title: Nitric oxide is a potent inhibitor of the cbb(3)-type heme-copper oxidases.
abstract: C-type heme-copper oxidases terminate the respiratory chain in many pathogenic bacteria, and will encounter elevated concentrations of NO produced by the immune defense of the host. Thus, a decreased sensitivity to NO in C-type oxidases would increase the survival of these pathogens. Here we have compared the inhibitory effect of NO in C-type oxidases to that in the mitochondrial A-type. We show that O2-reduction in both the Rhodobacter sphaeroides and Vibrio cholerae C-type oxidases is strongly and reversibly inhibited by submicromolar NO, with an inhibition pattern similar to the A-type. Thus, NO tolerance in pathogens with a C-type terminal oxidase has to rely mainly on other mechanisms.
authors: Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden.
authors: Davinia
authors: D
authors: Arjona
authors: Helsinki Bioenergetics Group, Institute of Biotechnology, University of Helsinki, FI-00014 Helsinki, Finland.
authors: Mårten
authors: M
authors: Wikström
authors: Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden. Electronic address: piaa@dbb.su.se.
authors: Pia
authors: P
authors: Ädelroth
mesh_terms: D001426:Bacterial Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics; D003576:Electron Transport Complex IV / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics; D004791:Enzyme Inhibitors / Q000737:chemistry*; D009569:Nitric Oxide / Q000737:chemistry*; D012242:Rhodobacter sphaeroides / Q000201:enzymology* / Q000235:genetics; D014734:Vibrio cholerae / Q000201:enzymology* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; D009569:Nitric Oxide; C414443:cbb3 oxidase; D003576:Electron Transport Complex IV
keywords: Catalytic site; Cytochrome c oxidase; IC(50); Nitrite; Respiration