PMID- 16306266
OWN - NLM
STAT- MEDLINE
DCOM- 20060118
LR  - 20181113
IS  - 0027-8424 (Print)
IS  - 1091-6490 (Electronic)
IS  - 0027-8424 (Linking)
VI  - 102
IP  - 49
DP  - 2005 Dec 6
TI  - The timing of proton migration in membrane-reconstituted cytochrome c oxidase.
PG  - 17624-9
AB  - In mitochondria and aerobic bacteria energy conservation involves electron 
      transfer through a number of membrane-bound protein complexes to O2. The 
      reduction of O2, accompanied by the uptake of substrate protons to form H2O, is 
      catalyzed by cytochrome c oxidase (CcO). This reaction is coupled to proton 
      translocation (pumping) across the membrane such that each electron transfer to 
      the catalytic site is linked to the uptake of two protons from one side and the 
      release of one proton to the other side of the membrane. To address the mechanism 
      of vectorial proton translocation, in this study we have investigated the solvent 
      deuterium isotope effect of proton-transfer rates in CcO oriented in small 
      unilamellar vesicles. Although in H2O the uptake and release reactions occur with 
      the same rates, in D2O the substrate and pumped protons are taken up first 
      (tau(D) congruent with 200 micros, "peroxy" to "ferryl" transition) followed by a 
      significantly slower proton release to the other side of the membrane (tau(D) 
      congruent with 1 ms). Thus, the results define the order and timing of the proton 
      transfers during a pumping cycle. Furthermore, the results indicate that during 
      CcO turnover internal electron transfer to the catalytic site is controlled by 
      the release of the pumped proton, which suggests a mechanism by which CcO 
      orchestrates a tight coupling between electron transfer and proton translocation.
FAU - Salomonsson, Lina
AU  - Salomonsson L
AD  - Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural 
      Sciences, Stockholm University SE-106 91 Stockholm, Sweden.
FAU - Faxen, Kristina
AU  - Faxen K
FAU - Adelroth, Pia
AU  - Adelroth P
FAU - Brzezinski, Peter
AU  - Brzezinski P
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20051123
PL  - United States
TA  - Proc Natl Acad Sci U S A
JT  - Proceedings of the National Academy of Sciences of the United States of America
JID - 7505876
RN  - 0 (Detergents)
RN  - 0 (Lipids)
RN  - 0 (Protons)
RN  - 0 (Solutions)
RN  - EC 1.9.3.1 (Electron Transport Complex IV)
SB  - IM
MH  - Detergents/pharmacology
MH  - Electron Transport Complex IV/*chemistry/*metabolism
MH  - Lipids/chemistry
MH  - Models, Molecular
MH  - Protein Structure, Quaternary
MH  - *Protons
MH  - Rhodobacter sphaeroides/*enzymology
MH  - Solutions
MH  - Time Factors
PMC - PMC1345723
EDAT- 2005/11/25 09:00
MHDA- 2006/01/19 09:00
PMCR- 2006/06/06
CRDT- 2005/11/25 09:00
PHST- 2005/11/25 09:00 [pubmed]
PHST- 2006/01/19 09:00 [medline]
PHST- 2005/11/25 09:00 [entrez]
PHST- 2006/06/06 00:00 [pmc-release]
AID - 0505431102 [pii]
AID - 17624 [pii]
AID - 10.1073/pnas.0505431102 [doi]
PST - ppublish
SO  - Proc Natl Acad Sci U S A. 2005 Dec 6;102(49):17624-9. doi: 
      10.1073/pnas.0505431102. Epub 2005 Nov 23.