PMID- 16829227
OWN - NLM
STAT- MEDLINE
DCOM- 20060929
LR  - 20161126
IS  - 0006-3002 (Print)
IS  - 0006-3002 (Linking)
VI  - 1757
IP  - 5-6
DP  - 2006 May-Jun
TI  - Elementary steps of proton translocation in the catalytic cycle of cytochrome 
      oxidase.
PG  - 401-7
AB  - Proton translocation in the catalytic cycle of cytochrome c oxidase (CcO) 
      proceeds sequentially in a four-stroke manner. Every electron donated by 
      cytochrome c drives the enzyme from one of four relatively stable intermediates 
      to another, and each of these transitions is coupled to proton translocation 
      across the membrane, and to uptake of another proton for production of water in 
      the catalytic site. Using cytochrome c oxidase from Paracoccus denitrificans we 
      have studied the kinetics of electron transfer and electric potential generation 
      during several such transitions, two of which are reported here. The extent of 
      electric potential generation during initial electron equilibration between CuA 
      and heme a confirms that this reaction is not kinetically linked to vectorial 
      proton transfer, whereas oxidation of heme a is kinetically coupled to the main 
      proton translocation events during functioning of the proton pump. We find that 
      the rates and amplitudes in multiphase heme a oxidation are different in the 
      OH-->EH and PM-->F steps of the catalytic cycle, and that this is reflected in 
      the kinetics of electric potential generation. We discuss this difference in 
      terms of different driving forces and relate our results, and data from the 
      literature, to proposed mechanisms of proton pumping in cytochrome c oxidase.
FAU - Verkhovsky, Michael I
AU  - Verkhovsky MI
AD  - Helsinki Bioenergetics Group, Institute of Biotechnology, University of Helsinki, 
      FIN-00014 University of Helsinki, Helsinki, Finland. 
      Micheal.Verkhovsky@helsinki.fi
FAU - Belevich, Ilya
AU  - Belevich I
FAU - Bloch, Dmitry A
AU  - Bloch DA
FAU - Wikstrom, Marten
AU  - Wikstrom M
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20060523
PL  - Netherlands
TA  - Biochim Biophys Acta
JT  - Biochimica et biophysica acta
JID - 0217513
RN  - 0 (Proton Pumps)
RN  - 0 (Protons)
RN  - 18535-39-2 (heme a)
RN  - 42VZT0U6YR (Heme)
RN  - EC 1.9.3.1 (Electron Transport Complex IV)
RN  - S88TT14065 (Oxygen)
SB  - IM
MH  - Catalysis
MH  - Electron Transport
MH  - Electron Transport Complex IV/*chemistry
MH  - Heme/analogs & derivatives/chemistry
MH  - Kinetics
MH  - Membrane Potentials
MH  - Models, Molecular
MH  - Oxidation-Reduction
MH  - Oxygen/chemistry
MH  - Paracoccus denitrificans/enzymology
MH  - Proton Pumps/*chemistry
MH  - *Protons
EDAT- 2006/07/11 09:00
MHDA- 2006/09/30 09:00
CRDT- 2006/07/11 09:00
PHST- 2006/01/03 00:00 [received]
PHST- 2006/05/18 00:00 [revised]
PHST- 2006/05/18 00:00 [accepted]
PHST- 2006/07/11 09:00 [pubmed]
PHST- 2006/09/30 09:00 [medline]
PHST- 2006/07/11 09:00 [entrez]
AID - S0005-2728(06)00167-8 [pii]
AID - 10.1016/j.bbabio.2006.05.026 [doi]
PST - ppublish
SO  - Biochim Biophys Acta. 2006 May-Jun;1757(5-6):401-7. doi: 
      10.1016/j.bbabio.2006.05.026. Epub 2006 May 23.