阅读说明：本技术 人胶原蛋白17型多肽、其生产方法和用途 (Human collagen 17-type polypeptide, production method and use thereof ) 是由 朱赟 于 2019-10-31 设计创作，主要内容包括：本发明提供了一种多肽,所述多肽包含SEQ ID No.9的63至1496个连续的氨基酸残基,其中所述多肽包含(A)<Sub>m</Sub>所示的序列或者由(A)<Sub>m</Sub>所示的序列组成,其中每个A为选自SEQ ID No.1、SEQ ID No.2和SEQ ID No.3任一个所示的氨基酸序列或SEQ ID No.1、SEQ ID No.2和SEQ ID No.3任一个取代、添加、或缺失了1或多个,例如2、3、4或5个氨基酸残基的氨基酸序列或者与SEQ ID No.1、SEQ ID No.2和SEQ ID No.3任一个所示的氨基酸序列具有83％-97％序列同一性的序列；m为1-10之间的整数；其中每个A相同或不同并且相邻两个A之间直接通过肽键连接或者通过1个以上的氨基酸残基连接；其中所述多肽具有细胞粘附活性,以及所述多肽的生产方法和用途。(The present invention provides a polypeptide comprising 63 to 1496 consecutive amino acid residues of SEQ ID No.9, wherein said polypeptide comprises (A)) m The sequence shown is either composed of (A) m The sequence composition shown in the specification, wherein each A is an amino acid sequence selected from any one of SEQ ID No.1, SEQ ID No.2 and SEQ ID No.3 or an amino acid sequence selected from any one of SEQ ID No.1, SEQ ID No.2 and SEQ ID No.3 with 1 or more, for example, 2, 3, 4 or 5 amino acid residues substituted, added or deleted or a sequence having 83-97% sequence identity with the amino acid sequence shown in any one of SEQ ID No.1, SEQ ID No.2 and SEQ ID No. 3; m is an integer between 1 and 10; wherein each A is the same or different and two adjacent A are linked directly by a peptide bond or by 1 or more amino acid residues; wherein the polypeptide has cell adhesion activity, and methods of producing and using the polypeptide.)

1. A polypeptide comprising 63 to 1496 consecutive amino acid residues of SEQ ID No.9, wherein said polypeptide has cell adhesion activity.

2. A polypeptide, wherein said polypeptide comprises (A)_mThe sequence shown is either composed of (A)_mA sequence composition set forth wherein each a is an amino acid sequence selected from any one of SEQ ID No.1, SEQ ID No.2 and SEQ ID No.3 or an amino acid sequence of any one of SEQ ID No.1, SEQ ID No.2 and SEQ ID No.3 with substitution, addition or deletion of 1 or more, for example, 2, 3, 4 or 5 amino acid residues or a sequence having 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96% or 97% sequence identity to the amino acid sequence set forth in any one of SEQ ID No.1, SEQ ID No.2 and SEQ ID No. 3; m is an integer between 1 and 10; wherein each A is the same or different and two adjacent A are linked directly by a peptide bond or by 1 or more amino acid residues; wherein the polypeptide has cell adhesion activity.

3. The polypeptide of claim 1 or 2, wherein the polypeptide comprises or consists of the amino acid sequence shown as SEQ ID No.1, SEQ ID No.2, SEQ ID No.3, SEQ ID No.4 or SEQ ID No. 6.

4. A polynucleotide encoding a polypeptide according to any one of claims 1-3, preferably said polynucleotide comprises or consists of the nucleotide sequence shown in SEQ ID No.5, SEQ ID No.7, or SEQ ID No. 8.

5. An expression vector comprising the polynucleotide of claim 4.

6. A host cell comprising the expression vector according to claim 5 or expressing the polypeptide of any one of claims 1-3, wherein the host cell is preferably an e.

7. A method of making the polypeptide of any one of claims 1-3, comprising:

(1) culturing the host cell of claim 6 in a production medium;

(2) isolating the polypeptide of any one of claims 1-3 from the host cell.

8. A composition comprising the polypeptide of any one of claims 1-3 or the polypeptide prepared by the method of claim 7.

