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Cherepanov DA, Kurashov V, Gostev FE, Shelaev IV, Zabelin AA, Shen G, Mamedov MD, Aybush A, Shkuropatov AY, Nadtochenko VA, Bryant DA, Golbeck JH, Semenov AY. Femtosecond optical studies of the primary charge separation reactions in far-red photosystem II from Synechococcus sp. PCC 7335. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1865:149044. [PMID: 38588942 DOI: 10.1016/j.bbabio.2024.149044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 01/26/2024] [Accepted: 04/02/2024] [Indexed: 04/10/2024]
Abstract
Primary processes of light energy conversion by Photosystem II (PSII) were studied using femtosecond broadband pump-probe absorption difference spectroscopy. Transient absorption changes of core complexes isolated from the cyanobacterium Synechococcus sp. PCC 7335 grown under far-red light (FRL-PSII) were compared with the canonical Chl a containing spinach PSII core complexes upon excitation into the red edge of the Qy band. Absorption changes of FRL-PSII were monitored at 278 K in the 400-800 nm spectral range on a timescale of 0.1-500 ps upon selective excitation at 740 nm of four chlorophyll (Chl) f molecules in the light harvesting antenna, or of one Chl d molecule at the ChlD1 position in the reaction center (RC) upon pumping at 710 nm. Numerical analysis of absorption changes and assessment of the energy levels of the presumed ion-radical states made it possible to identify PD1+ChlD1- as the predominant primary charge-separated radical pair, the formation of which upon selective excitation of Chl d has an apparent time of ∼1.6 ps. Electron transfer to the secondary acceptor pheophytin PheoD1 has an apparent time of ∼7 ps with a variety of excitation wavelengths. The energy redistribution between Chl a and Chl f in the antenna occurs within 1 ps, whereas the energy migration from Chl f to the RC occurs mostly with lifetimes of 60 and 400 ps. Potentiometric analysis suggests that in canonical PSII, PD1+ChlD1- can be partially formed from the excited (PD1ChlD1)* state.
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Affiliation(s)
- Dmitry A Cherepanov
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Kosygina st., 4, 119991 Moscow, Russia; A.N. Belozersky Institute of Physical-Chemical Biology, Lomonosov Moscow State University, Leninskiye Gory, 1, building 40, 119992 Moscow, Russia.
| | - Vasily Kurashov
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, 16802, USA
| | - Fedor E Gostev
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Kosygina st., 4, 119991 Moscow, Russia
| | - Ivan V Shelaev
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Kosygina st., 4, 119991 Moscow, Russia
| | - Alexey A Zabelin
- Institute of Basic Biological Problems of the Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", 142290 Pushchino, Moscow Region, Russia
| | - Gaozhong Shen
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, 16802, USA
| | - Mahir D Mamedov
- A.N. Belozersky Institute of Physical-Chemical Biology, Lomonosov Moscow State University, Leninskiye Gory, 1, building 40, 119992 Moscow, Russia
| | - Arseny Aybush
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Kosygina st., 4, 119991 Moscow, Russia
| | - Anatoly Ya Shkuropatov
- Institute of Basic Biological Problems of the Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", 142290 Pushchino, Moscow Region, Russia
| | - Victor A Nadtochenko
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Kosygina st., 4, 119991 Moscow, Russia; Chemistry Department, Lomonosov Moscow State University, Leninskiye Gory, 1, 119991 Moscow, Russia
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, 16802, USA
| | - John H Golbeck
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, 16802, USA; Department of Chemistry, The Pennsylvania State University, University Park, 16802, USA
| | - Alexey Yu Semenov
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Kosygina st., 4, 119991 Moscow, Russia; A.N. Belozersky Institute of Physical-Chemical Biology, Lomonosov Moscow State University, Leninskiye Gory, 1, building 40, 119992 Moscow, Russia.
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2
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Pirnia A, Maqdisi R, Mittal S, Sener M, Singharoy A. Perspective on Integrative Simulations of Bioenergetic Domains. J Phys Chem B 2024; 128:3302-3319. [PMID: 38562105 DOI: 10.1021/acs.jpcb.3c07335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Bioenergetic processes in cells, such as photosynthesis or respiration, integrate many time and length scales, which makes the simulation of energy conversion with a mere single level of theory impossible. Just like the myriad of experimental techniques required to examine each level of organization, an array of overlapping computational techniques is necessary to model energy conversion. Here, a perspective is presented on recent efforts for modeling bioenergetic phenomena with a focus on molecular dynamics simulations and its variants as a primary method. An overview of the various classical, quantum mechanical, enhanced sampling, coarse-grained, Brownian dynamics, and Monte Carlo methods is presented. Example applications discussed include multiscale simulations of membrane-wide electron transport, rate kinetics of ATP turnover from electrochemical gradients, and finally, integrative modeling of the chromatophore, a photosynthetic pseudo-organelle.
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Affiliation(s)
- Adam Pirnia
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1004, United States
| | - Ranel Maqdisi
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1004, United States
| | - Sumit Mittal
- VIT Bhopal University, Sehore 466114, Madhya Pradesh, India
| | - Melih Sener
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1004, United States
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Abhishek Singharoy
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1004, United States
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3
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Jha A, Zhang PP, Tiwari V, Chen L, Thorwart M, Miller RJD, Duan HG. Unraveling quantum coherences mediating primary charge transfer processes in photosystem II reaction center. SCIENCE ADVANCES 2024; 10:eadk1312. [PMID: 38446882 PMCID: PMC10917350 DOI: 10.1126/sciadv.adk1312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 01/31/2024] [Indexed: 03/08/2024]
Abstract
Photosystem II (PSII) reaction center (RC) is a unique complex that is capable of efficiently separating electronic charges across the membrane. The primary energy- and charge-transfer (CT) processes occur on comparable ultrafast timescales, which makes it extremely challenging to understand the fundamental mechanism responsible for the near-unity quantum efficiency of the transfer. Here, we elucidate the role of quantum coherences in the ultrafast energy and CT in the PSII RC by performing two-dimensional (2D) electronic spectroscopy at the cryogenic temperature of 20 kelvin, which captures the distinct underlying quantum coherences. Specifically, we uncover the electronic and vibrational coherences along with their lifetimes during the primary ultrafast processes of energy and CT. We construct an excitonic model that provides evidence for coherent energy and CT at low temperature in the 2D electronic spectra. The principles could provide valuable guidelines for creating artificial photosystems with exploitation of system-bath coupling and control of coherences to optimize the photon conversion efficiency to specific functions.
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Affiliation(s)
- Ajay Jha
- Department of Physics, School of Physical Science and Technology, Ningbo University, Ningbo, 315211, P.R. China
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761, Hamburg, Germany
- Rosalind Franklin Institute, Harwell, Oxfordshire OX11 0QX, UK
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Pan-Pan Zhang
- Department of Physics, School of Physical Science and Technology, Ningbo University, Ningbo, 315211, P.R. China
| | - Vandana Tiwari
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761, Hamburg, Germany
- Department of Chemistry, University of Hamburg, Martin-Luther-King Platz 6, 20146 Hamburg, Germany
| | - Lipeng Chen
- Zhejiang Laboratory, Hangzhou 311100, P.R. China
| | - Michael Thorwart
- I. Institut für Theoretische Physik, Universität Hamburg, Notkestr. 9, 22607 Hamburg, Germany
- The Hamburg Center for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - R. J. Dwayne Miller
- The Departments of Chemistry and Physics, University of Toronto, 80 St. George Street, Toronto, ON M5S 3H6, Canada
| | - Hong-Guang Duan
- Department of Physics, School of Physical Science and Technology, Ningbo University, Ningbo, 315211, P.R. China
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761, Hamburg, Germany
- I. Institut für Theoretische Physik, Universität Hamburg, Notkestr. 9, 22607 Hamburg, Germany
- The Hamburg Center for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
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4
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Pavlou A, Mokvist F, Styring S, Mamedov F. Far-red photosynthesis: Two charge separation pathways exist in plant Photosystem II reaction center. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148994. [PMID: 37355002 DOI: 10.1016/j.bbabio.2023.148994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 06/09/2023] [Accepted: 06/15/2023] [Indexed: 06/26/2023]
Abstract
An alternative charge separation pathway in Photosystem II under the far-red light was proposed by us on the basis of electron transfer properties at 295 K and 5 K. Here we extend these studies to the temperature range of 77-295 K with help of electron paramagnetic resonance spectroscopy. Induction of the S2 state multiline signal, oxidation of Cytochrome b559 and ChlorophyllZ was studied in Photosystem II membrane preparations from spinach after application of a laser flashes in visible (532 nm) or far-red (730-750 nm) spectral regions. Temperature dependence of the S2 state signal induction after single flash at 730-750 nm (Tinhibition ~ 240 K) was found to be different than that at 532 nm (Tinhibition ~ 157 K). No contaminant oxidation of the secondary electron donors cytochrome b559 or chlorophyllZ was observed. Photoaccumulation experiments with extensive flashing at 77 K showed similar results, with no or very little induction of the secondary electron donors. Thus, the partition ratio defined as (yield of YZ/CaMn4O5-cluster oxidation):(yield of Cytb559/ChlZ/CarD2 oxidation) was found to be 0.4 at under visible light and 1.7 at under far-red light at 77 K. Our data indicate that different products of charge separation after far-red light exists in the wide temperature range which further support the model of the different primary photochemistry in Photosystem II with localization of hole on the ChlD1 molecule.
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Affiliation(s)
- Andrea Pavlou
- Molecular Biomimetics, Department of Chemistry-Ångström, Uppsala University, P.O. Box 523, 751 20 Uppsala, Sweden
| | - Fredrik Mokvist
- Molecular Biomimetics, Department of Chemistry-Ångström, Uppsala University, P.O. Box 523, 751 20 Uppsala, Sweden
| | - Stenbjörn Styring
- Molecular Biomimetics, Department of Chemistry-Ångström, Uppsala University, P.O. Box 523, 751 20 Uppsala, Sweden
| | - Fikret Mamedov
- Molecular Biomimetics, Department of Chemistry-Ångström, Uppsala University, P.O. Box 523, 751 20 Uppsala, Sweden.
