Multi-frequency epr evidence for a binuclear cua center in cytochrome c oxidase: Studies with a 63cu- and 65cu-enriched, soluble domain of the cytochrome ba3 subunit II from thermus thermophilus

James A. Fee*, Donita Sanders, Claire E. Slutter, Peter E. Doan, Roland Aasa, Martin Karpefors, Tore Vänngård

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

We have recorded multi-frequency EPR spectra of 63Cu- and 65Cu-labeled, water-soluble CuA-protein from the cytochrome ba3 of T. thermophilus. The spectrum taken at the highest frequency (34.03 GHz) shows no hyperfine structure and is nominally axial with apparent gz ∼2.18 and gxy ∼2.00. The spectrum taken at the lowest frequency (3.93 GHz) shows a rich hyperfine structure. Analyses of the spectra show that the observed splitting arises from an interaction of the unpaired electron with two Cu nuclei and support the notion that CuA is a mixed-valent [Cu(II)/Cu(I)] complex in which the unpaired electronic spin is distributed evenly over the two Cu ions.

Original languageEnglish (US)
Pages (from-to)77-83
Number of pages7
JournalBiochemical and Biophysical Research Communications
Volume212
Issue number1
DOIs
StatePublished - Jul 6 1995

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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