PMID- 16460733
OWN - NLM
STAT- MEDLINE
DCOM- 20060417
LR  - 20131121
IS  - 0014-5793 (Print)
IS  - 0014-5793 (Linking)
VI  - 580
IP  - 5
DP  - 2006 Feb 20
TI  - The role of tryptophan 272 in the Paracoccus denitrificans cytochrome c oxidase.
PG  - 1345-9
AB  - The mechanism of electron coupled proton transfer in cytochrome c oxidase (CcO) 
      is still poorly understood. The P(M)-intermediate of the catalytic cycle is an 
      oxoferryl state whose generation requires one additional electron, which cannot 
      be provided by the two metal centres. The missing electron has been suggested to 
      be donated to this binuclear site by a tyrosine residue. A tyrosine radical 
      species has been detected in the P(M) and F* intermediates (formed by addition of 
      H2O2) of the Paraccocus denitrificans CcO using electron paramagnetic resonance 
      (EPR) spectroscopy. From the study of conserved variants its origin was 
      determined to be Y167 which is surprising as this residue is not part of the 
      active site. Upon inspection of the active site it becomes evident that W272 
      could be the actual donor of the missing electron, which can then be replenished 
      from Y167 or from the Y280-H276 cross link in the natural cycle. To address the 
      question, whether such a direct electron transfer pathway to the binuclear centre 
      exists two tryptophan 272 variants in subunit I have been generated. These 
      variants are characterised by their turnover rates as well as using EPR and 
      optical spectroscopy. From these experiments it is concluded, that W272 is an 
      important intermediate in the formation of the radical species appearing in P(M) 
      and F* intermediates produced with hydrogen peroxide. The significance of this 
      finding for the catalytic function of the enzyme is discussed.
FAU - MacMillan, Fraser
AU  - MacMillan F
AD  - Institut fur Physikalische and Theoretische Chemie, Center for Biomolecular 
      Magnetic Resonance, Johann Wolfgang Goethe-Universitat, Frankfurt D-60439, 
      Frankfurt am Main, Germany. macmillan@chemie.uni-frankfurt.de
FAU - Budiman, Kerstin
AU  - Budiman K
FAU - Angerer, Heike
AU  - Angerer H
FAU - Michel, Hartmut
AU  - Michel H
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20060126
PL  - England
TA  - FEBS Lett
JT  - FEBS letters
JID - 0155157
RN  - 0 (Free Radicals)
RN  - 42HK56048U (Tyrosine)
RN  - 8DUH1N11BX (Tryptophan)
RN  - BBX060AN9V (Hydrogen Peroxide)
RN  - EC 1.9.3.1 (Electron Transport Complex IV)
SB  - IM
MH  - Catalysis
MH  - Electron Spin Resonance Spectroscopy
MH  - Electron Transport
MH  - Electron Transport Complex IV/*chemistry
MH  - Free Radicals/chemistry
MH  - Hydrogen Peroxide
MH  - Paracoccus denitrificans/*enzymology
MH  - Tryptophan/*chemistry
MH  - Tyrosine/chemistry
EDAT- 2006/02/08 09:00
MHDA- 2006/04/18 09:00
CRDT- 2006/02/08 09:00
PHST- 2005/12/08 00:00 [received]
PHST- 2006/01/18 00:00 [revised]
PHST- 2006/01/18 00:00 [accepted]
PHST- 2006/02/08 09:00 [pubmed]
PHST- 2006/04/18 09:00 [medline]
PHST- 2006/02/08 09:00 [entrez]
AID - S0014-5793(06)00107-4 [pii]
AID - 10.1016/j.febslet.2006.01.054 [doi]
PST - ppublish
SO  - FEBS Lett. 2006 Feb 20;580(5):1345-9. doi: 10.1016/j.febslet.2006.01.054. Epub 
      2006 Jan 26.