犬链球菌M蛋白基因的克隆及生物信息学分析

Cloning and bioinformatics analysis of M gene in Streptococcus canis

本研究对犬链球菌M蛋白(SCM)基因克隆,并对其进行生物信息学分析,预测其蛋白质结构及功能,为链球菌表位疫苗的研究及链球菌病的诊断提供参考。利用ExPASy ProtParam在线分析软件,预测犬链球菌M蛋白为亲水性蛋白质且属于稳定蛋白。使用SignalP 4.1软件推测该蛋白有信号肽。利用SOPMA中5种相互独立的方法预测其二级结构,其中α螺旋占83.53%,可知α螺旋为二级结构的主要元件。应用SWISS-MODEL在线分析软件,进行三级构造同源建模,发现其结果与二级结构预测结论大致相同。使用DNAStar预测软件中的Protean部分对SCM亲水性、蛋白质的二级结构、抗原性指数、表面可能性、柔韧性进行归纳比较分析,在第55~59和第377~379氨基酸区段存在B细胞表位。

In order to provide the reference for developing epitope vaccine and diagnosis of Streptococcus,M protein of Streptococcus canis(SCM)gene was cloned and analyzed by bioinformatics software to predict its protein structure and function in this study.SCM was a stable hydrophilic protein and transmembrane protein proved by analysis of ExPASy ProtParam on-line software.This protein was predicted to contain signal peptide by SignalP 4.1 software.Five separate methods of SOPMA showed that SCM hadαhelix as the main component of secondary structure,accounted for 83.53%.The three-dimensional structure of SCM determined by using SWISS-MODEL work-space was predicted to have the same result with the secondary structure.By using Protean modules of DNAStar software,SCM hydrophilicity plot,secondary structure,antigenicity index,surface probability plot and flexible regions are analyzed and compared to find that B cell epitopes were predicted at the region No.55~59 and No.377~379.