title: Monte Carlo simulations of excitation and electron transfer in grana membranes.
abstract: Time-resolved fluorescence measurements on grana membranes with instrumental response function of 3 ps reveal faster excitation dynamics (120 ps) than those reported previously. A possible reason for the faster decay may be a relatively low amount of "extra" LHCII trimers per reaction center of Photosystem II. Monte Carlo modeling of excitation dynamics in C2S2M2 form of PSII-LHCII supercomplexes has been performed using a coarse grained model of this complex, constituting a large majority of proteins in grana membranes. The main factor responsible for the fast fluorescence decay reported in this work was the deep trap constituted by the primary charge separated state in the reaction center (950-1090 cm(-1)). This value is critical for a good fit, whereas typical hopping times between antenna polypeptides (from ~4.5 to ~10.5 ps) and reversible primary charge separation times (from ~4 to ~1.5 ps, respectively) are less critical. Consequently, respective mean migration times of excitation from anywhere in the PSII-LHCII supercomplexes to reaction center range from ~30 to ~80 ps. Thus 1/4-2/3 of the ~120-ps average excitation lifetime is necessary for the diffusion of excitation to reaction center, whereas the remaining time is due to the bottle-neck effect of the trap. Removal of 27% of the Lhcb6 apoprotein pool by mutagenesis of DEG5 gene caused the acceleration of the excitation decay from ~120 to ~100 ps. This effect may be due to the detachment of LHCII-M trimers from PSII-LHCII supercomplexes, accompanied by deepening of the reaction center trap.
authors.affiliation: Department of Molecular Biophysics, Faculty of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań, Poland. Electronic address: krzyszgi@amu.edu.pl.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Gibasiewicz
authors.affiliation: Department of Plant Physiology, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, ul. Umultowska 89, 61-614 Poznań, Poland.
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Adamiec
authors.affiliation: Department of Plant Physiology, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, ul. Umultowska 89, 61-614 Poznań, Poland.
authors.forename: Robert
authors.initials: R
authors.lastname: Luciński
authors.affiliation: Department of Molecular Biophysics, Faculty of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań, Poland.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Giera
authors.affiliation: Department of Molecular Biophysics, Faculty of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań, Poland.
authors.forename: Przemysław
authors.initials: P
authors.lastname: Chełminiak
authors.affiliation: Department of Molecular Biophysics, Faculty of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań, Poland.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Szewczyk
authors.affiliation: Department of Molecular Biophysics, Faculty of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań, Poland.
authors.forename: Weronika
authors.initials: W
authors.lastname: Sipińska
authors.affiliation: Department of Molecular Biophysics, Faculty of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań, Poland.
authors.forename: Edyta
authors.initials: E
authors.lastname: Głów
authors.affiliation: Department of Molecular Biophysics, Faculty of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań, Poland; Ultrafast Laser Spectroscopy Center, Faculty of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań, Poland.
authors.forename: Jerzy
authors.initials: J
authors.lastname: Karolczak
authors.affiliation: Department of Physics and Astronomy, VU University, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands.
authors.forename: Rienk
authors.initials: R
authors.lastname: van Grondelle
authors.affiliation: Department of Plant Physiology, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, ul. Umultowska 89, 61-614 Poznań, Poland.
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Jackowski
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D061146:Chlorophyll Binding Proteins / Q000378:metabolism; D003198:Computer Simulation; D004579:Electron Transport; D004735:Energy Transfer; D007700:Kinetics; D045342:Light-Harvesting Protein Complexes / Q000378:metabolism*; D008954:Models, Biological; D009010:Monte Carlo Method; D009154:Mutation; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism*; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D020524:Thylakoids / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D061146:Chlorophyll Binding Proteins; C529795:Lhcb6 protein, Arabidopsis; D045342:Light-Harvesting Protein Complexes; D045332:Photosystem II Protein Complex; C436319:SPPA protein, Arabidopsis; D012697:Serine Endopeptidases
keywords: Electron transfer; Excitation energy transfer; Light Harvesting Complex II; Monte Carlo simulation; Photosystem II; Streak camera