Time-resolved single-turnover of ba3 oxidase from Thermus thermophilus.
The kinetics of the oxidation of fully-reduced ba(3) cytochrome c oxidase from Thermus thermophilus by oxygen were followed by time-resolved optical spectroscopy and electrometry. Four catalytic intermediates were resolved during this reaction. The chemical nature and the spectral properties of three intermediates (compounds A, P and O) reproduce the general features of aa(3)-type oxidases. However the F intermediate in ba(3) oxidase has a spectrum identical to the P state. This indicates that the proton taken up during the P-->F transition does not reside in the binuclear site but is rather transferred to the covalently cross-linked tyrosine near that site. The total charge translocation associated with the F-->O transition in ba(3) oxidase is close to that observed during the F-->O transition in the aa(3) oxidases. However, the P(R)-->F transition is characterized by significantly lower charge translocation, which probably reflects the overall lower measured pumping efficiency during multiple turnovers.
Siletsky
Sergey A
SA
Department of Molecular Energetics of Microorganisms, A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation.
Belevich
Ilya
I
Jasaitis
Audrius
A
Konstantinov
Alexander A
AA
Wikström
Mårten
M
Soulimane
Tewfik
T
Verkhovsky
Michael I
MI
D002384:Catalysis; D003573:Cytochrome b Group / Q000737:chemistry / Q000378:metabolism*; D003576:Electron Transport Complex IV / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism*; D013053:Spectrophotometry; D016963:Thermus thermophilus / Q000201:enzymology*
D003573:Cytochrome b Group; C058557:cytochrome ba3; D003576:Electron Transport Complex IV; D010100:Oxygen