9. An article of manufacture comprising the polypeptide according to any one of claims 1-3 or the polypeptide prepared by the method of claim 7 or the composition of claim 8, wherein the article of manufacture is a pharmaceutical composition, a medical device, a tissue engineering product, a cosmetic or a nutraceutical, preferably the pharmaceutical composition is an external preparation, preferably an external application preparation, such as an external gel or an external infiltration preparation; wherein preferably, the external gel further comprises a pharmaceutically acceptable carrier, and the external infiltration preparation further comprises a sterile medical cotton ball.

10. Use of a polypeptide according to any one of claims 1-3 or a polypeptide prepared by the method of claim 7, a polynucleotide of claim 4, an expression vector of claim 5, a host cell of claim 6, or a composition of claim 8 in the manufacture of a product, preferably a medical device, a tissue engineering product, a cosmetic product, a nutraceutical product.

Technical Field

The invention belongs to the technical field of genetic engineering, and relates to a polypeptide, a production method and application thereof.

Background

Collagen protein

Collagen is generally white, transparent and unbranched fibril, is a basic support of skin and bones, can account for 25% -35% of the total amount of protein, is mainly distributed in skin, blood vessels, bones, tendons, teeth, cartilage and the like of a human body, is a main matrix and a support of the tissues, protects and binds various tissues, and plays an important physiological function in a body. Therefore, the collagen can be widely applied to industries such as medicine, cosmetics and the like.

Collagen products currently on the market are all derived from animal tissues such as pigs, cattle, fish, etc. Although some animals have a high degree of collagen similarity to humans, it is still difficult to avoid the risk of viral infection and sensitization. At present, a small amount of collagen derived from animals is applied to cosmetics, but is difficult to be widely applied to medical devices or more precise tissue engineering products, and cannot play the original biological function of the collagen at all. In addition, the collagen prepared by the conventional method generally has a strong blood coagulation function, so that when the collagen is applied to certain tissue engineering products, great risk of thrombosis is brought, and the wide and deep application of the collagen is greatly limited.

The conventional method for producing collagen is to treat animal-derived tissues by acid, alkali, and enzymatic hydrolysis to extract collagen derivatives. The collagen extracted by the methods loses the original biological activity and cannot be applied to the biomedical field to play a real function. Some research institutions at home and abroad express the human collagen in vitro by a conventional recombinant expression method, but the production cost is usually too high, the production period is too long, and the human collagen cannot be put into large-scale production. Therefore, a collagen material which has excellent biomaterial properties, has an amino acid sequence highly homologous to the human body, and can be prepared in a large amount in an industrial system is urgently needed in the market.

Type 17 human collagen

Structurally, the structure of natural collagen in human body is very complicated, so that it is very difficult to express and prepare human collagen in large quantities by conventional means. The most common structural feature of collagen is the triple-helical structure formed by 3 peptide chains, i.e. the protein is formed by 3 a peptide chains in a right-handed supercoiled manner, and such triple-helical regions are called collagen regions. Each A peptide chain is composed of repeated Gly-X-Y (X, Y represents any amino acid residue except Gly, X is Pro, Y is Hyp) peptide segments on the molecular structure to form a left-hand helix, and 3 chains form a stable triple helix structure by taking the same axis as the center and in a right-hand supercoiling mode under the interaction of the amino acid residues. Therefore, it is difficult for the sequences of collagen to spontaneously bind to form stable triple-helical structures to exert biological functions, and such difficulties seriously hinder the development and production of human collagen.

The human body contains 28 different types of collagen, which are classified into common fibrous collagen and uncommon non-fibrous collagen. Type I, type II, type III, etc. in human skin belong to fibrous collagen. Among the non-fibrillar collagens, a very important collagen subtype is type 17 collagen XVII (encoded by the COL17A1 gene in humans). Type 17 collagen is a homotrimer formed by three COL17a1 chains, with a single chain molecular weight of 180 kDa. The protein comprises a 70kDa globular intracellular domain, a transmembrane domain and a 120kDa extracellular collagen domain, and has very strong thermal stability. Recent studies have demonstrated that type 17 collagen is an important component of epidermal stem cell hemidesmosome in humans, and has important roles in both cell aging and skin differentiation. However, at present, human knowledge of the structural function of non-fibrous collagen is very limited, and particularly little is known about type 17 collagen.

