OmpT-like activity of purified CroP. (A) Proteolytic degradation of CRAMP by CroP. CRAMP was incubated with purified CroP with samples collected at the indicated times. Samples were resolved by Tris-Tricine SDS-PAGE on 10 to 20% polyacrylamide gels and visualized by Coomassie blue staining. The molecular mass of full-length CRAMP is indicated on the left. The data shown are representative of three independent experiments. (B) Cleavage of plasminogen into active plasmin by purified CroP and C. rodentium cells expressing various omptins. Glu-plasminogen and the plasmin substrate VLKpNA were incubated with purified CroP (□), control LPS buffer (○), and C. rodentium ΔwaaL (▲), ΔwaaL ΔcroP (⧫), and ΔwaaL ΔcroP(pYCpla) (●) strains. The absorbance at 405 nm was monitored over a 300-min period. For each data set, the initial absorbance was subtracted from all values. The data shown are expressed as means ± the SEM of triplicate samples and are representative of three independent experiments.