title: Multifrequency EPR evidence for a bimetallic center at the CuA site in cytochrome c oxidase.
abstract: Multifrequency electron paramagnetic resonance (EPR) spectra of the Cu(II) site in bovine heart cytochrome c oxidase (COX) and nitrous oxide reductase (N2OR) from Pseudomonas stutzeri confirm the existence of Cu-Cu interaction in both enzymes. C-band (4.5 GHz) proves to be a particularly good frequency complementing the spectra of COX and N2OR recorded at 2.4 and 3.5 GHz. Both the high and low field region of the EPR spectra show the presence of a well-resolved 7-line pattern consistent with the idea of a binuclear Cu center in COX and N2OR. Based on this assumption consistent g-values are calculated for gz and gx at four frequencies. No consistent g-values are obtained with the assumption of a 4-line pattern indicative for a mononuclear Cu site.
authors.affiliation: Fakultät für Biologie, Universität Konstanz, FRG.
authors.forename: P M
authors.initials: PM
authors.lastname: Kroneck
authors.forename: W E
authors.initials: WE
authors.lastname: Antholine
authors.forename: D H
authors.initials: DH
authors.lastname: Kastrau
authors.forename: G
authors.initials: G
authors.lastname: Buse
authors.forename: G C
authors.initials: GC
authors.lastname: Steffens
authors.forename: W G
authors.initials: WG
authors.lastname: Zumft
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D003300:Copper / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy; D003576:Electron Transport Complex IV / Q000378:metabolism*; D008969:Molecular Sequence Data; D009206:Myocardium / Q000201:enzymology; D010088:Oxidoreductases; D011549:Pseudomonas / Q000201:enzymology
chemical_list: D003300:Copper; D010088:Oxidoreductases; C022763:nitrous oxide reductase; D003576:Electron Transport Complex IV