This Article Full Text Full Text (PDF) All Versions of this Article: biophysj.104.050237v1 88/3/1948    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Rappaport, F. Articles by Lavergne, J. Search for Related Content PubMed PubMed Citation Articles by Rappaport, F. Articles by Lavergne, J.

Charge Recombination and Thermoluminescence in Photosystem II

Fabrice Rappaport ^*, Aude Cuni ^*, Ling Xiong , Richard Sayre  and Jérôme Lavergne 

^* Institut de Biologie Physico-Chimique, Centre National de la Recherche Scientifique UPR 1261, Paris, France; Department of Plant Cellular and Molecular Biology, Ohio State University, Columbus, Ohio; and UMR 6191 Centre National de la Recherche Scientifique, Commissariat à l'Energie Atomique, Aix Marseille II, Saint Paul lez Durance, France

Correspondence: Address reprint requests to Jérôme Lavergne, Tel.: 33-0-4-42-25-4580; Fax: 33-0-4-42-25-47-01; E-mail: jerome.lavergne{at}cea.fr.

In the recombination process of Photosystem II the limiting step is the electron transfer from the reduced primary acceptor pheophytin Ph^– to the oxidized primary donor P⁺ and the rate depends on the equilibrium constant between states and Accordingly, mutations that affect the midpoint potential of Ph or of P result in a modified recombination rate. A strong correlation is observed between the effects on the recombination rate and on thermoluminescence (TL, the light emission from during a warming ramp): a slower recombination corresponds to a large enhancement and higher temperature of the TL peak. The current theory of TL does not account for these effects, because it is based on the assumption that the rate-limiting step coincides with the radiative process. When implementing the known fact that the radiative pathway represents a minor leak, the modified TL theory readily accounts qualitatively for the observed behavior. However, the peak temperature is still lower than predicted from the temperature-dependence of recombination. We argue that this reflects the heterogeneity of the recombination process combined with the enhanced sensitivity of TL to slower components. The recombination kinetics are accurately fitted as a sum of two exponentials and we show that this is not due to a progressive stabilization of the charge-separated state, but to a pre-existing conformational heterogeneity.

This article has been cited by other articles:

				N. Ishida, M. Sugiura, F. Rappaport, T.-L. Lai, A. W. Rutherford, and A. Boussac Biosynthetic Exchange of Bromide for Chloride and Strontium for Calcium in the Photosystem II Oxygen-evolving Enzymes J. Biol. Chem., May 9, 2008; 283(19): 13330 - 13340. [Abstract] [Full Text] [PDF]