yarn can be easily manufactured. In addition, since it is not necessary to join a large number of spread tows, a finished product (chunky knit sweater, blanket, etc.) having no joints or few joints can be obtained. Furthermore, since the opened tow according to the present invention is composed of a bundle of filaments and does not require a step of spinning staples in its manufacture, it can be manufactured with high productivity. Furthermore, the opened tow according to the present invention can have desired characteristics such as characteristics similar to wool, characteristics not obtainable with natural silk and regenerated silk, by design of the modified fibroin.
　以下、実施例に基づいて本発明をより具体的に説明する。ただし、本発明は以下の実施例に限定されるものではない。 Hereinafter, the present invention will be described more specifically based on examples. However, the present invention is not limited to the following examples.
＜改変クモ糸フィブロインの製造＞
（１）プラスミド発現株の作製
　ネフィラ・クラビペス（Ｎｅｐｈｉｌａ　ｃｌａｖｉｐｅｓ）由来のフィブロイン（ＧｅｎＢａｎｋアクセッション番号：Ｐ４６８０４．１、ＧＩ：１１７４４１５）の塩基配列及びアミノ酸配列に基づき、配列番号１３で示されるアミノ酸配列を有する改変フィブロイン（以下、「ＰＲＴ７９９」ともいう。）を設計した。なお、配列番号１３で示されるアミノ酸配列は、ネフィラ・クラビペス由来のフィブロインのアミノ酸配列に対して、生産性の向上を目的としてアミノ酸残基の置換、挿入及び欠失を施したアミノ酸配列を有し、さらにＮ末端に配列番号５で示されるアミノ酸配列（タグ配列及びヒンジ配列）が付加されている。 <Manufacture of modified spider silk fibroin>
(1) Preparation of plasmid expression strain Based on the nucleotide sequence and amino acid sequence of fibroin (GenBank accession numbers: P46804.1, GI: 1174415) derived from Nephila clavipes, the amino acid sequence represented by SEQ ID NO: 13 A modified fibroin (hereinafter also referred to as “PRT799”) was designed. The amino acid sequence represented by SEQ ID NO: 13 has an amino acid sequence in which substitution, insertion, and deletion of amino acid residues are performed for the purpose of improving productivity with respect to the amino acid sequence of fibroin derived from Nephila clavipes. Furthermore, an amino acid sequence (tag sequence and hinge sequence) represented by SEQ ID NO: 5 is added to the N-terminus.
　次に、ＰＲＴ７９９をコードする核酸を合成した。当該核酸には、５’末端にＮｄｅＩサイト及び終止コドン下流にＥｃｏＲＩサイトを付加した。当該核酸をクローニングベクター（ｐＵＣ１１８）にクローニングした。その後、同核酸をＮｄｅＩ及びＥｃｏＲＩで制限酵素処理して切り出した後、タンパク質発現ベクターｐＥＴ－２２ｂ（＋）に組換えて発現ベクターを得た。 Next, a nucleic acid encoding PRT799 was synthesized. The nucleic acid was added with an NdeI site at the 5 'end and an EcoRI site downstream of the stop codon. The nucleic acid was cloned into a cloning vector (pUC118). Thereafter, the nucleic acid was cleaved by restriction enzyme treatment with NdeI and EcoRI, and then recombined with the protein expression vector pET-22b (+) to obtain an expression vector.
