Skip to main content
NCBI home page
Proceedings of the National Academy of Sciences of the United States of America logoLink to Proceedings of the National Academy of Sciences of the United States of America
. 1992 Sep 1;89(17):7929–7933. doi: 10.1073/pnas.89.17.7929

Redox state of a one-electron component controls the rate of photoinhibition of photosystem II.

L Nedbal 1, G Samson 1, J Whitmarsh 1
PMCID: PMC49828  PMID: 11607318

Abstract

Photosystem II reaction centers in plants, algae, and cyanobacteria are susceptible to damage by excess light that irreversibly impairs activity and eventually results in the proteolytic degradation of at least one of the core proteins. The sequence of events and underlying molecular mechanisms that lead to photoinhibition are poorly understood. Here we present evidence for a one-electron redox component that exerts strong control over the rate of photosystem II photoinhibition in isolated thylakoid membranes. Monitoring the impact of various doses of visible light on the rate of water oxidation and on the variable chlorophyll fluorescence, we found that reduction of the redox component increased the rate of photoinhibition >15-fold. Anaerobic potentiometric titrations of the rate of photoinhibition revealed a redox component with a midpoint potential near 20 mV at pH 7.5. The titrations fit a Nernst equation for a one-electron reaction and were nearly pH independent. Although we have not yet identified the chemical species being titrated, a likely candidate is lowpotential cytochrome b-559. We believe this observation reveals an electron transfer pathway in photosystem II that functions to protect the reaction center against excess light energy.

Full text

PDF
7929

Selected References

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

  1. Blubaugh D. J., Atamian M., Babcock G. T., Golbeck J. H., Cheniae G. M. Photoinhibition of hydroxylamine-extracted photosystem II membranes: identification of the sites of photodamage. Biochemistry. 1991 Jul 30;30(30):7586–7597. doi: 10.1021/bi00244a030. [DOI] [PubMed] [Google Scholar]
  2. Canaani O., Havaux M. Evidence for a biological role in photosynthesis for cytochrome b-559--a component of photosystem II reaction center. Proc Natl Acad Sci U S A. 1990 Dec 1;87(23):9295–9299. doi: 10.1073/pnas.87.23.9295. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Dutton P. L. Redox potentiometry: determination of midpoint potentials of oxidation-reduction components of biological electron-transfer systems. Methods Enzymol. 1978;54:411–435. doi: 10.1016/s0076-6879(78)54026-3. [DOI] [PubMed] [Google Scholar]
  4. Fan H. N., Cramer W. A. The redox poential of cytochromes b-559 and b-563 in spinach chloroplasts. Biochim Biophys Acta. 1970 Aug 4;216(1):200–207. doi: 10.1016/0005-2728(70)90171-4. [DOI] [PubMed] [Google Scholar]
  5. Golbeck J. H., Kok B. Redox titration of electron acceptor Q and the plastoquinone pool in photosystem II. Biochim Biophys Acta. 1979 Aug 14;547(2):347–360. doi: 10.1016/0005-2728(79)90016-1. [DOI] [PubMed] [Google Scholar]
  6. Kirilovsky D., Etienne A. L. Protection of reaction center II from photodamage by low temperature and anaerobiosis in spinach chloroplasts. FEBS Lett. 1991 Feb 25;279(2):201–204. doi: 10.1016/0014-5793(91)80149-w. [DOI] [PubMed] [Google Scholar]
  7. Klimov V. V., Klevanik A. V., Shuvalov V. A., Kransnovsky A. A. Reduction of pheophytin in the primary light reaction of photosystem II. FEBS Lett. 1977 Oct 15;82(2):183–186. doi: 10.1016/0014-5793(77)80580-2. [DOI] [PubMed] [Google Scholar]
  8. Kyle D. J., Ohad I., Arntzen C. J. Membrane protein damage and repair: Selective loss of a quinone-protein function in chloroplast membranes. Proc Natl Acad Sci U S A. 1984 Jul;81(13):4070–4074. doi: 10.1073/pnas.81.13.4070. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Nishio J. N., Whitmarsh J. Dissipation of the proton electrochemical potential in intact and lysed chloroplasts : I. The electrical potential. Plant Physiol. 1991 Feb;95(2):522–528. doi: 10.1104/pp.95.2.522. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. O'Reilly J. E. Oxidation-reduction potential of the ferro-ferricyanide system in buffer solutions. Biochim Biophys Acta. 1973 Apr 5;292(3):509–515. doi: 10.1016/0005-2728(73)90001-7. [DOI] [PubMed] [Google Scholar]
  11. Ortega J. M., Hervás M., Losada M. Redox and acid-base characterization of cytochrome b-559 in photosystem II particles. Eur J Biochem. 1988 Feb 1;171(3):449–455. doi: 10.1111/j.1432-1033.1988.tb13810.x. [DOI] [PubMed] [Google Scholar]
  12. Rich P. R., Bendall D. S. The redox potentials of the b-type cytochromes of higher plant chloroplasts. Biochim Biophys Acta. 1980 Jun 10;591(1):153–161. doi: 10.1016/0005-2728(80)90229-7. [DOI] [PubMed] [Google Scholar]
  13. Satoh K., Fork D. C. Photoinhibition of Reaction Centers of Photosystems I and II in Intact Bryopsis Chloroplasts under Anaerobic Conditions. Plant Physiol. 1982 Oct;70(4):1004–1008. doi: 10.1104/pp.70.4.1004. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Thompson L. K., Brudvig G. W. Cytochrome b-559 may function to protect photosystem II from photoinhibition. Biochemistry. 1988 Sep 6;27(18):6653–6658. doi: 10.1021/bi00418a002. [DOI] [PubMed] [Google Scholar]
  15. Thompson L. K., Miller A. F., Buser C. A., de Paula J. C., Brudvig G. W. Characterization of the multiple forms of cytochrome b559 in photosystem II. Biochemistry. 1989 Oct 3;28(20):8048–8056. doi: 10.1021/bi00446a012. [DOI] [PubMed] [Google Scholar]
  16. Vass I., Styring S., Hundal T., Koivuniemi A., Aro E., Andersson B. Reversible and irreversible intermediates during photoinhibition of photosystem II: stable reduced QA species promote chlorophyll triplet formation. Proc Natl Acad Sci U S A. 1992 Feb 15;89(4):1408–1412. doi: 10.1073/pnas.89.4.1408. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Whitmarsh J., Ort D. R. Stoichiometries of electron transport complexes in spinach chloroplasts. Arch Biochem Biophys. 1984 Jun;231(2):378–389. doi: 10.1016/0003-9861(84)90401-6. [DOI] [PubMed] [Google Scholar]

Articles from Proceedings of the National Academy of Sciences of the United States of America are provided here courtesy of National Academy of Sciences

RESOURCES