Abstract: Objective To construct an engineering strain that can express 65kD mycobacterial heat shock protein. Methods The gene encoding the Mycobacterium tuberculosis 65kD antigen was amplified using PCR and then was cloned in the plasmid. The recombinant plasmid was transformed into E. coli , and then was screened using enzyme digestion and sequencing. The screened recombinant plasmid was transported into E. coli , subsequently the recombinant E. coli was induced by IPTG to express 65kD protein. Results The gene encoding 65kD protein is 1.6kb. Base pairs of DNA sequencing were about 99.1% total gene. The constructed recombinant E. coli can produce 65kD protein of M.tuberculosis. Conclusion E.coli expression system is a rapid and simple means to obtain recombinant antigen of M.tuberculosis.

Key words: Mycobacterium, tuberculosis, 65kD, E.coli