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1pp9

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1pp9, resolution 2.10Å ()
Ligands: , , , , , , , , , ,
Activity: Ubiquinol--cytochrome-c reductase, with EC number 1.10.2.2
Resources: FirstGlance, OCA, RCSB, PDBsum
Coordinates: save as pdb, mmCIF, xml


Contents

Bovine cytochrome bc1 complex with stigmatellin bound

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.

Function

[CYB_BOVIN] Component of the ubiquinol-cytochrome c reductase complex (complex III or cytochrome b-c1 complex), which is a respiratory chain that generates an electrochemical potential coupled to ATP synthesis. [UCRI_BOVIN] Component of the ubiquinol-cytochrome c reductase complex (complex III or cytochrome b-c1 complex), which is a respiratory chain that generates an electrochemical potential coupled to ATP synthesis. The transit peptide of the Rieske protein seems to form part of the bc1 complex and is considered to be the subunit 11/IX of that complex. [QCR2_BOVIN] This is a component of the ubiquinol-cytochrome c reductase complex (complex III or cytochrome b-c1 complex), which is part of the mitochondrial respiratory chain. The core protein 2 is required for the assembly of the complex. [QCR6_BOVIN] This is a component of the ubiquinol-cytochrome c reductase complex (complex III or cytochrome b-c1 complex), which is part of the mitochondrial respiratory chain. This protein may mediate formation of the complex between cytochromes c and c1. [QCR1_BOVIN] This is a component of the ubiquinol-cytochrome c reductase complex (complex III or cytochrome b-c1 complex), which is part of the mitochondrial respiratory chain. This protein may mediate formation of the complex between cytochromes c and c1. [CY1_BOVIN] This is the heme-containing component of the cytochrome b-c1 complex, which accepts electrons from Rieske protein and transfers electrons to cytochrome c in the mitochondrial respiratory chain.

About this Structure

1pp9 is a 20 chain structure with sequence from Bos taurus. Full crystallographic information is available from OCA.

See Also

Reference

  • Huang LS, Cobessi D, Tung EY, Berry EA. Binding of the respiratory chain inhibitor antimycin to the mitochondrial bc1 complex: a new crystal structure reveals an altered intramolecular hydrogen-bonding pattern. J Mol Biol. 2005 Aug 19;351(3):573-97. PMID:16024040 doi:10.1016/j.jmb.2005.05.053
  • Kolling DR, Samoilova RI, Holland JT, Berry EA, Dikanov SA, Crofts AR. Exploration of ligands to the Qi site semiquinone in the bc1 complex using high-resolution EPR. J Biol Chem. 2003 Oct 10;278(41):39747-54. Epub 2003 Jul 21. PMID:12874282 doi:10.1074/jbc.M305913200

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