title: A 1H-NMR longitudinal relaxation study of the interaction between cytochrome c and cytochrome c oxidase.
abstract: The interaction between the oxidized forms of cytochrome c and cytochrome c oxidase (EC 1.9.3.1) has been investigated by 1H-NMR longitudinal relaxation measurements. It is found that relaxation of methyl groups on the heme ring of cytochrome c markedly deviates from a simple exponential behavior in the presence of small amounts of cytochrome oxidase. A comparison with the relaxation behavior of cytochrome c modified by 4-carboxy-3,5-dinitrophenyl at Lys-13 shows that the oxidase induces a conformation in native cytochrome c that is closely related to that of the derivative. It is suggested that this change in conformation consists of a rupture of the salt bridge between Lys-13 and Glu-90 and a concomitant perturbation of the methionine ligand.
mesh_terms: D000818:Animals; D002417:Cattle; D003574:Cytochrome c Group / Q000378:metabolism*; D003576:Electron Transport Complex IV / Q000378:metabolism*; D006321:Heart; D006736:Horses; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008929:Mitochondria, Heart / Q000201:enzymology; D011485:Protein Binding
chemical_list: D003574:Cytochrome c Group; D003576:Electron Transport Complex IV