A structural model for the membrane-integral domain of succinate: quinone oxidoreductases

• Published in: FEBS letters Vol. 389; no. 1; pp. 25 - 31
• Main Authors: Hägerhäll, C, Hederstedt, L
• Format: Journal Article
• Language: English
• Published: England 24.06.1996
• Subjects: Amino Acid Sequence; Animals; Binding Sites; Biochemistry and Molecular Biology; Biokemi och molekylärbiologi; Biologi; Biological Sciences; Cell Membrane - metabolism; Cytochrome c Group; Ecology; Ekologi; Electron Transport Complex II; Models, Molecular; Molecular Sequence Data; Multienzyme Complexes - chemistry; Multienzyme Complexes - metabolism; Natural Sciences; Naturvetenskap; Oxidoreductases - chemistry; Oxidoreductases - metabolism; Succinate Dehydrogenase - chemistry; Succinate Dehydrogenase - metabolism
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(96)00529-7

Many succinate:quinone oxidoreductases in bacteria and mitochondria, i.e. succinate:quinone reductases and fumarate reductases, contain in the membrane anchor a cytochrome b whose structure and function is poorly understood. Based on biochemical data and polypeptide sequence information, we show that the anchors in different organisms are related despite an apparent diversity in polypeptide and heme composition. A general structural model for the membrane-integral domain of the anchors is proposed. It is an antiparallel four-helix bundle with a novel arrangement of hexa-coordinated protoheme IX. The structure can be applied to a larger group of membrane-integral cytochromes of b-type and has evolutionary and functional implications.