S-bacillithiolation of the OhrR repressor and the methionine synthase MetE protect against hypochlorite stress in Bacillus subtilis
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ABSTRACT: Protein S-thiolation is a post-translational thiol-modification that controls redox-sensing transcription factors and protects active site cysteine residues against irreversible oxidation. In B. subtilis, the MarR-type repressor OhrR was shown to sense organic hydroperoxides via formation of mixed disulfides with the redox buffer bacillithiol (Cys-GlcN-Malate) termed as S-bacillithiolation. We have studied changes in the transcriptome and redox proteome caused by the strong oxidant hypochloric acid (NaOCl), the active component of house-hold bleach. The OhrR-controlled peroxiredoxin OhrA was most strongly up-regulated by NaOCl stress and conferred specific protection against NaOCl. Inactivation of the OhrR repressor was caused by S-bacillithiolation of the redox-sensing Cys15 residue in response to NaOCl. Two cobalamin-independent methionine synthases MetE and YxjG were identified as S-bacillithiolated at their essential active site cysteines resulting in hypochlorite-induced methionine limitation. In summary, our studies show that S-bacillithiolation of OhrR and the methionine synthases is the major mechanism in protection against hypochlorite stress in B. subtilis. The B. subtilis 168 wild type strain was grown in minimal medium to OD500 of 0.4 and harvested before and 10 minutes after exposure to 50 µM NaOCl. Microarray hybridizations were performed in triplicate using RNA isolated from independent cultures.
ORGANISM(S): Bacillus subtilis subsp. subtilis str. 168
SUBMITTER: Ulrike Mäder
PROVIDER: E-GEOD-27637 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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