（２）タンパク質の発現
　配列番号１３で示されるアミノ酸配列を有するタンパク質をコードする核酸を含むｐＥＴ２２ｂ（＋）発現ベクターで、大腸菌ＢＬＲ（ＤＥ３）を形質転換した。当該形質転換大腸菌を、アンピシリンを含む２ｍＬのＬＢ培地で１５時間培養した。当該培養液を、アンピシリンを含む１００ｍＬのシード培養用培地（表４）にＯＤ６００が０．００５となるように添加した。培養液温度を３０℃に保ち、ＯＤ６００が５になるまでフラスコ培養を行い（約１５時間）、シード培養液を得た。 (2) Expression of protein Escherichia coli BLR (DE3) was transformed with a pET22b (+) expression vector containing a nucleic acid encoding a protein having the amino acid sequence represented by SEQ ID NO: 13. The transformed Escherichia coli was cultured in 2 mL of LB medium containing ampicillin for 15 hours. The culture solution was added to 100 mL of a seed culture medium (Table 4) containing ampicillin so that the OD 600 was 0.005. The culture temperature was kept at 30 ° C., and flask culture was performed until the OD 600 reached 5 (about 15 hours) to obtain a seed culture solution.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　当該シード培養液を５００ｍＬの生産培地（表５）を添加したジャーファーメンターにＯＤ６００が０．０５となるように添加した。培養液温度を３７℃に保ち、ｐＨ６．９で一定に制御して培養した。また培養液中の溶存酸素濃度を、溶存酸素飽和濃度の２０％に維持するようにした。 The seed culture was added to a jar fermenter to which 500 mL of production medium (Table 5) was added so that the OD 600 was 0.05. The culture solution temperature was maintained at 37 ° C., and the culture was performed at a constant pH of 6.9. Further, the dissolved oxygen concentration in the culture solution was maintained at 20% of the dissolved oxygen saturation concentration.
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　生産培地中のグルコースが完全に消費された直後に、フィード液（グルコース４５５ｇ／１Ｌ、Ｙｅａｓｔ　Ｅｘｔｒａｃｔ　１２０ｇ／１Ｌ）を１ｍＬ／分の速度で添加した。培養液温度を３７℃に保ち、ｐＨ６．９で一定に制御して培養した。また培養液中の溶存酸素濃度を、溶存酸素飽和濃度の２０％に維持するようにし、２０時間培養を行った。その後、１Ｍのイソプロピル－β－チオガラクトピラノシド（ＩＰＴＧ）を培養液に対して終濃度１ｍＭになるよう添加し、改変フィブロインを発現誘導させた。ＩＰＴＧ添加後２０時間経過した時点で、培養液を遠心分離し、菌体を回収した。ＩＰＴＧ添加前とＩＰＴＧ添加後の培養液から調製した菌体を用いてＳＤＳ－ＰＡＧＥを行い、ＩＰＴＧ添加に依存した目的とする改変フィブロインサイズのバンドの出現により、目的とする改変フィブロインの発現を確認した。 Immediately after the glucose in the production medium was completely consumed, a feed solution (glucose 455 g / 1 L, Yeast Extract 120 g / 1 L) was added at a rate of 1 mL / min. The culture solution temperature was maintained at 37 ° C., and the culture was performed at a constant pH of 6.9. In addition, the dissolved oxygen concentration in the culture solution was maintained at 20% of the dissolved oxygen saturation concentration, and cultured for 20 hours. Thereafter, 1M isopropyl-β-thiogalactopyranoside (IPTG) was added to the culture solution to a final concentration of 1 mM to induce expression of the modified fibroin. At the time when 20 hours passed after the addition of IPTG, the culture solution was centrifuged, and the cells were collected. Perform SDS-PAGE using cells prepared from the culture solution before and after IPTG addition, and confirm the expression of the desired modified fibroin by the appearance of the desired modified fibroin size band depending on the addition of IPTG did.
