【摘要】 从E .coli 4 4 815株基因组DNA中扩增不耐热肠毒素B亚单位 (LTB)基因并分析了核苷酸序列 ,构建pET32a的LTB表达载体 ,在E .coliBL2 1DE3宿主菌中用不同浓度的IPTG诱导表达 ,采用SDS PAGE鉴定表达产物。克隆的LTB基因与报道的核苷酸和氨基酸序列同源性分别为 99.12 %～ 99.71%和 97.5 8%～ 99.19% ,pET32a LTB BL2 1DE3系统表达的rLTB量约占细菌总蛋白的 30 %。更多还原

【Abstract】 The gene of Escherichia coli heat-labile enterotoxin subunit B (LTB) was cloned and the nucleotide sequence of the cloned gene was analyzed. pET32a expression vector of LTB gene was constructed and was expressed in E.coli strain BL21DE3 induced by IPTG at different dosages. The expression product was identified by SDS-PAGE. In comparison with the reported LTB sequences, the nucleotide sequence homology of the cloned LTB gene was from 99.12% to 99.71%, while the putative amino acid sequence homology was as high as 97.58%～99.19%. The expression output of recombinant LTB protein (rLTB) in pET32a-LTB-BL21DE3 system was approximate 30% of the total bacterial protein. ;更多还原