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Non‐equivalent natures of the coordinated imidazole rings of cytochrome c 3 from D. vulgaris Miyazaki F as studied by 1 H NMR
Author(s) -
Akutsu Hideo,
Hirasawa Masaaki
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)81289-x
Subject(s) - imidazole , stereochemistry , chemistry , cytochrome c , crystallography , cytochrome , biochemistry , mitochondrion , enzyme
All of the C2 proton signals of the coordinated histidine residues in the 1 H NMR spectrum of cytochrome c 3 from D. vulgaris Miyuzaki 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 p 2 H dependence in the range of p 2 4.8–10.0.