抗菌肽Lactoferricin B基因的克隆及其在大肠杆菌中的融合表达

发布时间：2018-08-15 15:10

【摘要】：背景与目的 Lactoferricin B(简称Lfcin B)是一类富含色氨酸的小分子抗菌肽,是牛乳铁蛋白(bLf)在消化道内经胃蛋白酶水解而产生。同其他抗菌肽一样,Lactoferricin B具有广谱杀菌活力,此外可能还有抑制病毒和真菌增生、抑杀肿瘤细胞等多种生物学功能,而对真核细胞几乎没有毒性。基于这种选择性效应和无抗原性的特点,Lactoferricin B有望成为新一代的抗菌、抗病毒、抗肿瘤新药。然而,天然抗菌肽的来源十分困难,无论以何种生物为来源的抗菌肽,都面临培养和提取的问题,难以保证每一批次的抗菌肽有一致的生物活性,很难满足研究和临床应用的需要。因此,利用分子生物学技术重组表达外源基因成为获取目标蛋白的最有效途径。由于抗菌肽对细菌有很强的杀伤作用,不宜在原核系统中直接表达,一般的策略是采用融合表达或在真核细胞(如酵母)中进行表达。本研究采用融合表达的方法,体外合成抗菌肽Lactoferricin B基因并克隆入大肠杆菌中,重组表达Lactoferricin B蛋白。方法根据Lactoferricin B的氨基酸序列,采用大肠杆菌偏爱密码子反推其基因cDNA序列,化学合成LactoferricinB基因,并将基因克隆入
[Abstract]:Background & objective Lactoferricin B (is a class of tryptophan rich small molecular antimicrobial peptides, which is produced by hydrolysis of bovine lactoferrin (bLf) in digestive tract by pepsin. Lactoferricin B, like other antimicrobial peptides, has broad-spectrum bactericidal activity, in addition to inhibition of virus and fungal proliferation, inhibition of tumor cells and other biological functions, but almost no toxicity to eukaryotic cells. Lactoferricin B is expected to be a new generation of antimicrobial, antiviral and antitumor drugs based on its selectivity and antigenicity. However, the source of natural antimicrobial peptides is very difficult, no matter what biological source of antimicrobial peptides, are faced with the problem of culture and extraction, it is difficult to ensure that each batch of antimicrobial peptides have consistent biological activity. It is difficult to meet the needs of research and clinical application. Therefore, recombinant expression of foreign gene by molecular biology is the most effective way to obtain target protein. Because antimicrobial peptides have strong killing effect on bacteria, it is not suitable to express them directly in prokaryotic system. The general strategy is to express them by fusion or in eukaryotic cells (E. g. Yeast). In this study, Lactoferricin B gene was synthesized and cloned into Escherichia coli to express Lactoferricin B protein by fusion expression in vitro. Methods according to the amino acid sequence of Lactoferricin B, the LactoferricinB gene was chemically synthesized by using Escherichia coli codon preference codon to deduce its cDNA sequence.
【学位授予单位】：四川大学
【学位级别】：硕士
【学位授予年份】：2005
【分类号】：Q78

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