基于EV71交叉保护抗原P1的前体蛋白B细胞抗原位点的预测

Prediction of the B cell linear epitope of the cross-protective P1 precursor protein of Enterovirus 71

目的获得EV71P1保守氨基酸序列COBRA EV71 P1和基于此序列的B细胞抗原表位预测信息。方法从NCBI(http://www.ncbi.nlm.nih.gov/)上下载获取1970-2010年间世界各地暴发流行的包含P1或VP1基因片段的EV71源序列和对应的氨基酸序列,根据VP1基因片段信息构建系统进化树,对源序列进行基因分组;对多基因型的EV71 P1氨基酸源序列采用多序列比对,以优势氨基酸位点代替差异氨基酸位点的方法,获得EV71 P1保守序列(COBRA EV71 P1),并运用IEDB Analysis Resource (http://tools.immuneepitope.org/main/)在线预测工具和DNASTAR软件里的Protean模块,运用单参数和二级结构预测综合考虑的方法,对COBRA EV71 P1前体蛋白的B细胞抗原表位进行预测。结果成功比对出COBRA EV71 P1氨基酸序列,预测结果发现在COBRA EV71 P1前体蛋白的第10-24,41-60,68-82,208-225,328-345,498-514,592-609,664-678,772-786和841-855位点均具有较好的亲水性、表面可及性、柔韧性和抗原指数,并且在二级结构上含有易形成抗原表位的无规则卷曲和β-转角,有可能是COBRA EV71 P1前体蛋白的优势表位。结论经生物信息学分析,推测COBRA EV71 P1可能具有三个基因型EV7 1P1前体蛋白的候选B细胞线性抗原表位,为EV71重组多表位疫苗设计和多基因型病毒样颗粒疫苗实验提供了理论基础。

Objective To obtain the EV71 P1 conserved amino acid sequence （COBRA EV71 P1） and to predict the B cell linear epitope of COBRA EV71 P1 amino acid sequence. Methods The EV71 original sequences including the P1 or VP1 genetic segment and related amino acid sequences published between 1970 and 2010 were downloaded from NCBI （http：//www.ncbi.nlm.nih.gov/）.Based on the information of VP1 genetic fragments,the phylogenetic tree was constructed by virtue of Mega5.0. All original sequences were assigned to each gene group. With the help of multiple sequence alignment,variations of amino acid sites were found and taken up by the most common amino acid sites thus EV71 P1 conserved amino acid sequence was available. The B cell linear epitopes were predicted using the IEDB Analysis Resource web predictive tools and Protean module of DNASTAR software,based on the combination of univariate analysis and secondary structure prediction. Results EV71 P1 conserved amino acid sequence was constructed successfully. And the sites including 10 to 24,41 to 60,68 to 82,208 to 225, 328 to 345, 498 to 514, 592 to 609, 664 to 678, 772 to 786 and 841 to 855 of the B cell linear epitopes of the COBRA EV71 P1 precursor protein were all found to possess a good hydrophilicity, surface probability, flexibility as well as a relatively desirable antigenic index. These sites were also found to own random coils, which were prone to generate epitopes, and β turns. They might be the dominant epitopes of the COBRA EV71 P1 precursor protein. Conclusions There are three genetic type of B cell linear epitopes in COBRA EV71 P1 precursor protein. This study provides a theoretical basis for the design and production of recombination multiple epitope vaccine and multiple genetic virus like-particles vaccine of EV71.