Structure of fumarate reductase from Wolinella succinogenes at 2.2  resolution

• Published in: Nature (London) 1999-11, Vol.402 (6760), p.377-385
• Main Authors: Lancaster, C. Roy D, Michel, Hartmut, Kröger, Achim, Auer, Manfred
• Format: Article
• Language: English
• Subjects: Analytical, structural and metabolic biochemistry; Biological and medical sciences; Cell Membrane - enzymology; Crystallography, X-Ray; Dicarboxylic Acids - metabolism; Electron Transport; Enzymes and enzyme inhibitors; Escherichia coli - enzymology; Flavin-Adenine Dinucleotide - metabolism; Fundamental and applied biological sciences. Psychology; Heme - metabolism; Humanities and Social Sciences; Iron-Sulfur Proteins - metabolism; Metals - metabolism; Models, Molecular; multidisciplinary; Oxidation-Reduction; Oxidoreductases; Protein Binding; Protein Conformation; Quinones - metabolism; Science; Science (multidisciplinary); Solubility; Succinate Dehydrogenase - chemistry; Wolinella - enzymology
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/46483

Fumarate reductase couples the reduction of fumarate to succinate to the oxidation of quinol to quinone, in a reaction opposite to that catalysed by the related complex II of the respiratory chain (succinate dehydrogenase). Here we describe the crystal structure at 2.2 Å resolution of the three protein subunits containing fumarate reductase from the anaerobic bacterium Wolinella succinogenes . Subunit A contains the site of fumarate reduction and a covalently bound flavin adenine dinucleotide prosthetic group. Subunit B contains three iron–sulphur centres. The menaquinol-oxidizing subunit C consists of five membrane-spanning, primarily helical segments and binds two haem b molecules. On the basis of the structure, we propose a pathway of electron transfer from the dihaem cytochrome b to the site of fumarate reduction and a mechanism of fumarate reduction. The relative orientations of the soluble and membrane-embedded subunits of succinate:quinone oxidoreductases appear to be unique.