PsbS enhances nonphotochemical fluorescence quenching in the absence of zeaxanthin

Crouchman, Sophie; Ruban, Alexander; Horton, Peter

doi:10.1016/j.febslet.2006.03.005

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Volume 580, Issue 8 , Pages 2053-2058, 3 April 2006

PsbS enhances nonphotochemical fluorescence quenching in the absence of zeaxanthin

Edited by Peter Brzezinski

Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK

Received 9 February 2006; received in revised form 28 February 2006; accepted 2 March 2006. published online 09 March 2006.

Abstract

Leaves and chloroplasts from Arabidopsis plants with increased amounts of PsbS protein showed the same percentage increase in nonphotochemical quenching in comparison to the wild type both in the presence and absence of zeaxanthin. The absorption change at 525–535nm was also more pronounced in both cases. It is suggested that PsbS alone can cause the quenching, supporting the model in which zeaxanthin acts as an allosteric activator and is not the primary cause of the process. It is proposed that PsbS acts as a trigger of the conformational change that leads to the establishment of nonphotochemical quenching.