pyogenes were inoculated horizontally. Cfa activity is indicated by a wedge-shaped increase in hemolysis activity at the intersection of the two bacterial species. Discussion S. pyogenes exoproteins contribute Protein Tyrosine Kinase inhibitor substantially to interactions with the human host. Production is regulated by several, apparently redundant, transcriptional regulatory circuits working together to control expression. We used a proteomics approach to characterize the contribution of CodY

to the regulation of S. pyogenes exoproteins. The purposes of this study were to clarify how previously identified differences in transcript levels between a wild-type and codY mutant strain are manifest at the protein level and to determine if codY deletion is associated with additional differences in the exoproteome due to post-transcriptional effects. The AC220 datasheet results confirmed, at the protein level, previously identified differences between the strains in the production of SpeB, this website Cfa, and SdaB. Moreover, additional exoproteins were discovered to be regulated by CodY, including the virulence associated secreted nuclease Spd-3, which is encoded by a

prophage, a putative zinc binding transport protein AdcA, and HylA. Overall, the results contribute to defining the S. pyogenes exoproteome and the role CodY plays in determining its composition. The proteolytically active form of SpeB can degrade several streptococcal exoproteins [7, 32]. SpeB is secreted as a 40 kDa zymogen. It is subsequently converted to a 28 kDa proteolytically active form following a multi-step process involving intra- and inter-molecular SpeB cleavages and at least two peptidyl-prolyl, cis trans isomerases (RofA and PrsA; [32]). We harvested exoproteins by TCA/acetone precipitation prior to activation Tenofovir of the SpeB protease. Thus, under the conditions used in this study, only the zymogen form of SpeB was detected in the 2-DE gels and not the proteolytic form (Figure 3). In addition, no protease activity was detected in the culture supernatant samples (data not shown). Finally, the abundance of most exoproteins

was similar between the two strains, despite the significant increase in SpeB zymogen production in the codY mutant strain, indicating that the exoproteins were not being degraded by SpeB in the mutant strain. The production of two secreted nucleases was affected by codY deletion. The expression of SdaB was greater in the mutant strain, which is consistent with results previously obtained by using quantitative PCR during the exponential, but not stationary, phase of growth in rich media [18, 23]. In contrast, the amount of the prophage-encoded Spd-3 protein was less in a codY mutant (Figure 3). This difference was not evident in a previous study in either the exponential or stationary phases of growth, respectively [23].