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5
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Garab G, Magyar M, Sipka G, Lambrev PH. New foundations for the physical mechanism of variable chlorophyll a fluorescence. Quantum efficiency versus the light-adapted state of photosystem II. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:5458-5471. [PMID: 37410874 DOI: 10.1093/jxb/erad252] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 07/03/2023] [Indexed: 07/08/2023]
Abstract
Photosystem II (PSII) uses solar energy to oxidize water and delivers electrons to fix CO2. Although the structure at atomic resolution and the basic photophysical and photochemical functions of PSII are well understood, many important questions remain. The activity of PSII in vitro and in vivo is routinely monitored by recording the induction kinetics of chlorophyll a fluorescence (ChlF). According to the 'mainstream' model, the rise from the minimum level (Fo) to the maximum (Fm) of ChlF of dark-adapted PSII reflects the closure of all functionally active reaction centers, and the Fv/Fm ratio is equated with the maximum photochemical quantum yield of PSII (where Fv=Fm-Fo). However, this model has never been free of controversies. Recent experimental data from a number of studies have confirmed that the first single-turnover saturating flash (STSF), which generates the closed state (PSIIC), produces F1
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Affiliation(s)
- Győző Garab
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
- Department of Physics, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Melinda Magyar
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
| | - Gábor Sipka
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
| | - Petar H Lambrev
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
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6
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Capone M, Sirohiwal A, Aschi M, Pantazis DA, Daidone I. Alternative Fast and Slow Primary Charge-Separation Pathways in Photosystem II. Angew Chem Int Ed Engl 2023; 62:e202216276. [PMID: 36791234 DOI: 10.1002/anie.202216276] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 01/23/2023] [Accepted: 02/13/2023] [Indexed: 02/17/2023]
Abstract
Photosystem-II (PSII) is a multi-subunit protein complex that harvests sunlight to perform oxygenic photosynthesis. Initial light-activated charge separation takes place at a reaction centre consisting of four chlorophylls and two pheophytins. Understanding the processes following light excitation remains elusive due to spectral congestion, the ultrafast nature, and multi-component behaviour of the charge-separation process. Here, using advanced computational multiscale approaches which take into account the large-scale configurational flexibility of the system, we identify two possible primary pathways to radical-pair formation that differ by three orders of magnitude in their kinetics. The fast (short-range) pathway is dominant, but the existence of an alternative slow (long-range) charge-separation pathway hints at the evolution of redundancy that may serve other purposes, adaptive or protective, related to formation of the unique oxidative species that drives water oxidation in PSII.
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Affiliation(s)
- Matteo Capone
- Department of Physical and Chemical Sciences, University of L'Aquila, via Vetoio (Coppito 1), 67010, L'Aquila, Italy
| | - Abhishek Sirohiwal
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany.,Present Address: Department of Biochemistry and Biophysics, Arrhenius Laboratory, Stockholm University, 10691, Stockholm, Sweden
| | - Massimiliano Aschi
- Department of Physical and Chemical Sciences, University of L'Aquila, via Vetoio (Coppito 1), 67010, L'Aquila, Italy
| | - Dimitrios A Pantazis
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Isabella Daidone
- Department of Physical and Chemical Sciences, University of L'Aquila, via Vetoio (Coppito 1), 67010, L'Aquila, Italy
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7
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Yoneda Y, Arsenault EA, Yang SJ, Orcutt K, Iwai M, Fleming GR. The initial charge separation step in oxygenic photosynthesis. Nat Commun 2022; 13:2275. [PMID: 35477708 PMCID: PMC9046298 DOI: 10.1038/s41467-022-29983-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 04/11/2022] [Indexed: 11/09/2022] Open
Abstract
Photosystem II is crucial for life on Earth as it provides oxygen as a result of photoinduced electron transfer and water splitting reactions. The excited state dynamics of the photosystem II-reaction center (PSII-RC) has been a matter of vivid debate because the absorption spectra of the embedded chromophores significantly overlap and hence it is extremely difficult to distinguish transients. Here, we report the two-dimensional electronic-vibrational spectroscopic study of the PSII-RC. The simultaneous resolution along both the visible excitation and infrared detection axis is crucial in allowing for the character of the excitonic states and interplay between them to be clearly distinguished. In particular, this work demonstrates that the mixed exciton-charge transfer state, previously proposed to be responsible for the far-red light operation of photosynthesis, is characterized by the ChlD1+Phe radical pair and can be directly prepared upon photoexcitation. Further, we find that the initial electron acceptor in the PSII-RC is Phe, rather than PD1, regardless of excitation wavelength.
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Affiliation(s)
- Yusuke Yoneda
- Department of Chemistry, University of California, Berkeley, CA, 94720, United States
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, United States
- Research Center of Integrative Molecular Systems, Institute for Molecular Science, National Institute of Natural Sciences, Okazaki, Aichi, 444-8585, Japan
| | - Eric A Arsenault
- Department of Chemistry, University of California, Berkeley, CA, 94720, United States
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, United States
- Kavli Energy Nanoscience Institute at Berkeley, Berkeley, CA, 94720, United States
| | - Shiun-Jr Yang
- Department of Chemistry, University of California, Berkeley, CA, 94720, United States
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, United States
| | - Kaydren Orcutt
- Department of Chemistry, University of California, Berkeley, CA, 94720, United States
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, United States
| | - Masakazu Iwai
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, United States
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, 94720, United States
| | - Graham R Fleming
- Department of Chemistry, University of California, Berkeley, CA, 94720, United States.
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, United States.
- Kavli Energy Nanoscience Institute at Berkeley, Berkeley, CA, 94720, United States.
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8
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Lokstein H, Renger G, Götze JP. Photosynthetic Light-Harvesting (Antenna) Complexes-Structures and Functions. Molecules 2021; 26:molecules26113378. [PMID: 34204994 PMCID: PMC8199901 DOI: 10.3390/molecules26113378] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 05/27/2021] [Accepted: 05/28/2021] [Indexed: 02/07/2023] Open
Abstract
Chlorophylls and bacteriochlorophylls, together with carotenoids, serve, noncovalently bound to specific apoproteins, as principal light-harvesting and energy-transforming pigments in photosynthetic organisms. In recent years, enormous progress has been achieved in the elucidation of structures and functions of light-harvesting (antenna) complexes, photosynthetic reaction centers and even entire photosystems. It is becoming increasingly clear that light-harvesting complexes not only serve to enlarge the absorption cross sections of the respective reaction centers but are vitally important in short- and long-term adaptation of the photosynthetic apparatus and regulation of the energy-transforming processes in response to external and internal conditions. Thus, the wide variety of structural diversity in photosynthetic antenna “designs” becomes conceivable. It is, however, common for LHCs to form trimeric (or multiples thereof) structures. We propose a simple, tentative explanation of the trimer issue, based on the 2D world created by photosynthetic membrane systems.
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Affiliation(s)
- Heiko Lokstein
- Department of Chemical Physics and Optics, Charles University, Ke Karlovu 3, 12116 Prague, Czech Republic
- Correspondence:
| | - Gernot Renger
- Max-Volmer-Laboratorium, Technische Universität Berlin, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Jan P. Götze
- Institut für Chemie und Biochemie, Freie Universität Berlin, Arnimallee 22, D-14195 Berlin, Germany;
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9
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Ueno S, Tanimura Y. Modeling and Simulating the Excited-State Dynamics of a System with Condensed Phases: A Machine Learning Approach. J Chem Theory Comput 2021; 17:3618-3628. [PMID: 33999606 DOI: 10.1021/acs.jctc.1c00104] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Simulating the irreversible quantum dynamics of exciton- and electron-transfer problems poses a nontrivial challenge. Because the irreversibility of the system dynamics is a result of quantum thermal activation and dissipation caused by the surrounding environment, it is necessary to include infinite environmental degrees of freedom in the simulation. Because the capabilities of full quantum dynamics simulations that include the surrounding molecular degrees of freedom are limited, employing a system-bath model is a practical approach. In such a model, the dynamics of excitons or electrons are described by a system Hamiltonian, while the other degrees of freedom that arise from the environmental molecules are described by a harmonic oscillator bath (HOB) and system-bath interaction parameters. By extending on a previous study of molecular liquids [ J. Chem. Theory Comput. 2020, 16, 2099], here, we construct a system-bath model for exciton- and electron-transfer problems by means of a machine learning approach. We determine both the system and system-bath interaction parameters, including the spectral distribution of the bath, using the electronic excitation energies obtained from a quantum mechanics/molecular mechanics (QM/MM) simulation that is conducted as a function of time. Using the analytical expressions of optical response functions, we calculate linear and two-dimensional electronic spectra (2DES) for indocarbocyanine dimers in methanol. From these results, we demonstrate the capability of our approach to elucidate the nonequilibrium exciton dynamics of a quantum system in a nonintuitive manner.
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10
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Tamura H, Saito K, Ishikita H. The origin of unidirectional charge separation in photosynthetic reaction centers: nonadiabatic quantum dynamics of exciton and charge in pigment-protein complexes. Chem Sci 2021; 12:8131-8140. [PMID: 34194703 PMCID: PMC8208306 DOI: 10.1039/d1sc01497h] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 05/03/2021] [Indexed: 11/21/2022] Open
Abstract
Exciton charge separation in photosynthetic reaction centers from purple bacteria (PbRC) and photosystem II (PSII) occurs exclusively along one of the two pseudo-symmetric branches (active branch) of pigment-protein complexes. The microscopic origin of unidirectional charge separation in photosynthesis remains controversial. Here we elucidate the essential factors leading to unidirectional charge separation in PbRC and PSII, using nonadiabatic quantum dynamics calculations in conjunction with time-dependent density functional theory (TDDFT) with the quantum mechanics/molecular mechanics/polarizable continuum model (QM/MM/PCM) method. This approach accounts for energetics, electronic coupling, and vibronic coupling of the pigment excited states under electrostatic interactions and polarization of whole protein environments. The calculated time constants of charge separation along the active branches of PbRC and PSII are similar to those observed in time-resolved spectroscopic experiments. In PbRC, Tyr-M210 near the accessary bacteriochlorophyll reduces the energy of the intermediate state and drastically accelerates charge separation overcoming the electron-hole interaction. Remarkably, even though both the active and inactive branches in PSII can accept excitons from light-harvesting complexes, charge separation in the inactive branch is prevented by a weak electronic coupling due to symmetry-breaking of the chlorophyll configurations. The exciton in the inactive branch in PSII can be transferred to the active branch via direct and indirect pathways. Subsequently, the ultrafast electron transfer to pheophytin in the active branch prevents exciton back transfer to the inactive branch, thereby achieving unidirectional charge separation.
