Cytochromes c & b5
NMR spectroscopy was applied to study the conformational and electronic properties along with the stability of c- and b-type cytochromes from various sources (horse heart yeast and rat). NMR solution structures of horse heart cytochrome c ( PDB: 1GIW & 2GIW) and a variant of rat cytochrome b5 (PDB: 1MNY) have been determined and interesting redox-dependent or ligand dependent structural differences have been identified. These changes are thought to be related to the electron transfer process and conformational rearrangements of the heme propionic groups and key residues like Asn52 in cyt-c and Ser64 in cyt-b5 are considered as key residues for the functions of these proteins.