NMR-STUDIES OF THE EFFECTS OF AXIAL LIGAND SUBSTITUTION BY IMIDAZOLE ON THE CONFORMATION OF CYTOCHROME-C

A series of 1D and 2D H-1 NMR studies are presented, which aim at assi gning the hyperfine shifted resonances of the heme and the spin system s of more than 20 amino acid side chains, and characterizing the heme and ligand environment of the low spin imidazole complex of cytochrome c. Some details of the structure in the heme pocket of the cytochrome c-imidazole complex are shown qualitatively to have changed relativel y to the native oxidized protein. The orientation of the coordinated i midazole is also determined based on the interpretation of a number of NOEs.