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van Stokkum IHM, Müller MG, Holzwarth AR. Energy Transfer and Radical-Pair Dynamics in Photosystem I with Different Red Chlorophyll a Pigments. Int J Mol Sci 2024; 25:4125. [PMID: 38612934 PMCID: PMC11012434 DOI: 10.3390/ijms25074125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 04/03/2024] [Accepted: 04/06/2024] [Indexed: 04/14/2024] Open
Abstract
We establish a general kinetic scheme for the energy transfer and radical-pair dynamics in photosystem I (PSI) of Chlamydomonas reinhardtii, Synechocystis PCC6803, Thermosynechococcus elongatus and Spirulina platensis grown under white-light conditions. With the help of simultaneous target analysis of transient-absorption data sets measured with two selective excitations, we resolved the spectral and kinetic properties of the different species present in PSI. WL-PSI can be described as a Bulk Chl a in equilibrium with a higher-energy Chl a, one or two Red Chl a and a reaction-center compartment (WL-RC). Three radical pairs (RPs) have been resolved with very similar properties in the four model organisms. The charge separation is virtually irreversible with a rate of ≈900 ns-1. The second rate, of RP1 → RP2, ranges from 70-90 ns-1 and the third rate, of RP2 → RP3, is ≈30 ns-1. Since RP1 and the Red Chl a are simultaneously present, resolving the RP1 properties is challenging. In Chlamydomonas reinhardtii, the excited WL-RC and Bulk Chl a compartments equilibrate with a lifetime of ≈0.28 ps, whereas the Red and the Bulk Chl a compartments equilibrate with a lifetime of ≈2.65 ps. We present a description of the thermodynamic properties of the model organisms at room temperature.
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Affiliation(s)
- Ivo H. M. van Stokkum
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands;
| | - Marc G. Müller
- Max-Planck-Institut für Chemische Energiekonversion, D-45470 Mülheim a.d. Ruhr, Germany;
| | - Alfred R. Holzwarth
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands;
- Max-Planck-Institut für Chemische Energiekonversion, D-45470 Mülheim a.d. Ruhr, Germany;
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2
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van Stokkum IH, Müller MG, Weißenborn J, Weigand S, Snellenburg JJ, Holzwarth AR. Energy transfer and trapping in photosystem I with and without chlorophyll- f. iScience 2023; 26:107650. [PMID: 37680463 PMCID: PMC10480676 DOI: 10.1016/j.isci.2023.107650] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 06/14/2023] [Accepted: 08/11/2023] [Indexed: 09/09/2023] Open
Abstract
We establish a general kinetic scheme for energy transfer and trapping in the photosystem I (PSI) of cyanobacteria grown under white light (WL) or far-red light (FRL) conditions. With the help of simultaneous target analysis of all emission and transient absorption datasets measured in five cyanobacterial strains, we resolved the spectral and kinetic properties of the different species present in PSI. WL-PSI can be described by Bulk Chl a, two Red Chl a, and a reaction center compartment (WL-RC). The FRL-PSI contains two additional Chl f compartments. The lowest excited state of the FRL-RC is downshifted by ≈ 29 nm. The rate of charge separation drops from ≈900 ns-1 in WL-RC to ≈300 ns-1 in FRL-RC. The delayed trapping in the FRL-PSI (≈130 ps) is explained by uphill energy transfer from the Chl f compartments with Gibbs free energies of ≈kBT below that of the FRL-RC.
