大肠杆菌肠毒素ST_1-LT_B融合基因的构建

Construction of Fusion Gene of Escherichia coli Heat stable Enterotoxin Ⅰ(ST 1) and Heat labile Enterotoxin B Subunit (LT B)

用ＢａｍＨＩ和ＨｉｎｄⅢ双酶切含大肠杆菌不耐热肠毒素（ＬＴＢ）基因的质粒ｐＸＬＴ１－１，回收５０５ｂｐ的ＬＴＢ基因片段，再用ＢａｍＨＩ和ＨｉｎｄⅢ双酶切含大肠杆菌耐热肠毒素（ＳＴ１）基因的质粒ｐＸＳＴ１，与上述回收的ＬＴＢ基因片段连接，转化至受体菌ＪＭ１０９中。经ＥｃｏＲＩ、ＢａｍＨＩ、ＨｉｎｄⅢ酶切反应鉴定重组子质粒，得到了理想重组子质粒ｐＸＳＬＴ１。ＥＬＩＳＡ检测到了ＳＴ１－ＬＴＢ融合蛋白，而且该融合蛋白无天然ＳＴ１生物毒性。

Restriction endonucleases Bam HI and HindⅢ were used to cleave plasmid pXLT1 1 containing 505 bp LT B gene fragment and the LT B gene fragment was recovered, the 5′ terminus of LT B gene was genetically fused to the 3′ terminus of ST 1 gene encoding the heat stable enterotoxin of Escherichia coli. The recombinant plasmid pXSLT1 was studied in detail by restriction endonucleases analysis. The recombinant plasmid was shown to have carried the pre ST 1 and LT B gene fragments. By transformation of E coli JM109, E coli JM109 (pXSLT 1) was got. The recombinant strain was shown by ELISA to be able to produce pre ST 1 LT B fusion protein without toxicity.