title: Variation in proton donor/acceptor pathways in succinate:quinone oxidoreductases.
abstract: The anaerobically expressed fumarate reductase and aerobically expressed succinate dehydrogenase from Escherichia coli comprise two different classes of succinate:quinone oxidoreductases (SQR), often termed respiratory complex II. The X-ray structures of both membrane-bound complexes have revealed that while the catalytic/soluble domains are structurally similar the quinone binding domains of the enzyme complexes are significantly different. These results suggest that the anaerobic and aerobic forms of complex II have evolved different mechanisms for electron and proton transfer in their respective membrane domains.
authors.affiliation: Molecular Biology Division (151-S), VA Medical Center and Department of Biochemistry and Biophysics, University of California, San Francisco, CA, USA. ceccini@itsa.ucsf.edu
authors.forename: Gary
authors.initials: G
authors.lastname: Cecchini
authors.forename: Elena
authors.initials: E
authors.lastname: Maklashina
authors.forename: Victoria
authors.initials: V
authors.lastname: Yankovskaya
authors.forename: Tina M
authors.initials: TM
authors.lastname: Iverson
authors.forename: So
authors.initials: S
authors.lastname: Iwata
mesh_terms: D016227:Benzoquinones / Q000378:metabolism; D001665:Binding Sites; D002384:Catalysis; D004579:Electron Transport; D042963:Electron Transport Complex II; D004926:Escherichia coli / Q000201:enzymology*; D017136:Ion Transport; D008958:Models, Molecular; D009097:Multienzyme Complexes / Q000737:chemistry* / Q000378:metabolism*; D010088:Oxidoreductases / Q000737:chemistry* / Q000378:metabolism*; D011522:Protons; D013385:Succinate Dehydrogenase / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D016227:Benzoquinones; D009097:Multienzyme Complexes; D011522:Protons; C004532:quinone; D010088:Oxidoreductases; D042963:Electron Transport Complex II; C424907:quinol fumarate reductase; D013385:Succinate Dehydrogenase