WO2020027153A1 - Fibres de fibroïne modifiées et leur procédé de production - Google Patents

Fibres de fibroïne modifiées et leur procédé de production Download PDF

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WO2020027153A1
WO2020027153A1 PCT/JP2019/029892 JP2019029892W WO2020027153A1 WO 2020027153 A1 WO2020027153 A1 WO 2020027153A1 JP 2019029892 W JP2019029892 W JP 2019029892W WO 2020027153 A1 WO2020027153 A1 WO 2020027153A1
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amino acid
seq
modified fibroin
sequence
fibroin
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PCT/JP2019/029892
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English (en)
Japanese (ja)
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久弘 工藤
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Ｓｐｉｂｅｒ株式会社
小島プレス工業株式会社
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Publication of WO2020027153A1 publication Critical patent/WO2020027153A1/fr

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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
    • D02J1/22—Stretching or tensioning, shrinking or relaxing, e.g. by use of overfeed and underfeed apparatus, or preventing stretch

Definitions

  • the present invention relates to a modified fibroin fiber and a method for producing the same.
  • the wet spinning method and the dry-wet spinning method are also used when producing modified fibroin fibers containing modified fibroin as a main component (for example, see Patent Document 1).
  • modified fibroin fibers Various properties are required for the modified fibroin fiber depending on the application, and one of them may be required to have sufficient strength.
  • the modified fibroin fibers obtained by the wet method and the dry-wet method voids are generated inside the raw material fibers due to the removal of the solvent in the coagulation liquid, and the strength may be insufficient due to the voids.
  • an object of the present invention is to provide a modified fibroin fiber having high strength.
  • Another object of the present invention is to provide a method for producing a modified fibroin fiber having high strength.
  • the present invention relates to, for example, the following inventions.
  • a modified fibroin fiber comprising the modified fibroin and having a density greater than 1.34 g / cm 3 .
  • [3] (A) a first drawing step of drawing a raw fiber containing modified fibroin in a water bath, and (b) a heating step of heating and drying the raw fiber after the first drawing step, and heat-shrinking the fiber in the radial direction. And producing a modified fibroin fiber.
  • a modified fibroin fiber having high strength can be provided. Further, according to the present invention, a method for producing a modified fibroin fiber having high strength can be provided.
  • FIG. 7 (A) shows an undrawn yarn production device—first-stage drawing device
  • FIG. 7 (B) shows a second-stage drawing device.
  • the modified fibroin fiber according to the present embodiment contains modified fibroin, and has a density of more than 1.34 g / cm 3 .
  • the modified fibroin according to this 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. Including proteins.
  • the modified fibroin may further have an amino acid sequence (N-terminal sequence and C-terminal sequence) added to 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, but not limited to, typically a region having no repeat of the amino acid motif characteristic of fibroin, and are composed of about 100 amino acids.
  • modified fibroin means 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.
  • naturally-derived 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. Is a protein containing the domain sequence to be determined.
  • Modified fibroin may be a directly used amino acid sequence of a naturally occurring fibroin, or a modified amino acid sequence based on the amino acid sequence of a naturally occurring fibroin (for example, cloned naturally occurring fibroin).
  • the amino acid sequence may be modified by modifying the gene sequence of fibroin), or may be artificially designed and synthesized without using naturally occurring fibroin (for example, a nucleic acid encoding the designed amino acid sequence may be used). Which have a desired amino acid sequence by chemical synthesis).
  • domain sequence refers to a crystalline region unique to fibroin (typically, corresponding to the (A) n motif of the amino acid sequence) and an amorphous region (typically, the REP of the amino acid sequence).
  • the (A) n motif indicates an amino acid sequence mainly containing an alanine residue, and has 2 to 27 amino acid residues.
  • the number of amino acid residues in 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 n motif may be 40% or more, and is 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 of only alanine residues).
  • At least seven of the (A) n motifs present in the domain sequence may be composed of only alanine residues.
  • 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.
  • the plurality of (A) n motifs may have the same amino acid sequence or different amino acid sequences.
  • a plurality of REPs may have the same amino acid sequence or different amino acid sequences.
  • the modified fibroin according to the present embodiment has, for example, an amino acid sequence corresponding to, for example, substitution, deletion, insertion and / or addition of one or more amino acid residues with respect to a cloned natural fibroin gene sequence.
  • an amino acid sequence corresponding to, for example, substitution, deletion, insertion and / or addition of one or more amino acid residues with respect to a cloned natural fibroin gene sequence can be obtained by performing the following modification.
  • Substitution, deletion, insertion and / or addition of amino acid residues can be performed by methods well known to those skilled in the art, such as partial specific mutagenesis. Specifically, Nucleic Acid Res. 10, 6487 (1982) and Methods ⁇ in ⁇ Enzymology, 100, 448 (1983).
  • Naturally occurring 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. Yes, specifically, for example, fibroin produced by insects or spiders.
  • fibroin produced by insects examples include Bombyx @ mori, Bombyx @ mandarina, natural silkworm (Antheraea @ yamamai), tussah (Anterea @ pernii), and maple silkworm (Erioganyerii). ), Silkworms produced by silkworms (Samia cynthia), chestnut worms (Caligura japonica), tussah silkworms (Antheraea mylitta), silkworms such as moga silkworms (Antheraea assama), and silkworms produced by larvae of the hornet beetle Hornet silk protein.
  • fibroin produced by insects include, for example, silkworm fibroin L chain (GenBank Accession No. M76430 (base sequence) and AAA27840.1 (amino acid sequence)).
  • Examples of the fibroin produced by the spiders include spiders belonging to the genus Araneus (genus Araneus), such as the spiders, the spiders, the red spider, the red spider, the green spider, etc.
  • Spiders belonging to the genus Argiope genus such as spiders belonging to the genus Procarpus spp.
  • Spiders belonging to the genus Pronus such as spiders belonging to the genus Procarpus spp.
  • Spiders belonging to the genus Pronus and spider spiders belonging to the genus Cynotarachne, such as the genus Cyrtarachne, such as Torinofundamashi and Otorinofundamashi.
  • Spiders belonging to the genus Ordgarius such as spiders belonging to the genus (Gasteracantha), spiders belonging to the genus Orbalis, and spiders belonging to the genus Ordgarius, such as the spiders belonging to the genus Ordgarius.
  • Spiders belonging to the genus Argiope such as Argiope bruennichi, spiders belonging to the genus Argiope, such as Argiope spiders, spiders belonging to the genus Arachnura, spiders belonging to the genus Acusilas, such as spiders belonging to the genus Acusilas, and spider spiders belonging to the spider spiders, such as the spider spiders belonging to the genus Acusilas Spiders belonging to the genus Spider (Genus Poltys) such as spiders belonging to the genus (Cytophora) and spiders belonging to the genus (Potys), spiders belonging to the genus Spiders (genus Cyclosa) such as the spiders belonging to the genus Cyclosa and spiders belonging to the genus Cygnus spp.
  • Geneus Poltys such as spiders belonging to the genus (Cytophora) and spiders belonging to the genus (Potys
  • Spider silk proteins produced by spiders belonging to the genus Chorizopes), and asina such as red-headed spiders, red-backed spiders, blue-backed spiders and urocore-red spiders Spiders belonging to the genus Tetragnatha, spiders belonging to the genus Tetragnatha, spiders belonging to the genus Leucaegium, such as the spiders Argiope bruennichi and spiders spiders belonging to the genus Leucauge, such as the spiders belonging to the genus Nephila sp.
  • Spiders belonging to the genus Dyschiriognatha such as spiders belonging to the genus Menosira and spiders belonging to the genus Dyschiriognatha, such as spiders belonging to the genus Dyschiriognatha, and spiders belonging to the genus Latus sp. Spiders belonging to the family Tetragnathidae such as spiders belonging to the genus Prostenops (Euprosthenops) are produced. Spider silk protein. Examples of the spider silk protein include dragline proteins such as MaSp (MaSp1 and MaSp2) and ADF (ADF3 and ADF4), and MiSp (MiSp1 and MiSp2).
  • spider silk proteins produced by spiders include, for example, fibroin-3 (adf-3) [derived from Araneus diadematus] (GenBank accession number 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 spidroin 1 [derived from amino acid sequence of Nephila claviBAC04A4 and derived from amino acid sequence of ph ), U37520 (base sequence)), major ⁇ ampullate ⁇ spidro n 1 [Derived from Latrodictus hesperus] (GenBank accession number ABR68856 (amino acid sequence), EF595246 (base sequence)), dragline silk protein spidroin 2 [Derived from Nephila clavata (GenBank accession number
  • CAJ00428 amino acid sequence
  • AJ97155 base sequence
  • major ⁇ sample ⁇ spidroin ⁇ 2 [Euprosus] ] GenBank Accession No. CAM32249.1 (amino acid sequence), AM490169 (base sequence)
  • minor ⁇ silk ⁇ protein ⁇ 1 [Nephila ⁇ clavipes] GenBank Accession No. AAC14589.1 (amino acid sequence)
  • minor ⁇ ampilatte [in] Nephila clavipes] GenBank Accession No. AAC14591.1 (amino acid sequence)
  • minor ampoulate spidroin-like protein [Nephilengys Cruenata] GenBank Accession No. ABR3727.1.
  • fibroin in which sequence information is registered in NCBI GenBank.
  • sequence information is registered in NCBI GenBank.
  • spidroin, ampullate, fibroin, "silk and polypeptide", or “silk and protein” is described as a keyword in DEFINITION from among sequences including INV as DIVISION in the sequence information registered in NCBI @ GenBank. It can be confirmed by extracting a character string of a specific product from a sequence or CDS, and extracting a sequence in which a specific character string is described in TISSUE @ TYPE from SOURCE.
  • the modified fibroin according to this embodiment may be a modified silk (silk) fibroin (an amino acid sequence of a silk protein produced by a silkworm modified), and a modified spider silk fibroin (a spider silk protein produced by an arachnid). Modified amino acid sequence).