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Affiliation(s)
- Ivo H.M. van Stokkum
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, Amsterdam 1081 HV, the Netherlands
| | - Marc G. Müller
- Max-Planck-Institut für chemische Energiekonversion, 45470 Mülheim a.d. Ruhr, Germany
| | - Jörn Weißenborn
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, Amsterdam 1081 HV, the Netherlands
| | - Sebastian Weigand
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, Amsterdam 1081 HV, the Netherlands
| | - Joris J. Snellenburg
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, Amsterdam 1081 HV, the Netherlands
| | - Alfred R. Holzwarth
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, Amsterdam 1081 HV, the Netherlands
- Max-Planck-Institut für chemische Energiekonversion, 45470 Mülheim a.d. Ruhr, Germany
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3
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Russo M, Casazza AP, Cerullo G, Santabarbara S, Maiuri M. Direct Evidence for Excitation Energy Transfer Limitations Imposed by Low-Energy Chlorophylls in Photosystem I-Light Harvesting Complex I of Land Plants. J Phys Chem B 2021; 125:3566-3573. [PMID: 33788560 PMCID: PMC8154617 DOI: 10.1021/acs.jpcb.1c01498] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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The overall efficiency
of photosynthetic energy conversion depends
both on photochemical and excitation energy transfer processes from
extended light-harvesting antenna networks. Understanding the trade-offs
between increase in the antenna cross section and bandwidth and photochemical
conversion efficiency is of central importance both from a biological
perspective and for the design of biomimetic artificial photosynthetic
complexes. Here, we employ two-dimensional electronic spectroscopy
to spectrally resolve the excitation energy transfer dynamics and
directly correlate them with the initial site of excitation in photosystem
I–light harvesting complex I (PSI-LHCI) supercomplex of land
plants, which has both a large antenna dimension and a wide optical
bandwidth extending to energies lower than the peak of the reaction
center chlorophylls. Upon preferential excitation of the low-energy
chlorophylls (red forms), the average relaxation time in the bulk
supercomplex increases by a factor of 2–3 with respect to unselective
excitation at higher photon energies. This slowdown is interpreted
in terms of an excitation energy transfer limitation from low-energy
chlorophyll forms in the PSI-LHCI. These results aid in defining the
optimum balance between the extension of the antenna bandwidth to
the near-infrared region, which increases light-harvesting capacity,
and high photoconversion quantum efficiency.
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Affiliation(s)
- Mattia Russo
- Istituto di Fotonica e Nanotecnologie del Consiglio Nazionale delle Ricerche, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Anna Paola Casazza
- Istituto di Biologia e Biotecnologia Agraria, Consiglio Nazionale delle Ricerche, Via Bassini 15a, 20133 Milano, Italy
| | - Giulio Cerullo
- Istituto di Fotonica e Nanotecnologie del Consiglio Nazionale delle Ricerche, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Stefano Santabarbara
- Photosynthesis Research Unit, Centro Studi sulla Biologia Cellulare e Molecolare delle Piante, Consiglio Nazionale delle Ricerche, Via Celoria 26, 20133 Milano, Italy
| | - Margherita Maiuri
- Istituto di Fotonica e Nanotecnologie del Consiglio Nazionale delle Ricerche, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
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4
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Santabarbara S, Tibiletti T, Remelli W, Caffarri S. Kinetics and heterogeneity of energy transfer from light harvesting complex II to photosystem I in the supercomplex isolated from Arabidopsis. Phys Chem Chem Phys 2018; 19:9210-9222. [PMID: 28319223 DOI: 10.1039/c7cp00554g] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
State transitions are a phenomenon that maintains the excitation balance between photosystem II (PSII) and photosystem I (PSI-LHCI) by controlling their relative absorption cross-sections. Under light conditions exciting PSII preferentially, a trimeric LHCII antenna moves from PSII to PSI-LHCI to form the PSI-LHCI-LHCII supercomplex. In this work, the excited state dynamics in the PSI-LHCI and PSI-LHCI-LHCII supercomplexes isolated from Arabidopsis have been investigated by picosecond time-resolved fluorescence spectroscopy. The excited state decays were analysed using two approaches based on either (i) a sum of discrete exponentials or (ii) a continuous distribution of lifetimes. The results indicate that the energy transfer from LHCII to the bulk of the PSI antenna occurs with an average macroscopic transfer rate in the 35-65 ns-1 interval. Yet, the most satisfactory description of the data is obtained when considering a heterogeneous population containing two PSI-LHCI-LHCII supercomplexes characterised by a transfer time of ∼15 and ∼60 ns-1, likely due to the differences in the strength and orientation of LHCII harboured to PSI. Both these values are of the same order of magnitude of those estimated for the average energy transfer rates from the low energy spectral forms of LHCI to the bulk of the PSI antenna (15-40 ns-1), but they are slower than the transfer from the bulk antenna of PSI to the reaction centre (>150 ns-1), implying a relatively small kinetics bottleneck for the energy transfer from LHCII. Nevertheless, the kinetic limitation imposed by excited state diffusion has a negligible impact on the photochemical quantum efficiency of the supercomplex, which remains about 98% in the case of PSI-LHCI.
