Ethanol facilitates soluble expression of Mr 38 000 protein of mycobacterium tuberculosis in E.coli

    YANG Junª²Lan£¬XU Yan,SU Mingª²Quan,HAO Xiaoª²Ke,YU Wenª²Bin

    Department of Clinical Laboratories,Xijing Hospital,Fourth Military Medical University,Xi¬ðan 710033,China

    ¡¾Abstract¡¿ AIM: To increase the soluble expression of the recombinant Mr 38 000 protein by using ethanol.METHODS: Polymerase chain reaction (PCR) was employed to amplify the encoding gene of Mr 38 000 protein from mycobacterium tuberculosis H37Rv and the amplified fragment was ligated to plasmid pGEXª²4Tª²2.After the expression vector was transformed into E.coli BL21,ethanol and IPTG were added to induce the expression of the GSTª²38 fusion protein.The molecular mass and expression form of the fusion protein was analyzed by SDSª²PAGE 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 5ª²fold in the presence of ethanol.CONCLUSION: As a supplementation,ethanol can facilitate the soluble expression of the Mr 38 000 protein of mycobacterium tuberculosis in E.coli. ......