肠道病毒71型VP1基因及蛋白结构与功能的生物信息学分析

Bioinfornmtics analysis of the structure and function of enterovirus 71 VP1 gene and protein

目的分析肠道病毒71型（EV71）VP1基因及其编码蛋白的结构与功能，以指导其生物学功能研究。方法利用多种生物信息在线分析工具和分析软件包分析EV712008-GZCH07株VP1基因及编码蛋白与其他EV71代表株的序列，进行多序列同源比对，并构建分子进化树。预测该基因编码的蛋白质理化特性，二级结构、三维结构等结构特性，酶学特性和抗原表位等免疫学特性。结果2008-GZCH07株与ZJ001株同源性最高（97％和98％），与人柯萨奇病毒A16同源性最低，与EV71A、B、C型病毒的同源性为86％～98％。2008-GZCH07株与ZJ001株和BJ08-Z025—5株的进化距离较近，属于C4亚型；A、B、C三型EV71的VP1编码蛋白中，2008-GzcH07株VP1编码蛋白与B、C型进化距离较A型近。VP1基因全长510bp，开放读码框位于116～510bp区域，编码132个氨基酸，等电点为4．39。VP1蛋白富含α螺旋和无规卷曲，无跨膜区域，含5个高疏水性区域，属于胞外蛋白。蛋白质同源建模分析表明该区域位于蛋白表面，形成环状结构，含有5个抗原簇，7个关键催化位点位于该区域内或其附近。结论EV71-VP1基因编码蛋白分布有多个磷酸化位点，具有较多的生物功能位点和潜在的抗原表位区域，可能是免疫诊断、药物作用研究及疫苗研制的靶抗原，可为EV71诊断、治疗及预防方面的应用价值提供重要的参考依据。

Objective To understand the structures and functions of enterovirus 71 （EV71） VP1 gene and its encoded protein using bioinformatics method, so as to direct studies of its biological function. Methods VP1 gene and its encoded protein of EV71 2008-GZCH07 strain and other representative EV71 strains were analyzed by online analysis at bioinformatics websites and software packages. Multi-sequence homological alignment and phylogenetic analysis were performed. Physicochemical characteristics, secondary structure, homology modeling of tertiary structure, enzymological characteristics, antigenic epitope of VP1 gene encoded protein were predicted. Results The homology of EV71 2008-GZCH07 strain was highest （97% and 98%） with ZJ001 strain, and lowest with human eoxsaekievirus A16. The homology of EV71 2008-GZCH07 strain and EV71 types A,B,C was 86%- 98%o. Phylogenetic analysis demonstrated that 2008-GZCH07 stain was close to ZJ001 and BJ08-Z025-5 stains, which belonged to C4 subtype. In VP1 encoded proteins of EV71 types A,B,C, the relationship between 2008-GZCH07 and EVT1-B,EV71-C was closer than EVT1-A. The whole length of VP1 gene was 510 bp, with open reading frame （ORF） located at 116-510 hp region,and it encoded 132 amino acids with isoelectric point of 4. 39. The protein was rich of a-helix and random coilon without transmembrane regions, and contained 5 high hydrophobic regions and belonged to extracellular protein. The homology modeling of tertiary structure showed that the region was on the surface of protein and formed a binding loop. There was 5 antigen epitopes. And 7 key catalytic sites were located at or close to the loop. Conclusions EV71-VP1 encoded protein contains many phosphorylation sites, with many biological function sites and antigenic epitope regions, which might be a potential target antigen for immunodiagnosis, anti-schistosome drug and vaccine development, and would be basis of further study of diagnosis, treatment and prevention of EV71 infection.