Ethanol facilitates soluble expression of M_(r) 38000 protein of mycobacterium tuberculosis in E.coli

AIM: To increase the soluble expression of the recombinant M r 38 000 protein by using ethanol.METHODS: Polymerase chain reaction (PCR) was employed to amplify the encoding gene of M r 38 000 protein from mycobacterium tuberculosis H37Rv and the amplified fragment was ligated to plasmid pGEX-4T-2.After the expression vector was transformed into E.coli BL21,ethanol and IPTG were added to induce the expression of the GST-38 fusion protein.The molecular mass and expression form of the fusion protein was analyzed by SDS-PAGE and the activity of the protein was identified by western blotting.RESULTS: The expression vector was constructed successfully.There was about 18% of fusion protein in total cellular proteins of the E.coli.A little soluble protein could be identified in the absence of ethanol while soluble protein increase in the yield to 5-fold in the presence of ethanol.CONCLUSION: As a supplementation,ethanol can facilitate the soluble expression of the M r 38 000 protein of mycobacterium tuberculosis in E.coli.