  • a modified spider silk fibroin is preferable.
  • the modified fibroin include a modified fibroin (first modified fibroin) derived from a large spinal cord marker protein produced in a spider's large ampullate gland, and a domain sequence having a reduced content of glycine residues.
  • first modified fibroin derived from a large spinal cord marker protein produced in a spider's large ampullate gland
  • domain sequence having a reduced content of glycine residues derived from a large spinal cord marker protein produced in a spider's large ampullate gland
  • a second modified fibroin derived from a large spinal cord marker protein produced in a spider's large ampullate gland
  • a second modified fibroin derived from a large spinal cord marker protein produced in a spider's large ampullate gland
  • second modified fibroin derived from a large spinal cord marker protein produced in a spider's large ampullate gland
  • a domain sequence having a reduced content of glycine residues derived from a large spinal cord marker protein produced in a spider's large ampul
  • the first modified fibroin includes a protein containing a domain sequence represented by Formula 1: [(A) n motif-REP] m .
  • the number of amino acid residues of the (A) n motif is preferably an integer of 3 to 20, more preferably an integer of 4 to 20, still more preferably an integer of 8 to 20, and 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 in Formula 1 is preferably 10 to 200 residues, more preferably 10 to 150 residues, and more preferably 20 to 100 residues.
  • the first modified fibroin has the total number of glycine, serine and alanine residues contained in the amino acid sequence represented by Formula 1: [(A) n motif-REP] m
  • the total number is preferably 40% or more, more preferably 60% or more, and even more preferably 70% or more.
  • the first modified fibroin comprises a unit of the amino acid sequence represented by Formula 1: [(A) n motif-REP] m , and has a C-terminal sequence represented by any of SEQ ID NOS: 1 to 3 or
  • the polypeptide may be an amino acid sequence having 90% or more homology with the amino acid sequence shown in any one of SEQ ID NOs: 1 to 3.
  • the amino acid sequence shown in SEQ ID NO: 1 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: 2 is
  • the amino acid sequence shown in SEQ ID NO: 3 is identical to the amino acid sequence shown in SEQ ID NO: 1 by removing 20 residues, and the amino acid sequence shown in SEQ ID NO: 3 is obtained by removing 29 residues from the C-terminal of the amino acid sequence shown in SEQ ID NO: 1. It is identical to the amino acid sequence.
  • the first modified fibroin (1-i) an amino acid sequence represented by SEQ ID NO: 4 (recombinant ⁇ spider ⁇ silk ⁇ protein ⁇ ADF3KaiLargeNRSH1) or (1-ii) an amino acid sequence represented by SEQ ID NO: 4 and 90 Modified fibroin comprising an amino acid sequence having at least% sequence identity.
  • the sequence identity is preferably 95% or more.
  • the amino acid sequence represented by SEQ ID NO: 4 is the same as the amino acid sequence of ADF3 in which an amino acid sequence (SEQ ID NO: 5) comprising an initiation codon, a His10 tag, and an HRV3C protease (Human ⁇ rhinovirus @ 3C protease) recognition site at the N-terminus is added.
  • the 13th repeat region was increased so as to be approximately doubled, and the mutation was mutated so that translation was terminated at the 1154th amino acid residue.
  • the amino acid sequence at the C-terminus of the amino acid sequence represented by SEQ ID NO: 4 is the same as the amino acid sequence represented by SEQ ID NO: 3.
  • the modified fibroin of (1-i) may have an amino acid sequence represented by SEQ ID NO: 4.
  • the second modified fibroin has an amino acid sequence whose domain sequence has a reduced content of glycine residues as compared to naturally occurring fibroin.
  • the second modified fibroin can be said to have an amino acid sequence corresponding to at least one or more glycine residues in the REP replaced by another amino acid residue, as compared to a naturally occurring fibroin. .
  • the second modified fibroin has a domain sequence of GGX and GPGXX in REP (where G is a glycine residue, P is a proline residue, and X is an amino acid residue other than glycine, as compared with a naturally-derived fibroin. At least one motif sequence selected from the group consisting of at least one glycine residue in one or more of the motif sequences has been replaced with another amino acid residue. You may.
  • the ratio of the motif sequence in which the glycine residue is replaced with another amino acid residue may be 10% or more of the entire motif sequence.
  • the second modified fibroin comprises a domain sequence represented by Formula 1: [(A) n motif-REP] m , and from the (A) n motif located at the most C-terminal side to the domain sequence
  • 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 up to the C-terminus is represented by z, From, when the total number of amino acid residues in the sequence excluding the sequence from the (A) n motif located at the most C-terminal side to the C-terminal of the domain sequence is defined as w, z / w is 30% or more; It may have an amino acid sequence of 40% or more, 50% or more, or 50.9% or more.
  • 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 more preferably 95% or more. More preferably, it is even more preferably 100% (meaning that it is composed of only alanine residues).
  • the second modified fibroin is preferably one in which the content of the amino acid sequence consisting of XGX is increased by substituting one glycine residue of the GGX motif with another amino acid residue.
  • 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, further preferably 10% or less, and 6% or less. %, Still more preferably 4% or less, further 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 XGGX below.
  • z / w (%) can be calculated by dividing z by w.
  • z / w is preferably 50.9% or more, more preferably 56.1% or more, still more preferably 58.7% or more, and 70% or more. Is still more preferred, and even more preferably 80% or more.
  • the upper limit of z / w is not particularly limited, but may be, for example, 95% or less.
  • the second modified fibroin is modified, for example, by replacing at least a part of the base sequence encoding a glycine residue from the cloned natural fibroin gene sequence to encode another amino acid residue.
  • a GGX motif and one glycine residue in the GPGXX motif may be selected, or the glycine residue may be substituted so that z / w becomes 50.9% or more.
  • the amino acid sequence can be obtained by designing an amino acid sequence satisfying the above aspect from the amino acid sequence of naturally occurring fibroin, and chemically synthesizing a nucleic acid encoding the designed amino acid sequence.
  • one or more amino acid residues are further substituted or deleted.
  • the amino acid sequence corresponding to insertion, addition, 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 a glycine residue, but includes a valine (V) residue, a leucine (L) residue, an isoleucine (I) residue, and a methionine ( M) residue, hydrophobic amino acid residue 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 hydrophilic amino acid residues such as glutamic acid (E) residues, and valine (V) residues, leucine (L) residues, isoleucine (I) residues, phenylalanine ( F) residues and glutamine (Q) residues are more preferred, and glutamine (Q) residues are even more preferred.
  • the second modified fibroin examples include (2-i) SEQ ID NO: 6 (Met-PRT380), SEQ ID NO: 7 (Met-PRT410), SEQ ID NO: 8 (Met-PRT525) or SEQ ID NO: 9 (Met -PRT799), or (2-ii) an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, or SEQ ID NO: 9, Modified fibroin can be mentioned.
  • the modified fibroin (2-i) will be described.
  • the amino acid sequence represented by SEQ ID NO: 6 is obtained by replacing all GGX in the REP of the amino acid sequence represented by SEQ ID NO: 10 (Met-PRT313) corresponding to naturally occurring fibroin with GQX.
  • the amino acid sequence represented by SEQ ID NO: 7 is obtained by deleting every two (A) n motifs from the N-terminal side to the C-terminal side from the amino acid sequence represented by SEQ ID NO: 6, and further before the C-terminal sequence. In which one [(A) n motif-REP] was inserted.
  • the amino acid sequence represented by SEQ ID NO: 8 has two alanine residues inserted at the C-terminal side of each (A) n motif of the amino acid sequence represented by SEQ ID NO: 7, and further has a partial glutamine (Q) residue. It has been replaced with a serine (S) residue, and some amino acids on the C-terminal side have been deleted so that the molecular weight becomes almost the same as SEQ ID NO: 7.
  • the amino acid sequence represented by SEQ ID NO: 9 has a region of 20 domain sequences present in the amino acid sequence represented by SEQ ID NO: 7 (however, several amino acid residues on the C-terminal side of the region are substituted). Is repeated four times with a predetermined hinge sequence and His tag sequence added to the C-terminal.
  • the value of z / w in the amino acid sequence represented by SEQ ID NO: 10 (corresponding to naturally occurring fibroin) is 46.8%.
  • the values of z / w in the amino acid sequence represented by SEQ ID NO: 6, the amino acid sequence represented by SEQ ID NO: 7, the amino acid sequence represented by SEQ ID NO: 8, and the amino acid sequence represented by SEQ ID NO: 9 are 58.7%, respectively. 70.1%, 66.1% and 70.0%.
  • the value of x / y at the jagged ratio (described later) of 1: 1.8 to 11.3 of the amino acid sequences represented by SEQ ID NO: 10, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, and SEQ ID NO: 9 is as follows: They are 15.0%, 15.0%, 93.4%, 92.7% and 89.8%, respectively.
  • the modified fibroin of (2-i) may have an amino acid sequence represented by SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, or SEQ ID NO: 9.
  • the modified fibroin of (2-ii) contains an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8 or SEQ ID NO: 9.
  • 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 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, or SEQ ID NO: 9, and contains XGX ( Where X represents an amino acid residue other than glycine.)
  • z is the total number of amino acid residues in the amino acid sequence consisting of Is preferably 50.9% or more.
  • the second modified fibroin may include a tag sequence at one or both of the N-terminus and the C-terminus. As a result, the modified fibroin can be isolated, immobilized, detected, visualized, and the like.
  • the tag sequence examples include an affinity tag utilizing specific affinity (binding property, affinity) with another molecule.
  • affinity tag is a histidine tag (His tag).
  • His tag is a short peptide in which about 4 to 10 histidine residues are arranged, and has a property of specifically binding to a metal ion such as nickel. Therefore, isolation of a modified fibroin by metal chelation chromatography (chelating @ metal @ chromatography).
