重组人源性胶原蛋白的制备及表征

为了获得可实现工业化生产的重组人源性胶原蛋白，根据人I型胶原蛋白Gly-X-Y序列，优选亲水性的Gly-X-Y胶原肽段设计人源性胶原蛋白氨基酸序列及对应的核苷酸序列，利用酶切技术构建pPIC9K-COL表达载体，电转化毕赤酵母获得人源性胶原蛋白毕赤酵母工程菌，并对其进行发酵罐发酵、纯化及鉴定。结果显示，获得表达量达4.5 g/L，纯度大于95%的人源性胶原蛋白，经氨基酸N端测序、分子量测定、氨基酸分析及胶原酶降解试验，确定获得的蛋白与理论的人源性胶原蛋白一级结构一致；同时胶原经冷冻干燥后进行扫描电镜分析及细胞毒性试验，确定人源性胶原蛋白冻干品具有多孔纤维网状结构及优良的细胞相容性，预示其具备作为生物医学材料的潜质。

Preparation and characterization of recombinant human-source collagen

This study aimed to obtain a recombinant human-source collagen for industrialization. First, based on the Gly-X-Y sequence of human type I collagen, we optimized the hydrophilic Gly-X-Y collagen peptide, designed the human collagen amino acid sequence and the corresponding nucleotide sequence. Next, the expression vector pPIC9K-COL was constructed via endonuclease digestion technology. We obtained an engineering strain of human-source collagen by electrotransforming Pichia pastoris, and then it was fermented, purified and identified. As a result, the expression level reached 4.5 g/L and the purity was over 95%. After amino acid N-terminal sequencing, molecular weight analysis, amino acid analysis and collagenase degradation test, we confirmed that the obtained collagen was consistent with designed primary structure of human-source collagen. After freeze-drying, we analyzed the collagen by scanning electron microscope and cell cytotoxicity, confirming that the collagen has porous fiber reticular structure and superior cytocompatibility. This indicates that human-source collagen has potential to be applied as biomedical material. In conclusion, we successfully obtained the expected human-source collagen and laid a foundation to its further application.