Fig. 3

SDS–PAGE analysis of His-fRv3391 expression. The recombinant protein was expressed in strain BL21 (DE3) of E. coli. Lane 1,the induced BL21 cells (37°C, 1.0 mM IPTG, 2 h); lane 2 the induced BL21 cells (37°C, 0.5 mM IPTG, 6 h); lane 3 the induced BL21 cells (37°C, 0.5 mM IPTG, 4 h); lane 4 the induced BL21 cells (37°C, 0.5 mM IPTG, 2 h); lane 5 the non-induced BL21 cells; lane 6 molecular weight markers (P7708; New England Biolabs, USA). Proteins were visualized with Coomassi brilliant blue staining