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Crystal Structure Analysis of Bovine Bc1 with Stigmatellin A
Structural highlights
FunctionQCR8_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 subunit, together with cytochrome b, binds to ubiquinone. 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 PubMedCytochrome bc(1) is an integral membrane protein complex essential for cellular respiration and photosynthesis; it couples electron transfer from quinol to cytochrome c to proton translocation across the membrane. Specific bc(1) inhibitors have not only played crucial roles in elucidating the mechanism of bc(1) function but have also provided leads for the development of novel antibiotics. Crystal structures of bovine bc(1) in complex with the specific Q(o) site inhibitors azoxystrobin, MOAS, myxothiazol, stigmatellin and 5-undecyl-6-hydroxy-4,7-dioxobenzothiazole were determined. Interactions, conformational changes and possible mechanisms of resistance, specific to each inhibitor, were defined. Residues and secondary structure elements that are capable of discriminating different classes of Q(o) site inhibitors were identified for the cytochrome b subunit. Directions in the displacement of the cd1 helix of cytochrome b subunit in response to various Q(o) site inhibitors were correlated to the binary conformational switch of the extrinsic domain of the iron-sulfur protein subunit. The new structural information, together with structures previously determined, provide a basis that, combined with biophysical and mutational data, suggest a modification to the existing classification of bc(1) inhibitors. bc(1) inhibitors are grouped into three classes: class P inhibitors bind to the Q(o) site, class N inhibitors bind to the Q(i) site and the class PN inhibitors target both sites. Class P contains two subgroups, Pm and Pf, that are distinct by their ability to induce mobile or fixed conformation of iron-sulfur protein. Crystallographic studies of quinol oxidation site inhibitors: a modified classification of inhibitors for the cytochrome bc(1) complex.,Esser L, Quinn B, Li YF, Zhang M, Elberry M, Yu L, Yu CA, Xia D J Mol Biol. 2004 Jul 30;341(1):281-302. PMID:15312779[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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