1
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Saito K, Nishio S, Ishikita H. Interplay of two low-barrier hydrogen bonds in long-distance proton-coupled electron transfer for water oxidation. PNAS NEXUS 2023; 2:pgad423. [PMID: 38130665 PMCID: PMC10733176 DOI: 10.1093/pnasnexus/pgad423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 11/20/2023] [Indexed: 12/23/2023]
Abstract
D1-Tyr161 (TyrZ) forms a low-barrier H-bond with D1-His190 and functions as a redox-active group in photosystem II. When oxidized to the radical form (TyrZ-O•), it accepts an electron from the oxygen-evolving Mn4CaO5 cluster, facilitating an increase in the oxidation state (Sn; n = 0-3). In this study, we investigated the mechanism of how TyrZ-O• drives proton-coupled electron transfer during the S2 to S3 transition using a quantum mechanical/molecular mechanical approach. In response to TyrZ-O• formation and subsequent loss of the low-barrier H-bond, the ligand water molecule at the Ca2+ site (W4) reorients away from TyrZ and donates an H-bond to D1-Glu189 at Mn4 of Mn4CaO5 together with an adjacent water molecule. The H-bond donation to the Mn4CaO5 cluster triggers the release of the proton from the lowest pKa site (W1 at Mn4) along the W1…D1-Asp61 low-barrier H-bond, leading to protonation of D1-Asp61. The interplay of the two low-barrier H-bonds, involving the Ca2+ interface and forming the extended Grotthuss-like network [TyrZ…D1-His190]-[Mn4CaO5]-[W1…D1-Asp61], rather than the direct electrostatic interaction, is likely a basis of the apparent long-distance interaction (11.4 Å) between TyrZ-O• formation and D1-Asp61 protonation.
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Affiliation(s)
- Keisuke Saito
- Department of Applied Chemistry, The University of Tokyo, Bunkyo-ku, Tokyo 113-8654, Japan
- Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo 153-8904, Japan
| | - Shunya Nishio
- Department of Applied Chemistry, The University of Tokyo, Bunkyo-ku, Tokyo 113-8654, Japan
| | - Hiroshi Ishikita
- Department of Applied Chemistry, The University of Tokyo, Bunkyo-ku, Tokyo 113-8654, Japan
- Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo 153-8904, Japan
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2
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Mandal M, Saito K, Ishikita H. Substitution of Ca 2+ and changes in the H-bond network near the oxygen-evolving complex of photosystem II. Phys Chem Chem Phys 2023; 25:6473-6480. [PMID: 36785919 DOI: 10.1039/d2cp05036f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Ca2+, which provides binding sites for ligand water molecules W3 and W4 in the Mn4CaO5 cluster, is a prerequisite for O2 evolution in photosystem II (PSII). We report structural changes in the H-bond network and the catalytic cluster itself upon the replacement of Ca2+ with other alkaline earth metals, using a quantum mechanical/molecular mechanical approach. The small radius of Mg2+ makes W3 donate an H-bond to D1-Glu189 in Mg2+-PSII. If an additional water molecule binds at the large surface of Ba2+, it donates H-bonds to D1-Glu189 and the ligand water molecule at the dangling Mn, altering the H-bond network. The potential energy profiles of the H-bond between D1-Tyr161 (TyrZ) and D1-His190 and the interconversion between the open- and closed-cubane S2 conformations remain substantially unaltered upon the replacement of Ca2+. Remarkably, the O5⋯Ca2+ distance is shortest among all O5⋯metal distances irrespective of the radius being larger than that of Mg2+. Furthermore, Ca2+ is the only alkaline earth metal that equalizes the O5⋯metal and O2⋯metal distances and facilitates the formation of the symmetric cubane structure.
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Affiliation(s)
- Manoj Mandal
- Department of Chemical and Biological Sciences, S. N. Bose National Centre for Basic Sciences, Kolkata 700106, West Bengal, India.
| | - Keisuke Saito
- Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan. .,Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
| | - Hiroshi Ishikita
- Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan. .,Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
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3
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Tamura H, Saito K, Nishio S, Ishikita H. Electron-Transfer Route in the Early Oxidation States of the Mn 4CaO 5 Cluster in Photosystem II. J Phys Chem B 2023; 127:205-211. [PMID: 36542840 PMCID: PMC9841979 DOI: 10.1021/acs.jpcb.2c08246] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 12/07/2022] [Indexed: 12/24/2022]
Abstract
The electron transfer from the oxygen-evolving Mn4CaO5 cluster to the electron acceptor D1-Tyr161 (TyrZ) is a prerequisite for water oxidation and O2 evolution. Here, we analyzed the electronic coupling in the rate-limiting electron-transfer transitions using a combined quantum mechanical/molecular mechanical/polarizable continuum model approach. In the S0 to S1 transition, the electronic coupling between the electron-donor Mn3(III) and TyrZ is small (2 meV). In contrast, the electronic coupling between the dangling Mn4(III) and TyrZ is significantly large (172 meV), which suggests that the electron transfer proceeds from Mn3(III) to TyrZ via Mn4(III). In the S1 to S2 transition, the electronic coupling between Mn4(III) and TyrZ is also larger (124 meV) than that between Mn1(III) and TyrZ (1 meV), which favors the formation of the open-cubane S2 conformation with Mn4(IV) over the formation of the closed-cubane S2 conformation with Mn1(IV). In the S0 to S1 and S1 to S2 transitions, the Mn4 d-orbital and the TyrZ π-orbital are hybridized via D1-Asp170, which suggests that D1-Asp170 commonly provides a dominant electron-transfer route.
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Affiliation(s)
- Hiroyuki Tamura
- Department
of Applied Chemistry, The University of
Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo113-8654, Japan
- Research
Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo153-8904, Japan
| | - Keisuke Saito
- Department
of Applied Chemistry, The University of
Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo113-8654, Japan
- Research
Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo153-8904, Japan
| | - Shunya Nishio
- Department
of Applied Chemistry, The University of
Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo113-8654, Japan
| | - Hiroshi Ishikita
- Department
of Applied Chemistry, The University of
Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo113-8654, Japan
- Research
Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo153-8904, Japan
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4
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Eschenbach P, Neugebauer J. Subsystem density-functional theory: A reliable tool for spin-density based properties. J Chem Phys 2022; 157:130902. [PMID: 36209003 DOI: 10.1063/5.0103091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Subsystem density-functional theory compiles a set of features that allow for efficiently calculating properties of very large open-shell radical systems such as organic radical crystals, proteins, or deoxyribonucleic acid stacks. It is computationally less costly than correlated ab initio wave function approaches and can pragmatically avoid the overdelocalization problem of Kohn-Sham density-functional theory without employing hard constraints on the electron-density. Additionally, subsystem density-functional theory calculations commonly start from isolated fragment electron densities, pragmatically preserving a priori specified subsystem spin-patterns throughout the calculation. Methods based on subsystem density-functional theory have seen a rapid development over the past years and have become important tools for describing open-shell properties. In this Perspective, we address open questions and possible developments toward challenging future applications in connection with subsystem density-functional theory for spin-dependent properties.
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Affiliation(s)
- Patrick Eschenbach
- Theoretische Organische Chemie, Organisch-Chemisches Institut and Center for Multiscale Theory and Simulation, Westfälische Wilhelms-Universität Münster, Corrensstraße 36, 48149 Münster, Germany
| | - Johannes Neugebauer
- Theoretische Organische Chemie, Organisch-Chemisches Institut and Center for Multiscale Theory and Simulation, Westfälische Wilhelms-Universität Münster, Corrensstraße 36, 48149 Münster, Germany
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5
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Saito K, Mino H, Nishio S, Ishikita H. Protonation structure of the closed-cubane conformation of the O 2-evolving complex in photosystem II. PNAS NEXUS 2022; 1:pgac221. [PMID: 36712340 PMCID: PMC9802176 DOI: 10.1093/pnasnexus/pgac221] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 09/27/2022] [Indexed: 11/17/2022]
Abstract
In photosystem II (PSII), one-electron oxidation of the most stable state of the oxygen-evolving Mn4CaO5 cluster (S1) leads to the S2 state formation, Mn1(III)Mn2(IV)Mn3(IV)Mn4(IV) (open-cubane S2) or Mn1(IV)Mn2(IV)Mn3(IV)Mn4(III) (closed-cubane S2). In electron paramagnetic resonance (EPR) spectroscopy, the g = 4.1 signal is not observed in cyanobacterial PSII but in plant PSII, whereas the g = 4.8 signal is observed in cyanobacterial PSII and extrinsic-subunit-depleted plant PSII. Here, we investigated the closed-cubane S2 conformation, a candidate for a higher spin configuration that accounts for g > 4.1 EPR signal, considering all pairwise exchange couplings in the PSII protein environment (i.e. instead of considering only a single exchange coupling between the [Mn3(CaO4)] cubane region and the dangling Mn4 site). Only when a ligand water molecule that forms an H-bond with D1-Asp61 (W1) is deprotonated at dangling Mn4(IV), the g = 4.1 EPR spectra can be reproduced using the cyanobacterial PSII crystal structure. The closed-cubane S2 is less stable than the open-cubane S2 in cyanobacterial PSII, which may explain why the g = 4.1 EPR signal is absent in cyanobacterial PSII.