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Affiliation(s)
- Hiroyuki Tamura
- Department of Applied Chemistry, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-8654 Japan
- Research Center for Advanced Science and Technology, The University of Tokyo 4-6-1 Komaba, Meguro-ku Tokyo 153-8904 Japan
| | - Keisuke Saito
- Department of Applied Chemistry, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-8654 Japan
- Research Center for Advanced Science and Technology, The University of Tokyo 4-6-1 Komaba, Meguro-ku Tokyo 153-8904 Japan
| | - Hiroshi Ishikita
- Department of Applied Chemistry, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-8654 Japan
- Research Center for Advanced Science and Technology, The University of Tokyo 4-6-1 Komaba, Meguro-ku Tokyo 153-8904 Japan
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11
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Sirohiwal A, Neese F, Pantazis DA. How Can We Predict Accurate Electrochromic Shifts for Biochromophores? A Case Study on the Photosynthetic Reaction Center. J Chem Theory Comput 2021; 17:1858-1873. [PMID: 33566610 PMCID: PMC8023663 DOI: 10.1021/acs.jctc.0c01152] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Indexed: 01/28/2023]
Abstract
Protein-embedded chromophores are responsible for light harvesting, excitation energy transfer, and charge separation in photosynthesis. A critical part of the photosynthetic apparatus are reaction centers (RCs), which comprise groups of (bacterio)chlorophyll and (bacterio)pheophytin molecules that transform the excitation energy derived from light absorption into charge separation. The lowest excitation energies of individual pigments (site energies) are key for understanding photosynthetic systems, and form a prime target for quantum chemistry. A major theoretical challenge is to accurately describe the electrochromic (Stark) shifts in site energies produced by the inhomogeneous electric field of the protein matrix. Here, we present large-scale quantum mechanics/molecular mechanics calculations of electrochromic shifts for the RC chromophores of photosystem II (PSII) using various quantum chemical methods evaluated against the domain-based local pair natural orbital (DLPNO) implementation of the similarity-transformed equation of motion coupled cluster theory with single and double excitations (STEOM-CCSD). We show that certain range-separated density functionals (ωΒ97, ωΒ97X-V, ωΒ2PLYP, and LC-BLYP) correctly reproduce RC site energy shifts with time-dependent density functional theory (TD-DFT). The popular CAM-B3LYP functional underestimates the shifts and is not recommended. Global hybrid functionals are too insensitive to the environment and should be avoided, while nonhybrid functionals are strictly nonapplicable. Among the applicable approximate coupled cluster methods, the canonical versions of CC2 and ADC(2) were found to deviate significantly from the reference results both for the description of the lowest excited state and for the electrochromic shifts. By contrast, their spin-component-scaled (SCS) and particularly the scale-opposite-spin (SOS) variants compare well with the reference DLPNO-STEOM-CCSD and the best range-separated DFT methods. The emergence of RC excitation asymmetry is discussed in terms of intrinsic and protein electrostatic potentials. In addition, we evaluate a minimal structural scaffold of PSII, the D1-D2-CytB559 RC complex often employed in experimental studies, and show that it would have the same site energy distribution of RC chromophores as the full PSII supercomplex, but only under the unlikely conditions that the core protein organization and cofactor arrangement remain identical to those of the intact enzyme.
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Affiliation(s)
- Abhishek Sirohiwal
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
- Fakultät
für Chemie und Biochemie, Ruhr-Universität
Bochum, 44780 Bochum, Germany
| | - Frank Neese
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Dimitrios A. Pantazis
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
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12
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Sirohiwal A, Neese F, Pantazis DA. Protein Matrix Control of Reaction Center Excitation in Photosystem II. J Am Chem Soc 2020; 142:18174-18190. [PMID: 33034453 PMCID: PMC7582616 DOI: 10.1021/jacs.0c08526] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Indexed: 02/06/2023]
Abstract
Photosystem II (PSII) is a multisubunit pigment-protein complex that uses light-induced charge separation to power oxygenic photosynthesis. Its reaction center chromophores, where the charge transfer cascade is initiated, are arranged symmetrically along the D1 and D2 core polypeptides and comprise four chlorophyll (PD1, PD2, ChlD1, ChlD2) and two pheophytin molecules (PheoD1 and PheoD2). Evolution favored productive electron transfer only via the D1 branch, with the precise nature of primary excitation and the factors that control asymmetric charge transfer remaining under investigation. Here we present a detailed atomistic description for both. We combine large-scale simulations of membrane-embedded PSII with high-level quantum-mechanics/molecular-mechanics (QM/MM) calculations of individual and coupled reaction center chromophores to describe reaction center excited states. We employ both range-separated time-dependent density functional theory and the recently developed domain based local pair natural orbital (DLPNO) implementation of the similarity transformed equation of motion coupled cluster theory with single and double excitations (STEOM-CCSD), the first coupled cluster QM/MM calculations of the reaction center. We find that the protein matrix is exclusively responsible for both transverse (chlorophylls versus pheophytins) and lateral (D1 versus D2 branch) excitation asymmetry, making ChlD1 the chromophore with the lowest site energy. Multipigment calculations show that the protein matrix renders the ChlD1 → PheoD1 charge-transfer the lowest energy excitation globally within the reaction center, lower than any pigment-centered local excitation. Remarkably, no low-energy charge transfer states are located within the "special pair" PD1-PD2, which is therefore excluded as the site of initial charge separation in PSII. Finally, molecular dynamics simulations suggest that modulation of the electrostatic environment due to protein conformational flexibility enables direct excitation of low-lying charge transfer states by far-red light.
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Affiliation(s)
- Abhishek Sirohiwal
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
- Fakultät
für Chemie und Biochemie, Ruhr-Universität
Bochum, 44780 Bochum, Germany
| | - Frank Neese
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Dimitrios A. Pantazis
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
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13
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Nguyen HH, Loukianov AD, Ogilvie JP, Abramavicius D. Two-dimensional electronic Stark spectroscopy of a photosynthetic dimer. J Chem Phys 2020; 153:144203. [PMID: 33086821 DOI: 10.1063/5.0021529] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Stark spectroscopy, which measures changes in the linear absorption of a sample in the presence of an external DC electric field, is a powerful experimental tool for probing the existence of charge-transfer (CT) states in photosynthetic systems. CT states often have small transition dipole moments, making them insensitive to other spectroscopic methods, but are particularly sensitive to Stark spectroscopy due to their large permanent dipole moment. In a previous study, we demonstrated a new experimental method, two-dimensional electronic Stark spectroscopy (2DESS), which combines two-dimensional electronic spectroscopy (2DES) and Stark spectroscopy. In order to understand how the presence of CT states manifest in 2DESS, here, we perform computational modeling and calculations of 2DESS as well as 2DES and Stark spectra, studying a photosynthetic dimer inspired by the photosystem II reaction center. We identify specific cases where qualitatively different sets of system parameters produce similar Stark and 2DES spectra but significantly different 2DESS spectra, showing the potential for 2DESS to aid in identifying CT states and their coupling to excitonic states.
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Affiliation(s)
- Hoang H Nguyen
- Department of Physics, University of Michigan, 450 Church St., Ann Arbor, Michigan 48109, USA
| | - Anton D Loukianov
- Department of Physics, University of Michigan, 450 Church St., Ann Arbor, Michigan 48109, USA
| | - Jennifer P Ogilvie
- Department of Physics, University of Michigan, 450 Church St., Ann Arbor, Michigan 48109, USA
| | - Darius Abramavicius
- Institute of Chemical Physics, Faculty of Physics, Vilnius University, Sauletekio 9-III, 10222 Vilnius, Lithuania
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14
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Gao X, Lai Y, Geva E. Simulating Absorption Spectra of Multiexcitonic Systems via Quasiclassical Mapping Hamiltonian Methods. J Chem Theory Comput 2020; 16:6465-6480. [DOI: 10.1021/acs.jctc.0c00709] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xing Gao
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Yifan Lai
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Eitan Geva
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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15
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Gao X, Geva E. A Nonperturbative Methodology for Simulating Multidimensional Spectra of Multiexcitonic Molecular Systems via Quasiclassical Mapping Hamiltonian Methods. J Chem Theory Comput 2020; 16:6491-6502. [DOI: 10.1021/acs.jctc.0c00843] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xing Gao
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Eitan Geva
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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16
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Kavanagh MA, Karlsson JKG, Colburn JD, Barter LMC, Gould IR. A TDDFT investigation of the Photosystem II reaction center: Insights into the precursors to charge separation. Proc Natl Acad Sci U S A 2020; 117:19705-19712. [PMID: 32747579 PMCID: PMC7443915 DOI: 10.1073/pnas.1922158117] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Photosystem II (PS II) captures solar energy and directs charge separation (CS) across the thylakoid membrane during photosynthesis. The highly oxidizing, charge-separated state generated within its reaction center (RC) drives water oxidation. Spectroscopic studies on PS II RCs are difficult to interpret due to large spectral congestion, necessitating modeling to elucidate key spectral features. Herein, we present results from time-dependent density functional theory (TDDFT) calculations on the largest PS II RC model reported to date. This model explicitly includes six RC chromophores and both the chlorin phytol chains and the amino acid residues <6 Å from the pigments' porphyrin ring centers. Comparing our wild-type model results with calculations on mutant D1-His-198-Ala and D2-His-197-Ala RCs, our simulated absorption-difference spectra reproduce experimentally observed shifts in known chlorophyll absorption bands, demonstrating the predictive capabilities of this model. We find that inclusion of both nearby residues and phytol chains is necessary to reproduce this behavior. Our calculations provide a unique opportunity to observe the molecular orbitals that contribute to the excited states that are precursors to CS. Strikingly, we observe two high oscillator strength, low-lying states, in which molecular orbitals are delocalized over ChlD1 and PheD1 as well as one weaker oscillator strength state with molecular orbitals delocalized over the P chlorophylls. Both these configurations are a match for previously identified exciton-charge transfer states (ChlD1+PheD1-)* and (PD2+PD1-)*. Our results demonstrate the power of TDDFT as a tool, for studies of natural photosynthesis, or indeed future studies of artificial photosynthetic complexes.
