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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。
Objective: To analyze the effect of N and C termini on the superantigen activity and soluble expression of Staphylococcal enterotoxin C2 (SEC2). Methods: The N and C termini of SEC2 were partially deleted by genetic engineering, and three mutant proteins were obtained. The superantigen activity and soluble expression ability of the two kinds of mutants were compared. Results: The deletion of N and C termini of SEC2 all affected the superantigen activity and soluble expression to a certain extent. The deletion of the superantigen of the two deletion mutants at the N terminus decreased by 40% and 48% respectively The C-terminus decreased its soluble expression level to about 20% of the wild-type. CONCLUSIONS: The N-terminus of the SEC2 protein molecule plays a major role in its superantigen activity and the C-terminus has a significant effect on its soluble expression, whereas the intact SEC2 molecule is essential for its maximum biological activity.