1
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Krysiak S, Burda K. The Effect of Removal of External Proteins PsbO, PsbP and PsbQ on Flash-Induced Molecular Oxygen Evolution and Its Biphasicity in Tobacco PSII. Curr Issues Mol Biol 2024; 46:7187-7218. [PMID: 39057069 PMCID: PMC11276211 DOI: 10.3390/cimb46070428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2024] [Revised: 06/30/2024] [Accepted: 07/02/2024] [Indexed: 07/28/2024] Open
Abstract
The oxygen evolution within photosystem II (PSII) is one of the most enigmatic processes occurring in nature. It is suggested that external proteins surrounding the oxygen-evolving complex (OEC) not only stabilize it and provide an appropriate ionic environment but also create water channels, which could be involved in triggering the ingress of water and the removal of O2 and protons outside the system. To investigate the influence of these proteins on the rate of oxygen release and the efficiency of OEC function, we developed a measurement protocol for the direct measurement of the kinetics of oxygen release from PSII using a Joliot-type electrode. PSII-enriched tobacco thylakoids were used in the experiments. The results revealed the existence of slow and fast modes of oxygen evolution. This observation is model-independent and requires no specific assumptions about the initial distribution of the OEC states. The gradual removal of exogenous proteins resulted in a slowdown of the rapid phase (~ms) of O2 release and its gradual disappearance while the slow phase (~tens of ms) accelerated. The role of external proteins in regulating the biphasicity and efficiency of oxygen release is discussed based on observed phenomena and current knowledge.
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Affiliation(s)
| | - Kvetoslava Burda
- Faculty of Physics and Applied Computer Science, AGH University of Krakow, al. Mickiewicza 30, 30-059 Krakow, Poland;
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2
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Flesher DA, Liu J, Wang J, Gisriel CJ, Yang KR, Batista VS, Debus RJ, Brudvig GW. Mutation-induced shift of the photosystem II active site reveals insight into conserved water channels. J Biol Chem 2024; 300:107475. [PMID: 38879008 PMCID: PMC11294709 DOI: 10.1016/j.jbc.2024.107475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 06/02/2024] [Accepted: 06/09/2024] [Indexed: 07/11/2024] Open
Abstract
Photosystem II (PSII) is the water-plastoquinone photo-oxidoreductase central to oxygenic photosynthesis. PSII has been extensively studied for its ability to catalyze light-driven water oxidation at a Mn4CaO5 cluster called the oxygen-evolving complex (OEC). Despite these efforts, the complete reaction mechanism for water oxidation by PSII is still heavily debated. Previous mutagenesis studies have investigated the roles of conserved amino acids, but these studies have lacked a direct structural basis that would allow for a more meaningful interpretation. Here, we report a 2.14-Å resolution cryo-EM structure of a PSII complex containing the substitution Asp170Glu on the D1 subunit. This mutation directly perturbs a bridging carboxylate ligand of the OEC, which alters the spectroscopic properties of the OEC without fully abolishing water oxidation. The structure reveals that the mutation shifts the position of the OEC within the active site without markedly distorting the Mn4CaO5 cluster metal-metal geometry, instead shifting the OEC as a rigid body. This shift disturbs the hydrogen-bonding network of structured waters near the OEC, causing disorder in the conserved water channels. This mutation-induced disorder appears consistent with previous FTIR spectroscopic data. We further show using quantum mechanics/molecular mechanics methods that the mutation-induced structural changes can affect the magnetic properties of the OEC by altering the axes of the Jahn-Teller distortion of the Mn(III) ion coordinated to D1-170. These results offer new perspectives on the conserved water channels, the rigid body property of the OEC, and the role of D1-Asp170 in the enzymatic water oxidation mechanism.
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Affiliation(s)
- David A Flesher
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Jinchan Liu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Jimin Wang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | | | - Ke R Yang
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
| | - Victor S Batista
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
| | - Richard J Debus
- Department of Biochemistry, University of California, Riverside, California, USA.
| | - Gary W Brudvig
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA; Department of Chemistry, Yale University, New Haven, Connecticut, USA.
