Electron transfer and conformation states in bovine cytochrome c oxidase.
The fluorophores 1,5-I-AEDANS and eosin maleimide bind to subunit III of bovine cytochrome c oxidase. Fluorescence lifetime measurements have been made of bound AEDANS under a number of conditions. It appears that the spatial relationship between this bound probe and metal centers is unaffected by the redox changes in the enzyme. Cyanide binding to CuA-modified cytochrome c oxidase during turnover suggests that reduction of cytochrome a leads to exposure of the cytochrome a3-CuB binuclear center to incoming ligands. These results are discussed in terms of a model describing the roles of cytochrome a and CuA in triggering the "closed" to "open" transition.
Wilson
M T
MT
Department of Chemistry and Biological Chemistry, University of Essex, United Kingdom.
Alleyne
T
T
Clague
M
M
Conroy
K
K
el-Agez
B
B
D000818:Animals; D002417:Cattle; D003486:Cyanides / Q000378:metabolism; D004579:Electron Transport; D003576:Electron Transport Complex IV / Q000378:metabolism*; D005456:Fluorescent Dyes; D007700:Kinetics; D009282:Naphthalenesulfonates; D010084:Oxidation-Reduction; D011487:Protein Conformation; D013050:Spectrometry, Fluorescence
D003486:Cyanides; D005456:Fluorescent Dyes; D009282:Naphthalenesulfonates; C006421:1,5-I-AEDANS; D003576:Electron Transport Complex IV