title: Nitric oxide reacts with the ferryl-oxo catalytic intermediate of the CuB-lacking cytochrome bd terminal oxidase.
abstract: Cytochrome bd is a bacterial respiratory oxidase carrying three hemes but no copper. We show that nitric oxide (NO) reacts with the intermediate F of cytochrome bd from Azotobacter vinelandii: (i) with a 1:1 stoichiometry, (ii) rapidly (k=1.2 +/- 0.1 x 10(5)M(-1)s(-1) at 20 degrees C), and (iii) yielding the oxidized enzyme with nitrite bound to heme d at the active site. Unexpectedly, the NO reaction mechanism of this catalytic intermediate in the Cu(B)-lacking cytochrome bd appears similar to that of beef heart cytochrome c oxidase, where Cu(B) was proposed to play a key role.
authors.affiliation: Belozersky Institute of Physico-chemical Biology, Lomonosov Moscow State University, Moscow 119992, Russian Federation.
authors.forename: Vitaliy B
authors.initials: VB
authors.lastname: Borisov
authors.forename: Elena
authors.initials: E
authors.lastname: Forte
authors.forename: Paolo
authors.initials: P
authors.lastname: Sarti
authors.forename: Maurizio
authors.initials: M
authors.lastname: Brunori
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Konstantinov
authors.forename: Alessandro
authors.initials: A
authors.lastname: Giuffrè
mesh_terms: D016948:Azotobacter vinelandii / Q000201:enzymology*; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D003300:Copper / Q000737:chemistry* / Q000378:metabolism; D003573:Cytochrome b Group; D003580:Cytochromes / Q000737:chemistry / Q000378:metabolism*; D045222:Electron Transport Chain Complex Proteins / Q000737:chemistry / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism*; D007501:Iron / Q000737:chemistry* / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry / Q000378:metabolism*; D010100:Oxygen / Q000737:chemistry* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D003573:Cytochrome b Group; D003580:Cytochromes; D045222:Electron Transport Chain Complex Proteins; D029968:Escherichia coli Proteins; D009569:Nitric Oxide; D003300:Copper; D007501:Iron; D010088:Oxidoreductases; C040077:cytochrome bd terminal oxidase complex, E coli; D010100:Oxygen