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Affiliation(s)
- Maeve A Kavanagh
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, W12 0BZ London, United Kingdom
- Institute of Chemical Biology, Molecular Sciences Research Hub, Imperial College London, W12 0BZ London, United Kingdom
| | - Joshua K G Karlsson
- Molecular Photonics Laboratory, School of Natural and Environmental Sciences, Newcastle University, Newcastle Upon Tyne NE1 7RU, United Kingdom
| | - Jonathan D Colburn
- School of Chemistry, University of St. Andrews, St. Andrews KY16 9ST, Scotland
| | - Laura M C Barter
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, W12 0BZ London, United Kingdom;
- Institute of Chemical Biology, Molecular Sciences Research Hub, Imperial College London, W12 0BZ London, United Kingdom
| | - Ian R Gould
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, W12 0BZ London, United Kingdom;
- Institute of Chemical Biology, Molecular Sciences Research Hub, Imperial College London, W12 0BZ London, United Kingdom
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17
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Asymmetry in Charge Transfer Pathways Caused by Pigment–Protein Interactions in the Photosystem II Reaction Center Complex. Catalysts 2020. [DOI: 10.3390/catal10060718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
This article discusses the photoinduced charge transfer (CT) kinetics within the reaction center complex of photosystem II (PSII RC). The PSII RC exhibits a structural symmetry in its arrangement of pigments forming two prominent branches, D1 and D2. Despite this symmetry, the CT has been observed to occur exclusively in the D1 branch. The mechanism to realize such functional asymmetry is yet to be understood. To approach this matter, we applied the theoretical tight-binding model of pigment excitations and simulated CT dynamics based upon the framework of an open quantum system. This simulation used a recently developed method of computation based on the quasi-adiabatic propagator path integral. A quantum CT state is found to be dynamically active when its site energy is resonant with the exciton energies of the PSII RC, regardless of the excitonic landscape we utilized. Through our investigation, it was found that the relative displacement between the local molecular energy levels of pigments can play a crucial role in realizing this resonance and therefore greatly affects the CT asymmetry in the PSII RC. Using this mechanism phenomenologically, we demonstrate that a near 100-to-1 ratio of reduction between the pheophytins in the D1 and D2 branches can be realized at both 77 K and 300 K. Our results indicate that the chlorophyll Chl D 1 is the most active precursor of the primary charge separation in the D1 branch and that the reduction of the pheophytins can occur within pico-seconds. Additionally, a broad resonance of the active CT state implies that a large static disorder observed in the CT state originates in the fluctuations of the relative displacements between the local molecular energy levels of the pigments in the PSII RC.
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18
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Abstract
Nitrogenase is the only enzyme capable of reducing N2 to NH3. This challenging reaction requires the coordinated transfer of multiple electrons from the reductase, Fe-protein, to the catalytic component, MoFe-protein, in an ATP-dependent fashion. In the last two decades, there have been significant advances in our understanding of how nitrogenase orchestrates electron transfer (ET) from the Fe-protein to the catalytic site of MoFe-protein and how energy from ATP hydrolysis transduces the ET processes. In this review, we summarize these advances, with focus on the structural and thermodynamic redox properties of nitrogenase component proteins and their complexes, as well as on new insights regarding the mechanism of ET reactions during catalysis and how they are coupled to ATP hydrolysis. We also discuss recently developed chemical, photochemical, and electrochemical methods for uncoupling substrate reduction from ATP hydrolysis, which may provide new avenues for studying the catalytic mechanism of nitrogenase.
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Affiliation(s)
- Hannah L Rutledge
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
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19
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Moretti L, Kudisch B, Terazono Y, Moore AL, Moore TA, Gust D, Cerullo G, Scholes GD, Maiuri M. Ultrafast Dynamics of Nonrigid Zinc-Porphyrin Arrays Mimicking the Photosynthetic "Special Pair". J Phys Chem Lett 2020; 11:3443-3450. [PMID: 32290662 DOI: 10.1021/acs.jpclett.0c00856] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Conjugated porphyrin arrays are heavily investigated as efficient molecular systems for photosynthesis and photocatalysis. Recently, a series of one-, two-, and six-zinc-porphyrin arrays, noncovalently linked through benzene-based hubs, have been synthesized with the aim of mimicking the structure and function of the bacteriochlorophyll "special pair" in photosynthetic reaction centers. The excitonically coupled porphyrin subunits are expected to activate additional excited state relaxation channels with respect to the monomer. Here, we unveil the appearance of such supramolecular electronic interactions using ultrafast transient absorption spectroscopy with sub-25 fs time resolution. Upon photoexcitation of the Soret band, we resolve energy trapping within ∼150 fs in a delocalized dark excitonic manifold. Moreover, excitonic interactions promote an additional fast internal conversion from the Q-band to the ground state with an efficiency of up to 60% in the hexamer. These relaxation pathways appear to be common loss channels that limit the lifetime of the exciton states in noncovalently bound molecular aggregates.
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Affiliation(s)
- Luca Moretti
- IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, P.za Leonardo da Vinci 32, 20133 Milan, Italy
- Department of Chemistry, Princeton University, Princeton, New Jersey 08540, United States
| | - Bryan Kudisch
- Department of Chemistry, Princeton University, Princeton, New Jersey 08540, United States
| | - Yuichi Terazono
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
| | - Ana L Moore
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
| | - Thomas A Moore
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
| | - Devens Gust
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
| | - Giulio Cerullo
- IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, P.za Leonardo da Vinci 32, 20133 Milan, Italy
| | - Gregory D Scholes
- Department of Chemistry, Princeton University, Princeton, New Jersey 08540, United States
| | - Margherita Maiuri
- IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, P.za Leonardo da Vinci 32, 20133 Milan, Italy
- Department of Chemistry, Princeton University, Princeton, New Jersey 08540, United States
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20
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Müh F, Zouni A. Structural basis of light-harvesting in the photosystem II core complex. Protein Sci 2020; 29:1090-1119. [PMID: 32067287 PMCID: PMC7184784 DOI: 10.1002/pro.3841] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 02/06/2020] [Accepted: 02/06/2020] [Indexed: 12/20/2022]
Abstract
Photosystem II (PSII) is a membrane-spanning, multi-subunit pigment-protein complex responsible for the oxidation of water and the reduction of plastoquinone in oxygenic photosynthesis. In the present review, the recent explosive increase in available structural information about the PSII core complex based on X-ray crystallography and cryo-electron microscopy is described at a level of detail that is suitable for a future structure-based analysis of light-harvesting processes. This description includes a proposal for a consistent numbering scheme of protein-bound pigment cofactors across species. The structural survey is complemented by an overview of the state of affairs in structure-based modeling of excitation energy transfer in the PSII core complex with emphasis on electrostatic computations, optical properties of the reaction center, the assignment of long-wavelength chlorophylls, and energy trapping mechanisms.
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Affiliation(s)
- Frank Müh
- Department of Theoretical Biophysics, Institute for Theoretical Physics, Johannes Kepler University Linz, Linz, Austria
| | - Athina Zouni
- Humboldt-Universität zu Berlin, Institute for Biology, Biophysics of Photosynthesis, Berlin, Germany
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21
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Taylor N, Kassal I. Why are photosynthetic reaction centres dimeric? Chem Sci 2019; 10:9576-9585. [PMID: 32055331 PMCID: PMC6993572 DOI: 10.1039/c9sc03712h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Accepted: 08/23/2019] [Indexed: 11/21/2022] Open
Abstract
All photosynthetic organisms convert solar energy into chemical energy through charge separation in dimeric reaction centres. It is unknown why early reaction centres dimerised and completely displaced their monomeric ancestors. Here, we discuss several proposed explanations for reaction-centre dimerism and conclude-with only weak assumptions about the primordial dimerisation event-that the most probable explanation for the dimerism is that it arose because it enhanced light-harvesting efficiency by deepening the excitonic trap, i.e., by enhancing the rate of exciton transfer from an antenna complex and decreasing the rate of back transfer. This effect would have outweighed the negative effect dimerisation would have had on charge transfer within the reaction centre. Our argument implies that dimerisation likely occurred after the evolution of the first antennas, and it explains why the lower-energy state of the special pair is bright.
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Affiliation(s)
- Natasha Taylor
- School of Chemistry and University of Sydney Nano Institute , University of Queensland , QLD 4072 , Australia
| | - Ivan Kassal
- School of Chemistry , University of Sydney Nano Institute , University of Sydney , NSW 2006 , Australia .
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22
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Segatta F, Cupellini L, Garavelli M, Mennucci B. Quantum Chemical Modeling of the Photoinduced Activity of Multichromophoric Biosystems. Chem Rev 2019; 119:9361-9380. [PMID: 31276384 PMCID: PMC6716121 DOI: 10.1021/acs.chemrev.9b00135] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Indexed: 01/21/2023]
Abstract
Multichromophoric biosystems represent a broad family with very diverse members, ranging from light-harvesting pigment-protein complexes to nucleic acids. The former are designed to capture, harvest, efficiently transport, and transform energy from sunlight for photosynthesis, while the latter should dissipate the absorbed radiation as quickly as possible to prevent photodamages and corruption of the carried genetic information. Because of the unique electronic and structural characteristics, the modeling of their photoinduced activity is a real challenge. Numerous approaches have been devised building on the theoretical development achieved for single chromophores and on model Hamiltonians that capture the essential features of the system. Still, a question remains: is a general strategy for the accurate modeling of multichromophoric systems possible? By using a quantum chemical point of view, here we review the advancements developed so far highlighting differences and similarities with the single chromophore treatment. Finally, we outline the important limitations and challenges that still need to be tackled to reach a complete and accurate picture of their photoinduced properties and dynamics.
