Function of Oxygen Resistance Proteins in the Anaerobic, Sulfate-Reducing Bacterium Desulfovibrio vulgaris Hildenborough
Wildschut, Janine D.
Voordouw, Johanna K.
Schriemer, David C.
SubjectPhysiology and Metabolism
MetadataShow full item record
AbstractTwo mutant strains of Desulfovibrio vulgaris Hildenborough lacking either the sod gene for periplasmic superoxide dismutase or the rbr gene for rubrerythrin, a cytoplasmic hydrogen peroxide (H2O2) reductase, were constructed. Their resistance to oxidative stress was compared to that of the wild-type and of a sor mutant lacking the gene for the cytoplasmic superoxide reductase. The sor mutant was more sensitive to exposure to air or to internally or externally generated superoxide than was the sod mutant, which was in turn more sensitive than the wild-type strain. No obvious oxidative stress phenotype was found for the rbr mutant, indicating that H2O2 resistance may also be conferred by two other rbr genes in the D. vulgaris genome. Inhibition of Sod activity by azide and H2O2, but not by cyanide, indicated it to be an iron-containing Sod. The positions of Fe-Sod and Sor were mapped by two-dimensional gel electrophoresis (2DE). A strong decrease of Sor in continuously aerated cells, indicated by 2DE, may be a critical factor in causing cell death of D. vulgaris. Thus, Sor plays a key role in oxygen defense of D. vulgaris under fully aerobic conditions, when superoxide is generated mostly in the cytoplasm. Fe-Sod may be more important under microaerophilic conditions, when the periplasm contains oxygen-sensitive, superoxide-producing targets.
SponsorshipThis work was supported by a grant from the Natural Science and Engineering Research Council of Canada (NSERC) to G.V. A data-base of the D. vulgaris Hildenborough genome was searched at the website of The Institute for Genomic Research at http://www.tigr.org. Sequencing of this genome is financially supported by the U.S. Department of Energy. M.F. and Y.Z. contributed equally to this study. We thank Don Kurtz, Jr., and Heather Lumppio, Department of Chemistry, University of Georgia, for generating D. vulgaris SV2-6 and for polyclonal antibodies recognizing Rbr and D. Moinier from the IBSM Proteomics Facility for performing the Sod MALDI-TOF analysis. We thank John Heidelberg for making a preliminary annotation of the D. vulgaris genome available to us.
CitationFournier, M., Zhang, Y., Wildschut, J. D., Dolla, A., Voordouw, J. K., Schriemer, D. C., & Voordouw, G. (2003). Function of oxygen resistance proteins in the anaerobic, sulfate-reducing bacterium desulfovibrio vulgaris hildenborough. Journal of Bacteriology, 185(1), 71-79. doi:10.1128/JB.185.1.71-79.2003
DepartmentBiochemistry and Molecular Biology
FacultyCumming School of Medicine
InstitutionUniversity of Calgary
PublisherJournal of Bacteriology
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