Classifications

• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
  • C12N9/00—Enzymes; Proenzymes; Compositions thereof; Processes for preparing, activating, inhibiting, separating or purifying enzymes
  • C12N9/14—Hydrolases (3)
  • C12N9/48—Hydrolases (3) acting on peptide bonds (3.4)
  • C12N9/50—Proteinases, e.g. Endopeptidases (3.4.21-3.4.25)
  • C12N9/58—Proteinases, e.g. Endopeptidases (3.4.21-3.4.25) derived from fungi
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12Y—ENZYMES
  • C12Y304/00—Hydrolases acting on peptide bonds, i.e. peptidases (3.4)
  • C12Y304/21—Serine endopeptidases (3.4.21)
  • C12Y304/21064—Peptidase K (3.4.21.64)
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K2319/00—Fusion polypeptide

Definitions

• the present invention relates to the provision of recombinant proteinase K from Tritachirium album Limber and corresponding methods for expression, in vitro naturation and activation of the recombinant proteinase K.
• Proteinase K (EC 3.4.21.64, also known as endopeptidase K) is an extracellular endopeptidase that is synthesized by the fungus Tritirachium album Limber. It belongs to the class of serine proteases with the typical catalytic triad Asp 39 -His 69 -Ser 224 (Jany, KD et al. (1986) FEBS Letters Vol. 199 (2), 139-144). As the sequence of the 279 amino acid polypeptide chain (Gunkel, FA and Gassen, HG (1989) Eur. J. Biochem. Vol. 179 (1), 185-194) and the three-dimensional structure (Betzel, C. et al. (1988 ) Eur. J. Biochem.
• Proteinase K is one of the most active known endopeptidases with a specific activity of over 30 U / mg (Betzel, C. et al. (1986). FEBS Lett. Vol. 197 (1-2), 105-110) and hydrolyzes non-specifically native such as denatured proteins (Kraus, E. and Femfert, U, (1976) Hoppe Seylers Z. Physiol.ChemNol.357 (7): 937-947).
• the proteinase K from Tritirachium album Limber is translated as a preproprotein in the natural host.
• the gene for preproproteinase K is composed of 2 exons and codes for a 15 amino acid signal sequence, a 90 amino acid prosequence and a 279 amino acid mature proteinase K.
• a 63 bp intron is located in the prosequence region.
• the prepeptide is removed during translocation into the endoplasmic reticulum (ER). split. Very little is known about the subsequent processing to mature Proteinase K with the propeptide being split off.
• Proteinase K therefore consists of 279 amino acids.
• the compact structure is stabilized by two disulfide bridges and two bound calcium ions. This explains why proteinase K shows a significantly higher stability to extreme pH values, high temperatures, chaotropic substances and detergents compared to other subtilisins (Dolashka, P. et al. (1992) Int. J. Pept. Protein. Res. Vol. 40 (5), 465-471).
• Proteinase K is characterized by high thermal stability (up to 65 ° C, Bajorath et al. (1988), Eur. J. Biochem. Vol. 176, 441-447) and a wide pH range (pH 7.5-12, 0, Ebeling, W. et al.
• Proteinase K is obtained commercially in large quantities by fermentation of the fungus Tritirachium album Limber (e.g. CBS 348.55, Merck strain No.2429 or strain ATCC 22563). The production of proteinase K is suppressed by glucose or free amino acids. Since protein-containing media induce the expression of the proteases, the only nitrogen source that must be used is proteins such as BSA, milk powder or soybean meal. The secretion of the protease begins as soon as the stationary phase of growth is reached (Ebeling, W. et al. (1974) Eur. J. Biochem. Vol. 47 (1), 91-97).
• Tritirachium album Limber is poorly suited for large-scale fermentation and is also genetically difficult to manipulate, various attempts have been made to overexpress recombinant proteinase K in other host cells. However, due to a lack of expression, formation of inactive "inclusion bodies" or problems with naturalization, no significant activity could be detected in these experiments (Gunkel, FA and Gassen, HG (1989) Eur. J. Biochem. Vol. 179 (1), 185-194; Samal, BB et al. (1996) Adv. Exp. Med. Biol. Vol. 379, 95-104). Tritirachium album Limber is also a slow-growing fungus that only secretes small amounts of proteases into the medium.
• T. album also produces other proteases besides proteinase K which could contaminate the preparation (Samal, BB et al. (1991). Enzyme Microb. Technol. Vol. 13, 66-70).