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Affiliation(s)
- Francesco Segatta
- Dipartimento
di Chimica Industriale “Toso Montanari” University of Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - Lorenzo Cupellini
- Dipartimento
di Chimica e Chimica Industriale, University
of Pisa, via G. Moruzzi 13, 56124 Pisa, Italy
| | - Marco Garavelli
- Dipartimento
di Chimica Industriale “Toso Montanari” University of Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - Benedetta Mennucci
- Dipartimento
di Chimica e Chimica Industriale, University
of Pisa, via G. Moruzzi 13, 56124 Pisa, Italy
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23
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Hsieh ST, Zhang L, Ye DW, Huang X, Cheng YC. A theoretical study on the dynamics of light harvesting in the dimeric photosystem II core complex: regulation and robustness of energy transfer pathways. Faraday Discuss 2019; 216:94-115. [PMID: 31016302 DOI: 10.1039/c8fd00205c] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Here we present our theoretical investigations into the light reaction in the dimeric photosystem II (PSII) core complex. An effective model for excitation energy transfer (EET) and primary charge separation (CS) in the PSII core complex was developed, with model parameters constructed based on molecular dynamics (MD) simulation data. Compared to experimental results, we demonstrated that this model faithfully reproduces the absorption spectra of the RC and core light-harvesting complexes (CP43 and CP47) as well as the full EET dynamics among the chromophores in the PSII core complex. We then applied master equation simulations and network analysis to investigate detailed EET plus CS dynamics in the system, allowing us to identify key EET pathways and produce a coarse-grained cluster model for the light reaction in the dimeric PSII core complex. We show that non-equilibrium energy transfer channels play important roles in the efficient light harvesting process and that multiple EET pathways exist between subunits of PSII to ensure the robustness of light harvesting in the system. Furthermore, we revealed that inter-monomer energy transfer dominated by the coupling between the two CLA625 molecules enables efficient energy exchange between two CP47s in the dimeric PSII core complex, which leads to significant energy pooling in the CP47 domain during the light reaction. Our study provides a blueprint for the design of light harvesting in the PSII core and show that a structure-based approach using molecular dynamics simulations and quantum chemistry calculations can be effectively utilized to elucidate the dynamics of light harvesting in complex photosynthetic systems.
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Affiliation(s)
- Shou-Ting Hsieh
- Department of Chemistry, National Taiwan University, Taipei City, Taiwan.
| | - Lu Zhang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences Fuzhou, Fujian CN 350002, China
| | - De-Wei Ye
- Department of Chemistry, National Taiwan University, Taipei City, Taiwan.
| | - Xuhui Huang
- Department of Chemistry, Institute for Advance Study and School of Science, Hong Kong University of Science and Technology, Kowloon, Hong Kong.
| | - Yuan-Chung Cheng
- Department of Chemistry, National Taiwan University, Taipei City, Taiwan.
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24
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Fujihashi Y, Higashi M, Ishizaki A. Intramolecular Vibrations Complement the Robustness of Primary Charge Separation in a Dimer Model of the Photosystem II Reaction Center. J Phys Chem Lett 2018; 9:4921-4929. [PMID: 30095266 DOI: 10.1021/acs.jpclett.8b02119] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The energy conversion of oxygenic photosynthesis is triggered by primary charge separation in proteins at the photosystem II reaction center. Here, we investigate the impacts of the protein environment and intramolecular vibrations on primary charge separation at the photosystem II reaction center. This is accomplished by combining the quantum dynamic theories of condensed phase electron transfer with quantum chemical calculations to evaluate the vibrational Huang-Rhys factors of chlorophyll and pheophytin molecules. We report that individual vibrational modes play a minor role in promoting charge separation, contrary to the discussion in recent publications. Nevertheless, these small contributions accumulate to considerably influence the charge separation rate, resulting in subpicosecond charge separation almost independent of the driving force and temperature. We suggest that the intramolecular vibrations complement the robustness of the charge separation in the photosystem II reaction center against the inherently large static disorder of the involved electronic energies.
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Affiliation(s)
- Yuta Fujihashi
- Institute for Molecular Science , National Institutes of Natural Sciences , Okazaki 444-8585 , Japan
| | - Masahiro Higashi
- Department of Chemistry, Biology, and Marine Science , University of the Ryukyus , 1 Senbaru , Nishihara , Okinawa 903-0213 , Japan
| | - Akihito Ishizaki
- Institute for Molecular Science , National Institutes of Natural Sciences , Okazaki 444-8585 , Japan
- School of Physical Sciences , The Graduate University for Advanced Studies , Okazaki 444-8585 , Japan
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25
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The wavelength of the incident light determines the primary charge separation pathway in Photosystem II. Sci Rep 2018; 8:2837. [PMID: 29434283 PMCID: PMC5809461 DOI: 10.1038/s41598-018-21101-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 01/25/2018] [Indexed: 01/12/2023] Open
Abstract
Charge separation is a key component of the reactions cascade of photosynthesis, by which solar energy is converted to chemical energy. From this photochemical reaction, two radicals of opposite charge are formed, a highly reducing anion and a highly oxidising cation. We have previously proposed that the cation after far-red light excitation is located on a component different from PD1, which is the location of the primary electron hole after visible light excitation. Here, we attempt to provide further insight into the location of the primary charge separation upon far-red light excitation of PS II, using the EPR signal of the spin polarized 3P680 as a probe. We demonstrate that, under far-red light illumination, the spin polarized 3P680 is not formed, despite the primary charge separation still occurring at these conditions. We propose that this is because under far-red light excitation, the primary electron hole is localized on ChlD1, rather than on PD1. The fact that identical samples have demonstrated charge separation upon both far-red and visible light excitation supports our hypothesis that two pathways for primary charge separation exist in parallel in PS II reaction centres. These pathways are excited and activated dependent of the wavelength applied.
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26
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Novoderezhkin VI, Romero E, Prior J, van Grondelle R. Exciton-vibrational resonance and dynamics of charge separation in the photosystem II reaction center. Phys Chem Chem Phys 2018; 19:5195-5208. [PMID: 28149991 DOI: 10.1039/c6cp07308e] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The dynamics of charge separation in the photosystem II reaction center (PSII-RC) in the presence of intramolecular vibrations with their frequency matching the energy gap between the exciton state acting as the primary electron donor and the first charge-transfer (CT) state are investigated. A reduced PSII-RC 4-state model explicitly including a CT state is analyzed within Redfield relaxation theory in the multidimensional exciton-vibrational (vibronic) basis. This model is used to study coherent energy/electron transfers and their spectral signatures obtained by two-dimensional electronic spectroscopy (2DES). Modeling of the time-resolved 2D frequency maps obtained by wavelet analysis reveals the origins of the coherences which produce the observed oscillating features in 2DES and allows comparing the lifetimes of the coherences. The results suggest faster excitonic decoherence as compared with longer-lived vibronic oscillations. The emerging picture of the dynamics unravels the role of resonant vibrations in sustaining the effective energy conversion in the PSII-RC. We demonstrate that the mixing of the exciton and CT states promoted by a resonant vibrational quantum allows faster penetration of excitation energy into the CT with subsequent dynamic localization at the bottom of the CT potential induced by the remaining non-resonant nuclear modes. The degree of vibration-assisted mixing and, correspondingly, the rate of primary charge separation, increases significantly in the case of electron-vibrational resonance. The observed features illustrate the principles of quantum design of the photosynthetic unit. These principles are connected with the phenomenon of coherent mixing within vibronic eigenstates, increasing the effectiveness of charge separation not only upon coherent and impulsive laser excitation utilized in the 2DES experiment, but also under natural conditions under non-coherent non-impulsive solar light illumination.
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Affiliation(s)
- Vladimir I Novoderezhkin
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Leninskie Gory, 119992, Moscow, Russia.
| | - Elisabet Romero
- Department of Biophysics, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Javier Prior
- Departamento de Física Aplicada, Universidad Politécnica de Cartagena, Cartagena 30202, Spain
| | - Rienk van Grondelle
- Department of Biophysics, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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27
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Sakamoto S, Tanimura Y. Exciton-Coupled Electron Transfer Process Controlled by Non-Markovian Environments. J Phys Chem Lett 2017; 8:5390-5394. [PMID: 29039960 DOI: 10.1021/acs.jpclett.7b01535] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We theoretically investigate an exciton-coupled electron transfer (XCET) process that is conversion of an exciton into a charge transfer state. This conversion happens in an exciton transfer (XT) process, and the electron moves away in an electron transfer (ET) process in multiple environments (baths). This XCET process plays an essential role in the harvesting of solar energy in biological and photovoltaic materials. We develop a practical theoretical model to study the efficiency of the XCET process that occurs either in consecutive or concerted processes under the influence of non-Markovian baths. The role of quantum coherence in the XT-ET system and the baths is investigated using reduced hierarchal equations of motion (HEOM). This model includes independent baths for each XT and ET state, in addition to a XCET bath for the conversion process. We found that, while quantum system-bath coherence is important in the XT and ET processes, coherence between the XT and ET processes must be suppressed in order to realize that an efficient irreversible XCET process through the weak off-diagonal interaction between the XT and ET bridge sites arises from an XCET bath.
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Affiliation(s)
- Souichi Sakamoto
- Department of Chemistry, Graduate School of Science, Kyoto University , Sakyoku, Kyoto 606-8502, Japan
| | - Yoshitaka Tanimura
- Department of Chemistry, Graduate School of Science, Kyoto University , Sakyoku, Kyoto 606-8502, Japan
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28
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Stones R, Hossein-Nejad H, van Grondelle R, Olaya-Castro A. On the performance of a photosystem II reaction centre-based photocell. Chem Sci 2017; 8:6871-6880. [PMID: 29147512 PMCID: PMC5636947 DOI: 10.1039/c7sc02983g] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 08/04/2017] [Indexed: 12/26/2022] Open
Abstract
The photosystem II reaction centre is the photosynthetic complex responsible for oxygen production on Earth. Its water splitting function is particularly favoured by the formation of a stable charge separated state via a pathway that starts at an accessory chlorophyll. Here we envision a photovoltaic device that places one of these complexes between electrodes and investigate how the mean current and its fluctuations depend on the microscopic interactions underlying charge separation in the pathway considered. Our results indicate that coupling to well resolved vibrational modes does not necessarily offer an advantage in terms of power output but can lead to photo-currents with suppressed noise levels characterizing a multi-step ordered transport process. Besides giving insight into the suitability of these complexes for molecular-scale photovoltaics, our work suggests a new possible biological function for the vibrational environment of photosynthetic reaction centres, namely, to reduce the intrinsic current noise for regulatory processes.
