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Nitric oxide reacts with the ferryl‐oxo catalytic intermediate of the Cu B ‐lacking cytochrome bd terminal oxidase
Author(s) -
Borisov Vitaliy B.,
Forte Elena,
Sarti Paolo,
Brunori Maurizio,
Konstantinov Alexander A.,
Giuffrè Alessandro
Publication year - 2006
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2006.07.072
Subject(s) - chemistry , cytochrome , cytochrome c oxidase , catalysis , oxidase test , heme , cytochrome c , azotobacter vinelandii , nitrite , photochemistry , nitric oxide , stereochemistry , enzyme , biochemistry , nitrogenase , organic chemistry , mitochondrion , nitrate , nitrogen fixation , nitrogen
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 × 10 5 M −1 s −1 at 20 °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.