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Affiliation(s)
- Stefano Santabarbara
- Photosynthesis Research Unit, Centro di Studio per la Biologia Cellulare e Molecolare delle Piante, Via Celoria 26, 20133 Milan, Italy.
| | - Tania Tibiletti
- Aix Marseille Univ, CEA, CNRS UMR7265 BVME, Laboratoire de Génétique et Biophysique des Plantes, Marseille 13009, France
| | - William Remelli
- Photosynthesis Research Unit, Centro di Studio per la Biologia Cellulare e Molecolare delle Piante, Via Celoria 26, 20133 Milan, Italy.
| | - Stefano Caffarri
- Aix Marseille Univ, CEA, CNRS UMR7265 BVME, Laboratoire de Génétique et Biophysique des Plantes, Marseille 13009, France
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5
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Molotokaite E, Remelli W, Casazza AP, Zucchelli G, Polli D, Cerullo G, Santabarbara S. Trapping Dynamics in Photosystem I-Light Harvesting Complex I of Higher Plants Is Governed by the Competition Between Excited State Diffusion from Low Energy States and Photochemical Charge Separation. J Phys Chem B 2017; 121:9816-9830. [DOI: 10.1021/acs.jpcb.7b07064] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Egle Molotokaite
- Centro
Studi sulla Biologia Cellulare e Molecolare delle Piante, CNR, Via Celoria 26, 20133 Milan, Italy
| | - William Remelli
- Centro
Studi sulla Biologia Cellulare e Molecolare delle Piante, CNR, Via Celoria 26, 20133 Milan, Italy
| | - Anna Paola Casazza
- Istituto
di Biologia e Biotecnologia Agraria, Consiglio Nazionale delle Ricerche, Via Bassini 15a, 20133 Milano, Italy
| | - Giuseppe Zucchelli
- Centro
Studi sulla Biologia Cellulare e Molecolare delle Piante, CNR, Via Celoria 26, 20133 Milan, Italy
| | - Dario Polli
- Istituto di Fotonica e Nanotecnologie del CNR, Dipartimento di Fisica, Politecnico di Milano, P.zza Leonardo
da Vinci 32, 20133 Milano, Italy
- Center
for Nano Science and Technology at Polimi, Istituto Italiano di Tecnologia, Via Giovanni Pascoli, 70/3, 20133 Milano, Italy
| | - Giulio Cerullo
- Istituto di Fotonica e Nanotecnologie del CNR, Dipartimento di Fisica, Politecnico di Milano, P.zza Leonardo
da Vinci 32, 20133 Milano, Italy
| | - Stefano Santabarbara
- Centro
Studi sulla Biologia Cellulare e Molecolare delle Piante, CNR, Via Celoria 26, 20133 Milan, Italy
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6
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7
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Caffarri S, Tibiletti T, Jennings RC, Santabarbara S. A comparison between plant photosystem I and photosystem II architecture and functioning. Curr Protein Pept Sci 2015; 15:296-331. [PMID: 24678674 PMCID: PMC4030627 DOI: 10.2174/1389203715666140327102218] [Citation(s) in RCA: 133] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 11/22/2013] [Accepted: 03/16/2014] [Indexed: 01/31/2023]
Abstract
Oxygenic photosynthesis is indispensable both for the development and maintenance of life on earth by converting
light energy into chemical energy and by producing molecular oxygen and consuming carbon dioxide. This latter
process has been responsible for reducing the CO2 from its very high levels in the primitive atmosphere to the present low
levels and thus reducing global temperatures to levels conducive to the development of life. Photosystem I and photosystem
II are the two multi-protein complexes that contain the pigments necessary to harvest photons and use light energy to
catalyse the primary photosynthetic endergonic reactions producing high energy compounds. Both photosystems are
highly organised membrane supercomplexes composed of a core complex, containing the reaction centre where electron
transport is initiated, and of a peripheral antenna system, which is important for light harvesting and photosynthetic activity
regulation. If on the one hand both the chemical reactions catalysed by the two photosystems and their detailed structure
are different, on the other hand they share many similarities. In this review we discuss and compare various aspects of
the organisation, functioning and regulation of plant photosystems by comparing them for similarities and differences as
obtained by structural, biochemical and spectroscopic investigations.