  • SEQ ID NO: 11 amino acid sequence including a His tag sequence and a hinge sequence.
  • tag sequences such as glutathione-S-transferase (GST), which specifically binds to glutathione, and maltose binding protein (MBP), which specifically binds to maltose, can be used.
  • GST glutathione-S-transferase
  • MBP maltose binding protein
  • an “epitope tag” utilizing an antigen-antibody reaction can be used.
  • a peptide (epitope) showing antigenicity as a tag sequence an antibody against the epitope can be bound.
  • the epitope tag include an HA (peptide sequence of hemagglutinin of influenza virus) tag, myc tag, and FLAG tag.
  • a tag sequence that can be cleaved by a specific protease can be used.
  • protease treatment By subjecting the protein adsorbed via the tag sequence to protease treatment, the modified fibroin from which the tag sequence has been separated can also be recovered.
  • modified fibroin containing a tag sequence (2-iii) the amino acid represented by SEQ ID NO: 12 (PRT380), SEQ ID NO: 13 (PRT410), SEQ ID NO: 14 (PRT525), or SEQ ID NO: 15 (PRT799)
  • Modified fibroin comprising a sequence or (2-iv) an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, or SEQ ID NO: 15 can be mentioned. .
  • amino acid sequences represented by SEQ ID NO: 16 (PRT313), SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, and SEQ ID NO: 15 are represented by SEQ ID NO: 10, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, and SEQ ID NO: 9, respectively.
  • An amino acid sequence represented by SEQ ID NO: 11 (including a His tag sequence and a hinge sequence) is added to the N-terminal of the amino acid sequence shown.
  • the modified fibroin of (2-iii) may have an amino acid sequence represented by SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, or SEQ ID NO: 15.
  • the modified fibroin of (2-iv) includes an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, or SEQ ID NO: 15.
  • 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 of (2-iv) has 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, or SEQ ID NO: 15, and contains XGX (where X represents an amino acid residue other than glycine.)
  • z is the total number of amino acid residues in the amino acid sequence consisting of Is preferably 50.9% or more.
  • the second modified fibroin may include a secretion signal for releasing a 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 the host.
  • the third modified fibroin has an amino acid sequence whose domain sequence has a reduced content of the (A) n motif as compared to a naturally occurring fibroin. It can be said that the domain sequence of the third modified fibroin has an amino acid sequence corresponding to the deletion of at least one or a plurality of (A) n motifs as compared to naturally occurring fibroin.
  • the third modified fibroin may have an amino acid sequence corresponding to 10 to 40% deletion of the (A) n motif from naturally occurring fibroin.
  • the third modification fibroin its domain sequence, compared to the naturally occurring fibroin, at least from the N-terminal side toward the C-terminal one to three (A) n motif every one (A) n motif May have an amino acid sequence corresponding to the deletion of
  • the third modified fibroin has a domain sequence deletion of at least two (A) n motifs from the N-terminal side to the C-terminal side, and one (A) It may have an amino acid sequence corresponding to the deletion of the n motif repeated in this order.
  • the third modified fibroin may have a domain sequence having an amino acid sequence corresponding to the deletion of the (A) n motif at least every third sequence from the N-terminal side to the C-terminal side. .
  • the third modified fibroin comprises a domain sequence represented by Formula 1: [(A) n motif-REP] m , and two adjacent [(A) n motifs from the N-terminal side to the C-terminal side] -REP]
  • the number of amino acid residues of REP in the unit is sequentially compared, and when the number of amino acid residues of REP having a small number of amino acid residues is set to 1, the ratio of the number of amino acid residues of the other REP is 1.8 to When the maximum value of the sum of the number of amino acid residues of two adjacent [(A) n motif-REP] units that is 11.3 is x, and the total number of amino acid residues in the domain sequence is y In addition, 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.
  • 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 more preferably 95% or more. More preferably, it is even more preferably 100% (meaning that it is composed of only alanine residues).
  • FIG. 1 shows a domain sequence obtained by removing the N-terminal sequence and the C-terminal sequence from the modified fibroin. From the N-terminal side (left side), the domain sequence is (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 an n motif.
  • FIG. 1 shows pattern 1 (comparison of the first REP and the second REP, and comparison of the third REP with the fourth REP), pattern 2 (comparison of the first REP and the second REP, and Pattern 4 (comparison of the second REP with the third REP, and comparison of the fourth REP with the fifth REP), pattern 4 (the comparison of the fourth REP with the fifth REP), and pattern 4 (the first REP with the fifth REP). Second REP comparison). Note that there are other selection methods.
  • the number of amino acid residues of each REP in two selected adjacent [(A) n motif-REP] units is compared.
  • each pattern the total number of amino acid residues of two adjacent [(A) n motif-REP] units shown by a solid line is added (not only the REP but also the number of amino acid residues of the (A) n motif. is there.). Then, the sum total is compared, and the total value (maximum value of the total values) of the patterns having the maximum total value is 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 in the domain sequence.
  • x / y is preferably at least 50%, more preferably at least 60%, further preferably at least 65%, and even more preferably at least 70%. Preferably, it is still more preferably at least 75%, particularly preferably at least 80%.
  • the upper limit of x / y is not particularly limited, and may be, for example, 100% or less. When the indentation ratio is 1: 1.9 to 11.3, x / y is preferably 89.6% or more, and when the indentation ratio is 1: 1.8 to 3.4, x / y is x / y.
  • / Y is preferably at least 77.1%, and when the jagged ratio is 1: 1.9 to 8.4, x / y is preferably at least 75.9%, and the jagged ratio is 1 In the case of 1.9 to 4.1, x / y is preferably at least 64.2%.
  • x / y should be 46.4% or more. Is preferably 50% or more, more preferably 55% or more, still more preferably 60% or more, even more preferably 70% or more, and even more preferably 80% or more. It is particularly preferred that there is.
  • the upper limit of x / y is not particularly limited, and may be 100% or less.
  • x / y in naturally occurring fibroin will be described.
  • 663 types of fibroins (among them, 415 types of spider-derived fibroins) were extracted.
  • x / y was calculated from the amino acid sequence of the naturally occurring fibroin composed of the domain sequence represented by Formula 1: [(A) n motif-REP] m by the above calculation method.
  • FIG. 3 shows the results when the indentation ratio is 1: 1.9 to 4.1.
  • the horizontal axis in FIG. 3 indicates x / y (%), and the vertical axis indicates frequency.
  • the x / y of the naturally derived fibroin is less than 64.2% (the highest is 64.14%).
  • the third modified fibroin deletes one or more of the sequence encoding the (A) n motif from the cloned natural fibroin gene sequence such that x / y is 64.2% or more. Can be obtained. Further, for example, an amino acid sequence corresponding to deletion of one or more (A) n motifs is designed so that x / y is 64.2% or more based on the amino acid sequence of naturally occurring fibroin. It can also be obtained by chemically synthesizing a nucleic acid encoding the amino acid sequence.
  • amino acid residues are further substituted, deleted, inserted and / or added.
  • Amino acid sequence modification corresponding to the above may be performed.
  • the third modified fibroin (3-i) SEQ ID NO: 17 (Met-PRT399), SEQ ID NO: 7 (Met-PRT410), SEQ ID NO: 8 (Met-PRT525), or SEQ ID NO: 9 (Met-PRT525) -PRT799), or (3-ii) an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 17, SEQ ID NO: 7, SEQ ID NO: 8, or SEQ ID NO: 9, Modified fibroin can be mentioned.
  • the modified fibroin (3-i) will be described.
  • the amino acid sequence represented by SEQ ID NO: 17 differs from the amino acid sequence represented by SEQ ID NO: 10 (Met-PRT313) corresponding to naturally occurring fibroin in that every two amino acids from the N-terminal side to the C-terminal side (A) n The motif was deleted, and one [(A) n motif-REP] was inserted before the C-terminal sequence.
  • the amino acid sequence represented by SEQ ID NO: 7, SEQ ID NO: 8, or SEQ ID NO: 9 is as described for the second modified fibroin.
  • the amino acid sequence represented by SEQ ID NO: 10 (corresponding to naturally-occurring fibroin) has an x / y value of 15.0% at a giza ratio of 1: 1.8 to 11.3.
  • the value of x / y in the amino acid sequence represented by SEQ ID NO: 17 and the amino acid sequence represented by SEQ ID NO: 7 is 93.4%.
  • the value of x / y in the amino acid sequence represented by SEQ ID NO: 8 is 92.7%.
  • the value of x / y in the amino acid sequence represented by SEQ ID NO: 9 is 89.8%.
  • the values of z / w in the amino acid sequences represented by SEQ ID NO: 10, SEQ ID NO: 17, SEQ ID NO: 7, SEQ ID NO: 8, and SEQ ID NO: 9 are 46.8%, 56.2%, 70.1%, 66. 1% and 70.0%.
  • the modified fibroin of (3-i) may be composed of the amino acid sequence represented by SEQ ID NO: 17, SEQ ID NO: 7, SEQ ID NO: 8, or SEQ ID NO: 9.
  • the modified fibroin of (3-ii) contains an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 17, SEQ ID NO: 7, SEQ ID NO: 8, or SEQ ID NO: 9.
  • 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 (3-ii) has 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 17, SEQ ID NO: 7, SEQ ID NO: 8, or SEQ ID NO: 9, and is N-terminal to C-terminal.
  • the number of amino acid residues of REP of two adjacent [(A) n motif-REP] units is sequentially compared, and when the number of amino acid residues of REP having a small number of amino acid residues is set to 1, the other Amino acid residues of two adjacent [(A) n motif-REP] units having a ratio of the number of amino acid residues of REP of 1.8 to 11.3 (a giza ratio of 1: 1.8 to 11.3).
  • x / y be 64.2% or more, where x is the maximum value of the sum of the base numbers and y is the total number of amino acid residues in the domain sequence.
  • the third modified fibroin may include the above-described tag sequence at one or both of the N-terminus and the C-terminus.
