眼镜蛇科 cathelicidin 基因的分子克隆及活性研究
文献类型：学位论文
| 作者 | 甘同香 |
| 学位类别 | 硕士 |
| 答辩日期 | 2008-06 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 张云 |
| 关键词 | 抗菌肽 cathelicidin 毒蛇 分子克隆 进化树分析 |
| 其他题名 | Cathelicidins exist in reptile, characterization of cathelicidins from elapid snakes |
| 学位专业 | 生物化学与分子生物学 |
| 中文摘要 | Cathelicidins 是天然免疫系统中的一种带正电的宿主防御肽段，它们广泛地分布在哺乳类及其他一些物种如鱼类，鸟类中。它们均包含保守的前肽区和多变的C-末端成熟抗菌肽区域，该抗菌肽区域无论是在种间还是种内都不保守。 我们首次分别从爬行纲眼镜蛇科的眼镜蛇，金环蛇，眼镜王蛇三种毒蛇的毒腺cDNA文库中克隆了3个cathelicidin编码序列。所克隆到的序列编码的开放阅读框架均长576bp，编码191个氨基酸残基组成的蛋白前体。从cDNA开放阅读框推导得到的毒蛇cathelicidin都含有22个氨基酸残基组成的信号肽， 135个氨基酸残基组成的cathelin保守区域以及34个氨基酸残基组成的成熟肽区域。与哺乳类中的cathelicidin基因的高度多样性不同，来源于3种毒蛇的cathelicidin基因在核酸和蛋白水平都比较保守。结构分析表明，以上3种毒蛇的cathelicidin成熟肽由第157位的Val被elastase切割而产生。采用化学合成法合成推导得到的眼镜王蛇的cathelicidin（OH-CATH）。在1% NaCl的浓度下，该合成肽对测试的多种细菌具有很强的抑菌活性，MIC值为1-20 g/ml。与此同时，即使当浓度高达200 g/ml时，该合成的肽段对人的红细胞依然没有溶血活性。对脊椎动物的cathelicidin遗传进化树分析发现毒蛇类的cathelicidin聚在一起。从进化上看，蛇的cathelicidin与来源于小鼠、大鼠、兔的中性粒细胞颗粒蛋白更接近。毒蛇的cathelicidin可能为新药开发提供了一个很好的模板。 |
| 英文摘要 | Cathelicidins are a kind of cationic host defense peptides of the innate immunity and are widespread in mammals and also found in other species such as fishes and birds. Their structure comprises a conserved prepropiece and an antimicrobial domain that is structurally varied both intra- and inter-species. Three cDNA sequences coding for elapid cathelicidins were first cloned from constructed venom gland cDNA libraries of Naja atra, Bungarus fasciatus and Ophiophagus hannah, respectively. The open reading frames of the cloned elapid cathelicidins were all composed of 576 bp and coded for 191 amino acid residue protein precursors. Each of the deduced elapid cathelicidin has a 22 amino-acid-residue signal peptide, a conserved cathelin domain of 135 amino acid residues and a mature antimicrobial peptide of 34 amino acid residues. Unlike the highly divergent cathelicidins in mammals, the nucleotide and deduced protein sequences of the three cloned elapid cathelicidins were comparatively conserved. All the elapid mature cathelicidins were predicted to be cleaved at Valine157 by elastase. One of the deduced mature cathelicidins (OH-CATH), originated from king cobra, was chemically synthesized and it showed strong antibacterial activity against various tested bacteria with MICs of 1-20 g/ml in the presence of 1% NaCl. Meanwhile, the synthesized peptide showed no haemolytic activity toward human red blood cells even at a high dose of 200 g/ml. Phylogenetic analysis of cathelicidins from vertebrate suggested that elapid and viperid cathelicidins were grouped together in the tree. Snake cathelicidins were evolutionary more closely related to the neutrophilic granule proteins (NGPs) from mouse, rat and rabbit. Elapid cathelicidins might be served as a good model for the developing of novel therapeutic drugs. |
| 语种 | 中文 |
| 公开日期 | 2010-10-13 |
| 源URL | [http://159.226.149.42:8088/handle/152453/6082]  |
| 专题 | 昆明动物研究所_动物活性蛋白多肽组学 |
| 推荐引用方式 GB/T 7714 | 甘同香. 眼镜蛇科 cathelicidin 基因的分子克隆及活性研究[D]. 北京. 中国科学院研究生院. 2008. |
入库方式： OAI收割
来源：昆明动物研究所
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