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Affiliation(s)
| | - Hiroyuki Mino
- Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Shunya Nishio
- Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
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6
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Mandal M, Saito K, Ishikita H. Release of a Proton and Formation of a Low-Barrier Hydrogen Bond between Tyrosine D and D2-His189 in Photosystem II. ACS PHYSICAL CHEMISTRY AU 2022; 2:423-429. [PMID: 36855688 PMCID: PMC9955220 DOI: 10.1021/acsphyschemau.2c00019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In photosystem II (PSII), the second-lowest oxidation state (S1) of the oxygen-evolving Mn4CaO5 cluster is the most stable, as the radical form of the redox-active D2-Tyr160 is considered to be a candidate that accepts an electron from the lowest oxidation state (S0) in the dark. Using quantum mechanical/molecular mechanical calculations, we investigated the redox potential (E m) of TyrD and its H-bond partner, D2-His189. The potential energy profile indicates that the release of a proton from the TyrD...D2-His189 pair leads to the formation of a low-barrier H-bond. The E m depends on the H+ position along the low-barrier H-bond, e.g., 680 mV when the H+ is at the D2-His189 moiety and 800 mV when the H+ is at the TyrD moiety, which can explain why TyrD mediates both the S0 to S1 oxidation and the S2 to S1 reduction.
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Affiliation(s)
- Manoj Mandal
- Department
of Chemical, Biological & Macro-Molecular Sciences, S. N. Bose National Centre for Basic Sciences, Kolkata 700106, West Bengal, India
| | - Keisuke Saito
- Research
Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan,Department
of Applied Chemistry, The University of
Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
| | - Hiroshi Ishikita
- Research
Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan,Department
of Applied Chemistry, The University of
Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan,. Tel: +81-3-5452-5056. Fax: +81-3-5452-5083
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7
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Mandal M, Saito K, Ishikita H. Requirement of Chloride for the Downhill Electron Transfer Pathway from the Water-Splitting Center in Natural Photosynthesis. J Phys Chem B 2021; 126:123-131. [PMID: 34955014 DOI: 10.1021/acs.jpcb.1c09176] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In photosystem II (PSII), Cl- is a prerequisite for the second flash-induced oxidation of the Mn4CaO5 cluster (the S2 to S3 transition). We report proton transfer from the substrate water molecule via D1-Asp61 and electron transfer via redox-active D1-Tyr161 (TyrZ) to the chlorophyll pair in Cl--depleted PSII using a quantum mechanical/molecular mechanical approach. The low-barrier H-bond formation between the substrate water molecule and D1-Asp61 remained unaffected upon the depletion of Cl-. However, the binding site, D2-Lys317, formed a salt bridge with D1-Asp61, leading to the inhibition of the subsequent proton transfer. Remarkably, the redox potential (Em) of S2/S3 increased significantly, making electron transfer from S2 to TyrZ energetically uphill, as observed in Ca2+-depleted PSII. The uphill electron transfer pathway was induced by the significant increase in Em(S2/S3) caused by the loss of charge compensation for D2-Lys317 upon the depletion of Cl-, whereas it was induced by the significant decrease in Em(TyrZ) caused by the rearrangement of the water molecules at the Ca2+ binding moiety upon the depletion of Ca2+.
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Affiliation(s)
- Manoj Mandal
- Department of Chemical, Biological & Macro-Molecular Sciences, S. N. Bose National Centre for Basic Sciences, Kolkata, West Bengal 700106, India
| | - Keisuke Saito
- Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan.,Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
| | - Hiroshi Ishikita
- Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan.,Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
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8
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Gorka M, Baldansuren A, Malnati A, Gruszecki E, Golbeck JH, Lakshmi KV. Shedding Light on Primary Donors in Photosynthetic Reaction Centers. Front Microbiol 2021; 12:735666. [PMID: 34659164 PMCID: PMC8517396 DOI: 10.3389/fmicb.2021.735666] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Accepted: 08/30/2021] [Indexed: 11/17/2022] Open
Abstract
Chlorophylls (Chl)s exist in a variety of flavors and are ubiquitous in both the energy and electron transfer processes of photosynthesis. The functions they perform often occur on the ultrafast (fs-ns) time scale and until recently, these have been difficult to measure in real time. Further, the complexity of the binding pockets and the resulting protein-matrix effects that alter the respective electronic properties have rendered theoretical modeling of these states difficult. Recent advances in experimental methodology, computational modeling, and emergence of new reaction center (RC) structures have renewed interest in these processes and allowed researchers to elucidate previously ambiguous functions of Chls and related pheophytins. This is complemented by a wealth of experimental data obtained from decades of prior research. Studying the electronic properties of Chl molecules has advanced our understanding of both the nature of the primary charge separation and subsequent electron transfer processes of RCs. In this review, we examine the structures of primary electron donors in Type I and Type II RCs in relation to the vast body of spectroscopic research that has been performed on them to date. Further, we present density functional theory calculations on each oxidized primary donor to study both their electronic properties and our ability to model experimental spectroscopic data. This allows us to directly compare the electronic properties of hetero- and homodimeric RCs.
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Affiliation(s)
- Michael Gorka
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States
| | - Amgalanbaatar Baldansuren
- Department of Chemistry and Chemical Biology and The Baruch ’60 Center for Biochemical Solar Energy Research, Rensselaer Polytechnic Institute, Troy, NY, United States
| | - Amanda Malnati
- Department of Chemistry and Chemical Biology and The Baruch ’60 Center for Biochemical Solar Energy Research, Rensselaer Polytechnic Institute, Troy, NY, United States
| | - Elijah Gruszecki
- Department of Chemistry and Chemical Biology and The Baruch ’60 Center for Biochemical Solar Energy Research, Rensselaer Polytechnic Institute, Troy, NY, United States
| | - John H. Golbeck
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States
- Department of Chemistry, The Pennsylvania State University, University Park, PA, United States
| | - K. V. Lakshmi
- Department of Chemistry and Chemical Biology and The Baruch ’60 Center for Biochemical Solar Energy Research, Rensselaer Polytechnic Institute, Troy, NY, United States
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9
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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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10
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Artiukhin DG, Eschenbach P, Matysik J, Neugebauer J. Theoretical Assessment of Hinge-Type Models for Electron Donors in Reaction Centers of Photosystems I and II as well as of Purple Bacteria. J Phys Chem B 2021; 125:3066-3079. [PMID: 33749260 DOI: 10.1021/acs.jpcb.0c10656] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hinge-type molecular models for electron donors in reaction centers of Photosystems I and II and purple bacteria were investigated using a two-state computational approach based on frozen-density embedding (FDE). This methodology, dubbed FDE-diab, is known to avoid consequences of the self-interaction error as far as intermolecular phenomena are concerned, which allows a prediction of qualitatively correct spin densities for large biomolecular systems. The calculated spin density distributions are in a good agreement with available experimental results and demonstrated a very high sensitivity to changes in the relative orientation of cofactors and amino acid protonation states. This allows a validation of the previously proposed hinge-type models providing hints on possible protonation states of axial histidine molecules.