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Affiliation(s)
| | | | | | - Stefano Santabarbara
- Laboratoire de Génétique et de Biophysique des Plantes (LGBP), Aix-Marseille Université, Faculté des Sciences de Luminy, 163 Avenue de Luminy, 13009, Marseille, France.
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8
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Croce R, van Amerongen H. Light-harvesting in photosystem I. PHOTOSYNTHESIS RESEARCH 2013; 116:153-66. [PMID: 23645376 PMCID: PMC3825136 DOI: 10.1007/s11120-013-9838-x] [Citation(s) in RCA: 169] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 04/23/2013] [Indexed: 05/18/2023]
Abstract
This review focuses on the light-harvesting properties of photosystem I (PSI) and its LHCI outer antenna. LHCI consists of different chlorophyll a/b binding proteins called Lhca's, surrounding the core of PSI. In total, the PSI-LHCI complex of higher plants contains 173 chlorophyll molecules, most of which are there to harvest sunlight energy and to transfer the created excitation energy to the reaction center (RC) where it is used for charge separation. The efficiency of the complex is based on the capacity to deliver this energy to the RC as fast as possible, to minimize energy losses. The performance of PSI in this respect is remarkable: on average it takes around 50 ps for the excitation to reach the RC in plants, without being quenched in the meantime. This means that the internal quantum efficiency is close to 100% which makes PSI the most efficient energy converter in nature. In this review, we describe the light-harvesting properties of the complex in relation to protein and pigment organization/composition, and we discuss the important parameters that assure its very high quantum efficiency. Excitation energy transfer and trapping in the core and/or Lhcas, as well as in the supercomplexes PSI-LHCI and PSI-LHCI-LHCII are described in detail with the aim of giving an overview of the functional behavior of these complexes.
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Affiliation(s)
- Roberta Croce
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands,
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9
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Anna JM, Ostroumov EE, Maghlaoui K, Barber J, Scholes GD. Two-Dimensional Electronic Spectroscopy Reveals Ultrafast Downhill Energy Transfer in Photosystem I Trimers of the Cyanobacterium Thermosynechococcus elongatus. J Phys Chem Lett 2012; 3:3677-84. [PMID: 26291095 DOI: 10.1021/jz3018013] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Two-dimensional electronic spectroscopy (2DES) was used to investigate the ultrafast energy-transfer dynamics of trimeric photosystem I of the cyanobacterium Thermosynechococcus elongatus. We demonstrate the ability of 2DES to resolve dynamics in a large pigment-protein complex containing ∼300 chromophores with both high frequency and time resolution. Monitoring the waiting-time-dependent changes of the line shape of the inhomogeneously broadened Qy(0-0) transition, we directly observe downhill energy equilibration on the 50 fs time scale.
