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A structural moDAl for the membrane‐integral domain of succinate:quinone oxidoreductases
Author(s) -
Hägerhäll Cecilia,
Hederstedt Lars
Publication year - 1996
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(96)00529-7
Subject(s) - quinone , antiparallel (mathematics) , integral membrane protein , cytochrome , chemistry , sequence (biology) , domain (mathematical analysis) , membrane , stereochemistry , heme , biochemistry , membrane protein , enzyme , physics , mathematics , quantum mechanics , magnetic field , mathematical analysis
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 polypeptiDA sequence information, we show that the anchors in different organisms are related DAspite an apparent diversity in polypeptiDA and heme composition. A general structural moDAl 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.