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Affiliation(s)
- Denis G Artiukhin
- Department of Chemistry, Aarhus Universitet, DK-8000 Aarhus, Denmark
| | - Patrick Eschenbach
- Theoretische Organische Chemie, Organisch-Chemisches Institut and Center for Multiscale Theory and Simulation, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany
| | - Jörg Matysik
- Institut für Analytische Chemie, Universität Leipzig, Linnéstr. 3, 04103 Leipzig, Germany
| | - Johannes Neugebauer
- Theoretische Organische Chemie, Organisch-Chemisches Institut and Center for Multiscale Theory and Simulation, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany
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11
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Gorka M, Gruszecki E, Charles P, Kalendra V, Lakshmi KV, Golbeck JH. Two-dimensional HYSCORE spectroscopy reveals a histidine imidazole as the axial ligand to Chl 3A in the M688H PsaA genetic variant of Photosystem I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2021; 1862:148424. [PMID: 33785317 DOI: 10.1016/j.bbabio.2021.148424] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 02/28/2021] [Accepted: 03/24/2021] [Indexed: 12/17/2022]
Abstract
Recent studies on Photosystem I (PS I) have shown that the six core chlorophyll a molecules are highly coupled, allowing for efficient creation and stabilization of the charge-separated state. One area of particular interest is the identity and function of the primary acceptor, A0, as the factors that influence its ultrafast processes and redox properties are not yet fully elucidated. It was recently shown that A0 exists as a dimer of the closely-spaced Chl2/Chl3 molecules wherein the reduced A0- state has an asymmetric distribution of electron spin density that favors Chl3. Previous experimental work in which this ligand was changed to a hard base (histidine, M688HPsaA) revealed severely impacted electron transfer processes at both the A0 and A1 acceptors; molecular dynamics simulations further suggested two distinct conformations of PS I in which the His residue coordinates and forms a hydrogen bond to the A0 and A1 cofactors, respectively. In this study, we have applied 2D HYSCORE spectroscopy in conjunction with molecular dynamics simulations and density functional theory calculations to the study of the M688HPsaA variant. Analysis of the hyperfine parameters demonstrates that the His imidazole serves as the axial ligand to the central Mg2+ ion in Chl3A in the M688HPsaA variant. Although the change in ligand identity does not alter delocalization of electron density over the Chl2/Chl3 dimer, a small shift in the asymmetry of delocalization, coupled with the electron withdrawing properties of the ligand, most likely accounts for the inhibition of forward electron transfer in the His-ligated conformation.
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Affiliation(s)
- Michael Gorka
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, State College, PA 16802, USA
| | - Elijah Gruszecki
- Department of Chemistry and Chemical Biology and The Baruch '60 Center for Biochemical Solar Energy Research, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Philip Charles
- Department of Chemistry and Chemical Biology and The Baruch '60 Center for Biochemical Solar Energy Research, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Vidmantas Kalendra
- Department of Chemistry and Chemical Biology and The Baruch '60 Center for Biochemical Solar Energy Research, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - K V Lakshmi
- Department of Chemistry and Chemical Biology and The Baruch '60 Center for Biochemical Solar Energy Research, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
| | - John H Golbeck
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, State College, PA 16802, USA; Department of Chemistry, The Pennsylvania State University, State College, PA 16802, USA.
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12
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Mitsuhashi K, Tamura H, Saito K, Ishikita H. Nature of Asymmetric Electron Transfer in the Symmetric Pathways of Photosystem I. J Phys Chem B 2021; 125:2879-2885. [DOI: 10.1021/acs.jpcb.0c10885] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Koji Mitsuhashi
- Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
| | - 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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13
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Acquirement of water-splitting ability and alteration of the charge-separation mechanism in photosynthetic reaction centers. Proc Natl Acad Sci U S A 2020; 117:16373-16382. [PMID: 32601233 PMCID: PMC7368266 DOI: 10.1073/pnas.2000895117] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
In photosynthetic reaction centers from purple bacteria (PbRC) and the water-oxidizing enzyme, photosystem II (PSII), charge separation occurs along one of the two symmetrical electron-transfer branches. Here we report the microscopic origin of the unidirectional charge separation, fully considering electron-hole interaction, electronic coupling of the pigments, and electrostatic interaction with the polarizable entire protein environments. The electronic coupling between the pair of bacteriochlorophylls is large in PbRC, forming a delocalized excited state with the lowest excitation energy (i.e., the special pair). The charge-separated state in the active branch is stabilized by uncharged polar residues in the transmembrane region and charged residues on the cytochrome c 2 binding surface. In contrast, the accessory chlorophyll in the D1 protein (ChlD1) has the lowest excitation energy in PSII. The charge-separated state involves ChlD1 •+ and is stabilized predominantly by charged residues near the Mn4CaO5 cluster and the proceeding proton-transfer pathway. It seems likely that the acquirement of water-splitting ability makes ChlD1 the initial electron donor in PSII.
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Artiukhin DG, Eschenbach P, Neugebauer J. Computational Investigation of the Spin-Density Asymmetry in Photosynthetic Reaction Center Models from First Principles. J Phys Chem B 2020; 124:4873-4888. [DOI: 10.1021/acs.jpcb.0c02827] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Patrick Eschenbach
- Theoretische Organische Chemie, Organisch-Chemisches Institut and Center for Multiscale Theory and Simulation, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany
| | - Johannes Neugebauer
- Theoretische Organische Chemie, Organisch-Chemisches Institut and Center for Multiscale Theory and Simulation, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany
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15
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Mandal M, Kawashima K, Saito K, Ishikita H. Redox Potential of the Oxygen-Evolving Complex in the Electron Transfer Cascade of Photosystem II. J Phys Chem Lett 2020; 11:249-255. [PMID: 31729876 DOI: 10.1021/acs.jpclett.9b02831] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In photosystem II (PSII), water oxidation occurs in the Mn4CaO5 cluster with the release of electrons via the redox-active tyrosine (TyrZ) to the reaction-center chlorophylls (PD1/PD2). Using a quantum mechanical/molecular mechanical approach, we report the redox potentials (Em) of these cofactors in the PSII protein environment. The Em values suggest that the Mn4CaO5 cluster, TyrZ, and PD1/PD2 form a downhill electron transfer pathway. Em for the first oxidation step, Em(S0/S1), is uniquely low (730 mV) and is ∼100 mV lower than that for the second oxidation step, Em(S1/S2) (830 mV) only when the O4 site of the Mn4CaO5 cluster is protonated in S0. The O4-water chain, which directly forms a low-barrier H-bond with the Mn4CaO5 cluster and mediates proton-coupled electron transfer in the S0 to S1 transition, explains why the second lowest oxidation state, S1, is the most stable and S0 is converted to S1 even in the dark.
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Affiliation(s)
- Manoj Mandal
- Research Center for Advanced Science and Technology , The University of Tokyo , 4-6-1 Komaba , Meguro-ku, Tokyo 153-8904 , Japan
| | - Keisuke Kawashima
- Department of Applied Chemistry , The University of Tokyo , 7-3-1 Hongo , Bunkyo-ku, Tokyo 113-8654 , Japan
| | - Keisuke Saito
- Research Center for Advanced Science and Technology , The University of Tokyo , 4-6-1 Komaba , Meguro-ku, Tokyo 153-8904 , Japan
- Department of Applied Chemistry , The University of Tokyo , 7-3-1 Hongo , Bunkyo-ku, Tokyo 113-8654 , Japan
| | - Hiroshi Ishikita
- Research Center for Advanced Science and Technology , The University of Tokyo , 4-6-1 Komaba , Meguro-ku, Tokyo 153-8904 , Japan
- Department of Applied Chemistry , The University of Tokyo , 7-3-1 Hongo , Bunkyo-ku, Tokyo 113-8654 , Japan
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Saito K, Mandal M, Ishikita H. Redox potentials along the redox-active low-barrier H-bonds in electron transfer pathways. Phys Chem Chem Phys 2020; 22:25467-25473. [DOI: 10.1039/d0cp04265j] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Local proton transfer along redox-active low-barrier H-bonds can alter the driving force or electronic coupling for electron transfer, as the redox potential values depend on the H+ position in low-barrier H-bonds.
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Affiliation(s)
- Keisuke Saito
- Research Center for Advanced Science and Technology
- The University of Tokyo
- Tokyo 153-8904
- Japan
- Department of Applied Chemistry
| | - Manoj Mandal
- Research Center for Advanced Science and Technology
- The University of Tokyo
- Tokyo 153-8904
- Japan
| | - Hiroshi Ishikita
- Research Center for Advanced Science and Technology
- The University of Tokyo
- Tokyo 153-8904
- Japan
- Department of Applied Chemistry
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Kawashima K, Ishikita H. Structural Factors That Alter the Redox Potential of Quinones in Cyanobacterial and Plant Photosystem I. Biochemistry 2017; 56:3019-3028. [PMID: 28530393 DOI: 10.1021/acs.biochem.7b00082] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Using the cyanobacterial and plant photosystem I (PSI) crystal structures and by considering the protonation states of all titratable residues, redox potentials (Em) of the two phylloquinones-A1A and A1B-were calculated. The calculated Em values were Em(A1A) = -773 mV and Em(A1B) = -818 mV for the plant PSI structure and Em(A1A) = -612 mV and Em(A1B) = -719 mV for the cyanobacterial PSI structure. Our analysis of the PSI crystal structures suggested that the side-chain orientations of Lys-B542 and Gln-B678 in the cyanobacterial crystal structure differ from these side-chain orientations in the plant crystal structure. Quantum mechanical/molecular mechanical calculations indicated that the geometry of the cyanobacterial PSI crystal structure was best described as the conformation where Asp-B575 is protonated and A1A is reduced to A1A•-, which might represent the high-potential A1A form ( Rutherford, A. W., Osyczka, A., Rappaport, F. ( 2012 ) FEBS Lett. 586 , 603 - 616 ). Reorienting the Lys-B542 and Gln-B678 side-chains and rearranging the H-bond pattern of the water cluster near Asp-B575 lowered the Em to Em(A1A) = -718 mV and Em(A1B) = -795 mV. It seems possible that PSI has two conformations: the high-potential A1A form and the low-potential A1A form.
