定位诱变脊髓灰质炎疫苗株VP1壳蛋白提高疫苗的热稳定性

本文首次在脊髓灰质炎疫苗株VP1壳蛋白上用计算机探索了氨基酸取代对热稳定性的影响。Menendez-Arias等研究发现,使蛋白质α-螺旋区内刚性(螺旋趋势)增加,亲水性减少,能适应更热的环境。而少数几个氨基酸的取代则能实现这种改变。本文运用本室建立的蛋白质二级结构预测的计算机程序在VP1壳蛋白上寻找α-螺旋区,选择出亲水概率大的并与中和抗原决定簇区无关的α-螺旋区作为氨基酸取代的区域。在这些区域上进行了有效的几个氨基酸取代后,均能使α-螺旋趋势增加,亲水性减少,而取代部位两侧氨基酸残基构型基本上没有发生变化,这与文献报道的结果是一致的。这项工作可为将来利用基因工程方法,设计、寻找工程蛋白提高脊髓灰质炎疫苗的热稳定性提供理论依据。

Site-directed Mutagenesis of the Capsid Protein VP 1 of Polio-vaccine—Study of Increasing Thermostability of the Vaccine

We first studied the thermal stability of polio vaccine effected by aminoacid substitutions by using computer. According to Menendez-Arias' research, protein could be adapted to warmer environment with increasing its stiffness and decreasing hydrophilicity in alpha regions. This could be acieved by some few preferred residue exchanges in the alpha helical regions. We predicted the secondary structures of polio vaccines with computer, and selected high hydrophilic alpha helical regions of them, unrelated to neutralization-antigenic determinants, as the preusm able regions of site-directed mutagenesis for greater thermostability. We found that our results consisted with Menendez-Arias' findings and it would provide information about increasing thermostability of polio vaccines by the technology of protein engineering.