摘要： 为了分析FMDV AF72VP2蛋白结构和功能的关系.以口蹄疫病毒株AF72 RNA为模板,反转录并扩增目的基因,PCR纯化产物与pGEM-Teasy载体连接并转化JM109菌株,用凝胶电泳、PCR和SpeⅠ、SphⅠ双酶切法鉴定为阳性的重组质粒进行测序.比对测序结果确定AF72 VP2的核苷酸序列,利用同源建模的方法建立AF72 VP2结构蛋白的3D结构,在此基础上,综合亲水性、可塑性、抗原指数以及表面可能性等参数预测AF72 VP2结构蛋白的B细胞抗原表位.分析表明,口蹄疫病毒VP1,VP2,VP3 和VP4在核苷酸水平上的变异率是无差异的(P>0.05);而他们在氨基酸水平上的变异率差异显著(P<0.05).该毒株与20株源于GenBank中的VP2氨基酸序列比对发现其保守区主要位于第1～23、37～51、～7、85～101、124～142、15～199、205～219位.保守区氨基酸残基在维持VP2蛋白的空间构象和功能方面具有重要作用,其中1～10、129～140、15～17氨基酸区段是AF72 VP2结构蛋白可能的B细胞抗原表位区域,该结果将为进一步的FMDV多表位疫苗研究提供更有价值的参考信息.

关键词: 口蹄疫病毒, VP2结构蛋白, 3D结构, B细胞表位

Abstract: Foo-t and-mouth disease virus strain AF72 RNAs were used as templates for RT-PCR to amplify the target gene.The purified PCR products were cloned into pGEM-T easy Vectors and transformed into E. coli JM109.The positive recombinant plasmids identified by electrophoresis, PCR, and analysis of tow cleavages with Spe I and Sph I. The nucleot ide sequence were confirmed by comparing with the ful-l length sequence of the other reference strains. By homology modeling, the 3D model of AF72 VP2 structure protein was obtained.Then several parameters, including hydrophilicity, flexibility, antigenic index and surface probability were integrated, and B-cell epitopes in VP2 were predicted. After analyzing the difference among VP1, VP2, VP3, VP4, at the nucleotide level, the mutation rates of these 4 encoding sequences were no difference ( P > 0105), however, at the amino acid level, those mutation rates were different ( P< 0105).The regions of 1- 23th, 37- 51th, 66- 76th, 85- 101th, 124- 142th, 165- 199th, 205- 219th in VP2 protein most probably are conservative. This research should be used as an instruction in order to direct the work on FMDV VP2 protein, and Bcell epitopes in VP2 probably exist in the following regions: 1- 10aa, 129- 140aa, 165- 176aa. This result offers valuable information for research of FMDV mult-i epitope vaccine.

Key words: FMDV, VP2 structure protein, 3D model, B- cell epitope

中图分类号: 

• Q78