1PPJ

Bovine cytochrome bc1 complex with stigmatellin and antimycin

Summary for 1PPJ

• Entry DOI: 10.2210/pdb1ppj/pdb
• Related: 1PP9
• Descriptor: Ubiquinol-cytochrome C reductase complex core protein I, mitochondrial, Ubiquinol-cytochrome C reductase complex 7.2 kDa protein, hexyl beta-D-glucopyranoside, ... (22 entities in total)
• Functional Keywords: cytochrome bc1, membrane protein, heme protein, rieske iron sulfur protein, cytochrome b, cytochrome c1, complex iii, mitochondrial processing protease, mpp ubiquinone, oxidoreductase, redox enzyme, respiratory chain, stigmatellin, antimycin
• Biological source: Bos taurus (cattle); More
• Total number of polymer chains: 20
• Total formula weight: 488101.43

Authors

Huang, L.S.,Cobessi, D.,Tung, E.Y.,Berry, E.A. (deposition date: 2003-06-16, release date: 2004-07-20, Last modification date: 2023-08-16)

Primary citation

Huang, L.S.,Cobessi, D.,Tung, E.Y.,Berry, E.A.
Binding of the Respiratory Chain Inhibitor Antimycin to the Mitochondrial bc(1) Complex: A New Crystal Structure Reveals an Altered Intramolecular Hydrogen-bonding Pattern.
J.Mol.Biol., 351:573-597, 2005

PubMed Abstract: 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.

PubMed: 16024040
DOI: 10.1016/j.jmb.2005.05.053

Experimental method

X-RAY DIFFRACTION (2.1 Å)