The role of exciton delocalization in the major photosynthetic light-harvesting antenna of plants

Show simple item record Ramanan, Charusheela Gruber, J. Michael Maly, Pavel Negretti, Marco Novoderezhkin, Vladimir Kruger, T.P.J. (Tjaart) Man cal, Tomas Croce, Roberta Van Grondelle, Rienk 2016-02-12T10:17:26Z 2015-03
dc.description.abstract In the major peripheral plant light-harvesting complex LHCII, excitation energy is transferred between chlorophylls along an energetic cascade before it is transmitted further into the photosynthetic assembly to be converted into chemical energy. The efficiency of these energy transfer processes involves a complicated interplay of pigment-protein structural reorganization and protein dynamic disorder, and the system must stay robust within the fluctuating protein environment. The final, lowest energy site has been proposed to exist within a trimeric excitonically coupled chlorophyll (Chl) cluster, comprising Chls a610-a611-a612. We studied an LHCII monomer with a site-specific mutation resulting in the loss of Chls a611and a612, and find that this mutant exhibits two predominant overlapping fluorescence bands. From a combination of bulk measurements, single-molecule fluorescence characterization, and modeling, we propose the two fluorescence bands originate from differing conditions of exciton delocalization and localization realized in the mutant. Disruption of the excitonically coupled terminal emitter Chl trimer results in an increased sensitivity of the excited state energy landscape to the disorder induced by the protein conformations. Consequently, the mutant demonstrates a loss of energy transfer efficiency. On the contrary, in the wildtype complex, the strong resonance coupling and correspondingly high degree of excitation delocalization within the Chls a610- a611-a612 cluster dampens the influence of the environment and ensures optimal communication with neighboring pigments. These results indicate that the terminal emitter trimer is thus an essential design principle for maintaining the efficient light-harvesting function of LHCII in the presence of protein disorder. en_ZA
dc.description.embargo 2016-03-31
dc.description.librarian hb2015 en_ZA
dc.description.sponsorship VU University and by an Advanced Investigator grant from the European Research Council (No. 267333, PHOTPROT). Nederlandse Organisatie voor Wetenschappelijk Onderzoek, Council of Chemical Sciences (NWO-CW) via a TOP-grant (700.58.305), and by the EU FP7 project PAPETS (GA 323901). Netherlands Royal Academy of Sciences (KNAW).Earth and Life Sciences Council of the NWO (NWO-ALW).Consolidator Investigator grant from the European Research Council (No. 281341 ASAP).Czech Science Foundation (GACR, No. 14-25752S) and an NWO visitor grant 040.11.423 and grant 040.11.428. en_ZA
dc.description.uri http://www.cell.combiophysj en_ZA
dc.identifier.citation Ramanan, C, Gruber, JM, Malý, P, Negretti, M, Novoderezhkin, V, Krüger, TPJ, Mančal, T, Croce, R & Van Grondelle, R 2015, 'The role of exciton delocalization in the major photosynthetic light-harvesting antenna of plants', Biophysical Journal, vol. 108, no. 5, pp. 1047-1056. en_ZA
dc.identifier.issn 0006-3495 (print)
dc.identifier.issn 1542-0086 (online)
dc.identifier.other 10.1016/j.bpj.2015.01.019
dc.language.iso en en_ZA
dc.publisher Biophysical Society en_ZA
dc.rights © 2015 by the Biophysical Society en_ZA
dc.subject Photosynthetic en_ZA
dc.subject Light-harvesting en_ZA
dc.subject Antenna of plants en_ZA
dc.subject Exciton delocalization en_ZA
dc.title The role of exciton delocalization in the major photosynthetic light-harvesting antenna of plants en_ZA
dc.type Postprint Article en_ZA

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