RESUMO
To construct expressing vector carrying esat6 gene and express this protein in Streptococcus gor-donii GP251. esat6 gene was amplified by PCR with specific primer from genome of Mycobacterium tuber-culosis (MTB)H37Rv. Inserted esat6 into the pMD18-T vector by T/A clone to get recombinant vector pMD18-esat6. Then digested pMD18-esat6 with restriction enzyme, esat6 was cloned to vector PSMB104 and expressed in Streptococcus gordonii GP251. The expression of esat6 protein was detected by Tricine-SDS-PAGE and Western-blot, ELISA technique was also used to detect its secretory volume. Re-striction endonuclease, PCR, Tric ine-SDS-PAGE and Western-blot confirmed that esat6 gene was cloned into expressing vector successfully, and a 10 kD protein secreted in Streptococcus gordonii GP251, this pro-tein has a good immunogenicity. The expression vector of esat6 gene was constructed, and esat6 protein ex-pressed in Streptococcus gordonii1 successfully, it will be benefit for future study.
RESUMO
Objective:To construct prokaryotic expression vector carrying esat6 gene and express in E. coli. Methods: The MTb esat6 gene was amplified by PCR,then cloned into pQE30 plasmid, sequenced and then cloned into pET32a( + ) plasmid. Thus two kinds of prokaryotic expression vectors were constructed. Results: After being transformed into the E. coli and inducted with 1mM IPTG,no protein was expressed in the pQE30 - ESAT6 system, but a recombinant protein, about 19 kDa,was expressed in the pET32a( + ) - ESAT6 system. In the presence of 1mM IPTG for 4h,the protein was expressed to the maximum. The protein existed in cytoplasm in soluble form and represented 42% total protein of E. coli. It's antigenicity was confirmed by Westem blotting. The protein was purified through the Ni - NTA resin and the purity reached 92 % . Conclusion : The prokaryotic expression vector (pET32a( + ) - ESAT6) was constructed successfully,and the rESAT6 was obtained,providing an experimental basis for application of rESAT6.