Fig. 5

Heterologous expression of the C. pseudotuberculosis FRC41 putative virulence factors in E. coli and rPknG purification. a Coomassie blue-stained SDS-PAGE analyses of the protein expression experiments: PE1, rPknG expression (83 kDa, 10 % gel) in E. coli strain BL21 Star (DE3); PE2, rSpaC expression (86 kDa, 10 % gel) in E. coli strain C43 (DE3); PE3, rSodC expression (18 kDa, 15 % gel) in E. coli strain BL21 Star (DE3); PE4, rNanH expression (71.5 kDa, 10 % gel) in E. coli strain C43 (DE3). 1, pre-stained protein ladder; 2 (NI), non-induced time 0; 3 (I), induced with 1 mM IPTG for 5 h at 37 °C. Arrows indicate the recombinant protein position in the gels. b Chromatogram of the rPknG purification by gel filtration. SDS–PAGE shows an analysis of the purification steps. M molecular-weight markers (kDa); 1, rPknG after affinity chromatography by Ni Sepharose; 2, rPknG purified by gel filtration