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Inhibitor-complexed Structures of the Cytochrome bc[subscript 1] from the Photosynthetic Bacterium Rhodobacter sphaeroides

Journal Article · · J. Biol. Chem.
The cytochrome bc{sub 1} complex (bc{sub 1}) is a major contributor to the proton motive force across the membrane by coupling electron transfer to proton translocation. The crystal structures of wild type and mutant bc{sub 1} complexes from the photosynthetic purple bacterium Rhodobacter sphaeroides (Rsbc{sub 1}), stabilized with the quinol oxidation (Q{sub P}) site inhibitor stigmatellin alone or in combination with the quinone reduction (Q{sub N}) site inhibitor antimycin, were determined. The high quality electron density permitted assignments of a new metal-binding site to the cytochrome c1 subunit and a number of lipid and detergent molecules. Structural differences between Rsbc{sub 1} and its mitochondrial counterparts are mostly extra membranous and provide a basis for understanding the function of the predominantly longer sequences in the bacterial subunits. Functional implications for the bc{sub 1} complex are derived from analyses of 10 independent molecules in various crystal forms and from comparisons with mitochondrial complexes.
Research Organization:
Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
Sponsoring Organization:
USDOE
OSTI ID:
1006507
Journal Information:
J. Biol. Chem., Journal Name: J. Biol. Chem. Journal Issue: (5) ; 02, 2008 Vol. 283; ISSN JBCHA3; ISSN 0021-9258
Country of Publication:
United States
Language:
ENGLISH