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Insights into the mechanism of nitric oxide reductase from a Fe B ‐depleted variant
Author(s) -
Kahle Maximilian,
Blomberg Margareta R. A.,
Jareck Sascha,
Ädelroth Pia
Publication year - 2019
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 - 10.1002/1873-3468.13436
Subject(s) - chemistry , nitric oxide , heme , reductase , cofactor , catalysis , cytochrome , nitrous oxide , redox , denitrification , active site , stereochemistry , enzyme , biochemistry , inorganic chemistry , nitrogen , organic chemistry
A key step of denitrification, the reduction of toxic nitric oxide to nitrous oxide, is catalysed by cytochrome c ‐dependent NO reductase ( c NOR ). c NOR contains four redox‐active cofactors: three hemes and a nonheme iron (Fe B ). Heme b 3 and Fe B constitute the active site, but the specific mechanism of NO ‐binding events and reduction is under debate. Here, we used a recently constructed, fully folded and hemylated c NOR variant that lacks Fe B to investigate the role of Fe B during catalysis. We show that in the Fe B ‐less c NOR , binding of both NO and O 2 to heme b 3 still occurs but further reduction is impaired, although to a lesser degree for O 2 than for NO . Implications for the catalytic mechanisms of c NOR are discussed.