大肠杆菌热敏肠毒素B亚基的原核表达及生物学活性分析

摘要

从大肠杆菌K88（LT＋,ST＋）菌株中扩增热敏肠毒素B亚基基因（ltb）,得到454 bp片段,克隆至pMD18-T载体后,与pET32a（＋）定向连接,并转化入大肠杆菌BL21中,用IPTG 30℃诱导表达重组LTB蛋白。SDS-PAGE显示,重组蛋白分子量约为34 kDa,超声波裂解后,表达产物主要以包涵体形式存在。经鉴定,纯化复性后的LTB蛋白保留部分与GM1结合的生物学活性。%The gene of Escherichia coli heat-labile enterotoxin subunit B was cloned into plasmid pET32a vector and transformed into E.coli BL21.The recombinant protein was expressed after being induced by IPTG at 30℃.The SDS-PAGE indicated that the molecular weight of recombinant LTB was about 34 kDa.Most of the recombinant protein existed in inclusion body after ultrasonication,and part of protein regained bio-activity of binding with GM1 after renaturation.