Details

Autor(en) / Beteiligte

• WATMOUGH, Nicholas J.
• KATSONOURI, Andromachi
• LITTLE, Richard H.
• OSBORNE, Jeffrey P.
• FURLONG-NICKELS, Elizabeth
• GENNIS, Robert B.
• BRITTAIN, Thomas
• GREENWOOD, Colin

Titel

A Conserved Glutamic Acid in Helix VI of Cytochrome bo3 Influences a Key Step in Oxygen Reduction

Ist Teil von

• Biochemistry (Easton), 1997-11, Vol.36 (44), p.13736-13742

Ort / Verlag

United States: American Chemical Society

Erscheinungsjahr

1997

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• We have compared the reactions with dioxygen of wild-type cytochrome bo3 and a mutant in which a conserved glutamic acid at position-286 of subunit I has been changed to an alanine. Flow-flash experiments reveal that oxygen binding and the rate of heme-heme electron transfer are unaffected by the mutation. Reaction of the fully (3-electron) reduced mutant cytochrome bo3 with dioxygen yields a binuclear center which is substantially in the P (peroxy) state, not the well-characterized F (oxyferryl) state which is the product of the reaction of the fully reduced wild-type enzyme with dioxygen [Puustinen, A., et al. (1996) Proc. Natl. Acad. Sci. U.S.A. 93, 1545-1548]. These results confirm that proton uptake is important in controlling the later stages of dioxygen reduction in heme-copper oxidases and show that E286 is an important component of the channel that delivers these protons to the active site.