title: Virulent Salmonella typhimurium has two periplasmic Cu, Zn-superoxide dismutases.
abstract: Periplasmic Cu, Zn-cofactored superoxide dismutase (SodC) protects Gram-negative bacteria from exogenous oxidative damage. The virulent Salmonella typhimurium strain ATCC 14028s has been found to contain two discrete periplasmic Cu, Zn-SOD enzymes that are only 57% identical at the amino acid level. SodCI is carried by a cryptic bacteriophage, and SodCII is closely related to the Cu, Zn-superoxide dismutase of Escherichia coli. All Salmonella serotypes appear to carry the sodCII locus, but the phage-associated sodCI gene is found only in certain strains belonging to the most highly pathogenic serotypes. Expression of either sodC locus appears to be enhanced during stationary phase, but only sodCII is regulated by the alternative sigma factor sigmas (RpoS). Mutants lacking both sodC genes are less lethal for mice than mutants possessing either sodC locus alone, indicating that both Cu, Zn-SOD enzymes contribute to Salmonella pathogenicity. The evolutionary acquisition of an additional sodC gene has contributed to the enhanced virulence of selected Salmonella strains.
authors.affiliation: Departments of Medicine, Pathology, and Microbiology, University of Colorado Health Sciences Center, Denver, CO 80262, USA. ferric.fang@uchsc.edu
authors.forename: F C
authors.initials: FC
authors.lastname: Fang
authors.forename: M A
authors.initials: MA
authors.lastname: DeGroote
authors.forename: J W
authors.initials: JW
authors.lastname: Foster
authors.forename: A J
authors.initials: AJ
authors.lastname: Bäumler
authors.forename: U
authors.initials: U
authors.lastname: Ochsner
authors.forename: T
authors.initials: T
authors.lastname: Testerman
authors.forename: S
authors.initials: S
authors.lastname: Bearson
authors.forename: J C
authors.initials: JC
authors.lastname: Giárd
authors.forename: Y
authors.initials: Y
authors.lastname: Xu
authors.forename: G
authors.initials: G
authors.lastname: Campbell
authors.forename: T
authors.initials: T
authors.lastname: Laessig
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D010802:Phylogeny; D012486:Salmonella typhimurium / Q000201:enzymology* / Q000472:pathogenicity; D016415:Sequence Alignment; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism*; D014774:Virulence
chemical_list: D007527:Isoenzymes; D013482:Superoxide Dismutase