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. 2010 Apr 12;78(6):2754–2767. doi: 10.1128/IAI.01370-09

FIG. 2.

FIG. 2.

Contribution of cvfA to SpeB expression. (A) Protease production on indicator medium. The wild-type (WT) S. pyogenes strain (HSC5spc), CvfA− mutant strain (ΩCvfA strain), and CvfA− complemented strain (Comp.) (ΩCvfA::pCIV2::cvfA) were transferred to protease indicator medium and examined following overnight incubation. SpeB activity accounts for more than 95% activity of the secreted proteases by S. pyogenes. A zone of clearing resulted from protease activity. (B) Western blot analysis against SpeB. The SpeB cysteine protease in supernatants of 12-h cultures of strains are shown. Note that multiple proteolytic cleavages are required for activation of the 46-kDa SpeB zymogen to the active, 28-kDa SpeB. Lane S, protein size markers. (C) Quantitative assessment of protease activity. The SpeB cysteine protease activities in supernatants of 12-h cultures are shown relative to that of the wild-type strain. The data are the means ± standard errors of the means (SEs) derived from at least three independent experiments.