title: Axial ligation and heme environment in cytochrome c-555 from Prosthecochloris aestuarii. Investigation by absorption and solvent perturbation difference spectroscopy.
abstract: The near-IR absorption spectrum indicated that methionine is the sixth axial heme iron ligand in Prosthecochloris aestuarii cytochrome c-555. The heme environment has been investigated by the technique of solvent perturbation difference spectroscopy. The heme octapeptide from cytochrome c plus added imidazole was used as a model compound for the fully exposed chromophore. The heme was found to be minimally exposed to solvent. A comparison was made with cytochrome c, as to the possible causes of the difference in redox potentials betweeen these two cytochromes.
mesh_terms: D003574:Cytochrome c Group; D056890:Eukaryota / Q000201:enzymology*; D006418:Heme; D011485:Protein Binding; D011487:Protein Conformation; D012997:Solvents; D013053:Spectrophotometry; D013055:Spectrophotometry, Infrared
chemical_list: D003574:Cytochrome c Group; D012997:Solvents; D006418:Heme