title: Non-equivalent natures of the coordinated imidazole rings of cytochrome c3 from D. vulgaris Miyazaki F as studied by 1H NMR.
abstract: All of the C2 proton signals of the coordinated histidine residues in the 1H NMR spectrum of cytochrome c3 from D. vulgaris Miyazaki F were assigned by specific deuteration. They appeared at extremely high fields and scattered in a wide range from -4 to -22 ppm. This clearly shows that the chemical properties of the imidazole groups are quite different from one another. The extremely high-field shift of the C2 signal indicates that some of them must carry the imidazolate-like nature to some extent. This might be responsible for the extremely low redox potentials of the four hemes. On changing temperature, most of them showed Curie-type change. All of the C2 signals showed a small p2H dependence in the range of p2H 4.8-10.0.
authors.affiliation: Department of Bioengineering, Faculty of Engineering, Yokohama National University, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Akutsu
authors.forename: M
authors.initials: M
authors.lastname: Hirasawa
mesh_terms: D003574:Cytochrome c Group / Q000737:chemistry*; D016969:Desulfovibrio vulgaris / Q000201:enzymology*; D003903:Deuterium; D006358:Hot Temperature; D007093:Imidazoles / Q000737:chemistry*; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D010084:Oxidation-Reduction; D011522:Protons
chemical_list: D003574:Cytochrome c Group; D007093:Imidazoles; D008024:Ligands; D011522:Protons; C017165:cytochrome c(3); D003903:Deuterium