Structure of the copper sites in membrane-bound cytochrome c oxidase.
The structures of membrane proteins are difficult to obtain by crystallography and may be altered by the detergents used in their extraction. X-ray absorption spectroscopy has been used to identify the structures of the copper atoms of the membrane-bound enzyme in mitochondria and in submitochondrial particles at respective concentrations of 100 and 200 micron of molar copper. To within the experimental error, the x-ray absorption spectra of the copper atoms of the membrane-bound and the Yonetani (Yonetani, T. (1961) J. Biol. Chem. 236, 1680-1688) purified oxidase are identical; all detectable shells of the active site indicate no alteration of structural parameters. Significant differences are found when compared to the Hartzell-Beinert (Hartzell, R. C., and Beinert, H. (1974) Biochim. Biophys. Acta 368, 318-338) preparation. Extended x-ray absorption fine structure technology is now adequate for the direct studies of membrane proteins in situ in their natural environment.
D000818:Animals; D001665:Binding Sites; D002417:Cattle; D003300:Copper; D003576:Electron Transport Complex IV / Q000378:metabolism*; D007425:Intracellular Membranes / Q000201:enzymology; D008929:Mitochondria, Heart / Q000201:enzymology*; D013057:Spectrum Analysis; D013367:Submitochondrial Particles / Q000201:enzymology; D014965:X-Rays
D003300:Copper; D003576:Electron Transport Complex IV