（３）タンパク質の精製
　ＩＰＴＧを添加してから２時間後に回収した菌体を２０ｍＭ　Ｔｒｉｓ－ＨＣｌ　ｂｕｆｆｅｒ（ｐＨ７．４）で洗浄した。洗浄後の菌体を約１ｍＭのＰＭＳＦを含む２０ｍＭＴｒｉｓ－ＨＣｌ緩衝液（ｐＨ７．４）に懸濁させ、高圧ホモジナイザー（ＧＥＡ　Ｎｉｒｏ　Ｓｏａｖｉ社製）で細胞を破砕した。破砕した細胞を遠心分離し、沈殿物を得た。得られた沈殿物を、高純度になるまで２０ｍＭＴｒｉｓ－ＨＣｌ緩衝液（ｐＨ７．４）で洗浄した。洗浄後の沈殿物を１００ｍｇ／ｍＬの濃度になるように８Ｍ　グアニジン緩衝液（８Ｍグアニジン塩酸塩、１０ｍＭリン酸二水素ナトリウム、２０ｍＭＮａＣｌ、１ｍＭＴｒｉｓ－ＨＣｌ、ｐＨ７．０）で懸濁し、６０℃で３０分間、スターラーで撹拌し、溶解させた。溶解後、透析チューブ（三光純薬株式会社製のセルロースチューブ３６／３２）を用いて水で透析を行った。透析後に得られた白色の凝集タンパク質を遠心分離により回収し、凍結乾燥機で水分を除き、凍結乾燥粉末を回収することにより、改変クモ糸フィブロイン「ＰＲＴ７９９」を得た。 (3) Protein purification The cells recovered 2 hours after the addition of IPTG were washed with 20 mM Tris-HCl buffer (pH 7.4). The washed cells were suspended in 20 mM Tris-HCl buffer (pH 7.4) containing about 1 mM PMSF, and the cells were disrupted with a high-pressure homogenizer (GEA Niro Soavi). The disrupted cells were centrifuged to obtain a precipitate. The resulting precipitate was washed with 20 mM Tris-HCl buffer (pH 7.4) until high purity. The washed precipitate is suspended in 8 M guanidine buffer (8 M guanidine hydrochloride, 10 mM sodium dihydrogen phosphate, 20 mM NaCl, 1 mM Tris-HCl, pH 7.0) to a concentration of 100 mg / mL, and 30 ° C. at 30 ° C. Stir with a stirrer for minutes to dissolve. After dissolution, dialysis was performed with water using a dialysis tube (cellulose tube 36/32 manufactured by Sanko Junyaku Co., Ltd.). The white aggregated protein obtained after dialysis was collected by centrifugation, water was removed with a freeze dryer, and the lyophilized powder was collected to obtain a modified spider silk fibroin “PRT799”.
＜タンパク質フィラメントの製造＞
（１）ドープ液の調製
　ＤＭＳＯに、上述の改変フィブロイン（ＰＲＴ７９９）を濃度２４質量％となるよう添加した後、溶解促進剤としてＬｉＣｌを濃度４．０質量％となるように添加した。その後、シェーカーを使用して、改変フィブロインを３時間かけて溶解させ、ＤＭＳＯ溶液を得た。得られたＤＭＳＯ溶液中のゴミと泡を取り除き、ドープ液とした。ドープ液の溶液粘度は９０℃において５０００ｃＰ（センチポアズ）であった。 <Production of protein filament>
(1) Preparation of Dope Solution After adding the above-mentioned modified fibroin (PRT799) to DMSO to a concentration of 24% by mass, LiCl was added as a dissolution accelerator to a concentration of 4.0% by mass. Thereafter, the modified fibroin was dissolved over 3 hours using a shaker to obtain a DMSO solution. Dust and bubbles in the obtained DMSO solution were removed to prepare a dope solution. The solution viscosity of the dope solution was 5000 cP (centipoise) at 90 ° C.
（２）紡糸
　上記のようにして得られたドープ液と図４に示される紡糸装置１０を用いて公知の乾湿式紡糸を行って、ボビンに巻かれた繊度約４００デニールのタンパク質フィラメントを得た。なお、ここでは、乾湿式紡糸を下記の条件で行った。
　凝固液（メタノール）の温度：５～１０℃
　延伸倍率：４．５２倍
　乾燥温度：８０℃ (2) Spinning Known dry and wet spinning was performed using the dope obtained as described above and the spinning device 10 shown in FIG. 4 to obtain a protein filament having a fineness of about 400 denier wound around a bobbin. . Here, dry and wet spinning was performed under the following conditions.
