Detection of SmpB in E. coli. Detection of SmpB protein in E. coli was performed by western blot with an E. coli SmpB polyclonal antibody. Lane 1: wild type E. coli strain (predicted MW SmpBEc= 18,125 Da), lane 2: ΔsmpB E. coli mutant. Lanes 3-4: SmpBHpdetection in a ΔsmpB E. coli mutant carrying the inducible vector pILL786 expressing the smpBHpgene (predicted MW SmpBHp= 17,682 Da), with or without induction with 1 mM IPTG, respectively. Calibrated amounts of crude bacterial extracts were separated by SDS-15% PAGE. MW: molecular weight.