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Affiliation(s)
- Keisuke Kawashima
- Department of Applied Chemistry, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, 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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Nagao R, Yamaguchi M, Nakamura S, Ueoka-Nakanishi H, Noguchi T. Genetically introduced hydrogen bond interactions reveal an asymmetric charge distribution on the radical cation of the special-pair chlorophyll P680. J Biol Chem 2017; 292:7474-7486. [PMID: 28302724 DOI: 10.1074/jbc.m117.781062] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Revised: 03/08/2017] [Indexed: 11/06/2022] Open
Abstract
The special-pair chlorophyll (Chl) P680 in photosystem II has an extremely high redox potential (Em ) to enable water oxidation in photosynthesis. Significant positive-charge localization on one of the Chl constituents, PD1 or PD2, in P680+ has been proposed to contribute to this high Em To identify the Chl molecule on which the charge is mainly localized, we genetically introduced a hydrogen bond to the 131-keto C=O group of PD1 and PD2 by changing the nearby D1-Val-157 and D2-Val-156 residues to His, respectively. Successful hydrogen bond formation at PD1 and PD2 in the obtained D1-V157H and D2-V156H mutants, respectively, was monitored by detecting 131-keto C=O vibrations in Fourier transfer infrared (FTIR) difference spectra upon oxidation of P680 and the symmetrically located redox-active tyrosines YZ and YD, and they were simulated by quantum-chemical calculations. Analysis of the P680+/P680 FTIR difference spectra of D1-V157H and D2-V156H showed that upon P680+ formation, the 131-keto C=O frequency upshifts by a much larger extent in PD1 (23 cm-1) than in PD2 (<9 cm-1). In addition, thermoluminescence measurements revealed that the D1-V157H mutation increased the Em of P680 to a larger extent than did the D2-V156H mutation. These results, together with the previous results for the mutants of the His ligands of PD1 and PD2, lead to a definite conclusion that a charge is mainly localized to PD1 in P680<sup/>.
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Affiliation(s)
- Ryo Nagao
- From the Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Motoki Yamaguchi
- From the Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Shin Nakamura
- From the Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Hanayo Ueoka-Nakanishi
- From the Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Takumi Noguchi
- From the Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
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Zill JC, Kansy M, Goss R, Köhler L, Alia A, Wilhelm C, Matysik J. Photo-CIDNP in the Reaction Center of the Diatom Cyclotella meneghiniana Observed by 13C MAS NMR. Z PHYS CHEM 2016. [DOI: 10.1515/zpch-2016-0806] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Photo-CIDNP MAS NMR presents a unique tool to obtain insight into the photosynthetic reaction centers (RCs) of bacteria and plants. Using the dramatic enhancement of sensitivity and selectivity of the solid-state photo-CIDNP effect, structural as well as functional information can be obtained from the cofactor molecules forming a light-induced spin-correlated radical pair (SCRP) in a given reaction center. Here we demonstrate that the effect can be observed in a further species, which belongs neither to the plant nor the bacteria kingdom. Cyclotella (C.) meneghiniana is a member of the diatom phylum and, therefore, belongs to the kingdom of chromista. Chromista are some of the most productive organisms in nature, even in comparison to trees and terrestrial grasses. The observation of the effect in chromista indicates that the effect occurs in all photosynthetic organisms and completes the list with the last phototrophic kingdoms. Our data also demonstrate that the photo- and spin-chemical machineries of photosystem I of plants and chromista are very similar with respect to structure as well as function.
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Affiliation(s)
- Jeremias C. Zill
- University of Leipzig, Institute of Analytical Chemistry, Johannisallee 29, D-04103 Leipzig, Germany
| | - Marcel Kansy
- University of Leipzig, Institute of Biology, Abteilung Pflanzenphysiologie, Johannisallee 21-23, D-04103 Leipzig, Germany
| | - Reimund Goss
- University of Leipzig, Institute of Biology, Abteilung Pflanzenphysiologie, Johannisallee 21-23, D-04103 Leipzig, Germany
| | - Lisa Köhler
- 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
| | - Christian Wilhelm
- University of Leipzig, Institute of Biology, Abteilung Pflanzenphysiologie, Johannisallee 21-23, D-04103 Leipzig, Germany
| | - Jörg Matysik
- University of Leipzig, Institute of Analytical Chemistry, Johannisallee 29, D-04103 Leipzig, Germany
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20
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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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21
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Temperature dependence of the oxidation kinetics of TyrZ and TyrD in oxygen-evolving photosystem II complexes throughout the range from 320K to 5K. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:1283-96. [DOI: 10.1016/j.bbabio.2015.07.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 07/10/2015] [Accepted: 07/15/2015] [Indexed: 11/21/2022]
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22
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Möbius K, Lubitz W, Savitsky A. High-field EPR on membrane proteins - crossing the gap to NMR. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2013; 75:1-49. [PMID: 24160760 DOI: 10.1016/j.pnmrs.2013.07.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 07/15/2013] [Accepted: 07/15/2013] [Indexed: 06/02/2023]
Abstract
In this review on advanced EPR spectroscopy, which addresses both the EPR and NMR communities, considerable emphasis is put on delineating the complementarity of NMR and EPR concerning the measurement of molecular interactions in large biomolecules. From these interactions, detailed information can be revealed on structure and dynamics of macromolecules embedded in solution- or solid-state environments. New developments in pulsed microwave and sweepable cryomagnet technology as well as ultrafast electronics for signal data handling and processing have pushed to new horizons the limits of EPR spectroscopy and its multifrequency extensions concerning the sensitivity of detection, the selectivity with respect to interactions, and the resolution in frequency and time domains. One of the most important advances has been the extension of EPR to high magnetic fields and microwave frequencies, very much in analogy to what happens in NMR. This is exemplified by referring to ongoing efforts for signal enhancement in both NMR and EPR double-resonance techniques by exploiting dynamic nuclear or electron spin polarization via unpaired electron spins and their electron-nuclear or electron-electron interactions. Signal and resolution enhancements are particularly spectacular for double-resonance techniques such as ENDOR and PELDOR at high magnetic fields. They provide greatly improved orientational selection for disordered samples that approaches single-crystal resolution at canonical g-tensor orientations - even for molecules with small g-anisotropies. Exchange of experience between the EPR and NMR communities allows for handling polarization and resolution improvement strategies in an optimal manner. Consequently, a dramatic improvement of EPR detection sensitivity could be achieved, even for short-lived paramagnetic reaction intermediates. Unique structural and dynamic information is thus revealed that can hardly be obtained by any other analytical techniques. Micromolar quantities of sample molecules have become sufficient to characterize stable and transient reaction intermediates of complex molecular systems - offering highly interesting applications for chemists, biochemists and molecular biologists. In three case studies, representative examples of advanced EPR spectroscopy are reviewed: (I) High-field PELDOR and ENDOR structure determination of cation-anion radical pairs in reaction centers from photosynthetic purple bacteria and cyanobacteria (Photosystem I); (II) High-field ENDOR and ELDOR-detected NMR spectroscopy on the oxygen-evolving complex of Photosystem II; and (III) High-field electron dipolar spectroscopy on nitroxide spin-labelled bacteriorhodopsin for structure-function studies. An extended conclusion with an outlook to further developments and applications is also presented.
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Affiliation(s)
- Klaus Möbius
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany; Department of Physics, Free University Berlin, Arnimallee 14, D-14195 Berlin, Germany.
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Alia A, Buda F, de Groot HJ, Matysik J. Solid-State NMR of Nanomachines Involved in Photosynthetic Energy Conversion. Annu Rev Biophys 2013; 42:675-99. [DOI: 10.1146/annurev-biophys-083012-130415] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Magic-angle spinning NMR, often in combination with photo-CIDNP, is applied to determine how photosynthetic antennae and reaction centers are activated in the ground state to perform their biological function upon excitation by light. Molecular modeling resolves molecular mechanisms by way of computational integration of NMR data with other structure-function analyses. By taking evolutionary historical contingency into account, a better biophysical understanding is achieved. Chlorophyll cofactors and proteins go through self-assembly trajectories that are engineered during evolution and lead to highly homogeneous protein complexes optimized for exciton or charge transfer. Histidine-cofactor interactions allow biological nanomachines to lower energy barriers for light harvesting and charge separation in photosynthetic energy conversion. In contrast, in primordial chlorophyll antenna aggregates, excessive heterogeneity is paired with much less specific characteristics, and both exciton and charge-transfer character are encoded in the ground state.