The inventor has intensively studied the structure and function of collagen for many years, especially the new atomic structure of human collagen segments is firstly analyzed internationally and is delivered to the international protein structure database for public display, and the abundant research experience is accumulated. Through repeated research, the inventor successfully realizes the recombinant expression of a plurality of extracellular functional regions of the 17-type collagen, finds that the collagen has excellent biomaterial characteristics, has a simple preparation method, is easy to expand production, and can be widely applied to industries such as medicines, cosmetics and the like.

Disclosure of Invention

The present invention is based in part on the following findings:

compared with the existing human collagen, the polypeptides C17A3, C17B3 and C17C1 of the invention have equivalent or higher cell adhesion effect, and the polypeptides C17A3, C17B3 and C17C1 exist in a water-soluble form after being expressed in host cells, and the preparation method is simple and easy for expanded production.

Aiming at the defects of the prior art shown by the background technology, the invention provides:

a polypeptide comprising 63 to 1496 consecutive amino acid residues of SEQ ID No.9, wherein the polypeptide has cell adhesion activity.

Item 2. the polypeptide, wherein the polypeptide comprises (A)_mThe sequence shown is either composed of (A)_mA sequence composition set forth wherein each a is an amino acid sequence selected from any one of SEQ ID No.1, SEQ ID No.2 and SEQ ID No.3 or an amino acid sequence of any one of SEQ ID No.1, SEQ ID No.2 and SEQ ID No.3 with substitution, addition or deletion of 1 or more, for example, 2, 3, 4 or 5 amino acid residues or a sequence having 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96% or 97% sequence identity to the amino acid sequence set forth in any one of SEQ ID No.1, SEQ ID No.2 and SEQ ID No. 3; m is an integer between 1 and 10; wherein each A is the same or different and two adjacent A are linked directly by a peptide bond or by 1 or more amino acid residues; wherein the polypeptide has cell adhesion activity. The intervals described herein include endpoints, such as 1 to 10 inclusive, e.g. 1, 2, 3, 4, 5,6. 7, 8, 9, 10, i.e. m may be 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.

Item 3. the polypeptide of item 1 or 2, wherein the polypeptide comprises or consists of the amino acid sequence shown as SEQ ID No.1, SEQ ID No.2, SEQ ID No.3, SEQ ID No.4 or SEQ ID No. 6.

Item 4. a polynucleotide encoding a polypeptide according to any one of items 1 to 3, preferably said polynucleotide comprises or consists of the nucleotide sequence shown as SEQ ID No.5, SEQ ID No.7, or SEQ ID No. 8.

Item 5. an expression vector comprising the polynucleotide of item 4.

Item 6. a host cell comprising an expression vector according to item 5 or expressing a polypeptide according to any one of items 1 to 3, wherein the host cell is preferably an e.

Item 7. a method of preparing a polypeptide according to any one of items 1-3, comprising:

(1) culturing the host cell according to item 6 in a production medium;

(2) isolating the polypeptide of any one of items 1-3 from the host cell.

Item 8. a composition comprising a polypeptide according to any one of items 1-3 or a polypeptide prepared by the method of item 7.

Item 9. an article of manufacture comprising the polypeptide of any one of items 1-3 or the polypeptide prepared by the method of item 7, or the composition of item 8, wherein the article of manufacture is a pharmaceutical composition, a medical device, a tissue engineering product, a cosmetic or a nutraceutical, preferably the pharmaceutical composition is an external preparation, preferably an external application preparation, such as an external gel or an external infiltrant preparation; wherein preferably, the external gel further comprises a pharmaceutically acceptable carrier, and the external infiltration preparation further comprises a sterile medical cotton ball.

Item 10 use of a polypeptide according to any one of items 1 to 3 or a polypeptide prepared by the method of item 7, a polynucleotide of item 4, an expression vector of item 5, a host cell of item 6, or a composition of item 8 in the preparation of a finished product, preferably a medical device, a tissue engineering product, a cosmetic, a nutraceutical.

Compared with the prior art, the invention has the following characteristics:

(1) the 17-type human collagen sequence selected for the first time is a sequence optimized by long-term screening;

(2) the Escherichia coli expression system is suitable for large-scale amplification, one round of fermentation can be completed within 20 hours, the production cost is very low, and the yield is very high due to the codon optimization of Escherichia coli on a gene sequence and the selection of a2 XYT culture medium.

