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 language||English (US)|
|Number of pages||7|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Jul 6 1995|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology