奶牛乳房炎链球菌GapC蛋白的生物信息学分析与重组表位疫苗设计

Bioinformatics analysis of cow mastitis Streptococcus GapC protein and designing of recombinant epitope vaccine

为设计奶牛乳房炎链球菌GapC蛋白的多表位串联疫苗,进一步提高GapC蛋白的免疫效果,采用DNAMAN、MEGA软件分析GapC的同源性与系统发生,结果显示,不同种类链球菌亲缘关系均较近,尤其是与奶牛乳房炎有关的链球菌亲缘关系更近。利用在线软件预测GapC为亲水性蛋白,存在多个酶切位点;采用Signal P 4.1与TMHMM Server v.2.0软件预测GapC无信号肽和跨膜结构,定位于细胞表面;SOPMA服务器预测GapC二级结构中含无规则卷曲30.36%,α-螺旋33.93%,β-转角12.50%,β-片层23.21%。采用Swiss-Model预测的GapC三级结构与二级结构相符。利用ABCpred和Bepi Pred方案,预测GapC存在5个B细胞表位。运用神经网络与量化矩阵法预测GapC具有1个CTL表位。使用MHC-Ⅱ类分子结合肽在线程序预测显示GapC具有1个Th表位。采用DNASTAR Protean软件重组GapC抗原表位,设计获得抗原性较好的GapC重组表位多肽。

To design multi epitopes tandem vaccine of Streptococcus GapC protein of cow mastitis,and enhance the immunity of GapC protein,homology and phylogenetic analyses were performed on different species of Streptococcus spp..Streptococcus bacteria were closely related,especially for those associated with cow mastitis. GapC protein is predicted to be hydrophilic,and has multiple cleavage sites. Prediction with Signal P 4. 1 and TMHMM Server v. 2. 0 softwares reveals that GapC has no signal peptide and transmembrane structure,and is located on cell membrane. GapC secondary structure contains random coil( 30. 36%),alpha helix( 33. 93%),beta turn( 12. 50%),and extended strand( 23. 21%) by SOPMA,and the 3D structure is close to the secondary structure by SwissModel program. GapC has 5 B cell epitopes predicted by ABC pred and Bepipred programs. 1 CTL epitope was predicted using quantitative matrix and artificial neural network and 1 Th epitopes was predicted using an online MHC class II peptide binding affinity server. A GapC recombinant epitope peptide was designed with better immunogenicity by DNASTAR Protean software.