Crystal structure of the cytochrome bc1 complex from bovine heart mitochondria.
On the basis of x-ray diffraction data to a resolution of 2.9 angstroms, atomic models of most protein components of the bovine cytochrome bc1 complex were built, including core 1, core 2, cytochrome b, subunit 6, subunit 7, a carboxyl-terminal fragment of cytochrome c1, and an amino-terminal fragment of the iron-sulfur protein. The positions of the four iron centers within the bc1 complex and the binding sites of the two specific respiratory inhibitors antimycin A and myxothiazol were identified. The membrane-spanning region of each bc1 complex monomer consists of 13 transmembrane helices, eight of which belong to cytochrome b. Closely interacting monomers are arranged as symmetric dimers and form cavities through which the inhibitor binding pockets can be accessed. The proteins core 1 and core 2 are structurally similar to each other and consist of two domains of roughly equal size and identical folding topology.
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Howard Hughes Medical Institute and Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA.
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Kim
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Xia
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Kachurin
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AM
Zhang
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Yu
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Deisenhofer
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D000818:Animals; D000968:Antimycin A / Q000378:metabolism / Q000494:pharmacology; D001665:Binding Sites; D002417:Cattle; D018360:Crystallography, X-Ray; D003573:Cytochrome b Group / Q000737:chemistry; D003575:Cytochromes c1 / Q000737:chemistry; D019281:Dimerization; D014450:Electron Transport Complex III / Q000737:chemistry* / Q000378:metabolism; D007425:Intracellular Membranes / Q000201:enzymology; D007501:Iron / Q000378:metabolism; D008689:Methacrylates; D008929:Mitochondria, Heart / Q000201:enzymology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013844:Thiazoles / Q000378:metabolism / Q000494:pharmacology
D003573:Cytochrome b Group; D008689:Methacrylates; D013844:Thiazoles; D000968:Antimycin A; C030517:myxothiazol; D003575:Cytochromes c1; D007501:Iron; D014450:Electron Transport Complex III