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Affiliation(s)
- A. Alia
- Solid State NMR, Leiden Institute of Chemistry, Leiden University, Leiden 2300 RB, The Netherlands;, , ,
| | - Francesco Buda
- Solid State NMR, Leiden Institute of Chemistry, Leiden University, Leiden 2300 RB, The Netherlands;, , ,
| | - Huub J.M. de Groot
- Solid State NMR, Leiden Institute of Chemistry, Leiden University, Leiden 2300 RB, The Netherlands;, , ,
| | - Jörg Matysik
- Solid State NMR, Leiden Institute of Chemistry, Leiden University, Leiden 2300 RB, The Netherlands;, , ,
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Olson TL, Williams JC, Allen JP. Influence of protein interactions on oxidation/reduction midpoint potentials of cofactors in natural and de novo metalloproteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:914-22. [PMID: 23466333 DOI: 10.1016/j.bbabio.2013.02.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 02/13/2013] [Accepted: 02/23/2013] [Indexed: 01/14/2023]
Abstract
As discussed throughout this special issue, oxidation and reduction reactions play critical roles in the function of many organisms. In photosynthetic organisms, the conversion of light energy drives oxidation and reduction reactions through the transfer of electrons and protons in order to create energy-rich compounds. These reactions occur in proteins such as cytochrome c, a heme-containing water-soluble protein, the bacteriochlorophyll-containing reaction center, and photosystem II where water is oxidized at the manganese cluster. A critical measure describing the ability of cofactors in proteins to participate in such reactions is the oxidation/reduction midpoint potential. In this review, the basic concepts of oxidation/reduction reactions are reviewed with a summary of the experimental approaches used to measure the midpoint potential of metal cofactors. For cofactors in proteins, the midpoint potential not only depends upon the specific chemical characteristics of cofactors but also upon interactions with the surrounding protein, such as the nature of the coordinating ligands and protein environment. These interactions can be tailored to optimize an oxidation/reduction reaction carried out by the protein. As examples, the midpoint potentials of hemes in cytochromes, bacteriochlorophylls in reaction centers, and the manganese cluster of photosystem II are discussed with an emphasis on the influence that protein interactions have on these potentials. This article is part of a Special Issue entitled: Metals in Bioenergetics and Biomimetics Systems.
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Affiliation(s)
- T L Olson
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287-1604, USA
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Saito K, Shen JR, Ishikita H. Influence of the axial ligand on the cationic properties of the chlorophyll pair in photosystem II from Thermosynechococcus vulcanus. Biophys J 2012; 102:2634-40. [PMID: 22713579 DOI: 10.1016/j.bpj.2012.04.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 04/12/2012] [Accepted: 04/16/2012] [Indexed: 11/26/2022] Open
Abstract
Influence of the axial ligand of PD1 chlorophyll (D1-His-198) on the Em of monomer chlorophylls PD1 and PD2, and the PD1•+/PD2•+ charge ratio was investigated by theoretical calculations using the PSII crystal structure of Thermosynechococcus vulcanus analyzed at 1.9-Å resolution. It was found that the Em(PD1)/Em(PD2) values and PD1•+/PD2•+ ratio remained unchanged upon D1-H198Q mutation. However, Em(PD1) was increased in the D1-H198A mutant, resulting in a more even distribution of the positive charge over PD1/PD2. Introduction of a water molecule as an axial ligand resulted in equal Em values and PD1•+/PD2•+ ratios between the mutant and wild-type, thus confirming the presence of the water ligand in the mutant.
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Affiliation(s)
- Keisuke Saito
- Career-Path Promotion Unit for Young Life Scientists, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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26
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Saito K, Umena Y, Kawakami K, Shen JR, Kamiya N, Ishikita H. Deformation of Chlorin Rings in the Photosystem II Crystal Structure. Biochemistry 2012; 51:4290-9. [DOI: 10.1021/bi300428s] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Keisuke Saito
- 202 Building E, Career-Path
Promotion Unit for Young Life Scientists, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto
606-8501, Japan
| | - Yasufumi Umena
- The OCU
Advanced Research Institute
for Natural Science and Technology (OCARINA)/Graduate School of Science, Osaka City University, Sumiyoshi, Osaka 558-8585, Japan
- Japan Science and Technology Agency (JST), Precursory Research for Embryonic
Science and Technology, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012,
Japan
| | - Keisuke Kawakami
- The OCU
Advanced Research Institute
for Natural Science and Technology (OCARINA)/Graduate School of Science, Osaka City University, Sumiyoshi, Osaka 558-8585, Japan
| | - Jian-Ren Shen
- Division of Bioscience,
Graduate
School of Natural Science and Technology/Faculty of Science, Okayama University, Okayama 700-8530, Japan
| | - Nobuo Kamiya
- The OCU
Advanced Research Institute
for Natural Science and Technology (OCARINA)/Graduate School of Science, Osaka City University, Sumiyoshi, Osaka 558-8585, Japan
- Graduate School of Science, Osaka City University, Sumiyoshi, Osaka 558-8585, Japan
| | - Hiroshi Ishikita
- 202 Building E, Career-Path
Promotion Unit for Young Life Scientists, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto
606-8501, Japan
- Japan Science and Technology Agency (JST), Precursory Research for Embryonic
Science and Technology, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012,
Japan
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Saito K, Ishikita H. Cationic state distribution over the P700 chlorophyll pair in photosystem I. Biophys J 2012; 101:2018-25. [PMID: 22004756 DOI: 10.1016/j.bpj.2011.09.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 09/01/2011] [Accepted: 09/08/2011] [Indexed: 10/16/2022] Open
Abstract
The primary electron donor P700 in photosystem I is composed of two chlorophylls, P(A) and P(B). P700 forms the cationic [P(A)/P(B)](•+) state as a result of light-induced electron transfer. We obtained a P(A)(•+)/P(B)(•+) ratio of 28:72 and a spin distribution of 22:78 for the entire PSI protein-pigment complex. By considering the influence of the protein components on the redox potential for one-electron oxidation of P(A)/P(B) monomers, we found that the following three factors significantly contributed to a large P(B)(•+) population relative to P(A)(•+): 1), Thr-A743 forming a H-bond with P(A); 2), P(A) as a chlorophyll a epimer; and 3), a conserved PsaA/PsaB pair, the Arg-A750/Ser-B734 residue. In addition, 4), the methyl-ester groups of the accessory chlorophylls A(-1A)/A(-1B) significantly stabilized the cationic [P(A)/P(B)](•+) state and 5), the methyl-ester group orientations were completely different in A(-1A) and A(-1B) as seen in the crystal structure. When the methyl-ester group was rotated, the spin-density distribution over P(A)/P(B) ranged from 22:78 to 15:85.
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Affiliation(s)
- Keisuke Saito
- Career-Path Promotion Unit for Young Life Scientists, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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28
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Saito K, Shen JR, Ishikita H. Cationic state distribution over the chlorophyll d-containing P(D1)/P(D2) pair in photosystem II. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1817:1191-5. [PMID: 22192718 DOI: 10.1016/j.bbabio.2011.12.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 12/02/2011] [Accepted: 12/06/2011] [Indexed: 11/25/2022]
Abstract
Most of the chlorophyll (Chl) cofactors in photosystem II (PSII) from Acaryochloris marina are Chld, although a few Chla molecules are also present. To evaluate the possibility that Chla may participate in the P(D1)/P(D2) Chl pair in PSII from A. marina, the P(D1)(•+)/P(D2)(•+) charge ratio was investigated using the PSII crystal structure analyzed at 1.9-Å resolution, while considering all possibilities for the Chld-containing P(D1)/P(D2) pair, i.e., Chld/Chld, Chla/Chld, and Chld/Chla pairs. Chld/Chld and Chla/Chld pairs resulted in a large P(D1)(•+) population relative to P(D2)(•+), as identified in Chla/Chla homodimer pairs in PSII from other species, e.g., Thermosynechococcus elongatus PSII. However, the Chld/Chla pair possessed a P(D1)(•+)/P(D2)(•+) ratio of approximately 50/50, which is in contrast to previous spectroscopic studies on A. marina PSII. The present results strongly exclude the possibility that the Chld/Chla pair serves as P(D1)/P(D2) in A. marina PSII. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.