• the object was achieved by the provision of a process for the production of recombinant proteinase K, in which the inactive zymogene proform of proteinase K is produced in insoluble form in inclusion bodies, and then in subsequent steps the zymogene proform of proteinase K natured and the zymogene Proform processes ie is activated.
• the methods for the naturation and activation of proteinase K are also the subject of the present invention.
• the present invention relates to a process for the production of recombinant proteinase K, characterized in that the zymogenic proform is folded by in vitro naturation and converted into the active form by autocatalytic cleavage.
• the present invention relates in particular to a process for producing a recombinant proteinase K, a zymogenic precursor of proteinase K being converted from isolated and solubilized inclusion bodies by oxidative folding into the native structure, i.e. natured, and then, by adding detergents, the active proteinase K is obtained from the natively folded zymogen by autocatalytic cleavage.
• the present invention thus relates to a process for obtaining recombinant proteinase K by transforming a host cell with a DNA coding for the zymogenic proform of proteinase K, characterized by the following process steps:
• the DNA coding for the zymogenic proform of proteinase K corresponds to that in SEQ. ID. NO .: 2 DNA shown or a DNA corresponding to the degeneration of the genetic code.
• SEQ. ID. NO .: 2 includes both the DNA sequence encoding proteinase K and the propeptide.
• the DNA can also be codon-optimized for expression in a particular host. Methods for codon optimization are known to the person skilled in the art and are described in Example 1. The present invention thus relates to methods in which the host cell is transformed by a DNA which is selected from the group mentioned above.
• the process according to the invention enables proteinase K to be obtained which is homogeneous and is therefore particularly suitable for analytical and diagnostic applications.
• the zymogenic proform of proteinase K according to the invention can optionally contain further N-terminal modifications, in particular sequences which facilitate purification of the target protein ("affinity tags"), sequences which increase the efficiency of translation, sequences which increase the folding efficiency or Sequences that lead to secretion of the target protein into the culture medium (natural pre-sequence and other signal peptides).
• Proteinase K in the sense of the invention includes both those in SEQ. ID. NO .: 1 given sequence according to Gassen et al. (1989), as well as other variants of the proteinase K from Tritirachium album Limber, such as the Ch. Betzel et al. (Biochemistry 40 (2001), 3080-3088) disclosed amino acid sequence and in particular proteinase T (Samal, BB et al. (1989) Gene Vol. 85 (2), 329-333; Samal, BB et al. (1996) Adv. Exp. Med. Biol. Vol. 379, 95-104) and Proteinase R (Samal, BB et al. (1990) Mol. Microbiol. Vol.
• the in SEQ. ID. NO .: 1 sequence includes the signal sequence (1-15, 15 amino acids), the prosequence (16-105; 90 amino acids) and the sequence of the mature proteinase K (106-384, 279 amino acids).
• the by Betzel et al. Biochemistry 40 (2001), 3080-3088), the amino acid sequence described has, in particular, position 207 of the active protease aspartate instead of a serine residue.
• pro-proteinase K is to be understood as a proteinase K which is linked to its prosequence at the N-terminus.
• the propeptide can also act intermolecularly in trans as a chaperone on the folding of denatured, mature subtilisin protease (Ohta, Y. et al. (1991) Mol. Microbiol. Vol. 5 (6), 1507-1510; Hu , Z. et al. (1996) /. Biol. Chem. Vol. 271 (7), 3375-3384).
• the propeptide binds to the active center of subtilisin (Jain, SC et al. (1998) /. Mol Biol Vol. 284, 137-144) and acts as a specific inhibitor (Kojima, S. et al. (1998) /. Mol. Biol Vol.
• Insertions are microscopically visible particles from insoluble and inactive protein aggregates, which often arise when heterologous proteins are overexpressed, mostly in the cytoplasm of the host cell, and contain the target protein in high purity. Methods for producing and cleaning such "inclusion bodies” are described, for example, in Creighton, TE (1978) Prog. Biophys. Mol. Biol. Vol. 33 (3), 231-297; Marston, FA (1986) Biochem. J. Vol. 240 (1), 1-12; Rudolph, R. (1997). Folding proteins. In: Creighton, TE (ed.), Protein Function: A practical Approach. Oxford University Press ,. 57-99; Fink, AL (1998) Fold. Of. Vol. 3 (1), R9-23; and EP 0 114 506.
