title: The nature of CuA in cytochrome c oxidase.
abstract: The isolation and purification of yeast cytochrome c oxidase is described. Characterization of the purified protein indicates that it is spectroscopically identical with cytochrome c oxidase isolated from beef heart. Preparations of isotopically substituted yeast cytochrome c oxidase are obtained incorporating [1,3-15N2]histidine or [beta,beta-2H2]cysteine. Electron paramagnetic resonance and electron nuclear double resonance spectra of the isotopically substituted proteins identify unambiguously at least 1 cysteine and 1 histidine as ligands to CuA and suggest that substantial spin density is delocalized onto a cysteine sulfur in the oxidized protein to render the site Cu(I)--S.
mesh_terms: D003300:Copper / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy; D003576:Electron Transport Complex IV / Q000302:isolation & purification / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D013053:Spectrophotometry
chemical_list: D003300:Copper; D003576:Electron Transport Complex IV