Protein S-mycothiolation functions as redox-switch and thiol protection mechanism in Corynebacterium glutamicum under hypochlorite stress.

TitleProtein S-mycothiolation functions as redox-switch and thiol protection mechanism in Corynebacterium glutamicum under hypochlorite stress.
Publication TypeJournal Article
Year of Publication2014
AuthorsChi, B. Khanh, T. Busche, K. Van Laer, K. Bäsell, D. Becher, L. Clermont, G. M. Seibold, M. Persicke, J. Kalinowski, J. Messens, and H. Antelmann
JournalAntioxid Redox Signal
Volume20
Issue4
Pagination589-605
Date Published2014 Feb 01
Type of Articleredox
ISSN1557-7716
KeywordsBacterial Proteins, Corynebacterium glutamicum, Cysteine, Disulfides, Glucose, Glycogen, Glycopeptides, Inositol, Oxidants, Oxidation-Reduction, Peroxidases, Protein Processing, Post-Translational, Proteome, Sodium Hypochlorite, Stress, Physiological, Transcriptome
Abstract

AIMS: Protein S-bacillithiolation was recently discovered as important thiol protection and redox-switch mechanism in response to hypochlorite stress in Firmicutes bacteria. Here we used transcriptomics to analyze the NaOCl stress response in the mycothiol (MSH)-producing Corynebacterium glutamicum. We further applied thiol-redox proteomics and mass spectrometry (MS) to identify protein S-mycothiolation.RESULTS: Transcriptomics revealed the strong upregulation of the disulfide stress σ(H) regulon by NaOCl stress in C. glutamicum, including genes for the anti sigma factor (rshA), the thioredoxin and MSH pathways (trxB1, trxC, cg1375, trxB, mshC, mca, mtr) that maintain the redox balance. We identified 25 S-mycothiolated proteins in NaOCl-treated cells by liquid chromatography-tandem mass spectrometry (LC-MS/MS), including 16 proteins that are reversibly oxidized by NaOCl in the thiol-redox proteome. The S-mycothiolome includes the methionine synthase (MetE), the maltodextrin phosphorylase (MalP), the myoinositol-1-phosphate synthase (Ino1), enzymes for the biosynthesis of nucleotides (GuaB1, GuaB2, PurL, NadC), and thiamine (ThiD), translation proteins (TufA, PheT, RpsF, RplM, RpsM, RpsC), and antioxidant enzymes (Tpx, Gpx, MsrA). We further show that S-mycothiolation of the thiol peroxidase (Tpx) affects its peroxiredoxin activity in vitro that can be restored by mycoredoxin1. LC-MS/MS analysis further identified 8 proteins with S-cysteinylations in the mshC mutant suggesting that cysteine can be used for S-thiolations in the absence of MSH.INNOVATION AND CONCLUSION: We identified widespread protein S-mycothiolations in the MSH-producing C. glutamicum and demonstrate that S-mycothiolation reversibly affects the peroxidase activity of Tpx. Interestingly, many targets are conserved S-thiolated across bacillithiol- and MSH-producing bacteria, which could become future drug targets in related pathogenic Gram-positives.

DOI10.1089/ars.2013.5423
Alternate JournalAntioxid. Redox Signal.
PubMed ID23886307
PubMed Central IDPMC3901351
Grant List615585 / / European Research Council / International
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