2fyn
Crystal Structure Analysis of the double mutant Rhodobacter Sphaeroides bc1 complexCrystal Structure Analysis of the double mutant Rhodobacter Sphaeroides bc1 complex
Structural highlights
FunctionCYB_CERSP 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. 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 PubMedIn the cytochrome bc(1) complex, the swivel motion of the iron-sulfur protein (ISP) between two redox sites constitutes a key component of the mechanism that achieves the separation of the two electrons in a substrate molecule at the quinol oxidation (Q(o)) site. The question remaining is how the motion of ISP is controlled so that only one electron enters the thermodynamically favorable chain via ISP. An analysis of eight structures of mitochondrial bc(1) with bound Q(o) site inhibitors revealed that the presence of inhibitors causes a bidirectional repositioning of the cd1 helix in the cytochrome b subunit. As the cd1 helix forms a major part of the ISP binding crater, any positional shift of this helix modulates the ability of cytochrome b to bind ISP. The analysis also suggests a mechanism for reversal of the ISP fixation when the shape complementarity is significantly reduced after a positional reorientation of the reaction product quinone. The importance of shape complementarity in this mechanism was confirmed by functional studies of bc(1) mutants and by a structure determination of the bacterial form of bc(1). A mechanism for the high fidelity of the bifurcated electron transfer is proposed. Surface-modulated motion switch: capture and release of iron-sulfur protein in the cytochrome bc1 complex.,Esser L, Gong X, Yang S, Yu L, Yu CA, Xia D Proc Natl Acad Sci U S A. 2006 Aug 29;103(35):13045-50. Epub 2006 Aug 21. PMID:16924113[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences |
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