title: Mutations in msrA and msrB, encoding epimer-specific methionine sulfoxide reductases, affect expression of glycerol-catabolic operons in Enterococcus faecalis differently.
abstract: This study aims to define the cellular roles of methionine sulfoxide reductases A and B, evolutionarily highly conserved enzymes able to repair oxidized methionines in proteins. msrA and msrB mutants were exposed to an internal oxidative stress by growing them under aerobic conditions on glycerol. Interestingly, the msr mutants behave completely differently under these conditions. The msrA mutant is inhibited, whereas the msrB mutant is stimulated in its growth in comparison with the parent strain. Glycerol can be catabolized by either the GlpK or DhaK pathways in Enterococcus faecalis. Our results strongly suggest that in the msrA mutant, glycerol is catabolized via the GlpK pathway leading to increased synthesis of H2O2, which accumulates to concentrations inhibitory to growth in comparison with the parent strain. In contrast in the msrB mutant, glycerol is metabolized via the DhaK pathway which is not accompanied by the synthesis of H2O2. The molecular basis for the differences in glycerol flux seems to be due to expression differences of the two glycerol-catabolic operons in the msr mutants.
authors.affiliation: Academy of State Administration of Grain, 11 Baiwanzhuang Avenue, Xicheng District, 100037 Beijing, PR China.|Université de Caen Basse-Normandie, EA4655 U2RM Stress/Virulence, 14032 CAEN France.
authors.forename: Chen
authors.initials: C
authors.lastname: Zhao
authors.affiliation: Service of Infectious Diseases, University Hospital Center Lausanne (CHUV), Lausanne, Switzerland.
authors.forename: Alain
authors.initials: A
authors.lastname: Bizzini
authors.affiliation: Academy of State Administration of Grain, 11 Baiwanzhuang Avenue, Xicheng District, 100037 Beijing, PR China.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Université de Caen Basse-Normandie, EA4655 U2RM Stress/Virulence, 14032 CAEN France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Sauvageot
authors.affiliation: Université de Caen Basse-Normandie, EA4655 U2RM Stress/Virulence, 14032 CAEN France.
authors.forename: Axel
authors.initials: A
authors.lastname: Hartke
mesh_terms: D000332:Aerobiosis; D013293:Enterococcus faecalis / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D005990:Glycerol / Q000378:metabolism*; D053858:Metabolic Networks and Pathways / Q000235:genetics; D051150:Methionine Sulfoxide Reductases / Q000235:genetics* / Q000378:metabolism*; D009154:Mutation; D009876:Operon; D018384:Oxidative Stress
chemical_list: D051150:Methionine Sulfoxide Reductases; D005990:Glycerol