title: Excitation migration in fluctuating light-harvesting antenna systems.
abstract: Complex multi-exponential fluorescence decay kinetics observed in various photosynthetic systems like photosystem II (PSII) have often been explained by the reversible quenching mechanism of the charge separation taking place in the reaction center (RC) of PSII. However, this description does not account for the intrinsic dynamic disorder of the light-harvesting proteins as well as their fluctuating dislocations within the antenna, which also facilitate the repair of RCs, state transitions, and the process of non-photochemical quenching. Since dynamic fluctuations result in varying connectivity between pigment-protein complexes, they can also lead to non-exponential excitation decay kinetics. Based on this presumption, we have recently proposed a simple conceptual model describing excitation diffusion in a continuous medium and accounting for possible variations of the excitation transfer pathways. In the current work, this model is further developed and then applied to describe fluorescence kinetics originating from very diverse antenna systems, ranging from PSII of various sizes to LHCII aggregates and even the entire thylakoid membrane. In all cases, complex multi-exponential fluorescence kinetics are perfectly reproduced on the entire relevant time scale without assuming any radical pair equilibration at the side of the excitation quencher, but using just a few parameters reflecting the mean excitation energy transfer rate as well as the overall average organization of the photosynthetic antenna.
authors.affiliation: Department of Theoretical Physics, Faculty of Physics, Vilnius University, Saulėtekio Ave. 9, 10222, Vilnius, Lithuania.|Institute of Physics, Center for Physical Sciences and Technology, Gostauto 11, 01108, Vilnius, Lithuania.
authors.forename: Jevgenij
authors.initials: J
authors.lastname: Chmeliov
authors.affiliation: Department of Theoretical Physics, Faculty of Physics, Vilnius University, Saulėtekio Ave. 9, 10222, Vilnius, Lithuania.|Institute of Physics, Center for Physical Sciences and Technology, Gostauto 11, 01108, Vilnius, Lithuania.
authors.forename: Gediminas
authors.initials: G
authors.lastname: Trinkunas
authors.affiliation: Laboratory of Biophysics, Wageningen University, P.O. Box 8128, 6700, Wageningen, The Netherlands.
authors.forename: Herbert
authors.initials: H
authors.lastname: van Amerongen
authors.affiliation: Department of Theoretical Physics, Faculty of Physics, Vilnius University, Saulėtekio Ave. 9, 10222, Vilnius, Lithuania. leonas.valkunas@ff.vu.lt.|Institute of Physics, Center for Physical Sciences and Technology, Gostauto 11, 01108, Vilnius, Lithuania. leonas.valkunas@ff.vu.lt.
authors.forename: Leonas
authors.initials: L
authors.lastname: Valkunas
mesh_terms: D004735:Energy Transfer; D005453:Fluorescence; D007700:Kinetics; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry / Q000378:metabolism*; D008954:Models, Biological; D045332:Photosystem II Protein Complex / Q000737:chemistry / Q000378:metabolism; D020524:Thylakoids / Q000737:chemistry / Q000378:metabolism
chemical_list: D045342:Light-Harvesting Protein Complexes; D045332:Photosystem II Protein Complex
keywords: Diffusion; Fluctuating antenna; Light-harvesting complex; Photosystem II; Thylakoids