Reaction of wild-type and Glu243Asp variant yeast cytochrome c oxidase with O-2
2014 (English)In: Biochimica et Biophysica Acta - Bioenergetics, ISSN 0005-2728, E-ISSN 1879-2650, Vol. 1837, no 7, 1012-1018 p.Article in journal (Refereed) Published
We have studied internal electron transfer during the reaction of Saccharomyces cerevisiae mitochondrial cytochrome c oxidase with dioxygen. Similar absorbance changes were observed with this yeast oxidase as with the previously studied Rhodobacter sphaeroides and bovine mitochondrial oxidases, which suggests that the reaction proceeds along the same trajectory. However, notable differences were observed in rates and electron-transfer equilibrium constants of specific reaction steps, for example the ferryl (F) to oxidized (O) reaction was faster with the yeast (0.4 ms) than with the bovine oxidase (similar to 1 ms) and a larger fraction Cu-A was oxidized with the yeast than with the bovine oxidase in the peroxy (P-R) to F reaction. Furthermore, upon replacement of Glu243, located at the end of the so-called D proton pathway, by Asp the P-R -> F and F -> O reactions were slowed by factors of similar to 3 and similar to 10, respectively, and electron transfer from Cu-A to heme a during the P-R -> F reaction was not observed. These data indicate that during reduction of dioxygen protons are transferred through the D pathway, via Glu243, to the catalytic site in the yeast mitochondrial oxidase. This article is part of a Special Issue entitled: 18th European Bioenergetic Conference.
Place, publisher, year, edition, pages
2014. Vol. 1837, no 7, 1012-1018 p.
Electron transfer, Membrane protein, Respiration, Redox reaction, Metalloprotein, Cytochrome aa3
Biochemistry and Molecular Biology Biophysics
IdentifiersURN: urn:nbn:se:su:diva-106575DOI: 10.1016/j.bbabio.2014.03.012ISI: 000338815000008OAI: oai:DiVA.org:su-106575DiVA: diva2:737956