title: Role of the Porphyromonas gingivalis iron-binding protein PG1777 in oxidative stress resistance.
abstract: Whole genome sequencing of the response of Porphyromonas gingivalis W83 to hydrogen peroxide revealed an upregulation of several uncharacterized, novel genes. Under conditions of prolonged oxidative stress in P. gingivalis, increased expression of a unique transcriptional unit carrying the grpE, dnaJ and three other hypothetical genes (PG1777, PG1778 and PG1779) was observed. The transcriptional start site of this operon appears to be located 91 bp upstream of the translational start, with a potential -10 region at -3 nt and a -35 region at -39 nt. Isogenic P. gingivalis mutants FLL273 (PG1777 : : ermF-ermAM) and FLL293 (PG1779 : : ermF-ermAM) showed increased sensitivity to and decreased survival after treatment with hydrogen peroxide. P. gingivalis FLL273 showed a fivefold increase in the formation of spontaneous mutants when compared with the parent strain after exposure to hydrogen peroxide. The recombinant PG1777 protein displayed iron-binding properties when incubated with FeSO4 and Fe(NH4)2(SO4).6H2O. The rPG1777 protein protected DNA from degradation when exposed to hydrogen peroxide in the presence of iron. Taken together, the data suggest that the grpE-dnaJ-PG1777-PG1778-PG1779 transcriptional unit may play an important role in oxidative stress resistance in P. gingivalis via its ability to protect against DNA damage.
authors.affiliation: Division of Microbiology and Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA.
authors.forename: Rachelle M E
authors.initials: RME
authors.lastname: McKenzie
authors.affiliation: Division of Microbiology and Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA.
authors.forename: Leroy G
authors.initials: LG
authors.lastname: Henry
authors.affiliation: Division of Microbiology and Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA.
authors.forename: Marie-Claire
authors.initials: MC
authors.lastname: Boutrin
authors.affiliation: Division of Microbiology and Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA.
authors.forename: Alexia
authors.initials: A
authors.lastname: Ximinies
authors.affiliation: Institute of Oral Biology, Kyung Hee University, Seoul, Republic of Korea.|Division of Microbiology and Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA.
authors.forename: Hansel M
authors.initials: HM
authors.lastname: Fletcher
mesh_terms: D004249:DNA Damage / Q000187:drug effects; D015964:Gene Expression Regulation, Bacterial; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D033862:Iron-Binding Proteins / Q000378:metabolism*; D008826:Microbial Sensitivity Tests; D005810:Multigene Family / Q000235:genetics; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D016966:Porphyromonas gingivalis / Q000187:drug effects / Q000235:genetics*; D014158:Transcription, Genetic / Q000235:genetics
chemical_list: D033862:Iron-Binding Proteins; D006861:Hydrogen Peroxide