• the host cells are fermented by conventional methods, e.g. using ultrasound, high pressure dispersion or lysozyme.
• the digestion preferably takes place in an aqueous, neutral to slightly acidic buffer.
• the insoluble inclusion bodies can be separated and purified by various methods, preferably by centrifuging or filtering with several washing steps (Rudolph, R. (1997). Folding Proteins. In: Creighton, TE (ed.), Protein Function: A practical Approach, Oxford University Press, 57-99).
• the inclusion bodies obtained in this way are then solubilized in a manner known per se.
• denaturing agents are expediently used in a concentration which is suitable for dissolving the inclusion bodies, in particular guanidinium hydrochloride and other guanidinium salts and / or urea.
• a reducing agent such as difhiothreitol (DTT), dithioerythritol (DTE) or 2-mercaptoethanol during the solubilization in order to break any disulfide bridges which may be present by reduction.
• DTT difhiothreitol
• DTE dithioerythritol
• 2-mercaptoethanol 2-mercaptoethanol
• the inclusion bodies are therefore preferably solubilized by denaturing agents and reducing agents.
• 6-8M guanidinium hydrochloride or 8-10M urea are preferred as denaturing agents and 50-200mM DTT (dithiothreitol) or DTE (dithioerythritol) are preferred as reducing agents.
• the present invention thus encompasses both the 90 amino acid long prosequence according to SEQ. ID. NO .: 1 (amino acids 16-105), as well as other variants that fulfill a folding-promoting function. Also included is a propeptide that is added exogenously to the folding of mature proteinase K and performs the functions set out above.
• Another object of the invention is a recombinant vector which contains one or more copies of the recombinant DNA defined above.
• the basic vector is useful a plasmid, preferably with a multi-copy origin of replication, but viral vectors can also be used.
• the selection of the expression vector depends on the selected host cell. Methods which are known to the person skilled in the art and are described, for example, in Sambrook et al (1989), Molecular Cloning, see below, are used to produce the expression vector and to transform the host cell with this vector.
• coli is, for example, the pKKT5 expression vector, or also pKK177, pKK223, pUC, pET vectors (Novagen) and pQE vectors (Qiagen).
• the expression plasmid pKKT5 was created from pKK177-3 (Kopetzki et al., 1989, Mol Gen. Genet. 216: 149-155) by replacing the tac promoter with the T5 promoter from pDS (Bujard et al. 1987, Methods Enzymol. 155: 416-433).
• the EcoRI restriction endonuclease interface in the sequence of the T5 promoter was removed by two point mutations.
• the coding DNA in the vector according to the invention is under the control of a preferably strong, regulatable promoter.
• An IPTG inducible promoter such as the lac, lacUV5, tac or T5 promoter is preferred.
• the T5 promoter is particularly preferred.
• Any host cell in which proteins can form as inclusion bodies is to be understood as a host cell in the sense of the invention. It is usually a microorganism, e.g. Prokaryotes. Prokaryotic cells, in particular Escherichia coli, are preferred. In particular, the following strains are preferred: E. coli K12 strains JM83, JM105, UT5600, RR1 ⁇ 15, DH5 ⁇ , C600, TG1, NM522, M15 or the E. coli B derivatives BL21, HB101, E. coli M15 is particularly preferred.
• a host cell in the sense of the invention It is usually a microorganism, e.g. Prokaryotes. Prokaryotic cells, in particular Escherichia coli, are preferred. In particular, the following strains are preferred: E. coli K12 strains JM83, JM105, UT5600, RR1 ⁇ 15, DH5 ⁇ , C600, TG1, NM522, M15
• the corresponding host cells are transformed according to the invention with a recombinant nucleic acid encoding a recombinant zymogenic proteinase K according to SEQ. ID. NO .: 2 or with a nucleic acid, which has arisen from the above-mentioned DNA after codon optimization or with a DNA which has arisen from the above-mentioned DNA as part of the degeneration of the genetic code.
• the E. coli host cells are preferably transformed with a codon-optimized recombinant nucleic acid encoding a recombinant zymogenic proteinase K which has been optimized for expression in Escherichia coli.
• the present invention thus also relates to a suitable vector, for example selected from the abovementioned, which contains a recombinant nucleic acid which is codon-optimized for E. coli and which encodes a recombinant proteinase K or a recombinant zymogenic proteinase K.
• the present invention furthermore relates to a Host cell, for example selected from the above, which has been transformed by the above-mentioned vector.
