Structure of fumarate reductase from Wolinella succinogenes at 2.2 A resolution.
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 A 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.
Lancaster
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CR
Max-Planck-Institut für Biophysik, Frankfurt am Main, Germany. lancaster@mpibp-frankfurt.mpg.de
Kröger
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A
Auer
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Michel
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D002462:Cell Membrane / Q000201:enzymology; D018360:Crystallography, X-Ray; D003998:Dicarboxylic Acids / Q000378:metabolism; D004579:Electron Transport; D004926:Escherichia coli / Q000201:enzymology; D005182:Flavin-Adenine Dinucleotide / Q000378:metabolism; D006418:Heme / Q000378:metabolism; D007506:Iron-Sulfur Proteins / Q000378:metabolism; D008670:Metals / Q000378:metabolism; D008958:Models, Molecular; D010084:Oxidation-Reduction; D011485:Protein Binding; D011487:Protein Conformation; D011809:Quinones / Q000378:metabolism; D012995:Solubility; D013385:Succinate Dehydrogenase / Q000737:chemistry*; D016968:Wolinella / Q000201:enzymology*
D003998:Dicarboxylic Acids; D007506:Iron-Sulfur Proteins; D008670:Metals; D011809:Quinones; D005182:Flavin-Adenine Dinucleotide; D006418:Heme; D013385:Succinate Dehydrogenase