Coagulation liquid (methanol) temperature: 5-10 ° C
Stretch ratio: 4.52 times Drying temperature: 80 ° C
＜実施例１＞
　上記のようにして得られたタンパク質フィラメントを２５ボビン分合糸して束にし、２０℃の水に浸漬して縮ませることにより、タンパク質フィラメントの束を捲縮させた。次いで、タンパク質フィラメントの束を４０℃で１８時間乾燥させることで、図５に示す捲縮されたタンパク質フィラメントの束を得た。このとき、タンパク質フィラメントの収縮率は５０質量％であった。タンパク質フィラメントの束を十分に乾かした後、ハンドカードでタンパク質フィラメントの束を繊維軸方向にひっかき、図６に示す開繊トウを得た。かかる開繊トウの繊度は約２万デニールであり、優れたソフト感を有していた。 <Example 1>
The protein filaments obtained as described above were combined with 25 bobbins to form a bundle and immersed in water at 20 ° C. to shrink the protein filament, thereby crimping the protein filament bundle. Next, the bundle of protein filaments was dried at 40 ° C. for 18 hours to obtain a bundle of crimped protein filaments shown in FIG. At this time, the shrinkage ratio of the protein filament was 50% by mass. After sufficiently drying the bundle of protein filaments, the bundle of protein filaments was scratched in the direction of the fiber axis with a hand card to obtain an open tow as shown in FIG. The fineness of the spread tow was about 20,000 denier and had an excellent soft feeling.
＜実施例２＞
　実施例１同様、タンパク質フィラメントを２５ボビン分合糸して束にした。これを押込み法により捲縮させた。次いで、帯電防止用の油剤を２０質量％の濃度で分散させた２０℃の水に１分間浸漬させることにより、タンパク質フィラメントの束を再度捲縮させた。次いで、タンパク質フィラメントの束を４０℃で１８時間乾燥させることで、捲縮されたタンパク質フィラメントの束を得た。タンパク質フィラメントの束を十分に乾かした後、ハンドカードでタンパク質フィラメントの束を繊維軸方向にひっかき、図７に示す開繊トウを得た。かかる開繊トウの繊度は約２万デニールであり、優れたソフト感を有していた。 <Example 2>
As in Example 1, protein filaments were combined into 25 bobbins and bundled. This was crimped by the indentation method. Subsequently, the bundle of protein filaments was crimped again by immersing in 20 ° C. water in which an antistatic oil agent was dispersed at a concentration of 20% by mass for 1 minute. Next, the bundle of protein filaments was dried at 40 ° C. for 18 hours to obtain a bundle of crimped protein filaments. After sufficiently drying the bundle of protein filaments, the bundle of protein filaments was scratched in the fiber axis direction with a hand card to obtain a spread tow as shown in FIG. The fineness of the spread tow was about 20,000 denier and had an excellent soft feeling.
　１…押出し装置、２…未延伸糸製造装置、３…湿熱延伸装置、４…乾燥装置、６…ドープ液、１０…紡糸装置、２０…凝固液槽、２１…延伸浴槽、３６…タンパク質フィラメント。 DESCRIPTION OF SYMBOLS 1 ... Extrusion apparatus, 2 ... Undrawn yarn manufacturing apparatus, 3 ... Wet heat drawing apparatus, 4 ... Drying apparatus, 6 ... Dope liquid, 10 ... Spinning apparatus, 20 ... Coagulation liquid tank, 21 ... Drawing bath, 36 ... Protein filament.

Claims (9)

  1. 　タンパク質フィラメントの開繊トウであって、
    　前記タンパク質フィラメントは、改変フィブロインを含み、かつ、捲縮を有する、開繊トウ。     A protein filament opening tow,
    The opened tow, wherein the protein filament includes modified fibroin and has crimps.
  2. 　前記改変フィブロインが、改変クモ糸フィブロインである、請求項１に記載の開繊トウ。 The opened tow according to claim 1, wherein the modified fibroin is a modified spider silk fibroin.