• the present invention furthermore relates to a method for the naturation of denatured zymogenic proteinase K, the denatured, zymogenic proteinase K being transferred to a folding buffer, characterized in that the folding buffer has the following features:
• A) pH value of the buffer is in the range of 7.5 and 10.5,
• a low concentration of denaturing agents is preferably present during the naturation. Denaturing agents can be present, for example, because they are still in the reaction solution due to the previous solubilization of the inclusion bodies.
• the concentration of denaturing agents such as guanidine hydrochloride should be less than 50 mM.
• Naturation in the sense of the invention means a process in which denatured, essentially inactive protein is converted into a conformation in which the protein shows the desired activity after autocatalytic cleavage and activation.
• the solubilized inclusion bodies are transferred to a folding buffer while reducing the concentration of the denaturing agent.
• the conditions must be selected so that the protein remains in solution. This can expediently be carried out by rapid dilution or by dialysis against the folding buffer.
• the folding buffer has a pH of pH 8 to pH 9.
• Tris / HCl buffer and bicin buffer are particularly preferred as buffer substances.
• the naturation process according to the invention is preferably carried out at a temperature between 0 ° C. and 25 ° C.
• the low-molecular-weight folding aids contained in the folding buffer are preferably selected from the following group of low-molecular compounds and can be added both on their own and in mixtures, it being possible for further folding aids to be present:
• ⁇ -Cyclodextrin at a concentration of 60 mM to 120 mM.
• the redox shuffling system mentioned above is preferably a mixed disulfide or thiosulfonate.
• thiol components in oxidized and reduced form are suitable as a redox shuffling system.
• this enables the formation of disulfide bridges within the folding polypeptide chain during naturation by controlling the reduction potential, and on the other hand enables the "reshuffling" of incorrect disulfide bridges within or between the folding polypeptide chains (Rudolph, R. (1997), see above).
• Preferred thiol components are, for example:
• the Ca 2+ ions are preferably present in a concentration of 1 to 20 mM.
• CaCl 2 can be added in amounts of 1 to 20 mM.
• the Ca 2+ ions can bind to the calcium binding sites of the folding proteinase K.
• the presence of a complexing agent, preferably EDTA in a substoichiometric concentration to Ca 2+ serves to prevent oxidation of the reducing agent by atmospheric oxygen and to protect free SH groups.
• the present invention furthermore relates to the convolution buffer, which is characterized by the following features:
• A) pH value of the buffer is in the range of 7.5 and 10.5,
• the folding buffer has a pH of pH 8 to pH 9 and / or if the redox shuffling system is mixed disulfide or thiosulfonate.
• the invention furthermore relates to a method for activating the natural zymogenic precursor of proteinase K.
• an inactive complex of native proteinase K and the inhibitory propeptide is formed.
• the active proteinase K can be released from this complex.
• the addition of detergents is preferred, SDS in a concentration of 0.1 to 2% (w / v) is particularly preferred.
• nucleic acids which code for the mature proteinase K on the one hand and code for the propeptide of the proproteinase K on the other hand are expressed separately in host cells and then transferred together into a folding buffer for the naturalization of the mature proteinase K.
• Renatured and processed Proteinase K was analyzed using analytical ultracentrifugation. The centrifugation was carried out at 12,000 rpm, 20 ° C. for 63 h. The determined data (o) could be fitted to a homogeneous species with an apparent molecular weight of 29 490 Da. No systematic deviation of the fitted from the measured data can be observed (lower graph).
• the gene for the mature proteinase K from Tritirachium album Limber without signal sequence and without intron was generated by means of gene synthesis.
• a codon usage optimized for Escherichia coli was used as the basis for the back-translation (Andersson, SGE and Kurland, CG. (1990) Microbiol. Rev. Vol. 54 (2), 198-210, Kane, JFCurr. Opin. Biotechnol, Vol.6, pp. 494-500).
• the amino acid sequence is in SEQ.
• the gene was divided into 18 fragments of sense and reverse, complementary counter-strand oligonucleotides in an alternating sequence (SEQ. ID. NO .: 3-20).
• An area of at least 15 bp in length was appended to the 5 'and 3' ends, each overlapping with the adjacent oligonucleotides. Restriction endonuclease recognition sites were appended to the 5 'and 3' ends of the synthetic gene outside the coding region for later cloning in expression vectors.
• SEQ. ID. NO .: 20 shows the 3 'primer with HindIII interface.
