2a06

Bovine cytochrome bc1 complex with stigmatellin bound

spinqualitylabelsall models 2a06, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2a06 is a 20 chain structure with sequence from Bos taurus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: AZI, BHG, CDL, FES, GOL, HEC, HEM, PEE, PO4, SMA, UNL, UQ Related: 1pp9, 1ppj Activity: Ubiquinol--cytochrome-c reductase, with EC number 1.10.2.2 Resources: FirstGlance, OCA, RCSB, PDBsum Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Antimycin A (antimycin), one of the first known and most potent inhibitors of the mitochondrial respiratory chain, binds to the quinone reduction site of the cytochrome bc1 complex. Structure-activity relationship studies have shown that the N-formylamino-salicyl-amide group is responsible for most of the binding specificity, and suggested that a low pKa for the phenolic OH group and an intramolecular H-bond between that OH and the carbonyl O of the salicylamide linkage are important. Two previous X-ray structures of antimycin bound to vertebrate bc1 complex gave conflicting results. A new structure reported here of the bovine mitochondrial bc1 complex at 2.28 A resolution with antimycin bound, allows us for the first time to reliably describe the binding of antimycin and shows that the intramolecular hydrogen bond described in solution and in the small-molecule structure is replaced by one involving the NH rather than carbonyl O of the amide linkage, with rotation of the amide group relative to the aromatic ring. The phenolic OH and formylamino N form H-bonds with conserved Asp228 of cytochrome b, and the formylamino O H-bonds via a water molecule to Lys227. A strong density, the right size and shape for a diatomic molecule is found between the other side of the dilactone ring and the alphaA helix. Binding of the respiratory chain inhibitor antimycin to the mitochondrial bc1 complex: a new crystal structure reveals an altered intramolecular hydrogen-bonding pattern.,Huang LS, Cobessi D, Tung EY, Berry EA J Mol Biol. 2005 Aug 19;351(3):573-97. PMID:16024040 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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