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Steady-state cyclic electron transfer through solubilized Rhodobacter sphaeroides reaction centres

van Rotterdam, Bart LU ; Westerhoff, Hans V; Visschers, Ronald W; Jones, Michael R; Hellingwerf, Klaas J and Crielaard, Wim (2000) In Biophysical Chemistry 88(1-3). p.137-152
Abstract
The mechanism, thermodynamics and kinetics of light-induced cyclic electron transfer have been studied in a model energy-transducing system consisting of solubilized Rhodobacter sphaeroides reaction center/light harvesting-1 complexes (so-called core complexes), horse heart cytochrome c and a ubiquinone-0/ubiquinol-0 pool. An analysis of the steady-state kinetics of cytochrome c reduction by ubiquinol-0, after a light-induced steady-state electron flow had been attained, showed that the rate of this reaction is primarily controlled by the one-electron oxidation of the ubiquinol-anion. Re-reduction of the light-oxidized reaction center primary donor by cytochrome c was measured at different reduction levels of the ubiquinone-0/ubiquinol-0... (More)
The mechanism, thermodynamics and kinetics of light-induced cyclic electron transfer have been studied in a model energy-transducing system consisting of solubilized Rhodobacter sphaeroides reaction center/light harvesting-1 complexes (so-called core complexes), horse heart cytochrome c and a ubiquinone-0/ubiquinol-0 pool. An analysis of the steady-state kinetics of cytochrome c reduction by ubiquinol-0, after a light-induced steady-state electron flow had been attained, showed that the rate of this reaction is primarily controlled by the one-electron oxidation of the ubiquinol-anion. Re-reduction of the light-oxidized reaction center primary donor by cytochrome c was measured at different reduction levels of the ubiquinone-0/ubiquinol-0 pool. These experiments involved single turnover flash excitation on top of background illumination that elicited steady-state cyclic electron transfer. At low reduction levels of the ubiquinone-0/ubiquinol-0 pool, the total cytochrome c concentration had a major control over the rate of reduction of the primary donor. This control was lost at higher reduction levels of the ubiquinone/ubiquinol-pool, and possible reasons for this behaviour are discussed. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Rhodobacter sphaeroides, Reaction center, Electron transfer, Ubiquinone, Cytochrome c, Control theory
in
Biophysical Chemistry
volume
88
issue
1-3
pages
137 - 152
publisher
Elsevier
external identifiers
  • scopus:0034672774
ISSN
1873-4200
DOI
10.1016/S0301-4622(00)00206-4
language
English
LU publication?
yes
id
c6012212-2287-4351-8a9c-1449bcb4755d (old id 125223)
date added to LUP
2007-07-06 16:57:25
date last changed
2017-01-01 07:04:57
@article{c6012212-2287-4351-8a9c-1449bcb4755d,
  abstract     = {The mechanism, thermodynamics and kinetics of light-induced cyclic electron transfer have been studied in a model energy-transducing system consisting of solubilized Rhodobacter sphaeroides reaction center/light harvesting-1 complexes (so-called core complexes), horse heart cytochrome c and a ubiquinone-0/ubiquinol-0 pool. An analysis of the steady-state kinetics of cytochrome c reduction by ubiquinol-0, after a light-induced steady-state electron flow had been attained, showed that the rate of this reaction is primarily controlled by the one-electron oxidation of the ubiquinol-anion. Re-reduction of the light-oxidized reaction center primary donor by cytochrome c was measured at different reduction levels of the ubiquinone-0/ubiquinol-0 pool. These experiments involved single turnover flash excitation on top of background illumination that elicited steady-state cyclic electron transfer. At low reduction levels of the ubiquinone-0/ubiquinol-0 pool, the total cytochrome c concentration had a major control over the rate of reduction of the primary donor. This control was lost at higher reduction levels of the ubiquinone/ubiquinol-pool, and possible reasons for this behaviour are discussed.},
  author       = {van Rotterdam, Bart and Westerhoff, Hans V and Visschers, Ronald W and Jones, Michael R and Hellingwerf, Klaas J and Crielaard, Wim},
  issn         = {1873-4200},
  keyword      = {Rhodobacter sphaeroides,Reaction center,Electron transfer,Ubiquinone,Cytochrome c,Control theory},
  language     = {eng},
  number       = {1-3},
  pages        = {137--152},
  publisher    = {Elsevier},
  series       = {Biophysical Chemistry},
  title        = {Steady-state cyclic electron transfer through solubilized Rhodobacter sphaeroides reaction centres},
  url          = {http://dx.doi.org/10.1016/S0301-4622(00)00206-4},
  volume       = {88},
  year         = {2000},
}