  • modified fibroin containing a tag sequence (3-iii) the amino acid represented by SEQ ID NO: 18 (PRT399), SEQ ID NO: 13 (PRT410), SEQ ID NO: 14 (PRT525), or SEQ ID NO: 15 (PRT799)
  • Modified fibroin comprising a sequence or (3-iv) an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 18, SEQ ID NO: 13, SEQ ID NO: 14, or SEQ ID NO: 15 can be mentioned. .
  • amino acid sequences represented by SEQ ID NO: 18, SEQ ID NO: 13, SEQ ID NO: 14 and SEQ ID NO: 15 are obtained by adding SEQ ID NO: 11 to the N-terminal of the amino acid sequences represented by SEQ ID NO: 17, SEQ ID NO: 7, SEQ ID NO: 8 and SEQ ID NO: 9, respectively. (Including a His tag sequence and a hinge sequence).
  • the modified fibroin of (3-iii) may have an amino acid sequence represented by SEQ ID NO: 18, SEQ ID NO: 13, SEQ ID NO: 14, or SEQ ID NO: 15.
  • the modified fibroin of (3-iv) includes an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 18, SEQ ID NO: 13, SEQ ID NO: 14, or SEQ ID NO: 15.
  • 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 of (3-iv) has 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 18, SEQ ID NO: 13, SEQ ID NO: 14, or SEQ ID NO: 15 and is N-terminal to C-terminal.
  • the number of amino acid residues of REP of two adjacent [(A) n motif-REP] units is sequentially compared, and when the number of amino acid residues of REP having a small number of amino acid residues is set to 1, the other
  • the maximum value of the total value obtained by adding the number of amino acid residues of two adjacent [(A) n motif-REP] units having a ratio of the number of amino acid residues of REP of 1.8 to 11.3 is defined as x.
  • x / y is 64.2% or more, where y is the total number of amino acid residues in the domain sequence.
  • the third modified fibroin may include a secretion signal for releasing a 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 the host.
  • the fourth modified fibroin has an amino acid sequence whose domain sequence has a reduced content of a glycine residue in addition to the content of the (A) n motif reduced as compared to a naturally-derived fibroin.
  • the domain sequence of the fourth modified fibroin is at least one or more (A) n motifs deleted, and further at least one or more glycine residues in the REP, as compared to naturally occurring fibroin. It can be said that it has an amino acid sequence equivalent to being replaced with another amino acid residue. That is, the fourth modified fibroin is a modified fibroin having both the characteristics of the second modified fibroin and the third modified fibroin described above. Specific aspects and the like are as described for the second modified fibroin and the third modified fibroin.
  • the fourth modified fibroin (4-i) SEQ ID NO: 7 (Met-PRT410), SEQ ID NO: 8 (Met-PRT525), SEQ ID NO: 9 (Met-PRT799), SEQ ID NO: 13 (PRT410) ), The amino acid sequence represented by SEQ ID NO: 14 (PRT525) or SEQ ID NO: 15 (PRT799), or (4-ii) SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 13, SEQ ID NO: 14, or SEQ ID NO: 15
  • a modified fibroin comprising an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by.
  • Specific embodiments of the modified fibroin comprising the amino acid sequence represented by SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 13, SEQ ID NO: 14, or SEQ ID NO: 15 are as described above.
  • the fifth modified fibroin has a domain sequence in which one or more amino acid residues in REP have been replaced by amino acid residues having a large hydrophobicity index as compared to naturally occurring fibroin, and / or It may have an amino acid sequence locally including a region having a large hydrophobicity index, corresponding to insertion of one or more amino acid residues having a large hydrophobicity index therein.
  • a region having a locally large hydrophobicity index is preferably composed of 2 to 4 consecutive amino acid residues.
  • the amino acid residue having a large hydrophobicity index is selected from isoleucine (I), valine (V), leucine (L), phenylalanine (F), cysteine (C), methionine (M), and alanine (A). More preferably, it is a residue.
  • the fifth modified fibroin may have one or more amino acid residues in the REP replaced with amino acid residues having a higher hydrophobicity index, and / or one or more amino acids in the REP as compared to a naturally occurring fibroin.
  • one or more amino acid residues may be substituted, deleted, inserted and / or added as compared with naturally occurring fibroin.
  • the fifth modified fibroin is, for example, one or more hydrophilic amino acid residues (for example, amino acid residues having a negative hydrophobicity index) in the REP from the cloned natural fibroin gene sequence, It can be obtained by substituting a group (for example, an amino acid residue having a positive hydrophobicity index) and / or inserting one or more hydrophobic amino acid residues into REP.
  • a group for example, an amino acid residue having a positive hydrophobicity index
  • one or more hydrophilic amino acid residues in REP were replaced 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.
  • one or more hydrophilic amino acid residues in REP were replaced 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.
  • 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 fifth modified fibroin contains a domain sequence represented by Formula 1: [(A) n motif-REP] m and extends from the (A) n motif located at the most C-terminal side to the C-terminus of the domain sequence.
  • the total number of amino acid residues included in a region where the average value of the hydrophobicity index of four consecutive amino acid residues is 2.6 or more is p,
  • q the total number of amino acid residues contained in the sequence excluding the sequence from the (A) n motif located at the most C-terminal side to the C-terminal of the domain sequence from the domain sequence is defined as q
  • p / q is 6 .2% or more.
  • hydrophobicity index of amino acid residues
  • a publicly known index Kyte J, & Doolittle R (1982) "A simple method for display, the hydropathic charactor of aa protein, J.Pol.Mol. 105-132).
  • HI hydropathic index
  • sequence A [(A) n motif-REP] m (Hereinafter, referred to as “sequence A”).
  • 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 determined by dividing the total sum of HI of each amino acid residue contained in four consecutive amino acid residues by 4 (the number of amino acid residues).
  • the average value of the hydrophobicity index is determined for all four consecutive amino acid residues (each amino acid residue is used for calculating the average value one to four 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 when a certain amino acid residue corresponds to a plurality of “consecutive four amino acid residues having an average value of the hydrophobicity index of 2.6 or more”, it is included as one amino acid residue in the region. become. Then, 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.
  • p / q is preferably 6.2% or more, more preferably 7% or more, further preferably 10% or more, and more preferably 20% or more. Even more preferably, it is even more preferably 30% or more.
  • the upper limit of p / q is not particularly limited, but may be, for example, 45% or less.
  • the fifth modified fibroin is, for example, one or a plurality of hydrophilic amino acid residues (for example, a hydrophobicity index) in the REP so that the amino acid sequence of the cloned natural fibroin is satisfied so as to satisfy the above-mentioned p / q conditions.
  • a hydrophobic amino acid residue eg, an amino acid residue having a positive hydrophobicity index
  • inserting one or more hydrophobic amino acid residues into the REP By doing so, it 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-mentioned p / q condition from the amino acid sequence of naturally occurring fibroin and chemically synthesizing a nucleic acid encoding the designed amino acid sequence.
  • one or more amino acid residues in the REP have been replaced by amino acid residues with a higher hydrophobicity index and / or one or more amino acid residues in the REP as compared to naturally occurring fibroin.
  • a modification 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 Is preferred, and valine (V), leucine (L) and isoleucine (I) are more preferred.
  • the fifth modified fibroin (5-i) the amino acid sequence represented by SEQ ID NO: 19 (Met-PRT665), SEQ ID NO: 20 (Met-PRT665) or SEQ ID NO: 21 (Met-PRT666); Or (5-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: 19, SEQ ID NO: 20, or SEQ ID NO: 21.
  • the modified fibroin of (5-i) will be described.
  • the amino acid sequence represented by SEQ ID NO: 19 consists of three amino acid residues every other REP, except for the domain sequence of the terminal at the C-terminal side, with respect to the amino acid sequence represented by SEQ ID NO: 7 (Met-PRT410).
  • two amino acid sequences (VLI) were inserted, some glutamine (Q) residues were further substituted with serine (S) residues, and some C-terminal amino acids were deleted.
  • the amino acid sequence represented by SEQ ID NO: 20 is obtained by inserting one amino acid sequence (VLI) consisting of three amino acid residues every other REP into the amino acid sequence represented by SEQ ID NO: 8 (Met-PRT525). is there.
  • the amino acid sequence represented by SEQ ID NO: 21 is obtained by inserting two amino acid sequences (VLI) each consisting of three amino acid residues every other REP into the amino acid sequence represented by SEQ ID NO: 8.
  • the modified fibroin of (5-i) may be composed of the amino acid sequence represented by SEQ ID NO: 19, SEQ ID NO: 20 or SEQ ID NO: 21.
  • the modified fibroin of (5-ii) contains an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 19, SEQ ID NO: 20, or SEQ ID NO: 21.
  • 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 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 19, SEQ ID NO: 20, or SEQ ID NO: 21, and is located at the most C-terminal side (A) n
  • amino acids contained in a region where the average value of the hydrophobicity index of four consecutive amino acid residues is 2.6 or more When the total number of residues is p, and the total number of amino acid residues contained in the sequence obtained by removing the sequence from the (A) n motif located at the most C-terminal side to the C-terminal of the domain sequence from the domain sequence is q , P / q is preferably at least 6.2%.
  • the fifth modified fibroin may include a tag sequence at one or both of the N-terminus and the C-terminus.
  • modified fibroin containing the tag sequence (5-iii) the amino acid sequence represented by SEQ ID NO: 22 (PRT720), SEQ ID NO: 23 (PRT665) or SEQ ID NO: 24 (PRT666), or (5-iv) ) Modified fibroin comprising an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 22, SEQ ID NO: 23 or SEQ ID NO: 24.
  • amino acid sequences represented by SEQ ID NO: 22, SEQ ID NO: 23 and SEQ ID NO: 24 correspond to the amino acid sequence represented by SEQ ID NO: 11 (His tag) at the N-terminal of the amino acid sequences represented by SEQ ID NO: 19, SEQ ID NO: 20 and SEQ ID NO: 21, respectively. Sequences and hinge sequences).