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Affiliation(s)
- Richard Stones
- Department of Physics and Astronomy , University College London , Gower Street , London , WC1E 6BT , UK .
| | - Hoda Hossein-Nejad
- Department of Physics and Astronomy , University College London , Gower Street , London , WC1E 6BT , UK .
| | - Rienk van Grondelle
- Department of Physics and Astronomy , VU University , 1081 HV Amsterdam , The Netherlands
| | - Alexandra Olaya-Castro
- Department of Physics and Astronomy , University College London , Gower Street , London , WC1E 6BT , UK .
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29
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Primary Charge Separation in the Photosystem II Reaction Center Revealed by a Global Analysis of the Two-dimensional Electronic Spectra. Sci Rep 2017; 7:12347. [PMID: 28955056 PMCID: PMC5617839 DOI: 10.1038/s41598-017-12564-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 09/12/2017] [Indexed: 11/08/2022] Open
Abstract
The transfer of electronic charge in the reaction center of Photosystem II is one of the key building blocks of the conversion of sunlight energy into chemical energy within the cascade of the photosynthetic reactions. Since the charge transfer dynamics is mixed with the energy transfer dynamics, an effective tool for the direct resolution of charge separation in the reaction center is still missing. Here, we use experimental two-dimensional optical photon echo spectroscopy in combination with the theoretical calculation to resolve its signature. A global fitting analysis allows us to clearly and directly identify a decay pathway associated to the primary charge separation. In particular, it can be distinguished from regular energy transfer and occurs on a time scale of 1.5 ps under ambient conditions. This technique provides a general tool to identify charge separation signatures from the energy transport in two-dimensional optical spectroscopy.
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30
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Gelzinis A, Abramavicius D, Ogilvie JP, Valkunas L. Spectroscopic properties of photosystem II reaction center revisited. J Chem Phys 2017; 147:115102. [DOI: 10.1063/1.4997527] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- Andrius Gelzinis
- Department of Theoretical Physics, Faculty of Physics, Vilnius University, Sauletekio 9-III, 10222 Vilnius, Lithuania
- Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Sauletekio 3, 10257 Vilnius, Lithuania
| | - Darius Abramavicius
- Department of Theoretical Physics, Faculty of Physics, Vilnius University, Sauletekio 9-III, 10222 Vilnius, Lithuania
| | - Jennifer P. Ogilvie
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Leonas Valkunas
- Department of Theoretical Physics, Faculty of Physics, Vilnius University, Sauletekio 9-III, 10222 Vilnius, Lithuania
- Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Sauletekio 3, 10257 Vilnius, Lithuania
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31
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Quantum design of photosynthesis for bio-inspired solar-energy conversion. Nature 2017; 543:355-365. [PMID: 28300093 DOI: 10.1038/nature22012] [Citation(s) in RCA: 205] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 02/01/2017] [Indexed: 12/15/2022]
Abstract
Photosynthesis is the natural process that converts solar photons into energy-rich products that are needed to drive the biochemistry of life. Two ultrafast processes form the basis of photosynthesis: excitation energy transfer and charge separation. Under optimal conditions, every photon that is absorbed is used by the photosynthetic organism. Fundamental quantum mechanics phenomena, including delocalization, underlie the speed, efficiency and directionality of the charge-separation process. At least four design principles are active in natural photosynthesis, and these can be applied practically to stimulate the development of bio-inspired, human-made energy conversion systems.
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32
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Quantum - coherent dynamics in photosynthetic charge separation revealed by wavelet analysis. Sci Rep 2017; 7:2890. [PMID: 28588203 PMCID: PMC5460264 DOI: 10.1038/s41598-017-02906-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 04/20/2017] [Indexed: 11/22/2022] Open
Abstract
Experimental/theoretical evidence for sustained vibration-assisted electronic (vibronic) coherence in the Photosystem II Reaction Center (PSII RC) indicates that photosynthetic solar-energy conversion might be optimized through the interplay of electronic and vibrational quantum dynamics. This evidence has been obtained by investigating the primary charge separation process in the PSII RC by two-dimensional electronic spectroscopy (2DES) and Redfield modeling of the experimental data. However, while conventional Fourier transform analysis of the 2DES data allows oscillatory signatures of vibronic coherence to be identified in the frequency domain in the form of static 2D frequency maps, the real-time evolution of the coherences is lost. Here we apply for the first time wavelet analysis to the PSII RC 2DES data to obtain time-resolved 2D frequency maps. These maps allow us to demonstrate that (i) coherence between the excitons initiating the two different charge separation pathways is active for more than 500 fs, and (ii) coherence between exciton and charge-transfer states, the reactant and product of the charge separation reaction, respectively; is active for at least 1 ps. These findings imply that the PSII RC employs coherence (i) to sample competing electron transfer pathways, and ii) to perform directed, ultrafast and efficient electron transfer.
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33
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Müh F, Plöckinger M, Renger T. Electrostatic Asymmetry in the Reaction Center of Photosystem II. J Phys Chem Lett 2017; 8:850-858. [PMID: 28151674 DOI: 10.1021/acs.jpclett.6b02823] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The exciton Hamiltonian of the chlorophyll (Chl) and pheophytin (Pheo) pigments in the reaction center (RC) of photosystem II is computed based on recent crystal structures by using the Poisson-Boltzmann/quantum-chemical method. Computed site energies largely confirm a previous model inferred from fits of optical spectra, in which ChlD1 has the lowest site energy, while that of PheoD1 is higher than that of PheoD2. The latter assignment has been challenged recently under reference to mutagenesis experiments. We argue that these data are not in contradiction to our results. We conclude that ChlD1 is the primary electron donor in both isolated RCs and intact core complexes at least at cryogenic temperatures. The main source of asymmetry in site energies is the charge distribution in the protein. Because many small contributions from various structural elements have to be taken into account, it can be assumed that this asymmetry was established in evolution by global optimization of the RC protein.
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Affiliation(s)
- Frank Müh
- Institute of Theoretical Physics, Department of Theoretical Biophysics, Johannes Kepler University Linz , Altenberger Strasse 69, AT-4040 Linz, Austria
| | - Melanie Plöckinger
- Institute of Theoretical Physics, Department of Theoretical Biophysics, Johannes Kepler University Linz , Altenberger Strasse 69, AT-4040 Linz, Austria
| | - Thomas Renger
- Institute of Theoretical Physics, Department of Theoretical Biophysics, Johannes Kepler University Linz , Altenberger Strasse 69, AT-4040 Linz, Austria
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34
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Roden JJJ, Bennett DIG, Whaley KB. Long-range energy transport in photosystem II. J Chem Phys 2017; 144:245101. [PMID: 27369543 DOI: 10.1063/1.4953243] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
We simulate the long-range inter-complex electronic energy transfer in photosystem II-from the antenna complex, via a core complex, to the reaction center-using a non-Markovian (ZOFE) quantum master equation description that allows the electronic coherence involved in the energy transfer to be explicitly included at all length scales. This allows us to identify all locations where coherence is manifested and to further identify the pathways of the energy transfer in the full network of coupled chromophores using a description based on excitation probability currents. We investigate how the energy transfer depends on the initial excitation-localized, coherent initial excitation versus delocalized, incoherent initial excitation-and find that the overall energy transfer is remarkably robust with respect to such strong variations of the initial condition. To explore the importance of vibrationally enhanced transfer and to address the question of optimization in the system parameters, we systematically vary the strength of the coupling between the electronic and the vibrational degrees of freedom. We find that the natural parameters lie in a (broad) region that enables optimal transfer efficiency and that the overall long-range energy transfer on a ns time scale appears to be very robust with respect to variations in the vibronic coupling of up to an order of magnitude. Nevertheless, vibrationally enhanced transfer appears to be crucial to obtain a high transfer efficiency, with the latter falling sharply for couplings outside the optimal range. Comparison of our full quantum simulations to results obtained with a "classical" rate equation based on a modified-Redfield/generalized-Förster description previously used to simulate energy transfer dynamics in the entire photosystem II complex shows good agreement for the overall time scales of excitation energy transport.
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Affiliation(s)
- Jan J J Roden
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Doran I G Bennett
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - K Birgitta Whaley
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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35
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Kramer T, Rodríguez M, Zelinskyy Y. Modeling of Transient Absorption Spectra in Exciton–Charge-Transfer Systems. J Phys Chem B 2017; 121:463-470. [DOI: 10.1021/acs.jpcb.6b09858] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tobias Kramer
- Konrad-Zuse-Zentrum für Informationstechnik Berlin, 14195 Berlin, Germany
- Department
of Physics, Harvard University, 17 Oxford Street, 02138 Cambridge, Massachusetts, United States
| | - Mirta Rodríguez
- Konrad-Zuse-Zentrum für Informationstechnik Berlin, 14195 Berlin, Germany
| | - Yaroslav Zelinskyy
- Konrad-Zuse-Zentrum für Informationstechnik Berlin, 14195 Berlin, Germany
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36
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Novoderezhkin VI, Romero E, van Grondelle R. How exciton-vibrational coherences control charge separation in the photosystem II reaction center. Phys Chem Chem Phys 2016; 17:30828-41. [PMID: 25854607 DOI: 10.1039/c5cp00582e] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
In photosynthesis absorbed sun light produces collective excitations (excitons) that form a coherent superposition of electronic and vibrational states of the individual pigments. Two-dimensional (2D) electronic spectroscopy allows a visualization of how these coherences are involved in the primary processes of energy and charge transfer. Based on quantitative modeling we identify the exciton-vibrational coherences observed in 2D photon echo of the photosystem II reaction center (PSII-RC). We find that the vibrations resonant with the exciton splittings can modify the delocalization of the exciton states and produce additional states, thus promoting directed energy transfer and allowing a switch between the two charge separation pathways. We conclude that the coincidence of the frequencies of the most intense vibrations with the splittings within the manifold of exciton and charge-transfer states in the PSII-RC is not occurring by chance, but reflects a fundamental principle of how energy conversion in photosynthesis was optimized.