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3
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Yano J, Kern J, Yachandra VK. Structure Function Studies of Photosystem II Using X-Ray Free Electron Lasers. Annu Rev Biophys 2024; 53:343-365. [PMID: 39013027 DOI: 10.1146/annurev-biophys-071723-102519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2024]
Abstract
The structure and mechanism of the water-oxidation chemistry that occurs in photosystem II have been subjects of great interest. The advent of X-ray free electron lasers allowed the determination of structures of the stable intermediate states and of steps in the transitions between these intermediate states, bringing a new perspective to this field. The room-temperature structures collected as the photosynthetic water oxidation reaction proceeds in real time have provided important novel insights into the structural changes and the mechanism of the water oxidation reaction. The time-resolved measurements have also given us a view of how this reaction-which involves multielectron, multiproton processes-is facilitated by the interaction of the ligands and the protein residues in the oxygen-evolving complex. These structures have also provided a picture of the dynamics occurring in the channels within photosystem II that are involved in the transport of the substrate water to the catalytic center and protons to the bulk.
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Affiliation(s)
- Junko Yano
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA; , ,
| | - Jan Kern
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA; , ,
| | - Vittal K Yachandra
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA; , ,
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4
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Liu J, Yang KR, Long Z, Armstrong WH, Brudvig GW, Batista VS. Water Ligands Regulate the Redox Leveling Mechanism of the Oxygen-Evolving Complex of the Photosystem II. J Am Chem Soc 2024; 146:15986-15999. [PMID: 38833517 DOI: 10.1021/jacs.4c02926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2024]
Abstract
Understanding how water ligands regulate the conformational changes and functionality of the oxygen-evolving complex (OEC) in photosystem II (PSII) throughout the catalytic cycle of oxygen evolution remains a highly intriguing and unresolved challenge. In this study, we investigate the effect of water insertion (WI) on the redox state of the OEC by using the molecular dynamics (MD) and quantum mechanics/molecular mechanics (QM/MM) hybrid methods. We find that water binding significantly reduces the free energy change for proton-coupled electron transfer (PCET) from Mn to YZ•, underscoring the important regulatory role of water binding, which is essential for enabling the OEC redox-leveling mechanism along the catalytic cycle. We propose a water binding mechanism in which WI is thermodynamically favored by the closed-cubane form of the OEC, with water delivery mediated by Ca2+ ligand exchange. Isomerization from the closed- to open-cubane conformation at three post-WI states highlights the importance of the location of the MnIII center in the OEC and the orientation of its Jahn-Teller axis to conformational changes of the OEC, which might be critical for the formation of the O-O bond. These findings reveal a complex interplay between conformational changes in the OEC and the ligand environment during the activation of the OEC by YZ•. Analogous regulatory effects due to water ligand binding are expected to be important for a wide range of catalysts activated by redox state transitions in aqueous environments.
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Affiliation(s)
- Jinchan Liu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Ke R Yang
- Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), College of Chemistry, Nankai University, Tianjin 300071, China
| | - Zhuoran Long
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - William H Armstrong
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Gary W Brudvig
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, United States
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Victor S Batista
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
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5
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Barchenko M, O’Malley PJ. A Reappraisal of the S2 State of Nature's Water Oxidizing Complex in Its Low and High Spin Forms. J Phys Chem Lett 2024; 15:5883-5886. [PMID: 38804862 PMCID: PMC11163464 DOI: 10.1021/acs.jpclett.4c00997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 05/23/2024] [Accepted: 05/24/2024] [Indexed: 05/29/2024]
Abstract
Density functional theory calculated 14N hyperfine couplings are obtained for the Mn1 ligated π-N of residue His332 of the photosystem 2 water oxidizing complex. An open cubane, O4H, model closely matches the experimental coupling obtained for the high spin S = 5/2 form of the S2 state, supporting an open cubane structure for this state. We also investigate the unusual geometric features for the S2 state obtained by X-ray free electron laser structure determinations and rationalize it as an equilibrium occurring at room temperature between W1/O4 deprotonated and protonated forms of the open cubane structure.
