白喉毒素E154位突变及生物活性评价

在量子化学计算的基础上,结合目前关于白喉毒素结构与功能的研究状况,选择把白喉毒素催化区的第154位谷氨酸分别突变为天冬氨酸和精氨酸,研究此处电荷性质的改变对生物活性的影响.通过基因定点突变方法制备这两个突变体基因,并在大肠杆菌表达系统中获得高效表达,在此基础上对它们的生物活性进行了评价.结果表明,与重组野生型白喉毒素相比,突变体E154D的整体动物毒性和细胞毒性略有增加,而E154R的毒性下降.

Mutations in E154 of Diphtheria Toxin(DT)and Their Biologic Activity

According to the results of quantum chemistry calculation and the present research status in the relationship between the structures and the functions of DT, the E154 in DT catalyzing domain was mutated to aspartic acid and arginine in order to study the effects of the alteration on the biological activities. By means of gene site-direct mutation, two mutated genes were prepared and the high performance expression was obtained in E.coli system. The results of toxcity studies indicated that the acute toxicity in guinea pig and cytotoxicities of mutant E154D increased slightly in compared with those of recombination wild toxin, and contrarily, those of E154R decreased obviously.