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Affiliation(s)
- Jessica M Anna
- †Department of Chemistry, Institute for Optical Sciences and Centre for Quantum Information and Quantum Control, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6, Canada
| | - Evgeny E Ostroumov
- †Department of Chemistry, Institute for Optical Sciences and Centre for Quantum Information and Quantum Control, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6, Canada
| | - Karim Maghlaoui
- ‡Division of Molecular Bioscience, Department of Life Sciences, Imperial College London, Sir Ernst Chain Building - Wolfson Laboratories, South Kensington Campus, London, SW7 2AZ, United Kingdom
| | - James Barber
- ‡Division of Molecular Bioscience, Department of Life Sciences, Imperial College London, Sir Ernst Chain Building - Wolfson Laboratories, South Kensington Campus, London, SW7 2AZ, United Kingdom
| | - Gregory D Scholes
- †Department of Chemistry, Institute for Optical Sciences and Centre for Quantum Information and Quantum Control, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6, Canada
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10
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11
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Effect of the P700 pre-oxidation and point mutations near A(0) on the reversibility of the primary charge separation in Photosystem I from Chlamydomonas reinhardtii. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1797:106-12. [PMID: 19761751 DOI: 10.1016/j.bbabio.2009.09.006] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 07/31/2009] [Accepted: 09/09/2009] [Indexed: 11/22/2022]
Abstract
Time-resolved fluorescence studies with a 3-ps temporal resolution were performed in order to: (1) test the recent model of the reversible primary charge separation in Photosystem I (Müller et al., 2003; Holwzwarth et al., 2005, 2006), and (2) to reconcile this model with a mechanism of excitation energy quenching by closed Photosystem I (with P700 pre-oxidized to P700+). For these purposes, we performed experiments using Photosystem I core samples isolated from Chlamydomonas reinhardtii wild type, and two mutants in which the methionine axial ligand to primary electron acceptor, A(0), has been change to either histidine or serine. The temporal evolution of fluorescence spectra was recorded for each preparation under conditions where the "primary electron donor," P700, was either neutral or chemically pre-oxidized to P700+. For all the preparations under study, and under neutral and oxidizing conditions, we observed multiexponential fluorescence decay with the major phases of approximately 7 ps and approximately 25 ps. The relative amplitudes and, to a minor extent the lifetimes, of these two phases were modulated by the redox state of P700 and by the mutations near A(0): both pre-oxidation of P700 and mutations caused slight deceleration of the excited state decay. These results are consistent with a model in which P700 is not the primary electron donor, but rather a secondary electron donor, with the primary charge separation event occurring between the accessory chlorophyll, A, and A(0). We assign the faster phase to the equilibration process between the excited state of the antenna/reaction center ensemble and the primary radical pair, and the slower phase to the secondary electron transfer reaction. The pre-oxidation of P700 shifts the equilibrium between the excited state and the primary radical pair towards the excited state. This shift is proposed to be induced by the presence of the positive charge on P700+. The same charge is proposed to be responsible for the fast A+A(0)(-)-->AA(0) charge recombination to the ground state and, in consequence, excitation quenching in closed reaction centers. Mutations of the A(0) axial ligand shift the equilibrium in the same direction as pre-oxidation of P700 due to the up-shift of the free energy level of the state A+A(0)(-).
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12
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Abramavicius D, Mukamel S. Exciton delocalization and transport in photosystem I of cyanobacteria Synechococcus elongates: simulation study of coherent two-dimensional optical signals. J Phys Chem B 2009; 113:6097-108. [PMID: 19351124 PMCID: PMC2905166 DOI: 10.1021/jp811339p] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Electronic excitations and the optical properties of the photosynthetic complex PSI are analyzed using an effective exciton model developed by Vaitekonis et al. [Photosynth. Res. 2005, 86, 185]. States of the reaction center, the linker states, the highly delocalized antenna states and the red states are identified and assigned in absorption and circular dichroism spectra by taking into account the spectral distribution of density of exciton states, exciton delocalization length, and participation ratio in the reaction center. Signatures of exciton cooperative dynamics in nonchiral and chirality-induced two-dimensional (2D) photon-echo signals are identified. Nonchiral signals show resonances associated with the red, the reaction center, and the bulk antenna states as well as transport between them. Spectrally overlapping contributions of the linker and the delocalized antenna states are clearly resolved in the chirality-induced signals. Strong correlations are observed between the delocalized antenna states, the linker states, and the RC states. The active space of the complex covering the RC, the linker, and the delocalized antenna states is common to PSI complexes in bacteria and plants.
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Affiliation(s)
- Darius Abramavicius
- Chemistry Department, University of California Irvine, California 92697-2025, USA.
