Interaction of the bacterial terminal oxidase cytochrome bd with nitric oxide.
Cytochrome bd is a prokaryotic terminal oxidase catalyzing O2 reduction to H2O. The oxygen-reducing site has been proposed to contain two hemes, d and b595, the latter presumably replacing functionally CuB of heme-copper oxidases. We show that NO, in competition with O2, rapidly and potently (Ki = 100 +/- 34 nM at approximately 70 microM O2) inhibits cytochrome bd isolated from Escherichia coli and Azotobacter vinelandii in turnover, inhibition being quickly and fully reverted upon NO depletion. Under anaerobic reducing conditions, neither of the two enzymes reveals NO reductase activity, which is proposed to be associated with CuB in heme-copper oxidases.
A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Leninskie Gory, Moscow 119992, Russian Federation.
Vitaliy B
VB
Borisov
Elena
E
Forte
Alexander A
AA
Konstantinov
Robert K
RK
Poole
Paolo
P
Sarti
Alessandro
A
Giuffrè
D016948:Azotobacter vinelandii / Q000201:enzymology; D001426:Bacterial Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D003580:Cytochromes / Q000037:antagonists & inhibitors* / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology; D006418:Heme / Q000737:chemistry / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism
D001426:Bacterial Proteins; D003580:Cytochromes; D009569:Nitric Oxide; D006418:Heme; D010100:Oxygen