(3) The produced recombinant human collagen has good hydrophilicity and stability, the amino acid composition of the recombinant human collagen is 100 percent same as the corresponding part of the amino acid sequence of the natural collagen, and the recombinant human collagen can not generate immunological rejection and anaphylactic reaction when being applied to a human body and can be widely applied to the industries of biological medicine and cosmetics;

(4) the product of the invention has biological activity reaching or even exceeding the biological activity of natural protein of human body through activity detection, can perform the function of the natural protein in human body, and achieves the purpose of real product application.

(5) The technical design of the invention can effectively reduce the blood coagulation risk of the collagen when being used by a human body, simultaneously retains the high cell adhesion activity of the collagen, and has wide tissue engineering application prospect.

Drawings

FIG. 1 is a plasmid map constructed by the vectors of the invention, pET32a-C17A3, pET32a-C17B3 and PET32a-C17C 1;

FIG. 2 is the protein electrophoresis diagram obtained after the Trx-C17A3 protein expression and purification of the invention; the molecular weight of the Trx-C17A3 protein detected by electrophoresis is about 42 kDa.

FIG. 3 is the protein electrophoresis diagram obtained after the Trx-C17B3 protein expression and purification of the invention; the molecular weight of the Trx-C17B3 protein detected by electrophoresis is about 40 kDa.

FIG. 4 is the protein electrophoresis diagram obtained after the Trx-C17C1 protein expression and purification of the invention; the molecular weight of the Trx-C17C1 protein detected by electrophoresis is about 32 kDa.

FIG. 5 is an electrophoresis diagram of a target protein C17A3 protein obtained by enzyme digestion to remove the Trx tag and ion exchange purification after the Trx-C17A3 protein is expressed; electrophoresis of the C17A3 protein detected a molecular weight of approximately 25kDa, corresponding to a protein having the amino acid sequence of SEQ ID No. 4.

FIG. 6 is an electrophoresis diagram of a target protein C17B3 protein obtained by enzyme digestion to remove the Trx tag and ion exchange purification after the Trx-C17B3 protein is expressed; the electrophoretic detection of the C17B3 protein has a molecular weight of about 23kDa, corresponding to the protein having the amino acid sequence of SEQ ID NO. 6.

FIG. 7 is an electrophoresis diagram of a target protein C17C1 protein obtained by enzyme digestion to remove the Trx tag and ion exchange purification after the expression of the Trx-C17C1 protein of the invention; the electrophoretic detection of the C17C1 protein has a molecular weight of about 16kDa, corresponding to the protein having the amino acid sequence of SEQ ID No. 3.

FIG. 8 shows the results of the biological activity assay of the C17A3 protein of the present invention compared with the C17A1 protein (SEQ ID No.1) and human collagen.

FIG. 9 shows the results of the biological activity assay of the C17B3 protein of the present invention compared with the C17B1 protein (SEQ ID No.2) and human collagen.

FIG. 10 shows the results of the bioactivity assay of the C17C1 protein of the present invention compared with human collagen.

Detailed Description

Further description is provided below to facilitate understanding of the invention.

As used herein, "medical instrument" refers to instruments, devices, instruments, in vitro diagnostic reagents and calibrators, materials, and other similar or related items used, directly or indirectly, in the human body.

As used herein, "tissue engineering product" refers to a product used for tissue engineering. Tissue engineering is an emerging discipline for the construction of tissues or organs in vitro or in vivo, combining cell biology and material science.

As used herein, "isolating" refers to isolating a polypeptide of interest from a cultured host cell, e.g., disrupting the host cell and purifying the polypeptide of interest. In the case where the purified target polypeptide carries a purification tag, such as a Trx or His tag, "isolation" also includes enzymatic cleavage of the Trx or His tag.