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13
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Jensen PE, Bassi R, Boekema EJ, Dekker JP, Jansson S, Leister D, Robinson C, Scheller HV. Structure, function and regulation of plant photosystem I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2007; 1767:335-52. [PMID: 17442259 DOI: 10.1016/j.bbabio.2007.03.004] [Citation(s) in RCA: 168] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2007] [Revised: 03/03/2007] [Accepted: 03/06/2007] [Indexed: 12/20/2022]
Abstract
Photosystem I (PSI) is a multisubunit protein complex located in the thylakoid membranes of green plants and algae, where it initiates one of the first steps of solar energy conversion by light-driven electron transport. In this review, we discuss recent progress on several topics related to the functioning of the PSI complex, like the protein composition of the complex in the plant Arabidopsis thaliana, the function of these subunits and the mechanism by which nuclear-encoded subunits can be inserted into or transported through the thylakoid membrane. Furthermore, the structure of the native PSI complex in several oxygenic photosynthetic organisms and the role of the chlorophylls and carotenoids in the antenna complexes in light harvesting and photoprotection are reviewed. The special role of the 'red' chlorophylls (chlorophyll molecules that absorb at longer wavelength than the primary electron donor P700) is assessed. The physiology and mechanism of the association of the major light-harvesting complex of photosystem II (LHCII) with PSI during short term adaptation to changes in light quality and quantity is discussed in functional and structural terms. The mechanism of excitation energy transfer between the chlorophylls and the mechanism of primary charge separation is outlined and discussed. Finally, a number of regulatory processes like acclimatory responses and retrograde signalling is reviewed with respect to function of the thylakoid membrane. We finish this review by shortly discussing the perspectives for future research on PSI.
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Affiliation(s)
- Poul Erik Jensen
- Plant Biochemistry Laboratory, Department of Plant Biology, Faculty of Life Science, University of Copenhagen, DK-1871 Frederiksberg C, Denmark.
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14
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Sener MK, Park S, Lu D, Damjanovic A, Ritz T, Fromme P, Schulten K. Excitation migration in trimeric cyanobacterial photosystem I. J Chem Phys 2006; 120:11183-95. [PMID: 15268148 DOI: 10.1063/1.1739400] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A structure-based description of excitation migration in multireaction center light harvesting systems is introduced. The description is an extension of the sojourn expansion, which decomposes excitation migration in terms of repeated detrapping and recapture events. The approach is applied to light harvesting in the trimeric form of cyanobacterial photosystem I (PSI). Excitation is found to be shared between PSI monomers and the chlorophylls providing the strongest respective links are identified. Excitation sharing is investigated by computing cross-monomer excitation trapping probabilities. It is seen that on the average there is a nearly 40% chance of excitation cross transfer and trapping, indicating efficient coupling between monomers. The robustness and optimality of the chlorophyll network of trimeric PSI is examined.
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Affiliation(s)
- Melih K Sener
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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15
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Vaitekonis S, Trinkunas G, Valkunas L. Red chlorophylls in the exciton model of photosystem I. PHOTOSYNTHESIS RESEARCH 2005; 86:185-201. [PMID: 16172938 DOI: 10.1007/s11120-005-2747-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2004] [Accepted: 02/21/2005] [Indexed: 05/04/2023]
Abstract
Structural arrangement of pigment molecules of Photosystem I of photosynthetic cyanobacterium Synechococcus elongatus is used for theoretical modeling of the excitation energy spectrum. It is demonstrated that a straightforward application of the exciton theory with the assumption of the same molecular transition energy does not describe the red side of the absorption spectrum. Since the inhomogeneity in the molecular transition energies caused by a dispersive interaction with the molecular surrounding cannot be identified directly from the structural model, the evolutionary search procedure is used for fitting the low temperature absorption and circular dichroism spectra. As a result, one dimer, three trimers and one tetramer of chlorophyll molecules responsible for the red side of the absorption spectrum with their assignment to the spectroscopically established three bands at 708, 714 and 719 nm are determined. All of them are found to be situated not in the very close vicinity of the reaction center but are encircling it almost at the same distance. In order to explain the unusual broadening on the red side of the spectrum the exciton state mixing with the charge transfer (CT) states is considered. It is shown that two effects can be distinguished as caused by mixing of those states: (i) the oscillator strength borrowing by the CT state from the exciton transition and (ii) the borrowing of the high density of the CT state by the exciton state. The intermolecular vibrations between two counter-charged molecules determine the high density in the CT state. From the broad red absorption wing it is concluded that the CT state should be the lowest state in the complexes under consideration. Such mixing effect enables resolving the diversity in the molecular transition energies as determined by different theoretical approaches.
