GI双突变体GIK253RA198C的构建及其性质分析  

Construction and Characterization of the Glucose Isomerase Mutant, GIK253RA198C.

作　　者：伍传金[1] 王琛[1] 滕脉坤[1] 王淳[1] 肖亚中[1] 王玉珍[1] 牛立文[1] 崔涛[1] 

机构地区：[1]中国科学技术大学生物系,合肥230026

出　　处：《生物化学与生物物理进展》1997年第6期533-536,共4页Progress In Biochemistry and Biophysics

基　　金：国家"8 6 3"计划资助项目!(86 3 10 3 2 1 0 8)

摘　　要：以双引物法对葡萄糖异构酶 (GI)基因进行定点突变 ,将突变体基因于大肠杆菌中表达 ,获得了GI双点突变体GIK2 53RA1 98C .研究K2 53R和A1 98C双点突变对GI的结构和性质的作用 ,结果表明GIK2 53RA1 98C的热稳定性明显下降 ,最适反应温度降低 5℃ .文章从结构和机制上解释了为何同是K2 53R突变 ,对SM33GI和密苏里游动放线菌GI的热稳定性产生不同的影响 ,认为这是由于Lys2 53在两种GI结构的位置上存在微小差异 。The GI mutant, GIK253RA198C, was obtained by in vitro site directed mutagenesis using the double primer method and then expressed in E.coli K38. The characteristic analysis of the enzymes showed that thermostability of GIK253RA198C was significantly lower as compared with wild type GI in 80℃. Moreover, its optimum reaction temperature decreased from 75℃ to 70℃. The results are explained by the kinetic parameters. Previous experiment indicated that the same mutation of K253R produced different effects on the thermostablity of SM33 GI and A.missouriensis GI. It is clarified here, based on structure and mechanism, that the result was due to the minor difference between Lys253s positions in the two GI structures.

关 键 词：D-葡萄糖异构酶 突变体 基因表达 热稳定性 

分 类 号：Q558.02[生物学—生物化学]