福氏志贺菌毒力蛋白IpaC的表达与纯化

目的：表达和纯化福氏志贺菌毒力蛋白IpaC，研究福氏志贺菌的致病机制。方法：将含有ipaC基因的pET32a-i-paC表达质粒载体转化大肠杆菌BL21（λDE3），在异丙基硫代－β－D半乳糖苷（IPTG）诱导下表达，对诱导后的表达产物进行SDS－PAGE鉴定，并采用QIA expressionist^TM蛋白纯化系统来纯化目的蛋白。结果：诱导后的表达产物经SDS－PAGE发现有一相对分子质量约为63000的条带，其含量约占总蛋白量的11％，以350mmol/L咪唑洗脱液洗脱，目的蛋白纯度可达90％以上，结论：pET32a-ipaC重组表达质粒转入大肠杆菌后，可稳定，高效地表达目的蛋白，QIA－expressionistTM蛋白纯化系统是一种简便，高效的纯化系统，可获得高纯度的目的蛋白。

Expression and purification of invasion plasmid antigen C of Shigella flexneri.

OBJECTIVE: To induce the expression of and purify invasion plasmid antigen C (IpaC) of Shigella flexneri for studying the pathogenesis of Shigella flexneri. METHODS: Prokaryotic expression plasmid pET32a-ipaC was constructed and incorporated into E.coli BL21 (lambda DE3). The engineered bacteria were induced by isopropyl-beta-D-thiogalactopyranoside (IPTG) to express IpaC, which was identified by SDS-PAGE and purified by QIA expressionist system. RESULTS: SDS-PAGE presented a band for the fusion protein with the relative molecular mass of approximately 63 000, whose expression reached up to 11% of the total protein of E.coli BL21(lambda DE3). After proper purification, a purity of the target fusion protein of over 90% was achieved when the concentration of imidazole for elution was 350 mmol/L. CONCLUSION: The recombinant plasmid pET32a-ipaC has been stably and efficiently expressed in E.coli BL21 (lambda DE3), and QIA expressionist purification system proves to be simple and highly efficient.