• the 3 'primer contains an additional stop codon after the natural stop codon to ensure a reliable termination of the translation.
• oligonucleotide with 5 ⁇ raHI cleavage or that in SEQ. ID. NO .: 24 oligonucleotide described with _3 at the HI site and enterokinase cleavage site used.
• the oligonucleotides were linked to one another by means of a PCR reaction and the resulting gene was amplified.
• the gene was first divided into three fragments of 6 oligonucleotides each and the three sections were linked together in a second PCR cycle.
• Fragment 1 consists of the oligonucleotides as in SEQ. ID. NO .: 3-8 shown, fragment 2 from oligonucleotides as in SEQ. ID. NO .: 9-14 and fragment three from oligonucleotide as in SEQ. ID. NO .: 15-20 shown together.
• PCR reaction 1 generation of the three sections
• the PCR mixture was applied to an agarose gel and the approximately 1130 bp PCR fragment was isolated from the agarose gel (Geneclean II kit from Bio 101, Inc. CA USA). The fragment was cut with the EcoRI and Hmdlll restriction endonucleases (Röche Diagnostics GmbH, Germany) for 1 hour at 37 ° C. At the same time, the pUCl ⁇ plasmid (Röche Diagnostics GmbH, Germany) with the EcoRI and Hrndlll restriction endonucleases was cut for 1 hour at 37 ° C., the mixture was separated by agarose gel electrophoresis and the 2635 bp vector fragment was isolated. The PCR fragment and the vector fragment were then ligated together using T4 DNA ligase.
• the structural gene was cloned into the pKKT5 expression vector in such a way that the structural gene was oriented in the correct orientation under the control of a suitable promoter, preferably an IPTG-inducible promoter such as lac, lacUV5, tac or T5 promoter, particularly preferably the T5 promoter is inserted.
• a suitable promoter preferably an IPTG-inducible promoter such as lac, lacUV5, tac or T5 promoter, particularly preferably the T5 promoter is inserted.
• the structural gene for proteinase K was cut out of the plasmid pUC18 using EcoRI and Hmdll ⁇ , the restriction mixture was separated by agarose gel electrophoresis and the approximately 1130 bp fragment was isolated from the agarose gel.
• the expression plasmid pKKT5 was cut with ⁇ coRI and Hmdlll, the restriction mixture was separated by agarose gel electrophoresis and the approx. 2.5 kbp vector fragment was isolated from the agarose gel. The fragments thus obtained were ligated together as described. The correct insertion of the gene was checked by sequencing.
• the expression vector was transformed into various expression strains, which were pre-transformed with the plasmid pR ⁇ P4 and / or pUBS520.
• the plasmid pREP4 contains a gene for the / ⁇ d repressor, which is intended to ensure complete suppression of expression before induction.
• the plasmid pUBS520 (Brinkmann, U. et al. (1989) Gene Vol. 85 (1), 109-114) also contains the Z ⁇ d repressor and additionally the dnaY gene which codes for the tRNA which is responsible for the translation of the in E. coli rare arginine codons AGA and AGG is necessary. Competent cells from various E. coH strains were identified using the Hanahan, D.
• a B ⁇ mHI cleavage site was inserted before the 5 'end of the pro-proteinase K gene. This was done by means of PCR with the product obtained in Example 1 as a template and the one in SEQ. ID. NO .: 20, 23 and 24 described oligonucleotides achieved as primers.
• the one in SEQ. ID. NO .: 23 described primer contains a B mHI site before the 5 'region of the pro-proteinase K, which is described in SEQ. ID. NO .: 24 primers described additionally an enterokinase cleavage site directly before the first codon of the prosequence.
• SEQ. ID. NO .: 20 shows the 3 'primer with H dlll interface also used in Example 1.
• the PCR products obtained were isolated as described above, digested with Bam I and Hindill and purified by agarose electrophoresis.
• the affinity tag was inserted by means of a synthetic linker which was composed of two complementary oligonucleotides in such a way that an EcoRI site was formed at the 5 'end and a S ⁇ mHI interface at the 3' end without further restriction digestion.
• the sense strand had the one in SEQ. ID. NO .: 21, the anti-sense strand described in SEQ. ID. NO .: 22 indicated sequence.
• the linker encoded a hexa histag with an N-terminal RGS motif.
• the B ⁇ HI interface between linker and pro-proteinase K is translated to a Gly-Ser linker.
• the two oligonucleotides SEQ. ID.
