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Spectroscopic identification of the axial ligands of cytochrome b 560 in bovine heart succinate‐ubiquinone reductase
Author(s) -
Crouse Brian R.,
Yu Chang-An,
Yu Linda,
Johnson Michael K.
Publication year - 1995
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(95)00522-b
Subject(s) - reductase , chemistry , succinate dehydrogenase , identification (biology) , biochemistry , cytochrome b , cytochrome , stereochemistry , mitochondrion , biology , enzyme , botany , mitochondrial dna , gene
The axial ligands of low potential cytochrome b 560 in the five subunit bovine heart succinate‐ubiquinone reductase complex and in the isolated quinone binding proteins have been investigated using EPR and near‐infrared magnetic circular dichroism spectroscopies. The results are consistent with bis‐histidine ligation with near‐perpendicular imidazole rings for cytochrome b 560 in the four‐subunit complex. The pronounced changes in EPR properties that accompany isolation of the cytochrome‐ b 560 containing quinone binding proteins, are attributed to perturbation of the orientation of the imidazole rings of the heme bis‐histidine ligands, rather than a change in axial ligation.