  • the modified fibroin of (5-iii) may have an amino acid sequence represented by SEQ ID NO: 22, SEQ ID NO: 23 or SEQ ID NO: 24.
  • the modified fibroin of (5-iv) contains an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 22, SEQ ID NO: 23 or SEQ ID NO: 24.
  • 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 of (5-iv) has 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 22, SEQ ID NO: 23 or SEQ ID NO: 24, and is located at the most C-terminal side (A) n
  • all REPs contained in the sequence excluding the sequence from the motif to the C-terminus of the domain sequence from the domain sequence amino acids contained in a region where the average value of the hydrophobicity index of four consecutive amino acid residues is 2.6 or more
  • P / q is preferably at least 6.2%.
  • the fifth modified fibroin may include a secretion signal for releasing a 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 the host.
  • the sixth modified fibroin has an amino acid sequence in which the content of glutamine residues is reduced as compared with naturally occurring fibroin.
  • the sixth modified fibroin preferably contains at least one motif selected from GGX motif and GPGXX motif in the amino acid sequence of REP.
  • the content of the GPGXX motif is usually 1% or more, and may be 5% or more, and preferably 10% or more.
  • the upper limit of the GPGXX motif content is not particularly limited, and may be 50% or less, or 30% or less.
  • the “GPGXX motif content” is a value calculated by the following method.
  • Formula 1 Fibroin containing a domain sequence represented by [(A) n motif-REP] m or Formula 2: [(A) n motif-REP] m- (A) n motif (modified fibroin or naturally occurring fibroin) Fibroin), the number of GPGXX motifs contained in the region of all REPs contained in the sequence excluding the sequence from the (A) n motif located at the most C-terminal side to the C-terminus of the domain sequence from the domain sequence
  • the number obtained by multiplying the total number by 3 ie, the total number of G and P in the GPGXX motif
  • the sequence from the (A) n motif located at the most C-terminal side to the C-terminal of the domain sequence is represented by (A)
  • the content of the GPGXX motif content is represented by the content of the G
  • “the sequence obtained by removing the sequence from the (A) n motif located at the most C-terminal side to the C-terminal of the domain sequence from the domain sequence” to “the most C-terminal side” (A) Sequence from n motif to C-terminus of domain sequence (sequence corresponding to REP) may include a sequence having low correlation with a sequence characteristic of fibroin, and m may be small. In this case (that is, when the domain sequence is short), the calculation result of the GPGXX motif content is affected, so that this effect is eliminated.
  • “GPGXX motif” is located at the C-terminus of the REP, even when “XX” is, for example, “AA”, it is treated as a “GPGXX motif”.
  • FIG. 5 is a schematic diagram showing the domain sequence of a modified fibroin.
  • the method of calculating the content rate of the GPGXX motif will be specifically described with reference to FIG. First, in the domain sequence of the modified fibroin shown in FIG. 5 (“[(A) n motif-REP] m- (A) n motif” type), all REPs are located at the most C-terminal side.
  • (A) A sequence obtained by removing the sequence from the n motif to the C-terminus of the domain sequence from the domain sequence ”(the sequence shown as“ region A ”in FIG. 5).
  • the sixth modified fibroin preferably has a glutamine residue content of 9% or less, more preferably 7% or less, still more preferably 4% or less, and particularly preferably 0%. .
  • the “glutamine residue content” is a value calculated by the following method.
  • Formula 1 Fibroin containing a domain sequence represented by [(A) n motif-REP] m or Formula 2: [(A) n motif-REP] m- (A) n motif (modified fibroin or naturally occurring fibroin) Fibroin), the sequence (the sequence corresponding to “region A” in FIG. 5) in which the sequence from the (A) n motif located closest to the C-terminal side to the C-terminal of the domain sequence is excluded from the domain sequence.
  • the total number of glutamine residues contained in the region is defined as u, 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 further (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 the “sequence in which the sequence from the (A) n motif located closest to the C-terminal to the C-terminal of the domain sequence is excluded from the domain sequence” is targeted is as described above. The same is true.
  • the sixth modified fibroin corresponds to the fact that its domain sequence has one or more glutamine residues in the REP deleted or replaced with other amino acid residues, as compared to the naturally occurring fibroin. It may have an 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 a glutamine residue.
  • the hydrophobicity index of amino acid residues is 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), and 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.
  • the sixth modified fibroin preferably has a hydrophobicity of REP of -0.8 or more, more preferably -0.7 or more, still more preferably 0 or more, and 0.3 or more. Is still more preferable, and it is particularly preferable that it is 0.4 or more.
  • the upper limit of the hydrophobicity of REP is not particularly limited, and may be 1.0 or less, or may be 0.7 or less.
  • “REP hydrophobicity” is a value calculated by the following method.
  • Formula 1 Fibroin containing a domain sequence represented by [(A) n motif-REP] m or Formula 2: [(A) n motif-REP] m- (A) n motif (modified fibroin or naturally occurring fibroin) Fibroin), the sequence (the sequence corresponding to “region A” in FIG. 5) in which the sequence from the (A) n motif located closest to the C-terminal side to the C-terminal of the domain sequence is excluded from the domain sequence.
  • the sum of the hydrophobicity indices of each amino acid residue in the region is defined as v, and the sequence from the (A) n motif located closest to the C-terminal side to the C-terminal of the domain sequence is removed from the domain sequence.
  • A) The hydrophobicity of REP is calculated as v / t, where t is the total number of amino acid residues of all REPs excluding n motifs.
  • the degree of hydrophobicity of the REP the reason why the “sequence in which the sequence from the (A) n motif located closest to the C-terminal side to the C-terminal of the domain sequence is excluded from the domain sequence” is targeted is as follows. The same is true.
  • the sixth modified fibroin may have a domain sequence that is missing one or more glutamine residues in the REP and / or one or more glutamine residues in the REP, as compared to the naturally occurring fibroin.
  • the sixth modified fibroin may, for example, delete one or more glutamine residues in the REP from the cloned naturally occurring fibroin gene sequence and / or remove one or more glutamine residues in the REP. By substituting the amino acid residue with, for example, one or more glutamine residues in REP were deleted from the amino acid sequence of naturally occurring fibroin, and / or one or more glutamine residues in REP were replaced with other amino acid residues. It can also be obtained by designing an amino acid sequence corresponding to the above and chemically synthesizing a nucleic acid encoding the designed amino acid sequence.
  • modified fibroin (6-i) SEQ ID NO: 25 (Met-PRT988), SEQ ID NO: 26 (Met-PRT965), SEQ ID NO: 27 (Met-PRT889), SEQ ID NO: 28 (Met-PRT889) -PRT916), modified fibroin comprising the amino acid sequence represented by SEQ ID NO: 29 (Met-PRT699), SEQ ID NO: 30 (Met-PRT699), SEQ ID NO: 31 (Met-PRT698) or SEQ ID NO: 32 (Met-PRT966), or (6-ii) having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, or SEQ ID NO: 32 Modified fibroin containing the amino acid sequence having the same.
  • the modified fibroin of (6-i) will be described.
  • the amino acid sequence represented by SEQ ID NO: 25 is obtained by substituting VL for all QQ in the amino acid sequence represented by SEQ ID NO: 7 (Met-PRT410).
  • the amino acid sequence represented by SEQ ID NO: 26 is obtained by substituting all QQs in the amino acid sequence represented by SEQ ID NO: 7 with TS, and substituting the remaining Q with A.
  • the amino acid sequence represented by SEQ ID NO: 27 is obtained by substituting all QQs in the amino acid sequence represented by SEQ ID NO: 7 with VL, and substituting the remaining Q with I.
  • the amino acid sequence represented by SEQ ID NO: 28 is obtained by substituting all QQ in the amino acid sequence represented by SEQ ID NO: 7 with VI and substituting the remaining Q with L.
  • the amino acid sequence represented by SEQ ID NO: 29 is obtained by substituting all QQs in the amino acid sequence represented by SEQ ID NO: 7 with VF and substituting the remaining Q with I.
  • amino acid sequence represented by SEQ ID NO: 30 is obtained by replacing all QQ in the amino acid sequence represented by SEQ ID NO: 8 (Met-PRT525) with VL.
  • the amino acid sequence represented by SEQ ID NO: 31 is obtained by substituting all QQs in the amino acid sequence represented by SEQ ID NO: 8 with VL and substituting the remaining Q with I.
  • the amino acid sequence represented by SEQ ID NO: 32 replaces all QQs in the sequence obtained by repeating twice the domain of the 20 domain sequences present in the amino acid sequence represented by SEQ ID NO: 7 (Met-PRT410) with VF, In addition, the remaining Q is replaced with I.
  • amino acid sequences represented by SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, and SEQ ID NO: 32 all have a glutamine residue content of 9% or less. (Table 2).
  • the modified fibroin of (6-i) consists of the amino acid sequence represented by SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31 or SEQ ID NO: 32 There may be.
  • the modified fibroin of (6-ii) has 90% or more of the amino acid sequence represented by SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31 or SEQ ID NO: 32 And amino acid sequences having the same sequence identity.
  • the modified fibroin of (6-ii) also has 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.
  • the modified fibroin of (6-ii) preferably has a glutamine residue content of 9% or less. Further, the modified fibroin of (6-ii) preferably has a GPGXX motif content of 10% or more.
  • the sixth modified fibroin may include a tag sequence at one or both of the N-terminus and the C-terminus. As a result, the modified fibroin can be isolated, immobilized, detected, visualized, and the like.
