ABSTRACT
Objective To investigate the function of Mycobacterium tuberculosis EF4 protein in re-sponse to stress. Methods The plasmid pSMT-EF4 encoding Mycobacterium tuberculosis EF4 protein was transformed into Escherichia coli ( E. coli) BL21 to make it express EF4 protein. The successfully trans-formed E. coli BL21 strains were cultured under different stress conditions and the growth curves were recor-ded to study the function of EF4 protein in response to stress. Results In three media containing ampicil-lin, G418 and streptomycin respectively, the growth of E. coli BL21 expressing Mycobacterium tuberculosis EF4 protein was better than that of untransformed E. coli BL21, and significant differences were observed after culturing for 6 h, 9 h and 2 h, respectively. No significant difference in bacterial growth was found be-tween experimental and control groups cultured under the condition of H2 O2-containing medium, pH3, 20℃or 45℃. Conclusion E. coli BL21 overexpressing Mycobacterium tuberculosis EF4 protein showed certain resistance to antibiotics. Mycobacterium tuberculosis EF4 protein was not directly involved in responses to oxi-dative, acidic and temperature stresses.