title: Redox Imbalance Underlies the Fitness Defect Associated with Inactivation of the Pta-AckA Pathway in Staphylococcus aureus.
abstract: The phosphotransacetylase-acetate kinase (Pta-AckA) pathway is thought to be a vital ATP generating pathway for Staphylococcus aureus. Disruption of the Pta-AckA pathway during overflow metabolism causes significant reduction in growth rate and viability, albeit not due to intracellular ATP depletion. Here, we demonstrate that toxicity associated with inactivation of the Pta-AckA pathway resulted from an altered intracellular redox environment. Growth of the pta and ackA mutants under anaerobic conditions partially restored cell viability. NMR metabolomics analyses and (13)C6-glucose metabolism tracing experiments revealed the activity of multiple pathways that promote redox (NADH/NAD(+)) turnover to be enhanced in the pta and ackA mutants during anaerobic growth. Restoration of redox homeostasis in the pta mutant by overexpressing l- lactate dehydrogenase partially restored its viability under aerobic conditions. Together, our findings suggest that during overflow metabolism, the Pta-AckA pathway plays a critical role in preventing cell viability defects by promoting intracellular redox homeostasis.
authors.affiliation: Department of Chemistry, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States.
authors.forename: Darrell D
authors.initials: DD
authors.lastname: Marshall
authors.affiliation: Department of Pathology and Microbiology, University of Nebraska Medical Center , Omaha, Nebraska 68198, United States.
authors.forename: Marat R
authors.initials: MR
authors.lastname: Sadykov
authors.affiliation: Department of Pathology and Microbiology, University of Nebraska Medical Center , Omaha, Nebraska 68198, United States.
authors.forename: Vinai C
authors.initials: VC
authors.lastname: Thomas
authors.affiliation: Department of Pathology and Microbiology, University of Nebraska Medical Center , Omaha, Nebraska 68198, United States.
authors.forename: Kenneth W
authors.initials: KW
authors.lastname: Bayles
authors.affiliation: Department of Chemistry, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States.
authors.forename: Robert
authors.initials: R
authors.lastname: Powers
mesh_terms: D000084:Acetate Kinase / Q000172:deficiency / Q000235:genetics*; D000255:Adenosine Triphosphate / Q000096:biosynthesis; D000332:Aerobiosis; D000693:Anaerobiosis; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002247:Carbon Isotopes; D015964:Gene Expression Regulation, Bacterial; D005947:Glucose / Q000378:metabolism; D006706:Homeostasis; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D055432:Metabolomics; D050296:Microbial Viability; D009154:Mutation; D009243:NAD / Q000378:metabolism; D010084:Oxidation-Reduction; D010709:Phosphate Acetyltransferase / Q000172:deficiency / Q000235:genetics*; D013211:Staphylococcus aureus / Q000235:genetics* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D002247:Carbon Isotopes; D009243:NAD; D000255:Adenosine Triphosphate; D007770:L-Lactate Dehydrogenase; D010709:Phosphate Acetyltransferase; D000084:Acetate Kinase; D005947:Glucose
keywords: NMR; Pta-AckA pathway; Staphylococcus aureus; metabolomics; redox imbalance