title: Proteomic analysis of spontaneous mutants of Lactococcus lactis: Involvement of GAPDH and arginine deiminase pathway in H2O2 resistance.
abstract: Lactococcus lactis, one of the most commonly used dairy starters, is often subjected to oxidative stress in cheese manufacturing. A comparative proteomic analysis was performed to identify the molecular modifications responsible for the robustness of three spontaneous H(2)O(2)-resistant (SpOx) strains. In the parental strain, glyceraldehyde-3-phosphate deshydrogenase (GAPDH) activity is ensured by GapB and the second GAPDH GapA is not produced in standard growth conditions. We showed that GapA was overproduced in the highly resistant SpOx2 and SpOx3 mutants. Its overproduction in the MG1363 strain led to an increased H(2)O(2) resistance of exponential growing cells. Upon H(2)O(2) exposure, GapB was fully inactivated by oxidation in the parental strain. In SpOx mutants, it partly remained in the reduced form sustaining partially GAPDH activity. The analysis of gapA disruption in these SpOx strains indicated that additional unraveled mechanisms likely contribute to the resistance phenotype. In the SpOx1 mutant, the arginine deiminase pathway was found to be upregulated and disruption of arcA or arcB genes abolished H(2)O(2) resistance. We concluded that arginine consumption was directly responsible for the SpOx1 phenotype. Finally, these results suggest that sustaining energy supply is a major way of leading to oxidative stress resistance in L. lactis.
authors.affiliation: INRA, UMR1319 Micalis, Jouy-en-Josas, France. tatiana.rochat@u-psud.fr
authors.forename: Tatiana
authors.initials: T
authors.lastname: Rochat
authors.forename: Samira
authors.initials: S
authors.lastname: Boudebbouze
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Gratadoux
authors.forename: Sébastien
authors.initials: S
authors.lastname: Blugeon
authors.forename: Philippe
authors.initials: P
authors.lastname: Gaudu
authors.forename: Philippe
authors.initials: P
authors.lastname: Langella
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Maguin
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D024881:Drug Resistance, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D006867:Hydrolases / Q000235:genetics / Q000378:metabolism*; D013294:Lactococcus lactis / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress / Q000235:genetics; D040901:Proteomics; D015398:Signal Transduction / Q000235:genetics
chemical_list: D001425:Bacterial Outer Membrane Proteins; D006861:Hydrogen Peroxide; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D006867:Hydrolases; C019723:arginine deiminase