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16
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Andrizhiyevskaya EG, Frolov D, Van Grondelle R, Dekker JP. Energy transfer and trapping in the Photosystem I complex of Synechococcus PCC 7942 and in its supercomplex with IsiA. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2004; 1656:104-13. [PMID: 15178472 DOI: 10.1016/j.bbabio.2004.02.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2003] [Revised: 02/03/2004] [Accepted: 02/04/2004] [Indexed: 11/28/2022]
Abstract
The cyanobacterium Synechococcus PCC 7942 grown under iron starvation assembles a supercomplex consisting of a trimeric Photosystem I (PSI) complex encircled by a ring of 18 CP43' or IsiA complexes. It has previously been shown that PSI of Synechococcus PCC 7942 contains less special long-wavelength ('red') chlorophylls than PSI of most other cyanobacteria. Here we present a comparative analysis by time-resolved absorption difference and fluorescence spectroscopy of the processes of energy transfer and trapping in trimeric PSI and PSI-IsiA supercomplexes from Synechococcus PCC 7942. All experiments were performed with the primary electron donor of PSI (P700) in the oxidized state. Our data suggest that in the PSI complex the excitation energy is equilibrated with a lifetime of 0.6 ps among the so-called bulk chlorophylls, is distributed in 3-4 ps between the bulk and red chlorophylls, and is trapped in the reaction center in 19 ps. This trapping time is shorter than that observed for other cyanobacteria, which we attribute to the lower content of red chlorophylls in PSI of this organism. In the PSI-IsiA supercomplexes, the distribution of excited states is blue-shifted compared to that in PSI, leading to a lengthening of the equilibration processes. We attributed a phase of about 1 ps to initial energy equilibration steps among the IsiA and PSI core bulk chlorophylls, a 5-7 ps phase to equilibration between bulk and red chlorophylls within the PSI core, and a 38 ps phase to trapping in the reaction center. The data suggest that the excitation energy is equilibrated among the IsiA and PSI core antenna chlorophylls before trapping occurs. Data analysis based on a simple kinetic model revealed an intrinsic rate constant for energy transfer from IsiA to PSI in the range of 2+/-1 ps. Based on this value we suggest the presence of one or more linker chlorophylls between the IsiA and PSI core complexes. These results confirm that IsiA acts as an effective light-harvesting antenna for PSI.
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Affiliation(s)
- Elena G Andrizhiyevskaya
- Faculty of Sciences, Division of Physics and Astronomy, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands.
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Yang M, Damjanović A, Vaswani HM, Fleming GR. Energy transfer in photosystem I of cyanobacteria Synechococcus elongatus: model study with structure-based semi-empirical Hamiltonian and experimental spectral density. Biophys J 2003; 85:140-58. [PMID: 12829471 PMCID: PMC1303072 DOI: 10.1016/s0006-3495(03)74461-0] [Citation(s) in RCA: 133] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2002] [Accepted: 03/07/2003] [Indexed: 10/21/2022] Open
Abstract
We model the energy transfer and trapping kinetics in PSI. Rather than simply applying Förster theory, we develop a new approach to self-consistently describe energy transfer in a complex with heterogeneous couplings. Experimentally determined spectral densities are employed to calculate the energy transfer rates. The absorption spectrum and fluorescence decay time components of the complex at room temperature were reasonably reproduced. The roles of the special chlorophylls (red, linker, and reaction center, respectively) molecules are discussed. A formally exact expression for the trapping time is derived in terms of the intrinsic trapping time, mean first passage time to trap, and detrapping time. The energy transfer mechanism is discussed and the slowest steps of the arrival at the primary electron donor are found to contain two dominant steps: transfer-to-reaction-center, and transfer-to-trap-from-reaction-center. The intrinsic charge transfer time is estimated to be 0.8 approximately 1.7 ps. The optimality with respect to the trapping time of the calculated transition energies and the orientation of Chls is discussed.
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Affiliation(s)
- Mino Yang
- Department of Chemistry, University of California, Berkeley, California, USA
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