Redox-linked conformational changes in cytochrome c oxidase.
The CD spectrum of oxidized cytochrome oxidase in the wavelength region 185-260 nm shows that the secondary structure of the protein consists of close to 60% alpha-helix and slightly less than 20% beta-structure. CD spectra of oxidized cytochrome oxidase, of half and fully reduced carboxycytochrome oxidase as well as of fully reduced cytochrome oxidase, have been recorded in the wavelength region 200-260 nm. The results demonstrate a conformational change on going from the oxidized to the half reduced state in carboxycytochrome oxidase; no further change occurs on full reduction. A conformational change is also seen in the fully reduced enzyme without bound CO. The conformational transitions are suggested to be part of the proton pumping mechanism of cytochrome oxidase.
Wittung
P
P
Department of Physical Chemistry, Chalmers University of Technology, Göteborg, Sweden.
Malmström
B G
BG
D000818:Animals; D002417:Cattle; D002942:Circular Dichroism; D003576:Electron Transport Complex IV / Q000737:chemistry*; D010084:Oxidation-Reduction; D011487:Protein Conformation; D017433:Protein Structure, Secondary
D003576:Electron Transport Complex IV