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Affiliation(s)
- Keisuke Saito
- Graduate School of Medicine, Kyoto University, Kyoto, Japan
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Kitagawa Y, Matsuda K, Hasegawa JY. Theoretical study of the excited states of the photosynthetic reaction center in photosystem II: Electronic structure, interactions, and their origin. Biophys Chem 2011; 159:227-36. [DOI: 10.1016/j.bpc.2011.06.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2011] [Revised: 06/17/2011] [Accepted: 06/17/2011] [Indexed: 11/29/2022]
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SUN YUMING, DAI ZHENHONG, WANG WEITIAN, SUN YUANPING. A DFT STUDY ON THE ELECTRONIC CHARACTER OF P700+. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2011. [DOI: 10.1142/s0219633606002751] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This density functional study is devoted to the long debated electronic nature of P700+. We found that P700+ is intrinsically a dimer of chlorophyll molecules. The unpaired electron spin distributes equally over two chlorophyll molecule halves in the bare P700+, while the dressed P700+ shows the spin density asymmetry mainly coming from the H-bond donated to 131-keto-O of one half. The experimental contradictions on the electronic nature of P700+ are also discussed.
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Affiliation(s)
- YUMING SUN
- Department of Physics, Yantai University, 30 St Qingquon, Yantai 264005, China
| | - ZHENHONG DAI
- Department of Physics, Yantai University, 30 St Qingquon, Yantai 264005, China
| | - WEITIAN WANG
- Department of Physics, Yantai University, 30 St Qingquon, Yantai 264005, China
| | - YUANPING SUN
- Department of Physics, Yantai University, 30 St Qingquon, Yantai 264005, China
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Saito K, Ishida T, Sugiura M, Kawakami K, Umena Y, Kamiya N, Shen JR, Ishikita H. Distribution of the Cationic State over the Chlorophyll Pair of the Photosystem II Reaction Center. J Am Chem Soc 2011; 133:14379-88. [DOI: 10.1021/ja203947k] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Keisuke Saito
- 202 Building E, Career-Path Promotion Unit for Young Life Scientists, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Toyokazu Ishida
- Nanosystem Research Institute (NRI), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Miwa Sugiura
- Cell-Free Science and Technology Research Center, Ehime University, Bunkyo-cho, Matsuyama, Ehime, 790-8577, Japan
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan
| | - Keisuke Kawakami
- Department of Chemistry, Graduate School of Science, and The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka City University, Sumiyoshi, Osaka 558-8585, Japan
| | - Yasufumi Umena
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Nobuo Kamiya
- Department of Chemistry, Graduate School of Science, and The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka City University, Sumiyoshi, Osaka 558-8585, Japan
| | - Jian-Ren Shen
- Division of Bioscience, Graduate School of Natural Science and Technology/Faculty of Science, Okayama University, Okayama 700-8530, Japan
| | - Hiroshi Ishikita
- 202 Building E, Career-Path Promotion Unit for Young Life Scientists, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan
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Shinopoulos KE, Brudvig GW. Cytochrome b₅₅₉ and cyclic electron transfer within photosystem II. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1817:66-75. [PMID: 21864501 DOI: 10.1016/j.bbabio.2011.08.002] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 08/06/2011] [Accepted: 08/08/2011] [Indexed: 11/18/2022]
Abstract
Cytochrome b₅₅₉ (Cyt b₅₅₉), β-carotene (Car), and chlorophyll (Chl) cofactors participate in the secondary electron-transfer pathways in photosystem II (PSII), which are believed to protect PSII from photodamage under conditions in which the primary electron-donation pathway leading to water oxidation is inhibited. Among these cofactors, Cyt b₅₅₉ is preferentially photooxidized under conditions in which the primary electron-donation pathway is blocked. When Cyt b₅₅₉ is preoxidized, the photooxidation of several of the 11 Car and 35 Chl molecules present per PSII is observed. In this review, the discovery of the secondary electron donors, their structures and electron-transfer properties, and progress in the characterization of the secondary electron-transfer pathways are discussed. This article is part of a Special Issue entitled: Photosystem II.
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Renger T, Schlodder E. Optical properties, excitation energy and primary charge transfer in photosystem II: theory meets experiment. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2011; 104:126-41. [PMID: 21531572 DOI: 10.1016/j.jphotobiol.2011.03.016] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Revised: 03/04/2011] [Accepted: 03/21/2011] [Indexed: 11/29/2022]
Abstract
In this review we discuss structure-function relationships of the core complex of photosystem II, as uncovered from analysis of optical spectra of the complex and its subunits. Based on descriptions of optical difference spectra including site directed mutagenesis we propose a revision of the multimer model of the symmetrically arranged reaction center pigments, described by an asymmetric exciton Hamiltonian. Evidence is provided for the location of the triplet state, the identity of the primary electron donor, the localization of the cation and the secondary electron transfer pathway in the reaction center. We also discuss the stationary and time-dependent optical properties of the CP43 and CP47 subunits and the excitation energy transfer and trapping-by-charge-transfer kinetics in the core complex.
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Affiliation(s)
- Thomas Renger
- Institut für Theoretische Physik, Johannes Kepler Universität, Abteilung Theoretische Biophysik, Austria.
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Renger T, Schlodder E. Primary Photophysical Processes in Photosystem II: Bridging the Gap between Crystal Structure and Optical Spectra. Chemphyschem 2010; 11:1141-53. [DOI: 10.1002/cphc.200900932] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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D1 protein variants in Photosystem II from Thermosynechococcus elongatus studied by low temperature optical spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:11-9. [DOI: 10.1016/j.bbabio.2009.07.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Revised: 07/17/2009] [Accepted: 07/20/2009] [Indexed: 11/24/2022]
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YAMASAKI H, TAKANO Y, NAKAMURA H. The Structural Origin of the Electronic Asymmetry of the Special Pair in the Photosynthetic Reaction Center: Quantum Chemical and Bioinformatics Approaches. ACTA ACUST UNITED AC 2009. [DOI: 10.2142/biophys.49.084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
| | - Yu TAKANO
- Institute for Protein Research, Osaka University
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Yamasaki H, Takano Y, Nakamura H. Theoretical Investigation of the Electronic Asymmetry of the Special Pair Cation Radical in the Photosynthetic Type-II Reaction Center. J Phys Chem B 2008; 112:13923-33. [DOI: 10.1021/jp806309p] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Hideki Yamasaki
- Institute for Protein Research, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Yu Takano
- Institute for Protein Research, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Haruki Nakamura
- Institute for Protein Research, Osaka University, Suita, Osaka, 565-0871, Japan
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Khatypov RA, Khmelnitskiy AY, Leonova MM, Vasilieva LG, Shuvalov VA. Primary light-energy conversion in tetrameric chlorophyll structure of photosystem II and bacterial reaction centers: I. A review. PHOTOSYNTHESIS RESEARCH 2008; 98:81-93. [PMID: 18853274 DOI: 10.1007/s11120-008-9370-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2008] [Accepted: 09/15/2008] [Indexed: 05/26/2023]
Abstract
The purpose of the review is to show that the tetrameric (bacterio)chlorophyll ((B)Chl) structures in reaction centers of photosystem II (PSII) of green plants and in bacterial reaction centers (BRCs) are similar and play a key role in the primary charge separation. The Stark effect measurements on PSII reaction centers have revealed an increased dipole moment for the transition at approximately 730 nm (Frese et al., Biochemistry 42:9205-9213, 2003). It was found (Heber and Shuvalov, Photosynth Res 84:84-91, 2005) that two fluorescent bands at 685 and 720 nm are observed in different organisms. These two forms are registered in the action spectrum of Q(A) photoreduction. Similar results were obtained in core complexes of PSII at low temperature (Hughes et al., Biochim Biophys Acta 1757: 841-851, 2006). In all cases the far-red absorption and emission can be interpreted as indication of the state with charge transfer character in which the chlorophyll monomer plays a role of an electron donor. The role of bacteriochlorophyll monomers (B(A) and B(B)) in BRCs can be revealed by different mutations of axial ligand for Mg central atoms. RCs with substitution of histidine L153 by tyrosine or leucine and of histidine M182 by leucine (double mutant) are not stable in isolated state. They were studied in antennaless membrane by different kinds of spectroscopy including one with femtosecond time resolution. It was found that the single mutation (L153HY) was accompanied by disappearance of B(A) molecule absorption near 802 nm and by 14-fold decrease of photochemical activity measured with ms time resolution. The lifetime of P(870)* increased up to approximately 200 ps in agreement with very low rate of the electron transfer to A-branch. In the double mutant L153HY + M182HL, the B(A) appears to be lost and B(B) is replaced by bacteriopheophytin Phi(B) with the absence of any absorption near 800 nm. Femtosecond measurements have revealed the electron transfer to B-branch with a time constant of approximately 2 ps. These results are discussed in terms of obligatory role of B(A) and Phi(B) molecules located near P for efficient electron transfer from P*.
