PolA1, a putative DNA polymerase I, is coexpressed with PerR and contributes to peroxide stress defenses of group A Streptococcus.

The peroxide stress response regulator PerR coordinates the oxidative-stress defenses of group A Streptococcus (GAS). We now show that PerR is expressed from an operon encoding a putative DNA polymerase I (PolA1), among other GAS products. A polA1 deletion mutant exhibited wild-type growth but showed reduced capacity to repair DNA damage caused by UV light or ciprofloxacin.

Peroxide stimulon and role of PerR in group A Streptococcus.

We have characterized group A Streptococcus (GAS) genome-wide responses to hydrogen peroxide and assessed the role of the peroxide response regulator (PerR) in GAS under oxidative stress. Comparison of transcriptome changes elicited by peroxide in wild-type bacteria with those in a perR deletion mutant showed that 76 out of 237 peroxide-regulated genes are PerR dependent. Unlike the PerR-mediated upregulation of peroxidases and other peroxide stress defense mechanisms previously reported in gram-positive species, PerR-dependent genes in GAS were almost exclusively downregulated and encoded proteins involved in purine and deoxyribonucleotide biosynthesis, heme uptake, and amino acid/peptide transport, but they also included a strongly activated putative transcriptional regulator (SPy1198).

Shr is a broad-spectrum surface receptor that contributes to adherence and virulence in group A streptococcus.

Group A streptococcus (GAS) is a common hemolytic pathogen that produces a range of suppurative infections and autoimmune sequelae in humans. Shr is an exported protein in GAS, which binds in vitro to hemoglobin, myoglobin, and the hemoglobin-haptoglobin complex. We previously reported that Shr is found in association with whole GAS cells and in culture supernatant.

Characterization of MtsR, a new metal regulator in group A streptococcus, involved in iron acquisition and virulence.

Group A streptococcus (GAS) is a common pathogen of the human skin and mucosal surfaces capable of producing a variety of diseases. In this study, we investigated regulation of iron uptake in GAS and the role of a putative transcriptional regulator named MtsR (for Mts repressor) with homology to the DtxR family of metal-dependent regulatory proteins. An mtsR mutant was constructed in NZ131 (M49 serotype) and analyzed.