"pharmaceutically acceptable carriers" are well known to those skilled in the art and may be selected by those skilled in the art to be suitable for use in the compositions or articles of manufacture of the present invention. For example, pharmaceutically acceptable carriers include, but are not limited to, buffers such as phosphoric acid, citric acid and other organic acids; antioxidants, including ascorbic acid and methionine; preservatives (e.g. octadecyl dimethyl benzyl ammonium chloride; chlorhexidine di-ammonium; benzalkonium chloride; benzethonium chloride; phenol, butanol or benzyl alcohol; alkyl parabens such as methyl or propyl paraben; catechol; resorcinol; cyclohexanol; 3-pentanol; and m-cresol); low molecular weight (less than about 10 residues) polypeptides; proteins, such as serum albumin, gelatin, or immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone; amino acids such as glycine, glutamine, asparagine, histidine, arginine or lysine; monosaccharides, disaccharides, and other carbohydrates including glucose, mannose, or dextrins; chelating agents such as EDTA; sugars such as sucrose, mannitol, trehalose or sorbitol; salt-forming counterions such as sodium; metal complexes (e.g., Zn-protein complexes); and/or a non-ionic surfactant such as polyethylene glycol (PEG).

In the present invention, human type 17 collagen COL17a1 sequence was selected for screening optimization. The human collagen type 17 sequence is the NCBI reference sequence: Q9UMD9.3(SEQ ID No.9), see https:// www.ncbi.nlm.nih.gov/protein/Q9UMD9.3.

The amino acid sequences selected in the present invention are underlined in bold in the above sequences. The applicant finds through a large amount of researches that the selected sequence has strong water solubility, high recombinant expression yield and simple purification process, realizes better cell adhesion effect than other sequences in commercialized human collagen or SEQ ID No.9, and has a plurality of excellent biomaterial characteristics. In the present invention, the polypeptide is not the full-length sequence of SEQ ID No. 9.

The present invention is based in part on the following findings: a polypeptide comprising at least 63 consecutive amino acid residues of SEQ ID No.9 can have better biomaterial properties than commercial human collagen, as demonstrated in the examples. The continuous amino acid residues constituting the recombinant collagen can be appropriately selected by those skilled in the art. For example, contiguous amino acid residues can be 48-100, 50-72, 54-57, 48-72, and so forth in length.

In the present invention, the sequences of several specific amino acid regions were tested:

(1)C17A:GSPGPKGDMGSPGPKGDRGFPGTPGIPGPLGHPGPQGPKGQKGSVGDPGMEGPMGQRGREGPMGPRGEA(SEQ ID No.1)；

(2)C17B:GLQGLRGEVGLPGVKGDKGPMGPPGPKGDQGEKGPRGLTGEPGMRGLPGAVGEPGAKGAMGPA(SEQ ID No.2)；

(3)C17C:GADFAGDLDYNELAVRVSESMQRQGLLQGMAYTVQGPPGQPGPQGPPGISKVFSAYSNVTADLMDFFQTYGAIQGPPGQKGEMGTPGPKGDRGPAGPPGHPGPPGPRGHKGEKGDKGDQ(SEQ ID No.3)；

the polypeptide can be recombinant human collagen C17A3, and is a triple repeat sequence of C17A, comprising 207 amino acids, and the basic repeat unit is:

GSPGPKGDMGSPGPKGDRGFPGTPGIPGPLGHPGPQGPKGQKGSVGDPGMEGPMGQRGREGPMGPRGEA (SEQ ID No.1), which is a human collagen 17 peptide fragment.

The amino acid sequence of C17a3 is as follows:

GSPGPKGDMGSPGPKGDRGFPGTPGIPGPLGHPGPQGPKGQKGSVGDPGMEGPMGQRGREGPMGPRGEAGSPGPKGDMGSPGPKGDRGFPGTPGIPGPLGHPGPQGPKGQKGSVGDPGMEGPMGQRGREGPMGPRGEAGSPGPKGDMGSPGPKGDRGFPGTPGIPGPLGHPGPQGPKGQKGSVGDPGMEGPMGQRGREGPMGPRGEA(SEQ ID No.4)。

the DNA sequence of C17a3 is as follows:

GGTAGCCCAGGTCCAAAAGGTGATATGGGAAGCCCAGGTCCGAAAGGTGATCGTGGTTTTCCGGGTACACCAGGTATTCCGGGTCCACTGGGTCATCCAGGTCCGCAAGGTCCGAAAGGCCAGAAAGGTAGCGTGGGTGATCCGGGTATGGAAGGGCCTATGGGGCAGCGTGGGCGTGAAGGGCCGATGGGTCCGCGTGGTGAAGCAGGTAGCCCGGGGCCTAAAGGGGATATGGGGAGTCCGGGTCCGAAAGGGGATCGTGGATTTCCGGGTACGCCGGGTATCCCGGGTCCGCTGGGTCATCCGGGTCCGCAAGGGCCTAAAGGTCAGAAAGGTAGTGTGGGTGATCCTGGTATGGAAGGTCCGATGGGTCAGCGTGGTCGTGAGGGTCCGATGGGACCGCGTGGTGAGGCTGGTAGCCCTGGTCCGAAAGGAGATATGGGTAGCCCGGGTCCGAAAGGTGACCGTGGTTTTCCTGGTACACCGGGTATTCCAGGGCCTCTGGGTCATCCTGGTCCTCAGGGTCCGAAAGGTCAGAAAGGGAGTGTGGGAGATCCGGGTATGGAGGGTCCGATGGGGCAGCGCGGTCGTGAAGGTCCGATGGGCCCGCGTGGTGAAGCC(SEQ ID No.5)。

the polypeptide can be human collagen C17B3, and is a C17B triple repeat sequence, which comprises 189 amino acids, and the basic repeat unit is:

GLQGLRGEVGLPGVKGDKGPMGPPGPKGDQGEKGPRGLTGEPGMRGLPGAVGEPGAKGAMGPA (SEQ ID No.2), which is a human collagen 17 peptide fragment.

The amino acid sequence of C17B3 is as follows:

GLQGLRGEVGLPGVKGDKGPMGPPGPKGDQGEKGPRGLTGEPGMRGLPGAVGEPGAKGAMGPAGLQGLRGEVGLPGVKGDKGPMGPPGPKGDQGEKGPRGLTGEPGMRGLPGAVGEPGAKGAMGPAGLQGLRGEVGLPGVKGDKGPMGPPGPKGDQGEKGPRGLTGEPGMRGLPGAVGEPGAKGAMGPA(SEQ ID No.6)。

the DNA sequence of C17B3 is as follows:

GGTCTGCAGGGTCTGCGTGGTGAAGTAGGACTGCCGGGTGTGAAAGGAGATAAAGGACCAATGGGTCCACCAGGACCAAAAGGAGATCAAGGAGAAAAAGGACCACGTGGTCTGACAGGTGAACCGGGTATGCGTGGGCTGCCGGGAGCAGTTGGAGAACCGGGAGCAAAAGGAGCAATGGGTCCAGCAGGACTGCAGGGTCTGCGCGGTGAAGTGGGACTGCCTGGTGTTAAAGGGGATAAAGGGCCGATGGGTCCGCCGGGTCCGAAAGGAGATCAGGGAGAAAAAGGGCCGCGTGGTCTGACCGGTGAACCGGGAATGCGTGGTCTGCCGGGGGCTGTGGGTGAGCCAGGTGCAAAAGGTGCAATGGGTCCTGCAGGTCTGCAAGGACTGCGTGGAGAAGTGGGTCTGCCTGGTGTGAAAGGTGATAAAGGTCCGATGGGTCCTCCGGGTCCGAAAGGTGATCAGGGTGAAAAAGGTCCGCGTGGTCTGACGGGTGAACCGGGCATGCGTGGTCTGCCTGGGGCAGTTGGTGAACCGGGGGCAAAAGGTGCTATGGGGCCGGCA(SEQ ID No.7)。

the polypeptide can be human collagen C17C1, is 1 repeat of C17C, comprises 119 amino acids, and has the following basic repeat unit:

GADFAGDLDYNELAVRVSESMQRQGLLQGMAYTVQGPPGQPGPQGPPGISKVFSAYSNVTADLMDFFQTYGAIQGPPGQKGEMGTPGPKGDRGPAGPPGHPGPPGPRGHKGEKGDKGDQ (SEQ ID No.3), which is a human collagen 17 peptide fragment.

