STRUCTURAL CHARACTERIZATION OF ISOLATED MITOCHONDRIAL CYTOCHROME-C(1)

Resonance Raman spectroscopy (RRS) has been employed to characterize c ytochromes c1 isolated from bc1 complexes of beef heart mitochondria a nd Rhodopseudomonas sphaeroides. The data obtained in this study exten d the physical characterization of cytochromes c1 and focus on the eff ects of the local protein environment on the heme active site. While t he general characteristics of the cytochromes c1 are similar to those of smaller soluble cytochromes c, the behavior of several core-size an d ligation-sensitive heme modes reveal that significant systematic dif ferences exist between those species. These, most likely, result from changes in the heme axial-ligand interactions.