Skip to main content
NCBI home page
Plant Physiology logoLink to Plant Physiology
. 1977 Oct;60(4):597–601. doi: 10.1104/pp.60.4.597

Photophosphorylation Associated with Photosystem II

III. Characterization of Uncoupling, Energy Transfer Inhibition, and Proton Uptake Reactions Associated with Photosystem II Cyclic Photophosphorylation

Charles F Yocum 1
PMCID: PMC542671  PMID: 16660145

Abstract

A number of uncouplers and energy transfer inhibitors suppress photosystem II cyclic photophosphorylation catalyzed by either a proton/electron or electron donor. Valinomycin and 2,4-dinitrophenol also inhibit photosystem II cyclic photophosphorylation, but these compounds appear to act as electron transport inhibitors rather than as uncouplers. Only when valinomycin, KCl, and 2,4-dinitrophenol were added simultaneously to phosphorylation reaction mixtures was substantial uncoupling observed. Photosystem II noncyclic and cyclic electron transport reactions generate positive absorbance changes at 518 nm. Uncoupling and energy transfer inhibition diminished the magnitude of these absorbance changes. Photosystem II cyclic electron transport catalyzed by either p-phenylenediamine or N,N,N′,N′-tetramethyl-p-phenylenediamine stimulated proton uptake in KCN-Hg-NH2OH-inhibited spinach (Spinacia oleracea L.) chloroplasts. Illumination with 640 nm light produced an extent of proton uptake approximately 3-fold greater than did 700 nm illumination, indicating that photosystem II-catalyzed electron transport was responsible for proton uptake. Electron transport inhibitors, uncouplers, and energy transfer inhibitors produced inhibitions of photosystem II-dependent proton uptake consistent with the effects of these compounds on ATP synthesis by the photosystem II cycle. These results are interpreted as indicating that endogenous proton-translocating components of the thylakoid membrane participate in coupling of ATP synthesis to photosystem II cyclic electron transport.

Full text

PDF
597

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Arnon D. I., Tsujimoto H. Y., McSwain B. D. Ferredoxin and photosynthetic phosphorylation. Nature. 1967 May 6;214(5088):562–566. doi: 10.1038/214562a0. [DOI] [PubMed] [Google Scholar]
  2. Dilley R. A. Ion transport (H+, K+, Mg2+ exchange phenomena). Methods Enzymol. 1972;24:68–74. doi: 10.1016/0076-6879(72)24055-1. [DOI] [PubMed] [Google Scholar]
  3. Gould J. M. Inhibition by triphenyltin chloride of a tightly-bound membrane component involved in photophosphorylation. Eur J Biochem. 1976 Mar 1;62(3):567–575. doi: 10.1111/j.1432-1033.1976.tb10191.x. [DOI] [PubMed] [Google Scholar]
  4. Gould J. M., Izawa S. Studies on the energy coupling sites of photophosphorylation. I. Separation of site I and site II by partial reactions of the chloroplast electron transport chain. Biochim Biophys Acta. 1973 Aug 31;314(2):211–223. doi: 10.1016/0005-2728(73)90136-9. [DOI] [PubMed] [Google Scholar]
  5. Izawa S., Ort D. R. Photooxidation of ferrocyanide and iodide ions and associated phosphorylation in NH2OH-treated chloroplasts. Biochim Biophys Acta. 1974 Jul 25;357(1):127–143. doi: 10.1016/0005-2728(74)90118-2. [DOI] [PubMed] [Google Scholar]
  6. Junge W., Witt H. T. On the ion transport system of photosynthesis--investigations on a molecular level. Z Naturforsch B. 1968 Feb;23(2):244–254. doi: 10.1515/znb-1968-0222. [DOI] [PubMed] [Google Scholar]
  7. Karlish S. J., Shavit N., Avron M. On the mechanism of uncoupling in chloroplasts by ion-permeability inducing agents. Eur J Biochem. 1969 Jun;9(2):291–298. doi: 10.1111/j.1432-1033.1969.tb00608.x. [DOI] [PubMed] [Google Scholar]
  8. Nelson N., Nelson H., Naim Y., Neumann J. Effect of pyridine on the light-induced pH rise and postillumination ATP synthesis in chloroplasts. Arch Biochem Biophys. 1971 Jul;145(1):263–267. doi: 10.1016/0003-9861(71)90035-x. [DOI] [PubMed] [Google Scholar]
  9. Ort D. R., Izawa S. Studies on the Energy-coupling Sites of Photophosphorylation: V. Phosphorylation Efficiencies (P/e(2)) Associated with Aerobic Photooxidation of Artificial Electron Donors. Plant Physiol. 1974 Mar;53(3):370–376. doi: 10.1104/pp.53.3.370. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Ouitrakul R., Izawa S. Electron transport and photophosphorylation in chloroplasts as a function of the electron acceptor. II. Acceptor-specific inhibition by KCN. Biochim Biophys Acta. 1973 Apr 27;305(1):105–118. doi: 10.1016/0005-2728(73)90236-3. [DOI] [PubMed] [Google Scholar]
  11. Pick U., Avron M. A method for measuring the internal pH in illuminated chloroplasts based on the stimulation of proton uptake by amines. Eur J Biochem. 1976 Nov 15;70(2):569–576. doi: 10.1111/j.1432-1033.1976.tb11048.x. [DOI] [PubMed] [Google Scholar]
  12. Saha S., Ouitrakul R., Izawa S., Good N. E. Electron transport and photophosphorylation in chloroplasts as a function of the electron acceptor. J Biol Chem. 1971 May 25;246(10):3204–3209. [PubMed] [Google Scholar]
  13. Trebst A., Reimer S. Properties of photoreductions by photosystem II in isolated chloroplasts. An energy-conserving step in the photoreduction of benzoquinones by photosystem II in the presence of dibromothymoquinone. Biochim Biophys Acta. 1973 Apr 27;305(1):129–139. doi: 10.1016/0005-2728(73)90238-7. [DOI] [PubMed] [Google Scholar]
  14. Vater J. The action of indophenols and nitrophenols on the deactivation reactions in the water-splitting system of photosynthesis. Biochim Biophys Acta. 1973 Apr 5;292(3):786–795. doi: 10.1016/0005-2728(73)90025-x. [DOI] [PubMed] [Google Scholar]
  15. Witt H. T. Coupling of quanta, electrons, fields, ions and phosphrylation in the functional membrane of photosynthesis. Results by pulse spectroscopic methods. Q Rev Biophys. 1971 Nov;4(4):365–477. doi: 10.1017/s0033583500000834. [DOI] [PubMed] [Google Scholar]
  16. Yocum C. F., Guikema J. A. Photophosphorylation Associated with Photosystem II: I. Photosystem II Cyclic Photophosphorylation Catalyzed by p-Phenylenediamine. Plant Physiol. 1977 Jan;59(1):33–37. doi: 10.1104/pp.59.1.33. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Yocum C. F. Photophosphorylation Associated with Photosystem II: II. Effects of Electron Donors, Catalyst Oxidation, and Electron Transport Inhibitors on Photosystem II Cyclic Photophosphorylation. Plant Physiol. 1977 Oct;60(4):592–596. doi: 10.1104/pp.60.4.592. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Yocum C. F. Photosystem II - mediated cyclic photophosphorylation. Biochem Biophys Res Commun. 1976 Feb 9;68(3):828–835. doi: 10.1016/0006-291x(76)91220-1. [DOI] [PubMed] [Google Scholar]

Articles from Plant Physiology are provided here courtesy of Oxford University Press

RESOURCES