The amino acid sequence of C17C1 is as follows:

GADFAGDLDYNELAVRVSESMQRQGLLQGMAYTVQGPPGQPGPQGPPGISKVFSAYSNVTADLMDFFQTYGAIQGPPGQKGEMGTPGPKGDRGPAGPPGHPGPPGPRGHKGEKGDKGDQ(SEQ ID No.3)

the DNA sequence of C17C1 is as follows:

GGTGCAGATTTTGCAGGTGATCTGGATTATAATGAACTGGCAGTTCGTGTTAGCGAAAGCATGCAGCGTCAGGGACTGCTGCAGGGAATGGCATATACCGTTCAGGGTCCGCCGGGTCAGCCGGGTCCTCAAGGTCCTCCTGGTATTAGCAAAGTTTTTAGTGCATATTCAAACGTGACGGCAGATCTGATGGATTTTTTTCAGACGTATGGTGCAATTCAGGGTCCTCCTGGGCAAAAAGGTGAAATGGGTACACCTGGTCCGAAAGGCGATCGTGGTCCGGCCGGTCCGCCGGGCCACCCTGGTCCTCCTGGCCCTCGTGGTCATAAAGGTGAGAAAGGTGATAAAGGTGATCAA(SEQ ID No.8)。

herein, the polypeptide may include an amino acid sequence in which 1 or more, preferably 2, 3, 4 or 5 amino acid residues are substituted, added, deleted or inserted in an amino acid sequence shown in any one of SEQ ID No.1, SEQ ID No.2, SEQ ID No.3, SEQ ID No.4, SEQ ID No.6 and SEQ ID No.9 or an amino acid sequence having 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96% or 97% sequence identity with an amino acid sequence shown in any one of SEQ ID No.1, SEQ ID No.2, SEQ ID No.3, SEQ ID No.4, SEQ ID No.6 and SEQ ID No. 9. "percent amino acid sequence identity" with respect to a reference polypeptide sequence is defined as the percentage of amino acid residues in a candidate sequence that are identical with amino acid residues in the reference polypeptide sequence after the candidate sequence is aligned with the reference polypeptide sequence and gaps are introduced, if necessary, to achieve the maximum percent sequence identity, and no conservative substitutions are considered as part of the sequence identity. Alignments to determine percent amino acid sequence identity can be performed in a variety of ways well known to those skilled in the art, for example, using publicly available computer software, such as BLAST, BLAST-2, ALIGN, or Megalign (DNASTAR) software. One skilled in the art can determine suitable parameters for aligning sequences, including any algorithms required to achieve maximum alignment over the full length of the sequences being compared.

Amino acid addition refers to the addition of an amino acid at the C-terminus or N-terminus of an amino acid sequence, e.g., any of SEQ ID No.1, SEQ ID No.2, SEQ ID No.3, SEQ ID No.4, SEQ ID No.6 and SEQ ID No.9, as long as the polypeptide has collagen characteristics and cell adhesion activity.

Amino acid substitution refers to the replacement of an amino acid residue at a position in an amino acid sequence, such as any of the sequences of SEQ ID No.1, SEQ ID No.2, SEQ ID No.3, SEQ ID No.4, SEQ ID No.6 and SEQ ID No.9, with another amino acid residue, provided that the polypeptide has collagen characteristics and cell adhesion activity.

Amino acid insertion refers to the insertion of amino acid residues at appropriate positions in an amino acid sequence such as any of the sequences of SEQ ID No.1, SEQ ID No.2, SEQ ID No.3, SEQ ID No.4, SEQ ID No.6 and SEQ ID No.9, and the inserted amino acid residues may be adjacent to each other in whole or in part, or none of the inserted amino acids may be adjacent to each other, as long as the polypeptide has collagen characteristics and cell adhesion activity.

By amino acid deletion is meant that 1, 2 or more than 3 amino acids may be deleted from an amino acid sequence, such as any of SEQ ID No.1, SEQ ID No.2, SEQ ID No.3, SEQ ID No.4, SEQ ID No.6 and SEQ ID No.9, as long as the polypeptide has collagen characteristics and cell adhesion activity.

In the present invention, the substitution may be a conservative amino acid substitution, which means that 3, preferably 2, or 1 amino acid is substituted with an amino acid having a similar or analogous property to that of any one of SEQ ID No.1, SEQ ID No.2, SEQ ID No.3, SEQ ID No.4, SEQ ID No.6 and SEQ ID No.9 to form a peptide. These conservative variant peptides can be generated by amino acid substitutions according to table 1.

