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Domain movement of iron sulfur protein in cytochrome bc 1 complex is facilitated by the electron transfer from cytochrome b L to b H
Author(s) -
Cen Xiaowei,
Yu Linda,
Yu Chang-An
Publication year - 2008
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2008.01.016
Subject(s) - coenzyme q – cytochrome c reductase , cytochrome c , cytochrome , chemistry , cytochrome c1 , isothermal titration calorimetry , cytochrome b , electron transfer , ubiquinol , stereochemistry , electron transport chain , crystallography , heme , redox , biophysics , biochemistry , photochemistry , inorganic chemistry , mitochondrion , biology , enzyme , mitochondrial dna , gene
The key step of the “protonmotive Q‐cycle” mechanism for cytochrome bc 1 complex is the bifurcated oxidation of ubiquinol at the Qp site. ISP is reduced when its head domain is at the b ‐position and subsequent move to the c 1 position, to reduce cytochrome c 1 , upon protein conformational changes caused by the electron transfer from cytochrome b L to b H . Results of analyses of the inhibitory efficacy and the binding affinity, determined by isothermal titration calorimetry, of Pm and Pf, on different redox states of cytochrome bc 1 complexes, confirm this speculation. Pm inhibitor has a higher affinity and better efficacy with the cytochrome b H reduced complex and Pf binds better and has a higher efficacy with the ISP reduced complex.