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Interaction of the bacterial terminal oxidase cytochrome bd with nitric oxide
Author(s) -
Borisov Vitaliy B.,
Forte Elena,
Konstantinov Alexander A.,
Poole Robert K.,
Sarti Paolo,
Giuffrè Alessandro
Publication year - 2004
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.2004.09.013
Subject(s) - azotobacter vinelandii , chemistry , heme , cytochrome , cytochrome c oxidase , biochemistry , oxidase test , reductase , oxygen , nitric oxide , enzyme , nitrogenase , nitrogen fixation , organic chemistry , nitrogen
Cytochrome bd is a prokaryotic terminal oxidase catalyzing O 2 reduction to H 2 O. The oxygen‐reducing site has been proposed to contain two hemes, d and b 595 , the latter presumably replacing functionally Cu B of heme‐copper oxidases. We show that NO, in competition with O 2 , rapidly and potently ( K i =100±34 nM at ∼70 μM O 2 ) 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 Cu B in heme‐copper oxidases.