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Affiliation(s)
- Ravil A Khatypov
- Institute of Basic Biological Problems, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia
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Spectroscopic properties of reaction center pigments in photosystem II core complexes: revision of the multimer model. Biophys J 2008; 95:105-19. [PMID: 18339736 DOI: 10.1529/biophysj.107.123935] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Absorbance difference spectra associated with the light-induced formation of functional states in photosystem II core complexes from Thermosynechococcus elongatus and Synechocystis sp. PCC 6803 (e.g., P(+)Pheo(-),P(+)Q(A)(-),(3)P) are described quantitatively in the framework of exciton theory. In addition, effects are analyzed of site-directed mutations of D1-His(198), the axial ligand of the special-pair chlorophyll P(D1), and D1-Thr(179), an amino-acid residue nearest to the accessory chlorophyll Chl(D1), on the spectral properties of the reaction center pigments. Using pigment transition energies (site energies) determined previously from independent experiments on D1-D2-cytb559 complexes, good agreement between calculated and experimental spectra is obtained. The only difference in site energies of the reaction center pigments in D1-D2-cytb559 and photosystem II core complexes concerns Chl(D1). Compared to isolated reaction centers, the site energy of Chl(D1) is red-shifted by 4 nm and less inhomogeneously distributed in core complexes. The site energies cause primary electron transfer at cryogenic temperatures to be initiated by an excited state that is strongly localized on Chl(D1) rather than from a delocalized state as assumed in the previously described multimer model. This result is consistent with earlier experimental data on special-pair mutants and with our previous calculations on D1-D2-cytb559 complexes. The calculations show that at 5 K the lowest excited state of the reaction center is lower by approximately 10 nm than the low-energy exciton state of the two special-pair chlorophylls P(D1) and P(D2) which form an excitonic dimer. The experimental temperature dependence of the wild-type difference spectra can only be understood in this model if temperature-dependent site energies are assumed for Chl(D1) and P(D1), reducing the above energy gap from 10 to 6 nm upon increasing the temperature from 5 to 300 K. At physiological temperature, there are considerable contributions from all pigments to the equilibrated excited state P*. The contribution of Chl(D1) is twice that of P(D1) at ambient temperature, making it likely that the primary charge separation will be initiated by Chl(D1) under these conditions. The calculations of absorbance difference spectra provide independent evidence that after primary electron transfer the hole stabilizes at P(D1), and that the physiologically dangerous charge recombination triplets, which may form under light stress, equilibrate between Chl(D1) and P(D1).
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Primary charge separation in the photosystem II core from Synechocystis: a comparison of femtosecond visible/midinfrared pump-probe spectra of wild-type and two P680 mutants. Biophys J 2008; 94:4783-95. [PMID: 18326665 DOI: 10.1529/biophysj.107.122242] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It is now quite well accepted that charge separation in PS2 reaction centers starts predominantly from the accessory chlorophyll B(A) and not from the special pair P(680). To identify spectral signatures of B(A,) and to further clarify the process of primary charge separation, we compared the femtosecond-infrared pump-probe spectra of the wild-type (WT) PS2 core complex from the cyanobacterium Synechocystis sp. PCC 6803 with those of two mutants in which the histidine residue axially coordinated to P(B) (D2-His(197)) has been changed to Ala or Gln. By analogy with the structure of purple bacterial reaction centers, the mutated histidine is proposed to be indirectly H-bonded to the C(9)=O carbonyl of the putative primary donor B(A) through a water molecule. The constructed mutations are thus expected to perturb the vibrational properties of B(A) by modifying the hydrogen bond strength, possibly by displacing the H-bonded water molecule, and to modify the electronic properties and the charge localization of the oxidized donor P(680)(+). Analysis of steady-state light-induced Fourier transform infrared difference spectra of the WT and the D2-His(197)Ala mutant indeed shows that a modification of the axially coordinating ligand to P(B) induces a charge redistribution of P(680)(+). In addition, a comparison of the time-resolved visible/midinfrared spectra of the WT and mutants has allowed us to investigate the changes in the kinetics of primary charge separation induced by the mutations and to propose a band assignment identifying the characteristic vibrations of B(A).
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Schlodder E, Renger T, Raszewski G, Coleman WJ, Nixon PJ, Cohen RO, Diner BA. Site-directed mutations at D1-Thr179 of photosystem II in Synechocystis sp. PCC 6803 modify the spectroscopic properties of the accessory chlorophyll in the D1-branch of the reaction center. Biochemistry 2008; 47:3143-54. [PMID: 18278871 DOI: 10.1021/bi702059f] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
D1-Thr179, which overlies the reaction center chlorophyll Chl D1 of Photosystem II was replaced with His and Glu through site-directed mutation in Synechocystis sp. PCC 6803. Spectroscopic characterization of the mutants indicates that, compared to wild type, the main bleaching in the triplet-minus-singlet absorbance difference spectrum and the electrochromic band shift in the (P680 (+)Q A (-)-P680Q A) absorbance difference spectrum are displaced to the red by approximately 2 nm in the D1-Thr179His mutant and to the blue by approximately 1 nm in the D1-Thr179Glu mutant. These difference spectra are compared with the absorbance difference spectra, measured on the same states in the D1-His198Gln mutant in which the axial ligand D1-His198 of the special pair chlorophyll, P D1, was replaced by glutamine. Together, these results give direct evidence that (a) the reaction center triplet state, produced upon charge recombination from (3)[P (+)Pheo (-)], is primarily localized on Chl D1; (b) the cation of the oxidized donor P (+) is predominantly localized on chlorophyll P D1 of the special pair; and (c) the Q Y band of the accessory chlorophyll Chl D1 is electrochromically shifted in response to charges on P (+) and Q A (-). Light-induced absorbance difference spectra (between 650 and 710 nm), associated with the oxidation of secondary donors and the reduction of Q A, exhibit a bleaching attributed to the oxidation of a Chl Z and strong electrochromic band shifts. On the basis of mutation-induced spectroscopic changes and of structure-based calculations, we conclude that the experimental spectra are best explained by a blue-shift of the Q Y band of the accessory chlorophyll Chl D1, arising from charges on Car D2 (+) and Chl ZD2 (+) and on reduced Q A.
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Affiliation(s)
- Eberhard Schlodder
- Max-Volmer-Laboratorium für Biophysikalische Chemie, Technische Universität Berlin, Germany.
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Diller A, Roy E, Gast P, van Gorkom HJ, de Groot HJM, Glaubitz C, Jeschke G, Matysik J, Alia A. 15N photochemically induced dynamic nuclear polarization magic-angle spinning NMR analysis of the electron donor of photosystem II. Proc Natl Acad Sci U S A 2007; 104:12767-71. [PMID: 17652174 PMCID: PMC1937541 DOI: 10.1073/pnas.0701763104] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In natural photosynthesis, the two photosystems that operate in series to drive electron transport from water to carbon dioxide are quite similar in structure and function, but operate at widely different potentials. In both systems photochemistry begins by photo-oxidation of a chlorophyll a, but that in photosystem II (PS2) has a 0.7 eV higher midpoint potential than that in photosystem I (PS1), so their electronic structures must be very different. Using reaction centers from (15)N-labeled spinach, these electronic structures are compared by their photochemically induced dynamic nuclear polarization (photo-CIDNP) in magic-angle spinning (MAS) NMR measurements. The results show that the electron spin distribution in PS1, apart from its known delocalization over 2 chlorophyll molecules, reveals no marked disturbance, whereas the pattern of electron spin density distribution in PS2 is inverted in the oxidized radical state. A model for the donor of PS2 is presented explaining the inversion of electron spin density based on a tilt of the axial histidine toward pyrrole ring IV causing pi-pi overlap of both aromatic systems.
