title: Evidence that ORF3 at the Streptococcus parasanguis fimA locus encodes a thiol-specific antioxidant.
abstract: Streptococcus parasanguis is a primary colonizer of dental plaque and a major player in subacute bacterial endocarditis. In the present study, the authors report that an ORF (ORF3) located 77 bp downstream of the fimA operon on the S. parasanguis FW213 chromosome complements an Escherichia coli thiol peroxidase (tpx) mutation in glutamine synthetase (GS) protection assays and that GS is protected by the ORF3 gene product in S. parasanguis cell extracts. In addition, the putative streptococcal peroxidase (Tpx(Sp)) protects S. parasanguis from stress caused by H2O2 and is induced by oxygen, as revealed by Northern blot analysis. Taken collectively, these findings support a thiol-dependent antioxidant activity for Tpx in S. parasanguis.
authors.affiliation: Department of Biology, Middlebury College, Middlebury, VT 05753, USA1.
authors.forename: Grace
authors.initials: G
authors.lastname: Spatafora
authors.affiliation: Department of Biology, Middlebury College, Middlebury, VT 05753, USA1.
authors.forename: Neal
authors.initials: N
authors.lastname: Van Hoeven
authors.affiliation: Department of Biology, Middlebury College, Middlebury, VT 05753, USA1.
authors.forename: Katherine
authors.initials: K
authors.lastname: Wagner
authors.affiliation: Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA2.
authors.forename: Paula
authors.initials: P
authors.lastname: Fives-Taylor
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics; D029968:Escherichia coli Proteins / Q000235:genetics; D036781:Fimbriae Proteins; D015964:Gene Expression Regulation, Bacterial; D005816:Genetic Complementation Test; D005974:Glutamate-Ammonia Ligase; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D009154:Mutation; D016366:Open Reading Frames / Q000235:genetics*; D033903:Periplasmic Proteins; D009195:Peroxidase / Q000235:genetics / Q000378:metabolism*; D010544:Peroxidases / Q000235:genetics; D013291:Streptococcus / Q000201:enzymology* / Q000235:genetics; D013438:Sulfhydryl Compounds / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D033903:Periplasmic Proteins; D013438:Sulfhydryl Compounds; C063055:fimbrillin; D036781:Fimbriae Proteins; D006861:Hydrogen Peroxide; D010544:Peroxidases; C097049:Tpx protein, E coli; D009195:Peroxidase; D005974:Glutamate-Ammonia Ligase