  • modified fibroin containing the tag sequence (6-iii) SEQ ID NO: 33 (PRT888), SEQ ID NO: 34 (PRT965), SEQ ID NO: 35 (PRT889), SEQ ID NO: 36 (PRT916), SEQ ID NO: 37 (PRT918), modified fibroin comprising the amino acid sequence represented by SEQ ID NO: 38 (PRT699), SEQ ID NO: 39 (PRT698) or SEQ ID NO: 40 (PRT966), or (6-iv) SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 37, SEQ ID NO: 38, SEQ ID NO: 39, or a modified fibroin having an amino acid sequence having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 40.
  • amino acid sequences represented by SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 37, SEQ ID NO: 38, SEQ ID NO: 39, and SEQ ID NO: 40 are SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 27, respectively.
  • SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31 and SEQ ID NO: 32 were added with the amino acid sequence represented by SEQ ID NO: 11 (including His tag sequence and hinge sequence) at the N-terminus. Things.
  • amino acid sequence represented by SEQ ID NO: 40 has a glutamine residue content of 9% or less (Table 3).
  • the modified fibroin of (6-iii) comprises the amino acid sequence represented by SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 37, SEQ ID NO: 38, SEQ ID NO: 39 or SEQ ID NO: 40 There may be.
  • the modified fibroin of (6-iv) has an amino acid sequence represented by SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 37, SEQ ID NO: 38, SEQ ID NO: 39 or SEQ ID NO: 40 by 90% or more. And amino acid sequences having the same sequence identity.
  • the modified fibroin of (6-iv) also has 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.
  • the modified fibroin of (6-iv) preferably has a glutamine residue content of 9% or less.
  • the modified fibroin of (6-iv) preferably has a GPGXX motif content of 10% or more.
  • the sixth modified fibroin may contain a secretion signal for releasing a 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 the host.
  • the modified fibroin is at least two or more of the characteristics of the first modified fibroin, the second modified fibroin, the third modified fibroin, the fourth modified fibroin, the fifth modified fibroin, and the sixth modified fibroin. Modified fibroin having both of the following characteristics may be used.
  • the modified fibroin according to any of the above embodiments may be, for example, a host transformed with an expression vector having a nucleic acid sequence encoding the modified fibroin and one or more regulatory sequences operably linked to the nucleic acid sequence. Can be produced by expressing the nucleic acid.
  • the method for producing the nucleic acid encoding the modified fibroin is not particularly limited.
  • the nucleic acid is produced by a method of amplifying and cloning by a polymerase chain reaction (PCR) or the like using a gene encoding a natural fibroin and modifying it by a genetic engineering technique, or a chemical synthesis method. can do.
  • the method for chemically synthesizing nucleic acids is not particularly limited.
  • AKTA oligopilot plus10010 / 100 Genes can be chemically synthesized by a method of linking oligonucleotides synthesized automatically by PCR or the like.
  • a nucleic acid encoding a modified fibroin consisting of an amino acid sequence obtained by adding an amino acid sequence comprising an initiation codon and a His10 tag to the N-terminus of the above amino acid sequence is synthesized. May be.
  • the regulatory sequence is a sequence that controls the expression of the modified fibroin in the host (for example, a promoter, an enhancer, a ribosome binding sequence, a transcription termination sequence, and the like), and can be appropriately selected depending on the type of the host.
  • An inducible promoter that functions in a host cell and is capable of inducing the expression of a modified fibroin may be used as the promoter.
  • An inducible promoter is a promoter that can control transcription by the presence of an inducer (expression inducer), the absence of a repressor molecule, or a physical factor such as an increase or decrease in temperature, osmotic pressure, or pH value.
  • the type of expression vector can be appropriately selected depending on the type of host, such as a plasmid vector, a virus vector, a cosmid vector, a fosmid vector, an artificial chromosome vector, and the like.
  • a plasmid vector a virus vector
  • a cosmid vector a fosmid vector
  • an artificial chromosome vector an artificial chromosome vector
  • those capable of autonomous replication in a host cell or integration into a host chromosome and containing a promoter at a position where a nucleic acid encoding a modified fibroin can be transcribed are suitably used.
  • any of prokaryotes and eukaryotes such as yeast, filamentous fungi, insect cells, animal cells, and plant cells can be suitably used.
  • prokaryotic hosts include bacteria belonging to the genus Escherichia, Brevibacillus, Serratia, Bacillus, Microbacterium, Brevibacterium, Corynebacterium and Pseudomonas.
  • microorganisms belonging to the genus Escherichia include, for example, Escherichia coli.
  • microorganisms belonging to the genus Brevibacillus include Brevibacillus agri.
  • Microorganisms belonging to the genus Serratia include, for example, Serratia requestifaciens and the like.
  • microorganisms belonging to the genus Bacillus include Bacillus subtilis and the like.
  • Microorganisms belonging to the genus Microbacterium include, for example, Microbacterium ammonia phyllum.
  • Examples of microorganisms belonging to the genus Brevibacterium include Brevibacterium divaricatum.
  • Examples of the microorganism belonging to the genus Corynebacterium include Corynebacterium ammoniagenes.
  • Examples of microorganisms belonging to the genus Pseudomonas include Pseudomonas putida.
  • examples of a vector into which a nucleic acid encoding a modified fibroin is introduced include, for example, pBTrp2 (manufactured by Boehringer Mannheim), pGEX (manufactured by Pharmacia), pUC18, pBluescriptII, pSuex, pET22b, pCold, pUB110, pNCO2 (JP-A-2002-238569) and the like.
  • Examples of eukaryotic hosts include yeast and filamentous fungi (such as mold).
  • yeast include yeast belonging to the genus Saccharomyces, the genus Pichia, the genus Schizosaccharomyces, and the like.
  • filamentous fungi include filamentous fungi belonging to the genus Aspergillus, Penicillium, 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).
  • any 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, spheroplast, protoplast, lithium acetate, competent, 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, and the like can be performed according to the method described in Molecular Cloning, 2nd edition, and the like. .
  • 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 modified fibroin in the culture medium, and collecting the modified fibroin from the culture medium.
  • the method of culturing the host in the culture medium can be performed according to a method usually used for culturing the host.
  • the host is a prokaryote such as Escherichia coli or a eukaryote such as yeast, a culture medium containing a carbon source, a nitrogen source, inorganic salts, and the like which can be utilized by the host, so that the host can be cultured efficiently. If so, either a natural medium or a synthetic medium may be used.
  • a prokaryote such as Escherichia coli or a eukaryote such as yeast
  • a culture medium containing a carbon source, a nitrogen source, inorganic salts, and the like which can be utilized by the host, so that the host can be cultured efficiently. If so, either a natural medium or a synthetic medium may be used.
  • the carbon source may be any as long as the transformed microorganism can assimilate, for example, glucose, fructose, sucrose, and molasses containing these, carbohydrates such as starch and starch hydrolysate, acetic acid and propionic acid, and the like. Organic acids and alcohols such as ethanol and propanol can be used.
  • the nitrogen source for example, ammonia, ammonium chloride, ammonium sulfate, ammonium salts of inorganic or organic acids such as ammonium acetate and ammonium phosphate, other nitrogen-containing compounds, and peptone, meat extract, yeast extract, corn steep liquor, Casein hydrolyzate, soybean meal, soybean meal hydrolyzate, various fermented cells and digests thereof can be used.
  • the inorganic salts for example, potassium (I) phosphate, potassium (II) phosphate, magnesium phosphate, magnesium sulfate, sodium chloride, ferrous sulfate, manganese sulfate, copper sulfate, and calcium carbonate can be used.
  • ⁇ Cultivation of prokaryotes such as Escherichia coli or eukaryotes such as yeast can be performed under aerobic conditions such as shaking culture or deep aeration stirring culture.
  • the culture temperature is, for example, 15 to 40 ° C.
  • the culturing 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.
  • an inducer may be added to the medium as necessary.
  • lac promoter isopropyl- ⁇ -D-thiogalactopyranoside or the like is used.
  • indole acryl is used.
  • An acid or the like may be added to the medium.
  • the expressed and modified fibroin can be isolated and purified by a commonly used method. For example, when the modified fibroin is expressed in a lysed state in the cells, after completion of the culture, the host cells are collected by centrifugation, suspended in an aqueous buffer, and then sonicated with a sonicator, French press, Menton. The host cells are crushed with a Gaulin homogenizer, Dynomill or the like to obtain a cell-free extract.
  • a method commonly used for isolating and purifying proteins that is, a solvent extraction method, a salting-out method using ammonium sulfate, a desalting method, an organic solvent Precipitation method, anion exchange chromatography using a resin such as diethylaminoethyl (DEAE) -Sepharose, DIAION @ HPA-75 (manufactured by Mitsubishi Kasei), and cation using a resin such as S-Sepharose @ FF (manufactured by Pharmacia).
  • a resin such as diethylaminoethyl (DEAE) -Sepharose, DIAION @ HPA-75 (manufactured by Mitsubishi Kasei)
  • cation using a resin such as S-Sepharose @ FF (manufactured by Pharmacia).
  • Electrophoretic methods such as ion exchange chromatography, hydrophobic chromatography using resins such as butyl sepharose and phenyl sepharose, gel filtration using molecular sieves, affinity chromatography, chromatofocusing, isoelectric focusing, etc. Purification using methods such as alone or in combination It is possible to obtain the goods.
  • the modified fibroin When the modified fibroin is expressed by forming an insoluble form in the cells, the host cells are similarly recovered, crushed, and centrifuged to collect the insoluble form of the modified fibroin as a precipitate fraction.
  • the recovered insoluble form of the modified fibroin can be solubilized with a protein denaturant.
  • a purified sample of the modified fibroin can be obtained by the same isolation and purification method as described above.
  • the modified fibroin When the modified fibroin is secreted extracellularly, the modified fibroin can be recovered from the culture supernatant. That is, a culture supernatant is obtained by treating the culture by a method such as centrifugation, and a purified sample can be obtained from the culture supernatant by using the same isolation and purification method as described above.
  • the modified fibroin fiber according to the present embodiment is obtained by spinning the above-described modified fibroin, and contains the above-described modified fibroin as a main component.
