PMID: 41574Nov 8, 1979

Electron acceptors of bacterial photosynthetic reaction centers. II. H+ binding coupled to secondary electron transfer in the quinone acceptor complex

Biochimica Et Biophysica Acta
Colin A Wraight

Abstract

The photoreduction of ubiquinone in the electron acceptor complex (QIQII) of photosynthetic reaction centers from Rhodopseudomonas sphaeroides, R26, was studied in a series of short, saturating flashes. The specific involvement of H+ in the reduction was revealed by the pH dependence of the electron transfer events and by net H+ binding during the formation of ubiquinol, which requires two turnovers of the photochemical act. On the first flash QII receives an electron via QI to form a stable ubisemiquinone anion (QII-); the second flash generates QI-. At low pH the two semiquinones rapidly disproportionate with the uptake of 2 H+, to produce QIIH2. This yields out-of-phase binary oscillations for the formation of anionic semiquinone and for H+ uptake. Above pH 6 there is a progressive increase in H+ binding on the first flash and an equivalent decrease in binding on the second flash until, at about pH 9.5, the extent of H+ binding is the same on all flashes. The semiquinone oscillations, however, are undiminished up to pH 9. It is suggested that a non-chromophoric, acid-base group undergoes a pK shift in response to the appearance of the anionic semiquinone and that this group is the site of protonation on the first flash. The ...Continue Reading

References

Jul 1, 1993·Photosynthesis Research·Péter Maróti
May 2, 2002·Proceedings of the National Academy of Sciences of the United States of America·Julia TandoriL Baciou
Nov 15, 2000·Proceedings of the National Academy of Sciences of the United States of America·P AdelrothM Y Okamura
Oct 1, 1984·Proceedings of the National Academy of Sciences of the United States of America·A E BrownC J Arntzen
Sep 1, 1989·Proceedings of the National Academy of Sciences of the United States of America·M L PaddockM Y Okamura
Dec 15, 1991·Proceedings of the National Academy of Sciences of the United States of America·C K ChanG R Fleming
Sep 15, 1992·Proceedings of the National Academy of Sciences of the United States of America·M DuG R Fleming
Sep 30, 1998·Proceedings of the National Academy of Sciences of the United States of America·M S GraigeM Y Okamura
Nov 11, 1999·Proceedings of the National Academy of Sciences of the United States of America·O A GoptaArmen Y Mulkidjanian
Feb 6, 1999·Annual Review of Physical Chemistry·R I Cukier, D G Nocera
Nov 21, 2013·Photosynthesis Research·Colin A Wraight
Jul 24, 2015·Photosynthesis Research· GovindjeeDonald R Ort
Mar 9, 2002·Photochemistry and Photobiology·Julia TandoriPierre Sebban
Jun 1, 1981·Biochemical and Biophysical Research Communications·M W Kendall-Tobias, A R Crofts
May 13, 1981·Biochimica Et Biophysica Acta·M W Kendall-TobiasA R Crofts
May 17, 2000·Biochimica Et Biophysica Acta·M Y OkamuraG Feher
Mar 13, 1985·Biochimica Et Biophysica Acta·R J Shopes, Colin A Wraight
Aug 1, 1983·Archives of Biochemistry and Biophysics·J M BowesD S Bendall
Apr 21, 2006·Biochimica Et Biophysica Acta·Armen Y MulkidjanianDmitry A Cherepanov
Jul 28, 2009·Biochimica Et Biophysica Acta·Hélène CheapPierre Sebban

Citations

Aug 11, 1975·Biochimica Et Biophysica Acta·Colin A WraightR K Clayton
Dec 6, 1976·Biochimica Et Biophysica Acta·M P PullesJ G Willemsen
Sep 1, 1975·Proceedings of the National Academy of Sciences of the United States of America·M Y OkamuraG Feher
Apr 1, 1972·Proceedings of the National Academy of Sciences of the United States of America·P A Loach, R L Hall
Aug 31, 1973·Biochimica Et Biophysica Acta·B Bouges-Bocquet
Jan 18, 1974·Biochimica Et Biophysica Acta·B R Velthuys, J Amesz

Related Concepts

Thermodynamics
Ubiquinone (Lab Procedure)
Photopsia
Semiquinone
Benzoquinone
Photosynthetic Reaction Centers
Quinones
Ubiquinol
Uptake
Electron Transport

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