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Affiliation(s)
- Maxim Barchenko
- Department of Chemistry,
School of Natural Sciences, The University
of Manchester, Manchester M13 9PL, United
Kingdom
| | - Patrick J. O’Malley
- Department of Chemistry,
School of Natural Sciences, The University
of Manchester, Manchester M13 9PL, United
Kingdom
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6
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Saito K, Chen Y, Ishikita H. Exploring the Deprotonation Process during Incorporation of a Ligand Water Molecule at the Dangling Mn Site in Photosystem II. J Phys Chem B 2024; 128:4728-4734. [PMID: 38693711 PMCID: PMC11104351 DOI: 10.1021/acs.jpcb.4c01997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 04/18/2024] [Accepted: 04/22/2024] [Indexed: 05/03/2024]
Abstract
The Mn4CaO5 cluster, featuring four ligand water molecules (W1 to W4), serves as the water-splitting site in photosystem II (PSII). X-ray free electron laser (XFEL) structures exhibit an additional oxygen site (O6) adjacent to the O5 site in the fourth lowest oxidation state, S3, forming Mn4CaO6. Here, we investigate the mechanism of the second water ligand molecule at the dangling Mn (W2) as a potential incorporating species, using a quantum mechanical/molecular mechanical (QM/MM) approach. Previous QM/MM calculations demonstrated that W1 releases two protons through a low-barrier H-bond toward D1-Asp61 and subsequently releases an electron during the S2 to S3 transition, resulting in O•- at W1 and protonated D1-Asp61. During the process of Mn4CaO6 formation, O•-, rather than H2O or OH-, best reproduced the O5···O6 distance. Although the catalytic cluster with O•- at O6 is more stable than that with O•- at W1 in S3, it does not occur spontaneously due to the significantly uphill deprotonation process. Assuming O•- at W2 incorporates into the O6 site, an exergonic conversion from Mn1(III)Mn2(IV)Mn3(IV)Mn4(IV) (equivalent to the open-cubane S2 valence state) to Mn1(IV)Mn2(IV)Mn3(IV)Mn4(III) (equivalent to the closed-cubane S2 valence state) occurs. These findings provide energetic insights into the deprotonation and structural conversion events required for the Mn4CaO6 formation.
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Affiliation(s)
- 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
| | - Yang Chen
- 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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7
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Pavlou A, Styring S, Mamedov F. The S 1 to S 2 and S 2 to S 3 state transitions in plant photosystem II: relevance to the functional and structural heterogeneity of the water oxidizing complex. PHOTOSYNTHESIS RESEARCH 2024:10.1007/s11120-024-01096-4. [PMID: 38662327 DOI: 10.1007/s11120-024-01096-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 03/18/2024] [Indexed: 04/26/2024]
Abstract
In Photosystem II, light-induced water splitting occurs via the S state cycle of the CaMn4O5-cluster. To understand the role of various possible conformations of the CaMn4O5-cluster in this process, the temperature dependence of the S1 → S2 and S2 → S3 state transitions, induced by saturating laser flashes, was studied in spinach photosystem II membrane preparations under different conditions. The S1 → S2 transition temperature dependence was shown to be much dependent on the type of the cryoprotectant and presence of 3.5% methanol, resulting in the variation of transition half-inhibition temperature by 50 K. No similar effect was observed for the S2 → S3 state transition, for which we also show that both the low spin g = 2.0 multiline and high spin g = 4.1 EPR configurations of the S2 state advance with similar efficiency to the S3 state, both showing a transition half-inhibition temperature of 240 K. This was further confirmed by following the appearance of the Split S3 EPR signal. The results are discussed in relevance to the functional and structural heterogeneity of the water oxidizing complex intermediates in photosystem II.
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Affiliation(s)
- Andrea Pavlou
- Molecular Biomimetics, Department of Chemistry-Ångström, Uppsala University, P.O. Box 523, 751 20, Uppsala, Sweden
| | - Stenbjörn Styring
- Molecular Biomimetics, Department of Chemistry-Ångström, Uppsala University, P.O. Box 523, 751 20, Uppsala, Sweden
| | - Fikret Mamedov
- Molecular Biomimetics, Department of Chemistry-Ångström, Uppsala University, P.O. Box 523, 751 20, Uppsala, Sweden.
