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The nature of the Cu A center in cytochrome c oxidase
Author(s) -
Malmström Bo G.,
Aasa Roland
Publication year - 1993
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 - 10.1016/0014-5793(93)81411-r
Subject(s) - electron paramagnetic resonance , chemistry , hyperfine structure , cytochrome c oxidase , spectral line , valence (chemistry) , stereochemistry , oxidase test , metal , electron transport complex iv , crystallography , enzyme , nuclear magnetic resonance , biochemistry , physics , atomic physics , organic chemistry , astronomy
The merits of the suggestion that cu A in cytochrome oxidase is a mixed‐valence binuclear site is reviewed on the basis of recent analytical and spectroscopic studies. First an alternative mononuclear model is presented. Metal analyses indicate that homogeneous oxidase preparations with high activity contain 3Cu/2Fe. Multifrequency EPR measurements demonstrate a close similarity with a copper site in nitrous oxide reductase, and this is also supported by optical and MCD spectra. Strong evidence for a binuclear site is provided by a 7‐line hyperfine structure in the EPR spectra of both enzymes. A binuclear model consistent with amino acid sequence data can be formulated.