肠毒素C2蛋白C,N末端对其活性的影响

目的:分析金黄色葡萄球菌肠毒素C2(SEC2)中N,C末端对其超抗原活性和可溶性表达能力的影响。方法:应用基因工程技术对SEC2的N,C末端进行部分删除,获得三种突变蛋白,并对其进行体外超抗原活性和可溶性表达能力的比较。结果:对SEC2的N,C末端的删除都在一定程度上影响其超抗原活性和可溶性表达能力,其中,N末端的两个删除突变体的超抗原活性分别降低40%和48%,而删除C末端则使其可溶性表达水平下降到野生型的20%左右。结论:SEC2蛋白分子的N末端对其超抗原活性起主要作用,C末端对其可溶性表达具有显著影响,而完整的SEC2分子对于其发挥最大生物学活性是必要的。

Effects of the Amino Terminal and the Carboxyl Terminal on Staphylococcal enterotoxin C2

Objective:The purpose of this study is to analyze the effects of the amino terminal and the carboxyl terminal of Staphylococcal enterotoxin C2(SEC2) on its superantigen activity and soluble expression.Method:In this study,the amino terminal and the carboxyl terminal of SEC2 were partly deleted by gene engineering method to construct three truncated mutants.The superantigen activity and the soluble expression of the three mutants were evaluated compare with wild-type SEC2.Result:The deletions of both the amino terminal and the carboxyl terminal of SEC2 resulted in decreased superantigen activity and decreased solubility.The superantigen activity of two amino terminal truncated mutants showed 40% and 48% reduction compared with native SEC2,respectively.And the deletion of carboxyl terminal significantly decreased the soluble expression ability to about 20% of native SEC2.Conclusion:The amino terminal of SEC2 is important for superantigen activity,and the carboxyl terminal is important for the solubility of SEC2.The intact structure of SEC2 is essential to its effective biological activity.