Diamide triggers mainly S Thiolations in the cytoplasmic proteomes of Bacillus subtilis and Staphylococcus aureus.
Glutathione constitutes a key player in the thiol redox buffer in many organisms. However, the gram-positive bacteria Bacillus subtilis and Staphylococcus aureus lack this low-molecular-weight thiol. Recently, we identified S-cysteinylated proteins in B. subtilis after treatment of cells with the disulfide-generating electrophile diamide. S cysteinylation is thought to protect protein thiols against irreversible oxidation to sulfinic and sulfonic acids. Here we show that S thiolation occurs also in S. aureus proteins after exposure to diamide. We further analyzed the formation of inter- and intramolecular disulfide bonds in cytoplasmic proteins using diagonal nonreducing/reducing sodium dodecyl sulfate gel electrophoresis. However, only a few proteins were identified that form inter- or intramolecular disulfide bonds under control and diamide stress conditions in B. subtilis and S. aureus. Depletion of the cysteine pool was concomitantly measured in B. subtilis using a metabolomics approach. Thus, the majority of reversible thiol modifications that were previously detected by two-dimensional gel fluorescence-based thiol modification assay are most likely based on S thiolations. Finally, we found that a glutathione-producing B. subtilis strain which expresses the Listeria monocytogenes gshF gene did not show enhanced oxidative stress resistance compared to the wild type.
Pöther
Dierk-Christoph
DC
Institute of Microbiology1 and Institute of Pharmaceutical Biology,2 Ernst-Moritz-Arndt-University of Greifswald, F-L-Jahnstr 15, D-17487 Greifswald, Germany.
Liebeke
Manuel
M
Hochgräfe
Falko
F
Antelmann
Haike
H
Becher
Dörte
D
Lalk
Michael
M
Lindequist
Ulrike
U
Borovok
Ilya
I
Cohen
Gerald
G
Aharonowitz
Yair
Y
Hecker
Michael
M
D001412:Bacillus subtilis / Q000187:drug effects* / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D003958:Diamide / Q000378:metabolism*; D018384:Oxidative Stress; D011499:Protein Processing, Post-Translational; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000378:metabolism*; D013312:Stress, Physiological; D013438:Sulfhydryl Compounds / Q000378:metabolism*
D001426:Bacterial Proteins; D013438:Sulfhydryl Compounds; D003958:Diamide