  • the density of the modified fibroin fiber according to this embodiment is more than 1.34 g / cm 3 .
  • the density of the modified fibroin fiber is 1.35 g / cm 3 or more, 1.36 g / cm 3 or more, 1.37 g / cm 3 or more, 1.38 g / cm 3 or more, 1.39 g / cm 3 or more, or 1.40 g. / may be cm 3 or more, 1.45 g / cm 3 or less, 1.44 g / cm 3 or less, 1.43 g / cm 3 or less, there at 1.42 g / cm 3 or less, or 1.41 g / cm 3 or less May be.
  • the density of the modified fibroin fiber means a value measured according to JISL 1013.
  • the strength of the modified fibroin fiber according to the present embodiment may be more than 200 MPa, 220 MPa or more, 240 MPa or more, 260 MPa or more, 280 MPa or more, 300 MPa or more, 320 MPa or more, 340 MPa or more, or 350 MPa or more, 600 MPa or less, 500 MPa or less, 400 MPa. Or 380 MPa or less.
  • the strength of the modified fibroin fiber can be measured by the method described in Examples described later.
  • the method for producing a modified fibroin fiber comprises: (a) a first drawing step of drawing a raw fiber containing a modified fibroin in water; and (b) heating the raw fiber that has passed through the first drawing step. And a densification step of drying and thermally shrinking in the radial direction.
  • modified fibroin fibers having high strength for example, having a density of more than 1.34 g / cm 3 .
  • the method for producing a modified fibroin fiber according to the present embodiment may further include (c) a second drawing step of drawing the raw material fiber after the densification step. In this case, the strength of the modified fibroin fiber obtained by the production method is further increased.
  • the raw fiber containing the modified fibroin can be produced through a spinning process.
  • a dope solution containing a solvent for dissolution and modified fibroin dissolved in the solvent for dissolution is extruded into a coagulation liquid to obtain raw fibers containing modified fibroin as undrawn yarn. That is, the raw fiber containing the modified fibroin can be obtained by removing the solvent for dissolution from the dope solution (also referred to as desolvation or coagulation) and forming the fiber by a spinning step.
  • the dissolving solvent examples include dimethyl sulfoxide (DMSO), N, N-dimethylformamide (DMF), formic acid, and hexafluoroisopropanol (HFIP).
  • DMSO dimethyl sulfoxide
  • DMF N, N-dimethylformamide
  • HFIP hexafluoroisopropanol
  • the dope solution may further contain a dissolution accelerator such as an inorganic salt, if necessary.
  • the concentration of the modified fibroin in the dope solution is preferably 3% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more based on the total amount of the dope solution. From the viewpoint of maintaining good solubility of the modified fibroin, the concentration of the modified fibroin in the dope solution is preferably 60% by mass or less, more preferably 50% by mass or less, and more preferably 40% by mass or less. Is more preferable, and it is still more preferable that it is 30 mass% or less.
  • the coagulation liquid is not particularly limited as long as it can remove the solvent.
  • lower alcohols having 1 to 5 carbon atoms such as methanol, ethanol and 2-propanol, and acetone can be used.
  • Water may be appropriately added to the coagulation liquid.
  • the temperature of the coagulating liquid is, for example, 5 to 30 ° C. If the temperature of the coagulation liquid is within this range, spinning can be performed more stably.
  • an undrawn yarn is obtained by extruding a dope solution from a spinneret (spinner) into a coagulating solution in a desolvation tank.
  • the extrusion speed may be, for example, 0.2 to 6.0 ml / hour per hole, and may be 1.4 to 4 ml. 0.0 ml / hour. If the extrusion speed is in this range, spinning can be performed more stably.
  • First stretching step In the first drawing step, the raw fiber containing the modified fibroin is drawn (first drawing) in a water bath.
  • the first stretching may be performed in one-stage stretching, or may be performed in two or more stages.
  • the modified fibroin is a protein in which molecules such as the modified spider silk fibroin are difficult to orient
  • the molecules can be oriented in multiple stages by performing multi-stage stretching, and the total stretching ratio can be increased. Fiber with a high fiber density can be obtained.
  • the first stretching is performed in a water bath. That is, the first stretching is a wet heat stretching.
  • the water bath may contain a solvent other than water.
  • the temperature of the water bath in the first stretching step may be 5-60 ° C, 10-55 ° C, 15-52 ° C, 20-50 ° C, 30-48 ° C or 35-45 ° C.
  • the temperature of the water bath in the first stretching step is preferably 60 ° C or less.
  • the temperature of the water bath is preferably 5 ° C. or higher.
  • the wet heat draw ratio in the first drawing may be, for example, 1 to 3 times the undrawn yarn.
  • the raw fiber (hereinafter also referred to as “first drawn yarn”) that has passed through the first drawing step is heated and dried, and is thermally shrunk in the radial direction (the direction perpendicular to the fiber axis).
  • first drawn yarn the raw fiber that has passed through the first drawing step is heated and dried, and is thermally shrunk in the radial direction (the direction perpendicular to the fiber axis).
  • the dope solution containing the modified fibroin particularly the modified spider silk fibroin
  • voids are formed inside the raw material fibers.
  • a solvent such as water may be present in the void inside the raw fiber.
  • a solvent eg, water
  • water such as water present in the voids included in the first drawn yarn
  • the densification step may be a step of removing water present in the voids contained in the raw fiber (first drawn yarn) that has passed through the first drawing step and flattening the voids.
  • the densification step may be performed such that the moisture content of the raw fiber (first drawn yarn) that has passed through the first drawing step is 15% or less, 10% or less, or 5% or less.
  • the water content of the raw fiber (first drawn yarn) that has passed through the first drawing step means the ratio of the mass of water to the total mass of the first drawn yarn.
  • the moisture content of the first drawn yarn can be measured by a Karl Fischer method or the like.
  • the densification step may be performed in a drying device.
  • the drying device may be a contact type drying device such as a hot roller or a dry heat plate, or may be a non-contact type drying device such as a hot air drying furnace.
  • the drying device is preferably a non-contact type drying device. In this case, the yarn breakage is further suppressed.
  • the temperature (heating temperature) and the time (heating time) in the densification step are not particularly limited as long as moisture in the voids present in the first drawn yarn can be removed and the fiber can shrink in the radial direction.
  • the temperature (heating temperature) in the densification step is 70 to 150 ° C, 75 to 140 ° C, 78 to 135 ° C, 80 to 120 ° C, 82 to 110 ° C, or 85 to 100 ° C. It may be.
  • the time (heating time) in the densification step may be 5 to 40 seconds, 7 to 35 seconds, or 8 to 30 seconds.
  • the densification step is preferably performed in a state where tension is applied to the first drawn yarn to prevent shrinkage in the length direction.
  • the amount of shrinkage (diameter reduction amount) of the first drawn yarn in the radial direction is further increased, and the voids are further flattened. Furthermore, by flattening the voids in the densification step, the occurrence of yarn breakage in the second stretching step described later is further suppressed.
  • the densification step may be performed, for example, with the end of the first drawn yarn fixed.
  • the fixing of the first drawn yarn may be capable of reducing the shrinkage in the length direction.
  • the first drawn yarn may be fixed by, for example, stretching a drawn yarn of a predetermined length without looseness in a state where no external force is applied (natural state), and fixing both ends of the fiber in this state.
  • the end portion of the first drawn yarn may be fixed at least at the end portion of the first drawn yarn, and the whole raw material fiber may be fixed by sandwiching the whole raw material fiber between two metal plates. Good.
  • the means for fixing the raw fibers is not particularly limited, and any fixing means may be used.
  • the fixing means is preferably a detachable one, and examples thereof include an adhesive tape, an adhesive, and a clamp.
  • the densification step may be performed between the first stretching step and the second stretching step.
  • the densification step may be performed once, or may be performed in multiple stages by providing a drying device in multiple stages, but since the effect of the present invention is more remarkably exhibited, it is preferable to perform the process once. Is preferred.
  • ⁇ Second stretching step> the raw fibers that have undergone the densification step are drawn (second drawing).
  • the voids flattened in the densification step can be further flattened.
  • the resulting modified fibroin fiber has a higher density, and as a result, a modified fibroin having higher strength is obtained.
  • the second stretching step is performed after flattening the voids in the densification step, the occurrence of yarn breakage in the second stretching step is further suppressed.
  • the second stretching may be performed in one-stage stretching or in two or more stages.
  • the second stretching may be wet heat stretching or dry heat stretching.
  • the wet heat stretching in the second 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. Note that the wet heat stretching performed during the steam heating is referred to as steam stretching.
  • the second stretching is preferably a steam stretching or a dry heat stretching, particularly preferably a steam stretching.
  • the second stretching step preferably includes performing steam stretching. It is expected that high stretching can be achieved more reliably by steam stretching because of high thermal conductivity or by the moisture permeated into the fiber functioning as a plasticizer or the like.
  • the temperature for performing the wet heat stretching other than the steam stretching may be, for example, 50 to 90 ° C, and preferably 75 to 85 ° C.
  • the temperature for performing the steam stretching may be, for example, 100 to 200 ° C., 100 to 150 ° C., or 100 to 120 ° C.
  • the wet heat stretching ratio in the second stretching may be 1 to 10 times or 2 to 8 times with respect to the raw material fiber that has passed through the densification step.
  • Dry heat drawing can be performed using an electric tube furnace, a dry heat plate or the like.
  • the second stretching step preferably includes a stretching operation on a dry heat plate.
  • the temperature at which the dry heat stretching is performed (dry heat drawing temperature) may be, for example, 140 ° C. to 270 ° C., or may be 150 ° C. to 260 ° C.
  • the dry heat drawing ratio in the second drawing may be, for example, 0.5 to 8 times or 1 to 6 times with respect to the raw material fiber that has passed through the densification step. If the second stretching step is performed by dry heat stretching, it is expected that re-entry of water into the void from which the solvent such as water has been removed in the densification step is prevented.
