OBJECTIVETo construct recombinant plasmid with isocitrate lyase (ICL) gene of Mycobacterium tuberculosis H37Rv for stable and high level expression of ICL in prokaryotic expression system.

METHODSThe recombinant plasmid with ICL gene (pET30 (a)-Rv0467) was constructed by polymerase chain reaction and cloning. The fusion protein was expressed in E. coli host strain BL21 (DE3). Activity of the fusion protein was studied after it was purified with metal chelating chromatography.

RESULTSWe constructed the plasmid which could highly express Mycobacterium tuberculosis H37Rv ICL. The plasmid was highly expressed in E. coli BL21 (DE3), in which the fusion protein accounted for 30% of total protein content. After having been purified by metal chelating chromatography, the purity of the soluble fusion protein was 90%. The fusion protein had activity of ICL.

CONCLUSIONUsing the prokaryotic expression system, the ICL gene of Mycobacterium tuberculosis H37Rv was successfully cloned and expressed, which build the basis for screening new anti-tuberculosis drugs with ICL as the target point.