title: Protein S-mycothiolation functions as redox-switch and thiol protection mechanism in Corynebacterium glutamicum under hypochlorite stress.
abstract: OBJECTIVE
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: 1 Institute for Microbiology, Ernst-Moritz-Arndt-University of Greifswald , Greifswald, Germany .
authors.forename: Bui Khanh
authors.initials: BK
authors.lastname: Chi
authors.forename: Tobias
authors.initials: T
authors.lastname: Busche
authors.forename: Koen
authors.initials: K
authors.lastname: Van Laer
authors.forename: Katrin
authors.initials: K
authors.lastname: Bäsell
authors.forename: Dörte
authors.initials: D
authors.lastname: Becher
authors.forename: Lina
authors.initials: L
authors.lastname: Clermont
authors.forename: Gerd M
authors.initials: GM
authors.lastname: Seibold
authors.forename: Marcus
authors.initials: M
authors.lastname: Persicke
authors.forename: Jörn
authors.initials: J
authors.lastname: Kalinowski
authors.forename: Joris
authors.initials: J
authors.lastname: Messens
authors.forename: Haike
authors.initials: H
authors.lastname: Antelmann
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D048230:Corynebacterium glutamicum / Q000187:drug effects / Q000378:metabolism*; D003545:Cysteine / Q000378:metabolism*; D004220:Disulfides / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D006003:Glycogen / Q000378:metabolism; D006020:Glycopeptides / Q000378:metabolism*; D007294:Inositol / Q000378:metabolism*; D016877:Oxidants / Q000494:pharmacology*; D010084:Oxidation-Reduction; D010544:Peroxidases / Q000235:genetics / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D020543:Proteome / Q000378:metabolism; D012973:Sodium Hypochlorite / Q000494:pharmacology*; D013312:Stress, Physiological; D059467:Transcriptome / Q000187:drug effects
chemical_list: D001426:Bacterial Proteins; D004220:Disulfides; D006020:Glycopeptides; D016877:Oxidants; D020543:Proteome; C089265:mycothiol; D007294:Inositol; D006003:Glycogen; D012973:Sodium Hypochlorite; D010544:Peroxidases; D005947:Glucose; D003545:Cysteine