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Affiliation(s)
- Vladimir I Novoderezhkin
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Leninskie Gory, 119992, Moscow, Russia.
| | - Elisabet Romero
- Department of Biophysics, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Rienk van Grondelle
- Department of Biophysics, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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37
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Mirkovic T, Ostroumov EE, Anna JM, van Grondelle R, Govindjee, Scholes GD. Light Absorption and Energy Transfer in the Antenna Complexes of Photosynthetic Organisms. Chem Rev 2016; 117:249-293. [PMID: 27428615 DOI: 10.1021/acs.chemrev.6b00002] [Citation(s) in RCA: 610] [Impact Index Per Article: 76.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The process of photosynthesis is initiated by the capture of sunlight by a network of light-absorbing molecules (chromophores), which are also responsible for the subsequent funneling of the excitation energy to the reaction centers. Through evolution, genetic drift, and speciation, photosynthetic organisms have discovered many solutions for light harvesting. In this review, we describe the underlying photophysical principles by which this energy is absorbed, as well as the mechanisms of electronic excitation energy transfer (EET). First, optical properties of the individual pigment chromophores present in light-harvesting antenna complexes are introduced, and then we examine the collective behavior of pigment-pigment and pigment-protein interactions. The description of energy transfer, in particular multichromophoric antenna structures, is shown to vary depending on the spatial and energetic landscape, which dictates the relative coupling strength between constituent pigment molecules. In the latter half of the article, we focus on the light-harvesting complexes of purple bacteria as a model to illustrate the present understanding of the synergetic effects leading to EET optimization of light-harvesting antenna systems while exploring the structure and function of the integral chromophores. We end this review with a brief overview of the energy-transfer dynamics and pathways in the light-harvesting antennas of various photosynthetic organisms.
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Affiliation(s)
- Tihana Mirkovic
- Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Evgeny E Ostroumov
- Department of Chemistry, Princeton University , Washington Road, Princeton, New Jersey 08544, United States
| | - Jessica M Anna
- Department of Chemistry, University of Pennsylvania , 231 S. 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Rienk van Grondelle
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam , De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Govindjee
- Department of Biochemistry, Center of Biophysics & Quantitative Biology, and Department of Plant Biology, University of Illinois at Urbana-Champaign , 265 Morrill Hall, 505 South Goodwin Avenue, Urbana, Illinois 61801, United States
| | - Gregory D Scholes
- Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.,Department of Chemistry, Princeton University , Washington Road, Princeton, New Jersey 08544, United States
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38
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Kreisbeck C, Aspuru-Guzik A. Efficiency of energy funneling in the photosystem II supercomplex of higher plants. Chem Sci 2016; 7:4174-4183. [PMID: 30155062 PMCID: PMC6014079 DOI: 10.1039/c5sc04296h] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 02/24/2016] [Indexed: 01/16/2023] Open
Abstract
The investigation of energy transfer properties in photosynthetic multi-protein networks gives insight into their underlying design principles. Here, we discuss the excitonic energy transfer mechanisms of the photosystem II (PS-II) C2S2M2 supercomplex, which is the largest isolated functional unit of the photosynthetic apparatus of higher plants. Despite the lack of a definite energy gradient in C2S2M2, we show that the energy transfer is directed by relaxation to low energy states. C2S2M2 is not organized to form pathways with strict energetically downhill transfer, which has direct consequences for the transfer efficiency, transfer pathways and transfer limiting steps. The exciton dynamics is sensitive to small changes in the energetic layout which, for instance, are induced by the reorganization of vibrational coordinates. In order to incorporate the reorganization process in our numerical simulations, we go beyond rate equations and use the hierarchically coupled equation of motion approach (HEOM). While transfer from the peripheral antenna to the proteins in proximity to the reaction center occurs on a faster time scale, the final step of the energy transfer to the RC core is rather slow, and thus the limiting step in the transfer chain. Our findings suggest that the structure of the PS-II supercomplex guarantees photoprotection rather than optimized efficiency.
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Affiliation(s)
- Christoph Kreisbeck
- Department of Chemistry and Chemical Biology , Harvard University , Cambridge , MA , USA . ;
| | - Alán Aspuru-Guzik
- Department of Chemistry and Chemical Biology , Harvard University , Cambridge , MA , USA . ;
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39
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Challenges facing an understanding of the nature of low-energy excited states in photosynthesis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1627-1640. [PMID: 27372198 DOI: 10.1016/j.bbabio.2016.06.010] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 06/27/2016] [Accepted: 06/28/2016] [Indexed: 01/09/2023]
Abstract
While the majority of the photochemical states and pathways related to the biological capture of solar energy are now well understood and provide paradigms for artificial device design, additional low-energy states have been discovered in many systems with obscure origins and significance. However, as low-energy states are naively expected to be critical to function, these observations pose important challenges. A review of known properties of low energy states covering eight photochemical systems, and options for their interpretation, are presented. A concerted experimental and theoretical research strategy is suggested and outlined, this being aimed at providing a fully comprehensive understanding.
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40
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Lee MK, Huo P, Coker DF. Semiclassical Path Integral Dynamics: Photosynthetic Energy Transfer with Realistic Environment Interactions. Annu Rev Phys Chem 2016; 67:639-68. [DOI: 10.1146/annurev-physchem-040215-112252] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Mi Kyung Lee
- Department of Chemistry, Boston University, Boston, Massachusetts 02215;
| | - Pengfei Huo
- Department of Chemistry, University of Rochester, Rochester, New York 14627;
| | - David F. Coker
- Department of Chemistry, Boston University, Boston, Massachusetts 02215;
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41
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Qin M, Shen HZ, Yi XX. A multi-pathway model for photosynthetic reaction center. J Chem Phys 2016; 144:125103. [PMID: 27036480 DOI: 10.1063/1.4944730] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Charge separation occurs in a pair of tightly coupled chlorophylls at the heart of photosynthetic reaction centers of both plants and bacteria. Recently it has been shown that quantum coherence can, in principle, enhance the efficiency of a solar cell, working like a quantum heat engine. Here, we propose a biological quantum heat engine (BQHE) motivated by Photosystem II reaction center (PSII RC) to describe the charge separation. Our model mainly considers two charge-separation pathways which is more than that typically considered in the published literature. We explore how these cross-couplings increase the current and power of the charge separation and discuss the effects of multiple pathways in terms of current and power. The robustness of the BQHE against the charge recombination in natural PSII RC and dephasing induced by environments is also explored, and extension from two pathways to multiple pathways is made. These results suggest that noise-induced quantum coherence helps to suppress the influence of acceptor-to-donor charge recombination, and besides, nature-mimicking architectures with engineered multiple pathways for charge separations might be better for artificial solar energy devices considering the influence of environments.
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Affiliation(s)
- M Qin
- School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024, China
| | - H Z Shen
- School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024, China
| | - X X Yi
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun 130024, China
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42
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Najafpour MM, Renger G, Hołyńska M, Moghaddam AN, Aro EM, Carpentier R, Nishihara H, Eaton-Rye JJ, Shen JR, Allakhverdiev SI. Manganese Compounds as Water-Oxidizing Catalysts: From the Natural Water-Oxidizing Complex to Nanosized Manganese Oxide Structures. Chem Rev 2016; 116:2886-936. [PMID: 26812090 DOI: 10.1021/acs.chemrev.5b00340] [Citation(s) in RCA: 337] [Impact Index Per Article: 42.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
All cyanobacteria, algae, and plants use a similar water-oxidizing catalyst for water oxidation. This catalyst is housed in Photosystem II, a membrane-protein complex that functions as a light-driven water oxidase in oxygenic photosynthesis. Water oxidation is also an important reaction in artificial photosynthesis because it has the potential to provide cheap electrons from water for hydrogen production or for the reduction of carbon dioxide on an industrial scale. The water-oxidizing complex of Photosystem II is a Mn-Ca cluster that oxidizes water with a low overpotential and high turnover frequency number of up to 25-90 molecules of O2 released per second. In this Review, we discuss the atomic structure of the Mn-Ca cluster of the Photosystem II water-oxidizing complex from the viewpoint that the underlying mechanism can be informative when designing artificial water-oxidizing catalysts. This is followed by consideration of functional Mn-based model complexes for water oxidation and the issue of Mn complexes decomposing to Mn oxide. We then provide a detailed assessment of the chemistry of Mn oxides by considering how their bulk and nanoscale properties contribute to their effectiveness as water-oxidizing catalysts.
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Affiliation(s)
| | - Gernot Renger
- Institute of Chemistry, Max-Volmer-Laboratory of Biophysical Chemistry, Technical University Berlin , Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Małgorzata Hołyńska
- Fachbereich Chemie und Wissenschaftliches Zentrum für Materialwissenschaften (WZMW), Philipps-Universität Marburg , Hans-Meerwein-Straße, D-35032 Marburg, Germany
| | | | - Eva-Mari Aro
- Department of Biochemistry and Food Chemistry, University of Turku , 20014 Turku, Finland
| | - Robert Carpentier
- Groupe de Recherche en Biologie Végétale (GRBV), Université du Québec à Trois-Rivières , C.P. 500, Trois-Rivières, Québec G9A 5H7, Canada
| | - Hiroshi Nishihara
- Department of Chemistry, School of Science, The University of Tokyo , 7-3-1, Hongo, Bunkyo-Ku, Tokyo 113-0033, Japan
| | - Julian J Eaton-Rye
- Department of Biochemistry, University of Otago , P.O. Box 56, Dunedin 9054, New Zealand
| | - Jian-Ren Shen
- Photosynthesis Research Center, Graduate School of Natural Science and Technology, Faculty of Science, Okayama University , Okayama 700-8530, Japan.,Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences , Beijing 100093, China
| | - Suleyman I Allakhverdiev
- Controlled Photobiosynthesis Laboratory, Institute of Plant Physiology, Russian Academy of Sciences , Botanicheskaya Street 35, Moscow 127276, Russia.,Institute of Basic Biological Problems, Russian Academy of Sciences , Pushchino, Moscow Region 142290, Russia.,Department of Plant Physiology, Faculty of Biology, M.V. Lomonosov Moscow State University , Leninskie Gory 1-12, Moscow 119991, Russia
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43
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Abramavicius D, Valkunas L. Role of coherent vibrations in energy transfer and conversion in photosynthetic pigment-protein complexes. PHOTOSYNTHESIS RESEARCH 2016; 127:33-47. [PMID: 25618783 DOI: 10.1007/s11120-015-0080-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 01/05/2015] [Indexed: 06/04/2023]
Abstract
Oscillatory features of two-dimensional spectra of photosynthetic pigment-protein complexes during few picoseconds after electronic excitations of chlorophylls in various pigment-proteins were recently related to the coherent nuclear vibrations. It has been also speculated that the vibrations may assist the excitonic energy transfer and charge separation, hence contributing to energy transport and energy conversion efficiency. Here, we consider three theoretical approaches usually used for characterization of the excitation dynamics and charge separation, namely Redfield, Förster, and Marcus model descriptions, regarding this question. We show that two out of the three mechanisms require explicit resonances of excitonic splittings and the nuclear vibration frequencies. However, the third one related to the electron transfer is in principle off resonant.
