title: Nitrate, nitrite and nitric oxide reductases: from the last universal common ancestor to modern bacterial pathogens.
abstract: The electrochemical gradient that ensues from the enzymatic activity of cytochromes such as nitrate reductase, nitric oxide reductase, and quinol oxidase contributes to the bioenergetics of the bacterial cell. Reduction of nitrogen oxides by bacterial pathogens can, however, be uncoupled from proton translocation and biosynthesis of ATP or NH4(+), but still linked to quinol and NADH oxidation. Ancestral nitric oxide reductases, as well as cytochrome c oxidases and quinol bo oxidases evolved from the former, are capable of binding and detoxifying nitric oxide to nitrous oxide. The NO-metabolizing activity associated with these cytochromes can be a sizable source of antinitrosative defense in bacteria during their associations with host cells. Nitrosylation of terminal cytochromes arrests respiration, reprograms bacterial metabolism, stimulates antioxidant defenses and alters antibiotic cytotoxicity. Collectively, the bioenergetics and regulation of redox homeostasis that accompanies the utilization of nitrogen oxides and detoxification of nitric oxide by cytochromes of the electron transport chain increases fitness of many Gram-positive and -negative pathogens during their associations with invertebrate and vertebrate hosts.
authors.affiliation: Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, United States; Veterans Affairs Eastern Colorado Health Care System, Denver, CO, United States. Electronic address: andres.vazquez-torres@ucdenver.edu.
authors.forename: Andrés
authors.initials: A
authors.lastname: Vázquez-Torres
authors.affiliation: Department of Medical Microbiology and Immunology, University of California Davis, School of Medicine, Davis, CA, United States. Electronic address: ajbaumler@ucdavis.edu.
authors.forename: Andreas J
authors.initials: AJ
authors.lastname: Bäumler
mesh_terms: D000693:Anaerobiosis; D001419:Bacteria / Q000378:metabolism* / Q000472:pathogenicity*; D003580:Cytochromes / Q000378:metabolism*; D024881:Drug Resistance, Bacterial; D004579:Electron Transport; D004734:Energy Metabolism; D006706:Homeostasis; D009565:Nitrate Reductases / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism*
chemical_list: D003580:Cytochromes; D009573:Nitrites; D009569:Nitric Oxide; D010088:Oxidoreductases; D009565:Nitrate Reductases; C034747:nitric-oxide reductase