S-bacillithiolation protects conserved and essential proteins against hypochlorite stress in firmicutes bacteria

Antioxid Redox Signal. 2013 Apr 10;18(11):1273-95. doi: 10.1089/ars.2012.4686. Epub 2012 Oct 18.


Aims: Protein S-bacillithiolations are mixed disulfides between protein thiols and the bacillithiol (BSH) redox buffer that occur in response to NaOCl in Bacillus subtilis. We used BSH-specific immunoblots, shotgun liquid chromatography (LC)-tandem mass spectrometry (MS/MS) analysis and redox proteomics to characterize the S-bacillithiolomes of B. subtilis, B. megaterium, B. pumilus, B. amyloliquefaciens, and Staphylococcus carnosus and also measured the BSH/oxidized bacillithiol disulfide (BSSB) redox ratio after NaOCl stress.

Results: In total, 54 proteins with characteristic S-bacillithiolation (SSB) sites were identified, including 29 unique proteins and eight proteins conserved in two or more of these bacteria. The methionine synthase MetE is the most abundant S-bacillithiolated protein in Bacillus species after NaOCl exposure. Further, S-bacillithiolated proteins include the translation elongation factor EF-Tu and aminoacyl-tRNA synthetases (ThrS), the DnaK and GrpE chaperones, the two-Cys peroxiredoxin YkuU, the ferredoxin-NADP(+) oxidoreductase YumC, the inorganic pyrophosphatase PpaC, the inosine-5'-monophosphate dehydrogenase GuaB, proteins involved in thiamine biosynthesis (ThiG and ThiM), queuosine biosynthesis (QueF), biosynthesis of aromatic amino acids (AroA and AroE), serine (SerA), branched-chain amino acids (YwaA), and homocysteine (LuxS and MetI). The thioredoxin-like proteins, YphP and YtxJ, are S-bacillithiolated at their active sites, suggesting a function in the de-bacillithiolation process. S-bacillithiolation is accompanied by a two-fold increase in the BSSB level and a decrease in the BSH/BSSB redox ratio in B. subtilis.

Innovation: Many essential and conserved proteins, including the dominant MetE, were identified in the S-bacillithiolome of different Bacillus species and S. carnosus using shotgun-LC-MS/MS analyses.

Conclusion: S-bacillithiolation is a widespread redox control mechanism among Firmicutes bacteria that protects conserved metabolic enzymes and essential proteins against overoxidation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacillus / drug effects
  • Bacillus / metabolism*
  • Bacterial Proteins / metabolism*
  • Biosynthetic Pathways
  • Cysteine / analogs & derivatives*
  • Cysteine / metabolism
  • Glucosamine / analogs & derivatives*
  • Glucosamine / metabolism
  • Hypochlorous Acid / metabolism*
  • Metabolomics
  • Methyltransferases / metabolism
  • Oxidation-Reduction
  • Oxidative Stress
  • Proteome / metabolism
  • Proteomics
  • Sodium Hypochlorite / metabolism
  • Sodium Hypochlorite / pharmacology
  • Stress, Physiological*


  • Bacterial Proteins
  • Proteome
  • bacillithiol
  • Hypochlorous Acid
  • Sodium Hypochlorite
  • Methyltransferases
  • Cysteine
  • Glucosamine