【摘要】 PCR方法扩增产肠毒素大肠杆菌 (EnterotoxigenicEscherichiacoli,ETEC)LTB、STⅠ、STⅡ基因 ,将LTB、STⅠ、STⅡ基因重组入pET32a质粒载体 ,对构建的重组质粒pBST进行酶切分析、PCR检测以及核苷酸序列分析 ,结果表明 ,插入片段LTB_STⅡ_STⅠ的核苷酸序列与预期一致 ,且阅读框正确。pBST在宿主菌BL2 1(DE3 )RIL中的表达产物经SDS_PAGE初步分析 ,显示重组融合蛋白的分子量约为 40kD ,其表达量约占菌体总蛋白的 46 %。更多还原

【Abstract】 The genes encoding heat-labile toxin B subunit(LTB),heat-stable toxin Ⅰ and Ⅱ(STⅠ,STⅡ)of Enterotoxigenic Escherichia coli (ETEC) were amplified by PCR and were fused into plasmid pET32a.The recombinant plasmid pBST was transformed into the expression host BL 21(DE 3)RIL.The recombinant was identified by PCR,restriction endonuclease analysis and DNA sequencing.The results indicate that the recombinated plasmid pBST was correctly constructed.The fusion protein containing LTB-STⅡ-STⅠ was expressed in BL 21(DE 3)RIL(pBST)and analyzed by SDS-PAGE.The molecular weight of the fusion protein was about 40kD.And the content of fusion protein was about 46 percent of that of total bacterial proteins.更多还原