Inhibitor-complexed structures of the cytochrome bc1 from the photosynthetic bacterium Rhodobacter sphaeroides.
The cytochrome bc(1) complex (bc(1)) is a major contributor to the proton motive force across the membrane by coupling electron transfer to proton translocation. The crystal structures of wild type and mutant bc(1) complexes from the photosynthetic purple bacterium Rhodobacter sphaeroides (Rsbc(1)), stabilized with the quinol oxidation (Q(P)) site inhibitor stigmatellin alone or in combination with the quinone reduction (Q(N)) site inhibitor antimycin, were determined. The high quality electron density permitted assignments of a new metal-binding site to the cytochrome c(1) subunit and a number of lipid and detergent molecules. Structural differences between Rsbc(1) and its mitochondrial counterparts are mostly extra membranous and provide a basis for understanding the function of the predominantly longer sequences in the bacterial subunits. Functional implications for the bc(1) complex are derived from analyses of 10 independent molecules in various crystal forms and from comparisons with mitochondrial complexes.
Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Lothar
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Esser
Maria
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Elberry
Fei
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Zhou
Chang-An
CA
Yu
Linda
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Yu
Di
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Xia
D000595:Amino Acid Sequence; D000968:Antimycin A / Q000031:analogs & derivatives / Q000494:pharmacology; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D018360:Crystallography, X-Ray; D014450:Electron Transport Complex III / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D007506:Iron-Sulfur Proteins / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes; D016297:Mutagenesis, Site-Directed; D011090:Polyenes / Q000494:pharmacology; D021122:Protein Subunits; D018892:Proton-Motive Force; D012242:Rhodobacter sphaeroides / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D001426:Bacterial Proteins; D007506:Iron-Sulfur Proteins; D046912:Multiprotein Complexes; D011090:Polyenes; D021122:Protein Subunits; C032456:antimycin; D000968:Antimycin A; C041573:stigmatellin; D014450:Electron Transport Complex III