  • the wet heat stretching and the dry heat stretching may each be performed alone, 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 further the third stage stretching is performed by dry heat stretching.
  • wet heat stretching and dry heat stretching can be performed in an appropriate combination.
  • the lower limit of the total draw ratio is preferably more than 1 time, 2 times or more, 3 times or more, 4 times or more, 5 times or more, 6 times or more of the undrawn yarn. , 7 times or more, 8 times or more, 9 times or more, and the 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, It is 12 times or less, 11 times or less, and 10 times or less.
  • the first stretching step, the densification step, and the second stretching step may or may not be performed continuously.
  • the raw material fiber after the densification step is used as a wound body, and while the wound body is unwound, the second fiber is unwound.
  • a stretching step may be performed.
  • FIGS. 6 and 7 are explanatory diagrams showing an example of an apparatus for producing a modified fibroin fiber.
  • the manufacturing apparatus shown in FIG. 6 is a spin stretching apparatus that continuously performs a spinning step and a first stretching step.
  • the spinning and drawing apparatus 100 includes an extruder 1, an undrawn yarn manufacturing apparatus 2, a wet heat drawing apparatus 3, a drying apparatus 10, and a dry heat drawing apparatus 4.
  • the dope solution 6 is stored in a storage tank 7 and pushed out of a base 9 by a gear pump 8.
  • a dope solution may be filled in a cylinder and extruded from a nozzle using a syringe pump.
  • the extruded dope liquid 6 is supplied into the coagulation liquid 11 of the coagulation liquid tank 20 via the air gap 19 or directly without passing through the air gap 19.
  • the solvent is removed from the dope solution 6 in the coagulation solution 11, and an undrawn yarn (raw material fiber) is formed.
  • the undrawn yarn is supplied into the hot water 12 in the drawing bath 21 and the first-stage drawing is performed.
  • the stretching ratio is determined by the speed ratio between the supply nip roller 13 and the take-off nip roller 14.
  • the drawn yarn (first drawn yarn) that has passed through the first-stage drawing is then supplied to the drying device 10 and heated in the yarn path 22a.
  • the heated first drawn yarn is supplied to the dry heat drawing device 17, and the second stage drawing is performed in the yarn path 22b.
  • the drawn yarn (second drawn yarn) that has passed through the second-stage drawing is wound up to form a wound body 5.
  • the stretching ratio in the second stage stretching is determined by the speed ratio between the supply nip roller 15 and the take-off nip roller 16.
  • 18a to 18g are yarn guides.
  • FIG. 7 The production apparatus shown in FIG. 7 is a spinning and stretching apparatus that performs a spinning step and a stretching step (two-stage stretching).
  • FIG. 7A shows an undrawn yarn production device 30, a first-stage drawing device 40, and a drying device 60
  • FIG. 7B shows a second-stage drawing device 50.
  • the yarn may be wound in each device or stored in a container without being wound.
  • the dope liquid 32 is put in an extruder (micro syringe) 31, and is moved in the direction of arrow P using a syringe pump, and the dope liquid 32 is extruded from the nozzle 33 to form a coagulating liquid tank.
  • the dope liquid 32 is supplied to the coagulating liquid 35 in 34 to make an undrawn yarn 36 (raw fiber).
  • the undrawn yarn 36 is supplied into the hot water 38 in the drawing bath 37 to perform the first-stage drawing.
  • the first-stage drawn yarn (first drawn yarn) is supplied to the drying device 60 and heated in the yarn path 61.
  • the first-stage drawn yarn after heating is wound into a wound body 39.
  • the stretching ratio is determined by the speed ratio between the supply nip roller 41 and the take-off nip roller 42.
  • the first-stage drawn yarn is drawn from the wound body 39, supplied to the dry heat drawing device 43, and subjected to the second-stage drawing in the yarn path 47.
  • the stretching ratio is determined by the speed ratio between the supply nip roller 45 and the take-off nip roller 46.
  • the second-stage drawn yarn (second drawn yarn) is wound around the wound body 44.
  • a modified fibroin (PRT799) having the amino acid sequence represented by SEQ ID NO: 15 was designed.
  • a nucleic acid encoding the designed modified fibroin was synthesized.
  • An NdeI site was added to the 5 'end of the nucleic acid, and an EcoRI site was added downstream of the stop codon.
  • This nucleic acid was cloned into a cloning vector (pUC118). Thereafter, the nucleic acid was digested with NdeI and EcoRI and cut out, followed by recombination into a protein expression vector pET-22b (+) to obtain an expression vector.
  • Escherichia coli BLR (DE3) was transformed with the obtained pET-22b (+) expression vector.
  • the transformed E. 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 containing ampicillin (Table 4) so that the OD 600 became 0.005.
  • the temperature of the culture was maintained at 30 ° C., and the flask was cultured until the OD 600 reached 5 (about 15 hours) to obtain a seed culture.
  • the seed culture solution was added to a jar fermenter to which 500 mL of a production medium (Table 5) had been added so that the OD 600 was 0.05.
  • the temperature of the culture was maintained at 37 ° C., and the culture was performed at a constant pH of 6.9.
  • the concentration of dissolved oxygen in the culture was maintained at 20% of the saturated concentration of dissolved oxygen.
  • a feed solution (455 g / 1 L of glucose, Yeast Extract 120 g / 1 L) was added at a rate of 1 mL / min.
  • the temperature of the culture was maintained at 37 ° C., and the culture was performed at a constant pH of 6.9. Culture was performed for 20 hours while maintaining the dissolved oxygen concentration in the culture solution at 20% of the dissolved oxygen saturation concentration. Thereafter, 1 M isopropyl- ⁇ -thiogalactopyranoside (IPTG) was added to the culture solution to a final concentration of 1 mM to induce the expression of the desired modified fibroin. Twenty hours after the addition of IPTG, the culture was centrifuged to collect the cells.
  • IPTG isopropyl- ⁇ -thiogalactopyranoside
  • SDS-PAGE was performed using the cells prepared from the culture solution before and after the addition of IPTG, and the appearance of a band corresponding to the size of the target modified fibroin depending on the addition of IPTG revealed the presence of the target modified fibroin. Expression was confirmed.
  • the precipitate after washing 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) so as to have a concentration of 100 mg / mL, and then suspended at 60 ° C. For 30 minutes with a stirrer 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 recovered by centrifugation. Water was removed from the collected aggregated protein using a freeze dryer to obtain a freeze-dried powder of the desired modified fibroin.
  • 8 M guanidine buffer 8 M guanidine hydrochloride, 10 mM sodium dihydrogen phosphate, 20 mM NaCl, 1 mM Tris-HCl, pH 7.0
  • modified fibroin fibers of Examples 1 to 4 and Comparative Example 1 were produced.
  • the modified fibroin fibers of Examples 1 to 3 were obtained by spinning and drawing using the spinning and drawing apparatus 100 shown in FIG.
  • the modified fibroin fiber of Example 4 was spun and drawn by using a spin drawing apparatus provided with a wet heat drawing apparatus (steam drawing (steam drawing) apparatus) instead of the dry heat drawing apparatus in the spin drawing apparatus 100 shown in FIG. It is what went.
  • the modified fibroin fiber of Comparative Example 1 was obtained by spinning and drawing using a spinning and drawing apparatus without the drying apparatus 10 in the spinning and drawing apparatus 100 of FIG.
  • the manufacturing conditions are as follows.

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  • Textile Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Artificial Filaments (AREA)
  • Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
  • Peptides Or Proteins (AREA)

Abstract

La présente invention concerne des fibres de fibroïne modifiées comprenant une fibroïne modifiée et ayant une densité supérieure à 1,34 g/cm 3.
PCT/JP2019/029892 2018-07-31 2019-07-30 Fibres de fibroïne modifiées et leur procédé de production WO2020027153A1 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4361326A1 (fr) * 2022-10-31 2024-05-01 Universidad de Sevilla Procédé de production d'une pluralité de fibres biocompatibles

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Publication number Priority date Publication date Assignee Title
WO2012165476A1 (fr) * 2011-06-01 2012-12-06 スパイバー株式会社 Fibre polypeptidique artificielle et procédé pour la produire
WO2014002605A1 (fr) * 2012-06-28 2014-01-03 スパイバー株式会社 Fibre de protéine teintée dans la masse et procédé pour produire celle-ci
JP6337252B1 (ja) * 2017-03-10 2018-06-06 Ｓｐｉｂｅｒ株式会社 高収縮人造フィブロイン繊維及びその製造方法、並びに人造フィブロイン繊維の収縮方法
WO2019066047A1 (fr) * 2017-09-29 2019-04-04 Ｓｐｉｂｅｒ株式会社 Procédé et dispositif de production de fibre protéique, procédé de traitement de fibre protéique

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Publication number Priority date Publication date Assignee Title
WO2012165476A1 (fr) * 2011-06-01 2012-12-06 スパイバー株式会社 Fibre polypeptidique artificielle et procédé pour la produire
WO2014002605A1 (fr) * 2012-06-28 2014-01-03 スパイバー株式会社 Fibre de protéine teintée dans la masse et procédé pour produire celle-ci
JP6337252B1 (ja) * 2017-03-10 2018-06-06 Ｓｐｉｂｅｒ株式会社 高収縮人造フィブロイン繊維及びその製造方法、並びに人造フィブロイン繊維の収縮方法
WO2019066047A1 (fr) * 2017-09-29 2019-04-04 Ｓｐｉｂｅｒ株式会社 Procédé et dispositif de production de fibre protéique, procédé de traitement de fibre protéique

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4361326A1 (fr) * 2022-10-31 2024-05-01 Universidad de Sevilla Procédé de production d'une pluralité de fibres biocompatibles
WO2024094556A1 (fr) * 2022-10-31 2024-05-10 Universidad De Sevilla Procédé de génération d'une pluralité de fibres biocompatibles

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