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Electron transfer by domain movement in cytochrome bc1. Nature 1998 Apr 16;392(6677):677-84

Date

05/16/1998

Pubmed ID

9565029

DOI

10.1038/33612

Scopus ID

2-s2.0-0032537117 (requires institutional sign-in at Scopus site)   963 Citations

Abstract

The cytochrome bc1 is one of the three major respiratory enzyme complexes residing in the inner mitochondrial membrane. Cytochrome bc1 transfers electrons from ubiquinol to cytochrome c and uses the energy thus released to form an electrochemical gradient across the inner membrane. Our X-ray crystal structures of the complex from chicken, cow and rabbit in both the presence and absence of inhibitors of quinone oxidation, reveal two different locations for the extrinsic domain of one component of the enzyme, an iron-sulphur protein. One location is close enough to the supposed quinol oxidation site to allow reduction of the Fe-S protein by ubiquinol. The other site is close enough to cytochrome c1 to allow oxidation of the Fe-S protein by the cytochrome. As neither location will allow both reactions to proceed at a suitable rate, the reaction mechanism must involve movement of the extrinsic domain of the Fe-S component in order to shuttle electrons from ubiquinol to cytochrome c1. Such a mechanism has not previously been observed in redox protein complexes.

Author List

Zhang Z, Huang L, Shulmeister VM, Chi YI, Kim KK, Hung LW, Crofts AR, Berry EA, Kim SH

Author

Young-In Chi PhD Assistant Professor in the Surgery department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Animals
Antimycin A
Binding Sites
Cattle
Chickens
Crystallography, X-Ray
Cytochrome c Group
Electron Transport
Electron Transport Complex III
Humans
Iron-Sulfur Proteins
Methacrylates
Models, Chemical
Models, Molecular
Oxidation-Reduction
Polyenes
Protein Conformation
Rabbits
Thiazoles