  3. 　前記改変フィブロインが、配列番号９、配列番号１１、配列番号１３、配列番号２４、配列番号２５、配列番号２６、配列番号３２、配列番号３３、配列番号３４、配列番号３５、配列番号３６、配列番号４０、若しくは配列番号４１で示されるアミノ酸配列を有する、又は、配列番号９、配列番号１１、配列番号１３、配列番号２４、配列番号２５、配列番号２６、配列番号３２、配列番号３３、配列番号３４、配列番号３５、配列番号３６、配列番号４０、若しくは配列番号４１で示されるアミノ酸配列と９０％以上の配列同一性を有するアミノ酸配列を有する、請求項１又は２に記載の開繊トウ。 The modified fibroin is SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 32, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 40, or the amino acid sequence shown by SEQ ID NO: 41, or SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 32, SEQ ID NO: 33, sequence The open tow according to claim 1 or 2, which has an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 40, or SEQ ID NO: 41. .
  4. 　タンパク質フィラメントの開繊トウを製造する方法であって、
    　タンパク質フィラメントの束を捲縮させる工程と、
    　捲縮された前記タンパク質フィラメントの前記束を開繊して、開繊トウを得る工程と、を備え、
    　前記タンパク質フィラメントは改変フィブロインを含む、製造方法。     A method for producing an open tow of a protein filament comprising:
    Crimping a bundle of protein filaments;
    Opening the bundle of crimped protein filaments to obtain a spread tow,
    The production method, wherein the protein filament comprises a modified fibroin.
  5. 　前記改変フィブロインが、改変クモ糸フィブロインである、請求項４に記載の製造方法。 The production method according to claim 4, wherein the modified fibroin is a modified spider silk fibroin.
  6. 　前記捲縮させる工程が、前記タンパク質フィラメントの前記束を機械的に捲縮させること、又は、前記タンパク質フィラメントの前記束を水性媒体に接触させることを含む、請求項４又は５に記載の製造方法。 The manufacturing method according to claim 4 or 5, wherein the crimping step includes mechanically crimping the bundle of protein filaments, or contacting the bundle of protein filaments with an aqueous medium. .
  7. 　前記捲縮させる工程が、前記タンパク質フィラメントの前記束を機械的に捲縮させ、次いで水性媒体に接触させることを含む、請求項６に記載の製造方法。 The method according to claim 6, wherein the crimping step includes mechanically crimping the bundle of protein filaments and then contacting the bundle with an aqueous medium.
  8. 　前記水性媒体の温度が、１０～２３０℃である、請求項６又は７に記載の製造方法。 The production method according to claim 6 or 7, wherein the temperature of the aqueous medium is 10 to 230 ° C.
  9. 　前記改変フィブロインが、配列番号９、配列番号１１、配列番号１３、配列番号２４、配列番号２５、若しくは配列番号２６、配列番号３２、配列番号３３、配列番号３４、配列番号３５、配列番号３６、配列番号４０、若しくは配列番号４１で示されるアミノ酸配列を有する、又は、配列番号９、配列番号１１、配列番号１３、配列番号２４、配列番号２５、若しくは配列番号２６、配列番号３２、配列番号３３、配列番号３４、配列番号３５、配列番号３６、配列番号４０、若しくは配列番号４１で示されるアミノ酸配列と９０％以上の配列同一性を有するアミノ酸配列を有する、請求項４～８のいずれか一項に記載の製造方法。 The modified fibroin is SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 24, SEQ ID NO: 25, or SEQ ID NO: 26, SEQ ID NO: 32, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, It has the amino acid sequence represented by SEQ ID NO: 40 or SEQ ID NO: 41, or is SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 24, SEQ ID NO: 25, or SEQ ID NO: 26, SEQ ID NO: 32, SEQ ID NO: 33 The amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 40, or SEQ ID NO: 41. The production method according to item.
PCT/JP2019/003470 2018-01-31 2019-01-31 Opened tow of protein filament and method for manufacturing same WO2019151433A1 (en)

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JPS62171697A (en) * 1986-01-24 1987-07-28 ピイ・エイ・コンサルテイング・サ−ビシズ・リミテツド Production of silk component
JPS63219611A (en) * 1987-03-03 1988-09-13 Katakura Kogyo Kk Production of silk-based wadding
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