Crystallization of part of the mitochondrial electron transfer chain: cytochrome c oxidase--cytochrome c complex.
Cytochrome c oxidase (ferrocytochrome c oxygen oxidoreductase, EC 1.9.3.1) was purified from beef heart mitochondria by affinity chromatography. Phospholipids were removed by washing the oxidase with detergent on the affinity column; 1 mole of cardiolipin remained per mole of heme a. The oxidase was mixed with excess cytochrome c in 1.5% (wt/vol) cholate to form a complex. Slow removal of the detergent from the mixture by dialysis resulted in crystallization of cytochrome oxidase in the form of a 1:1 complex with cytochrome c. The chemical composition and spectrophotometric properties of the crystal are described. Increasing the solubility of a hydrophobic membrane protein by combination with hydropholic ligand is demonstrated as a maneuver for crystallizing the membrane protein.
D000818:Animals; D002417:Cattle; D003460:Crystallization; D003574:Cytochrome c Group / Q000378:metabolism; D004579:Electron Transport; D003576:Electron Transport Complex IV / Q000378:metabolism; D008929:Mitochondria, Heart / Q000201:enzymology* / Q000648:ultrastructure; D010101:Oxygen Consumption; D011487:Protein Conformation
D003574:Cytochrome c Group; D003576:Electron Transport Complex IV