• the linker was ligated with the S ⁇ mHI / H dlll-digested PCR product (Rapid Ligation Kit from Röche Diagnostics GmbH, Germany) and purified by agarose gel electrophoresis. (QIAquick Gel Extraction Kit from Qiagen, Germany).
• the ligation product thus obtained was ligated into an expression vector via the J3coRI and Hfndlll overhangs analogously to Example 2b and correspondingly transformed into expression strains.
• This module system makes it possible to fuse different affinity tags, which are encoded by the synthetic linker, to the structural gene for pro-proteinase K.
• an enterokinase cleavage site can alternatively be inserted between the tag and the propeptide if a later removal of the tag is desired.
• a certain area of the proteinase K gene such as the mature proteinase K or the propeptide can be amplified (FIG. 1).
• proteinase K is a very active non-specific protease
• expression in inactive form should preferably be aimed for as inclusion bodies.
• Plasmid-containing clones were inoculated in 3 ml Lb am medium and incubated at 37 ° C. in a shaker.
• the cells were induced with ImM IPTG and incubated for 4 hours at 37 ° C. in a shaker.
• the optical density of the individual expression clones was then determined, an aliquot corresponding to an OD 550 of 3 / ml was removed and the cells were centrifuged off (10 min 6000 rpm, 4 ° C.).
• the cells were resuspended in 400 ⁇ L TE buffer, disrupted by ultrasound and the soluble protein fraction was separated from the insoluble protein fraction by centrifugation (10 min, 14000 rpm, 4 ° C.).
• AUS fractions were mixed with application buffer containing SDS and ⁇ -mercaptoethanol and the proteins were denatured by heating (5 min at 95 ° C.). Subsequently, 10 ⁇ l were analyzed using a 12.5% analytical SDS gel (Laemmli, UK (1970) Nature Vol. 227 (259), 680-685). A very strong expression in the form of insoluble protein aggregates ("inclusion bodies") was observed both for the clones of the mature proteinase K and for the clones of the pro-proteinase K. Accordingly, no proteinase activity was measured.
• Wash buffer 1 100 mM Tris / HCl
• the pellet of the last washing step are the raw inclusion bodies, which already contain the target protein in great purity.
• Example 6 is the raw inclusion bodies, which already contain the target protein in great purity.
• Solubilization buffer 100 mM Tris / HCl
• the solubüisate was titrated to pH 3 with 25% HC1 and dialyzed twice for 4 h at RT against 500 ml of 6 M guanidine hydrochloride pH 3 and then overnight at 4 ° C. against 1000 ml of guanidine hydrochloride pH 7.
• the protein concentration was determined by the Bradford method (Bradford, 1976) and by a calculated extinction coefficient at 280 nm and was between 10 and 20 mg / ml.
• the number of free cysteines was determined according to Ellman. In accordance with the sequence, 5 mol of free cysteines per mol of proteinase K were found.
• the purity of the solubilized inclusion bodies was determined by 12.5% SDS PAGE and quantification of the bands after Coomassie staining.
• Solubilization buffer 100 mM Tris / HCl
• test buffer 100 mM Tris / HCl, 5 mM CaCl 2 , pH 8.5 at 25 ° C. was used as the test buffer.
• concentration of the peptide in the test was 2 mM from a 200 mM stock solution in DMSO.
• SDS 0.1% SDS was added to the sample (see Example 8). For the measurement, the absorbance at 410 nm was monitored over a period of 20 min and the activity was calculated from the slope.
• the folding buffer with 100 mM Tris, 1.0 mM L-arginine, 10 mM CaCl 2 was equilibrated at different temperatures. After adding 3 mM GSH and 1 mM GSSG, the pH was adjusted at the appropriate temperature. The reaction was started by adding 50 ⁇ g / ml pro-proteinase K. Aliquots were removed after 12 h, 36 h and 60 h and tested for activity. The results are shown in Figure 2:
• a universal buffer with 50 mM citrate, 50 mM MES, 50 mM bicin, 500 mM arginine, 2 mM CaCl 2 and 1 mM EDTA was tempered at 15 ° C. and 3 mM GSH and 1 mM GSSG were added. The pH values in the range between pH 4.0 and pH 12.0 were simulated.
• the folding reaction was started by adding 50 ⁇ g / ml pro-proteinase K inclusion bodies. The activity measured after 18 h, 3 d and 5 d is shown in FIG. 3. c) Redox potential
• renaturation buffer with 1.0 M L-arginine, 100 mM bicin, 2 mM CaCl 2 and 10 mM CaCl 2 by mixing different ratios of oxidized and reduced glutathione.