Table 1: conservative substitution of amino acid

Initial residue(s)	Representative substitutions	Preferred substitutions
			Ala(A)	Val；Leu；Ile	Val
Arg(R)	Lys；Gln；Asn	Lys
			Asn(N)	Gln；His；Lys；Arg	Gln
Asp(D)	Glu	Glu
			Cys(C)	Ser	Ser
Gln(Q)	Asn	Asn
			Glu(E)	Asp	Asp
Gly(G)	Pro；Ala	Ala
			His(H)	Asn；Gln；Lys；Arg	Arg
Ile(I)	Leu；Val；Met；Ala；Phe	Leu
			Leu(L)	Ile；Val；Met；Ala；Phe	Ile
Lys(K)	Arg；Gln；Asn	Arg
			Met(M)	Leu；Phe；Ile	Leu
Phe(F)	Leu；Val；Ile；Ala；Tyr	Leu
			Pro(P)	Ala	Ala
Ser(S)	Thr	Thr
			Thr(T)	Ser	Ser
Trp(W)	Tyr；Phe	Tyr
			Tyr(Y)	Trp；Phe；Thr；Ser	Phe
Val(V)	Ile；Leu；Met；Phe；Ala	Leu

All amino acids in the polypeptide sequences herein can be L-form amino acids, one or more (e.g., 2-5, 2-4, or 2-3) of which can also be substituted with D-form amino acids in conformation, artificially modified amino acids, naturally occurring unusual amino acids, and the like, to enhance the bioavailability, stability, and/or antiviral activity of the polypeptide. Wherein the D-form amino acid is an amino acid corresponding to the L-form amino acid constituting the protein; the artificially modified amino acid refers to common L-type amino acid which is modified by methylation, phosphorylation and the like and forms protein; the rare amino acids existing in nature include unusual amino acids constituting proteins and amino acids not constituting proteins, such as 5-hydroxylysine, methylhistidine, gamma-aminobutyric acid, homoserine and the like.

In the present invention, the recombinant human collagen can be prepared by a method conventional in the art. For example, it can be produced by the following steps: (1) constructing escherichia coli genetic engineering bacteria; (2) fermenting and culturing the escherichia coli genetic engineering bacteria; (3) inducing and expressing the recombinant human collagen; and (4) purifying and optionally carrying out enzyme digestion on the recombinant human collagen.

In the step (1), the construction of the engineered Escherichia coli can be carried out as follows: (1) carrying out codon optimization and splicing recombination on a DNA fragment of a gene spiral region of the human-derived type 17 collagen by using a PCR (polymerase chain reaction) method to finally obtain a target gene fragment; (2) inserting the obtained target gene fragment into a PET-32a expression vector to obtain a recombinant expression plasmid; (3) transferring the recombinant expression plasmid into an escherichia coli competent cell BL21(DE3), and screening to obtain the positive escherichia coli genetic engineering bacteria.

In the steps (2) and (3), the fermentation culture of the escherichia coli genetic engineering bacteria and the induction and expression of the recombinant human collagen can be carried out as follows: (1) picking out the optimized single colony of the escherichia coli genetic engineering bacteria from the LAB plate, and placing the single colony in 10ml of LB culture medium at 37 ℃ and 220rpm for culturing for 12-16 hours; (2) and (3) mixing the bacterial liquid according to the proportion of 1:100 inoculating into 2 XYT medium, culturing at 37 deg.C for about 3 hr until OD reaches₆₀₀At 0.4-0.6, adding IPTG with final concentration of 0.5mM for induction, culturing at 16 deg.C for 20 hr, and centrifuging to collect thallus.

In step (4), the purification and enzymatic cleavage of the recombinant human collagen polypeptide may be performed as follows: (1) with phosphate buffer (40mM NaH)₂PO₃500mM NaCl, pH7.8), resuspending the bacteria, sonicating, centrifuging, and collecting the supernatant; (2) combining an NI-NTA affinity column with recombinant human collagen, rinsing the hybrid protein by 10mM imidazole, adding Tev protease (Tobacetch Virus enzyme) at 4 ℃, and carrying out enzyme digestion on the column for 16h to finally obtain the target collagen polypeptide.

The host cell may be a eukaryotic cell, such as a fungus and a yeast, a prokaryotic cell, such as a bacterium of the family Enterobacteriaceae, e.g., E.coli. It is understood that one skilled in the art may substitute the above E.coli strain for other expression strains as host cells.