Expression and purification of SrtB
. E. coli NiCo21(DE3) expressing SrtBΔN26, in which the N-terminal membrane anchor has been replaced with a six-histidine tag, were lysed by sonication and cleared lysates purified by nickel affinity chromatography. A. Anti-his western testing for expression of SrtBΔN26. Lane M: molecular mass marker, N: whole cell lysate of non-induced culture, I: whole cell lysate of culture induced with 1 mM IPTG. B. Coomassie-stained SDS-PAGE analysis of SrtBΔN26 purification over an imidazole gradient. Lane L: molecular mass marker, W: column wash, imidazole gradient indicated by grey triangle, arrows indicate the SrtBΔN26 protein.