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Affiliation(s)
- Darius Abramavicius
- Department of Theoretical Physics, Vilnius University, Sauletekio al. 9-III, 10222, Vilnius, Lithuania.
| | - Leonas Valkunas
- Department of Theoretical Physics, Vilnius University, Sauletekio al. 9-III, 10222, Vilnius, Lithuania.
- Center for Physical Sciences and Technology, A. Gostauto 11, 01108, Vilnius, Lithuania.
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44
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Novoderezhkin VI, Croce R, Wahadoszamen M, Polukhina I, Romero E, van Grondelle R. Mixing of exciton and charge-transfer states in light-harvesting complex Lhca4. Phys Chem Chem Phys 2016; 18:19368-77. [DOI: 10.1039/c6cp02225a] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Structure-based modeling of spectra of the wild-type Lhca4 and NH mutant enables us to build the exciton model of the complex that includes a charge-transfer state mixed with the excited-state manifold.
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Affiliation(s)
| | - Roberta Croce
- Department of Biophysics
- Faculty of Sciences
- VU University Amsterdam
- 1081 HV Amsterdam
- The Netherlands
| | - Md. Wahadoszamen
- Department of Biophysics
- Faculty of Sciences
- VU University Amsterdam
- 1081 HV Amsterdam
- The Netherlands
| | - Iryna Polukhina
- Department of Biophysics
- Faculty of Sciences
- VU University Amsterdam
- 1081 HV Amsterdam
- The Netherlands
| | - Elisabet Romero
- Department of Biophysics
- Faculty of Sciences
- VU University Amsterdam
- 1081 HV Amsterdam
- The Netherlands
| | - Rienk van Grondelle
- Department of Biophysics
- Faculty of Sciences
- VU University Amsterdam
- 1081 HV Amsterdam
- The Netherlands
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Narzi D, Bovi D, De Gaetano P, Guidoni L. Dynamics of the Special Pair of Chlorophylls of Photosystem II. J Am Chem Soc 2015; 138:257-64. [PMID: 26587662 DOI: 10.1021/jacs.5b10523] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cholophylls are at the basis of the photosynthetic energy conversion mechanisms in algae, plants, and cyanobacteria. In photosystem II, the photoproduced electrons leave a special pair of chlorophylls (namely, P(D1) and P(D2)) that becomes cationic. This oxidizing pair [P(D1),P(D2)](+), in turn, triggers a cascade of oxidative events, eventually leading to water splitting and oxygen evolution. In the present work, using quantum mechanics/molecular mechanics calculations, we investigate the electronic structure and the dynamics of the P(D1)P(D2) special pair in both its oxidized and reduced states. In agreement with previously reported static calculations, the symmetry between the two chlorophylls was found to be broken, the positive charge being preferentially located on P(D1). Nevertheless, this study reveals for the first time that large charge fluctuations occur along dynamics, temporarily inverting the charge preference for the two branches. Finally, a vibrational analysis pinpointed that such charge fluctuations are strongly coupled to specific modes of the special pair.
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Zabelin AA, Shkuropatova VA, Shkuropatov AY, Shuvalov VA. Temperature dependence of light-induced absorbance changes associated with chlorophyll photooxidation in manganese-depleted core complexes of photosystem II. BIOCHEMISTRY (MOSCOW) 2015; 80:1279-87. [DOI: 10.1134/s0006297915100089] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Najdanova M, Janssen GJ, de Groot HJM, Matysik J, Alia A. Analysis of electron donors in photosystems in oxygenic photosynthesis by photo-CIDNP MAS NMR. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2015; 152:261-71. [PMID: 26282679 DOI: 10.1016/j.jphotobiol.2015.08.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 08/04/2015] [Accepted: 08/05/2015] [Indexed: 10/23/2022]
Abstract
Both photosystem I and photosystem II are considerably similar in molecular architecture but they operate at very different electrochemical potentials. The origin of the different redox properties of these RCs is not yet clear. In recent years, insight was gained into the electronic structure of photosynthetic cofactors through the application of photochemically induced dynamic nuclear polarization (photo-CIDNP) with magic-angle spinning NMR (MAS NMR). Non-Boltzmann populated nuclear spin states of the radical pair lead to strongly enhanced signal intensities that allow one to observe the solid-state photo-CIDNP effect from both photosystem I and II from isolated reaction center of spinach (Spinacia oleracea) and duckweed (Spirodela oligorrhiza) and from the intact cells of the cyanobacterium Synechocystis by (13)C and (15)N MAS NMR. This review provides an overview on the photo-CIDNP MAS NMR studies performed on PSI and PSII that provide important ingredients toward reconstruction of the electronic structures of the donors in PSI and PSII.
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Affiliation(s)
- M Najdanova
- University of Leipzig, Institute of Analytical Chemistry, Johannisallee 29, D-04103 Leipzig, Germany
| | - G J Janssen
- University of Leiden, Leiden Institute of Chemistry, Einsteinweg 55, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - H J M de Groot
- University of Leiden, Leiden Institute of Chemistry, Einsteinweg 55, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - J Matysik
- University of Leipzig, Institute of Analytical Chemistry, Johannisallee 29, D-04103 Leipzig, Germany
| | - A Alia
- University of Leiden, Leiden Institute of Chemistry, Einsteinweg 55, P.O. Box 9502, 2300 RA Leiden, The Netherlands; University of Leipzig, Institute of Medical Physics and Biophysics, Härtelstr. 16-18, D-04107 Leipzig, Germany.
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48
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Mamedov M, Nadtochenko V, Semenov A. Primary electron transfer processes in photosynthetic reaction centers from oxygenic organisms. PHOTOSYNTHESIS RESEARCH 2015; 125:51-63. [PMID: 25648636 DOI: 10.1007/s11120-015-0088-y] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 01/12/2015] [Indexed: 05/22/2023]
Abstract
This minireview is written in honor of Vladimir A. Shuvalov, a pioneer in the area of primary photochemistry of both oxygenic and anoxygenic photosyntheses (See a News Report: Allakhverdiev et al. 2014). In the present paper, we describe the current state of the formation of the primary and secondary ion-radical pairs within photosystems (PS) II and I in oxygenic organisms. Spectral-kinetic studies of primary events in PS II and PS I, upon excitation by ~20 fs laser pulses, are now available and reviewed here; for PS II, excitation was centered at 710 nm, and for PS I, it was at 720 nm. In PS I, conditions were chosen to maximally increase the relative contribution of the direct excitation of the reaction center (RC) in order to separate the kinetics of the primary steps of charge separation in the RC from that of the excitation energy transfer in the antenna. Our results suggest that the sequence of the primary electron transfer reactions is P680 → ChlD1 → PheD1 → QA (PS II) and P700 → A 0A/A 0B → A 1A/A 1B (PS I). However, alternate routes of charge separation in PS II, under different excitation conditions, are not ruled out.
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Affiliation(s)
- Mahir Mamedov
- A.N. Belozersky Institute of Physical-Chemical Biology, Moscow State University, 119991, Moscow, Russia,
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Yakovlev AG, Shuvalov VA. Spectral exhibition of electron-vibrational relaxation in P* state of Rhodobacter sphaeroides reaction centers. PHOTOSYNTHESIS RESEARCH 2015; 125:9-22. [PMID: 25240681 DOI: 10.1007/s11120-014-0041-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 09/15/2014] [Indexed: 06/03/2023]
Abstract
Electron-vibrational relaxation in the excited state of the primary electron donor, bacteriochlorophyll dimer P, in the reaction centers (RCs) of purple photosynthetic bacteria Rhodobacter sphaeroides is modeled. A multimode model of three states (i.e., the ground state Pg, initially excited P1*, and relaxed excited P2*) is used to calculate the incoherent dynamics of the difference (ΔA) spectra on a femtosecond timescale for the YM210 W mutant RCs. The relaxation processes are described by the step-ladder model. The model shows that the electron-vibrational relaxation in the excited state of P is visualized by the transient red shift of the stimulated emission from P*. The dynamics of this shift is observed as a change in the ΔA spectrum shape in its red-most part, within a few hundreds of femtoseconds after excitation. As a result, an initial rise in the red-side ΔA kinetics is delayed with respect to the blue-side kinetics. The time constant of the P1* → P2* electronic relaxation (54 fs) and the Pg, P1*, and P2* vibrational relaxations (120 fs), used in the model, provided the best fit of the experimental time-resolved ΔA spectra and kinetics at 90 and 293 K. The possible nature of the P1* → P2* electronic relaxation is discussed.
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Affiliation(s)
- Andrei G Yakovlev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory, 119991, Moscow, Russia,
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50
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Rancova O, Jankowiak R, Abramavicius D. Probing environment fluctuations by two-dimensional electronic spectroscopy of molecular systems at temperatures below 5 K. J Chem Phys 2015; 142:212428. [DOI: 10.1063/1.4918584] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Olga Rancova
- Department of Theoretical Physics, Vilnius University, Sauletekio al 9-III, 10222 Vilnius, Lithuania
| | - Ryszard Jankowiak
- Department of Chemistry and Department of Physics, Kansas State University, 213 CBC Building Manhattan, Kansas 66506-0401, USA
| | - Darius Abramavicius
- Department of Theoretical Physics, Vilnius University, Sauletekio al 9-III, 10222 Vilnius, Lithuania
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