嗜水气单胞菌气溶素基因克隆与蛋白结构预测

Cloning and Homology Modeling of Aerolysin Gene from Aeromonas hydrophila

目的:对嗜水气单胞菌气溶素(Aer)基因进行克隆、序列分析及蛋白三级结构(3D结构)预测。方法:利用PCR方法扩增嗜水气单胞菌Zf1菌株的Aer基因,进行生物信息学分析。结果:获得Aer基因长1 479bp,推导编码493aa,预测Aer蛋白抗原表位位于44-48、230-236、355-361、370-374和447-459,并含有APT结构域(PF03440)、Aer结构域(PF01117),以及2个高度保守序列SYLAHYLGYAWVGG(140-153)和GFLRWGGNAW(343-352)。Aer蛋白的3D结构与模板(PDB:3G4O_B)相似性达93.79%,其中气溶素生理活性相关亚单位(PS50233)构成Aer的核心区,抗原表位(447-459)位于C端外侧表面,并与拉马钱德兰图检测分析Aer蛋白的空间结构基本一致。结论:对嗜水气单胞Zf1菌株Aer基因编码蛋白分子进行结构和功能分析,有助于理解其致病机理,为进一步验证Aer生物学特性提供科学参考。

Objective：Cloning and homology modeling of aerolysin gene from Aeromonas hydrophila. Method： The aerolysin genc （Aer） was amplified by PCR and was analyzed by bioinformafics methods. Result：The sequencing analysis of Aer gene showed that the expected fragment was 1479 bp long, encoding a protein of 493 amino acids. Antigenic epitope prediction showed that the antigenic epitopes of Aer protein were mainly located in the five regions （ie. , 44-48,230- 236,355 -361,370 -374 and 447 -459）. Furthermore, the ATP- domain （PF03440）, acrolysin- domain （PF01117） and two high conserved sequences named SYIAHYLYAWVGG （ 140 - 153） and GFLRWGGNAW （343 - 352）, were found by using sequence alignment and Motif Scan analysis. The Aer protein exhibited the high ho- mology of 93.79% with the standard model which is aerolysin mutant H132N （PDB ：3C,40_B）, and the physiological activity subunit of aerolysin （ PS50233 ） constituted a common core and the antigenic epitope region （447 -459） was located in the outer surface of the C - terminal Conclusion：Both of the structure prediction and function analysis of Aer gene encoding protein contribute to the understanding of the pathogenic mechanisms of Aeromonas hydrophi!a and provide a scientific basis for ~e further verify the biological characteristics of Aer genc.