• the protein concentration in the folding mixture was 50 ⁇ g / ml.
• the folding was carried out at 15 ° C.
• the concentrations of GSH and GSSG are shown in Table 1, the measured values in Figure 4.
• FIG. 5 shows the relative yields of active proteinase K as a function of the concentration of the chosen buffer additive.
• SDS was added to the folding mixture in a concentration of 2% (v / v) and then the folding additives and the SDS were removed by dialysis. Alternatively, SDS could also be added after the additives had been removed by dialysis. Full activity of proteinase K was detected in the outside.
• the folded and activated proteinase K as well as the authentic proteinase K from T. album and the pro-proteinase K inclusion bodies were analyzed by means of reversed phase HPLC.
• a Vydac C4 column with dimensions of 15 cm x 4.6 mm was used det.
• the samples were eluted with an acetonitrile gradient from 0% to 80% in 0.1% TFA.
• the folding product shows identical running properties as the authentic proteinase K used as standard (see FIG. 12).
• the naturalized and activated recombinant proteinase K was subjected to a sequence analysis.
• the folding product was desalted by RP-HPLC as in Example 9 b) and the first 6 residues were examined by N-terminal sequencing.
• the result (AAQTNA) matches the authentic N-terminus of the mature proteinase K.
• the K m value of the folded and activated proteinase K was compared with that of the authentic proteinase K.
• the tetrapeptide Suc-Ala-Ala-Pro-Phe-pNA was used as the substrate.
• the test was carried out in 2.0 ml 50 mM Tris, pH 8.5 with 1 mM CaCl 2 at 25 ° C.
• the hydrolysis of the peptide was monitored spectroscopically at 410 nm.
• a K m value of 0.16 mM was found for the recombinant proteinase K in good agreement with the K m value of the authentic proteinase K (see FIG. 14).
• the cleavage pattern of blood serum proteins was examined in a further test to characterize the activity. For this purpose, a defined amount of blood serum proteins was digested with 1 ⁇ g of recombinant Proteinase K or the same amount of authentic Proteinase K. The cleavage pattern was analyzed by RP-HPLC under the same conditions as in Example 9 b). In Figure 15 it can be seen that the recombinant and the authentic Proteinase K lead to an identical degradation pattern.
• Example 10 Example 10:
• the recombinant proproteinase K naturalized by the process according to the invention was purified by gel filtration. After the naturation as described in FIG. 11, the concentrated naturation solution was separated in the first run without prior activation, in the second run with previous activation by means of 0.15% (w / v) SDS (30 min, 4 ° C.) on a Superdex 75 pg , 100 mM Tris / HCl, 150 mM NaCl pH 8.75 (4 ° C.) was used as the running buffer. The order volume was 10 ml with a column volume of 1200 ml and a flow rate of 5 ml / min. After the job was completed, 14 ml fractions were collected.
• a first peak shows unprocessed recombinant proproteinase K, which probably runs in the form of microaggregates in the exclusion volume.
• a second peak shows processed recombinant proteinase K, which coelutes with the propeptide, which is non-covalently bound and acts as an inhibitor. Therefore, no activity could be determined without further activation. Only after adding SDS to the fractions does the second peak show clear Proteinase K activity (not shown).
• the second run in which the folded recombinant proteinase K was previously activated with SDS, shows only one peak which elutes after an identical volume as the proteinase K under the same conditions (not shown).
• On the SDS gel clean, mature recombinant proteinase K without propeptide can be seen in this peak. All impurities and the propeptide appear to have been digested by the activated recombinant proteinase K on order.
• the fractions of the Proteinase K peak showed activity without further activation with SDS.
• the recombinant proteinase K purified in this way appears to be almost 100% pure on the SDS gel (FIG. 16) and shows an identical running behavior to the authentic proteinase K.

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• 2001
  • 2001-02-09 DE DE10105912A patent/DE10105912A1/de not_active Withdrawn
• 2002
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  • 2002-02-08 CA CA002435753A patent/CA2435753A1/en not_active Abandoned
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  • 2002-02-08 US US10/467,532 patent/US20070099283A1/en not_active Abandoned
  • 2002-02-08 EP EP02750504A patent/EP1360284B1/de not_active Expired - Lifetime
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