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Affiliation(s)
- Anna Diller
- *Gorlaeus Laboratoria, Leiden Institute of Chemistry, Einsteinweg 55, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Esha Roy
- *Gorlaeus Laboratoria, Leiden Institute of Chemistry, Einsteinweg 55, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Peter Gast
- Huygens Laboratorium, Leiden Institute of Physics, Niels Bohrweg 2, P.O. Box 9504, 2300 RA Leiden, The Netherlands
| | - Hans J. van Gorkom
- Huygens Laboratorium, Leiden Institute of Physics, Niels Bohrweg 2, P.O. Box 9504, 2300 RA Leiden, The Netherlands
| | - Huub J. M. de Groot
- *Gorlaeus Laboratoria, Leiden Institute of Chemistry, Einsteinweg 55, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Clemens Glaubitz
- Institute of Biophysical Chemistry, Johann Wolfgang Goethe Universität, Max-von-Laue-Strasse 9, 60438 Frankfurt/Main, Germany; and
| | - Gunnar Jeschke
- Department of Chemistry, Universität Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
| | - Jörg Matysik
- *Gorlaeus Laboratoria, Leiden Institute of Chemistry, Einsteinweg 55, P.O. Box 9502, 2300 RA Leiden, The Netherlands
- To whom correspondence should be addressed. E-mail:
| | - A. Alia
- *Gorlaeus Laboratoria, Leiden Institute of Chemistry, Einsteinweg 55, P.O. Box 9502, 2300 RA Leiden, The Netherlands
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Schlodder E, Cetin M, Eckert HJ, Schmitt FJ, Barber J, Telfer A. Both chlorophylls a and d are essential for the photochemistry in photosystem II of the cyanobacteria, Acaryochloris marina. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2007; 1767:589-95. [PMID: 17428440 DOI: 10.1016/j.bbabio.2007.02.018] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2006] [Revised: 02/02/2007] [Accepted: 02/23/2007] [Indexed: 11/20/2022]
Abstract
We have measured the flash-induced absorbance difference spectrum attributed to the formation of the secondary radical pair, P(+)Q(-), between 270 nm and 1000 nm at 77 K in photosystem II of the chlorophyll d containing cyanobacterium, Acaryochloris marina. Despite the high level of chlorophyll d present, the flash-induced absorption difference spectrum of an approximately 2 ms decay component shows a number of features which are typical of the difference spectrum seen in oxygenic photosynthetic organisms containing no chlorophyll d. The spectral shape in the near-UV indicates that a plastoquinone is the secondary acceptor molecule (Q(A)). The strong C-550 change at 543 nm confirms previous reports that pheophytin a is the primary electron acceptor. The bleach at 435 nm and increase in absorption at 820 nm indicates that the positive charge is stabilized on a chlorophyll a molecule. In addition a strong electrochromic band shift, centred at 723 nm, has been observed. It is assigned to a shift of the Qy band of the neighbouring accessory chlorophyll d, Chl(D1). It seems highly likely that it accepts excitation energy from the chlorophyll d containing antenna. We therefore propose that primary charge separation is initiated from this chlorophyll d molecule and functions as the primary electron donor. Despite its lower excited state energy (0.1 V less), as compared to chlorophyll a, this chlorophyll d molecule is capable of driving the plastoquinone oxidoreductase activity of photosystem II. However, chlorophyll a is used to stabilize the positive charge and ultimately to drive water oxidation.
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Affiliation(s)
- Eberhard Schlodder
- Max-Volmer-Laboratorium für Biophysikalische Chemie, Technische Universität Berlin, Strasse des 17.Juni 135, 10623 Berlin, Germany.
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Ishikita H, Stehlik D, Golbeck JH, Knapp EW. Electrostatic influence of PsaC protein binding to the PsaA/PsaB heterodimer in photosystem I. Biophys J 2005; 90:1081-9. [PMID: 16258043 PMCID: PMC1367094 DOI: 10.1529/biophysj.105.069781] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The absence of the PsaC subunit in the photosystem I (PSI) complex (native PSI complex) by mutagenesis or chemical manipulation yields a PSI core (P700-F(X) core) that also lacks subunits PsaD and PsaE and the two iron-sulfur clusters F(A) and F(B), which constitute an integral part of PsaC. In this P700-F(X) core, the redox potentials (E(m)) of the two quinones A(1A/B) and the iron-sulfur cluster F(X) as well as the corresponding protonation patterns are investigated by evaluating the electrostatic energies from the solution of the linearized Poisson-Boltzmann equation. The B-side specific Asp-B558 changes its protonation state significantly upon isolating the P700-F(X) core, being mainly protonated in the native PSI complex but ionized in the P700-F(X) core. In the P700-F(X) core, E(m)(A(1A/B)) remains practically unchanged, whereas E(m)(F(X)) is upshifted by 42 mV. With these calculated E(m) values, the electron transfer rate from A(1) to F(X) in the P700-F(X) core is estimated to be slightly faster on the A(1A) side than that of the wild type, which is consistent with kinetic measurements.
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Affiliation(s)
- Hiroshi Ishikita
- Institute of Chemistry and Biochemistry, Department of Biology, Free University of Berlin, D-14195 Berlin, Germany
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45
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Proton ENDOR study of the primary donor P740+, a special pair of chlorophyll d in photosystem I reaction center of Acaryochloris marina. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2005.06.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Diller A, Roy E, Gast P, van Gorkom HJ, Zaanen J, de Groot HJM, Glaubitz C, Matysik J. Photo-CIDNP solid-state NMR on photosystems I and II:what makes P680 special? PHOTOSYNTHESIS RESEARCH 2005; 84:303-8. [PMID: 16049790 DOI: 10.1007/s11120-005-0411-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2004] [Accepted: 01/11/2005] [Indexed: 05/03/2023]
Abstract
The origin of the extraordinary high redox potential of P680, the primary electron donor of Photosystem II, is still unknown. Photochemically induced dynamic nuclear polarisation (photo-CIDNP) 13C magic-angle spinning (MAS) NMR is a powerful method to study primary electron donors. In order to reveal the electronic structure of P680, we compare new photo-CIDNP MAS NMR data of Photosystem II to those of Photosystem I. The comparison reveals that the electronic structure of the P680 radical cation is a Chl a cofactor with strong matrix interaction, while the radical cation of P700, the primary electron donor of Photosystem I, appears to be a Chl a cofactor which is essentially undisturbed. Possible forms of cofactor-matrix interactions are discussed.
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Affiliation(s)
- Anna Diller
- Gorlaeus Laboratoria, Leiden Institute of Chemistry, Einsteinweg 55, P.O. Box 9502, 2300 RA, Leiden, The Netherlands
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Ishikita H, Knapp EW. Redox potential of quinones in both electron transfer branches of photosystem I. J Biol Chem 2003; 278:52002-11. [PMID: 12972408 DOI: 10.1074/jbc.m306434200] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The redox potentials of the two electron transfer (ET) active quinones in the central part of photosystem I (PSI) were determined by evaluating the electrostatic energies from the solution of the Poisson-Boltzmann equation based on the crystal structure. The calculated redox potentials are -531 mV for A1A and -686 mV for A1B. From these results we conclude the following. (i) Both branches are active with a much faster ET in the B-branch than in the A-branch. (ii) The measured lifetime of 200-290 ns of reduced quinones agrees with the estimate for the A-branch and corroborates with an uphill ET from this quinone to the iron-sulfur cluster as observed in recent kinetic measurements. (iii) The electron paramagnetic resonance spectroscopic data refer to the A-branch quinone where the corresponding ET is uphill in energy. The negative redox potential of A1 in PSI is primarily because of the influence from the negatively charged FX, in contrast to the positive shift on the quinone redox potential in bacterial reaction center and PSII that is attributed to the positively charged non-heme iron atom. The conserved residue Asp-B575 changes its protonation state after quinone reduction. The difference of 155 mV in the quinone redox potentials of the two branches were attributed to the conformation of the backbone with a large contribution from Ser-A692 and Ser-B672 and to the side chain of Asp-B575, whose protonation state couples differently with the formation of the quinone radicals.
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Affiliation(s)
- Hiroshi Ishikita
- Department of Biology, Chemistry, and Pharmacy, Institute of Chemistry, Free University of Berlin, Takustrasse 6, Berlin D-14195, Germany
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Pashenko S, Proskuryakov I, Germano M, van Gorkom H, Gast P. Triplet state in photosystem II reaction centers as studied by 130 GHz EPR. Chem Phys 2003. [DOI: 10.1016/s0301-0104(03)00324-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Plato M, Krauß N, Fromme P, Lubitz W. Molecular orbital study of the primary electron donor P700 of photosystem I based on a recent X-ray single crystal structure analysis. Chem Phys 2003. [DOI: 10.1016/s0301-0104(03)00378-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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50
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Proton ENDOR spectroscopy of the anion radicals of the chlorophyll primary electron acceptors in type I photosynthetic reaction centres. Chem Phys 2003. [DOI: 10.1016/s0301-0104(03)00284-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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