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8
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Chernev P, Aydin AO, Messinger J. On the simulation and interpretation of substrate-water exchange experiments in photosynthetic water oxidation. PHOTOSYNTHESIS RESEARCH 2024:10.1007/s11120-024-01084-8. [PMID: 38512410 DOI: 10.1007/s11120-024-01084-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 02/01/2024] [Indexed: 03/23/2024]
Abstract
Water oxidation by photosystem II (PSII) sustains most life on Earth, but the molecular mechanism of this unique process remains controversial. The ongoing identification of the binding sites and modes of the two water-derived substrate oxygens ('substrate waters') in the various intermediates (Si states, i = 0, 1, 2, 3, 4) that the water-splitting tetra-manganese calcium penta-oxygen (Mn4CaO5) cluster attains during the reaction cycle provides central information towards resolving the unique chemistry of biological water oxidation. Mass spectrometric measurements of single- and double-labeled dioxygen species after various incubation times of PSII with H218O provide insight into the substrate binding modes and sites via determination of exchange rates. Such experiments have revealed that the two substrate waters exchange with different rates that vary independently with the Si state and are hence referred to as the fast (Wf) and the slow (WS) substrate waters. New insight for the molecular interpretation of these rates arises from our recent finding that in the S2 state, under special experimental conditions, two different rates of WS exchange are observed that appear to correlate with the high spin and low spin conformations of the Mn4CaO5 cluster. Here, we reexamine and unite various proposed methods for extracting and assigning rate constants from this recent data set. The analysis results in a molecular model for substrate-water binding and exchange that reconciles the expected non-exchangeability of the central oxo bridge O5 when located between two Mn(IV) ions with the experimental and theoretical assignment of O5 as WS in all S states. The analysis also excludes other published proposals for explaining the water exchange kinetics.
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Affiliation(s)
- Petko Chernev
- Molecular Biomimetics, Department of Chemistry - Ångström Laboratory, 75120, Uppsala, Sweden
| | - A Orkun Aydin
- Molecular Biomimetics, Department of Chemistry - Ångström Laboratory, 75120, Uppsala, Sweden
| | - Johannes Messinger
- Molecular Biomimetics, Department of Chemistry - Ångström Laboratory, 75120, Uppsala, Sweden.
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9
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Amin M, Kaur D, Brudvig GW, Brooks BR. Mapping the Oxygens in the Oxygen-Evolving Complex of Photosystem II by Their Nucleophilicity Using Quantum Descriptors. J Chem Theory Comput 2024. [PMID: 38306696 DOI: 10.1021/acs.jctc.3c00926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2024]
Abstract
The oxygen-evolving complex (OEC) of Photosystem II catalyzes the water-splitting reaction using solar energy. Thus, understanding the reaction mechanism will inspire the design of biomimetic artificial catalysts that convert solar energy to chemical energy. Conceptual Density Functional Theory (CDFT) focuses on understanding the reactivity of molecules and the atomic contribution to the overall nucleophilicity and electrophilicity of the molecule using quantum descriptors. However, this method has not been applied to the OEC before. Here, we use Fukui functions and the dual descriptor to provide quantitative measures of the nucleophilicity and electrophilicity of oxygens in the OEC for different models in different S states. Our results show that the μ-oxo bridges connected to terminal Mn4 are nucleophilic, and those in the cube formed by Mn1, Mn2, and Mn3 are mostly electrophilic. The dual descriptors of the bridging oxygens in the OEC showed a similar reactivity to that of bridging oxygens in Mn model compounds. However, the terminal water W1, which is bound to Mn4, showed very strong reactivity in some of the S3 models. Thus, our calculations support the model that proposes the formation of the O2 molecule through nucleophilic attack by a terminal water.
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Affiliation(s)
- Muhamed Amin
- Laboratory of Computational Biology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
- Department of Sciences, University College Groningen, University of Groningen, 9718 BG Groningen, The Netherlands
| | - Divya Kaur
- Department of Chemistry, Brock University, 500 Glenridge Avenue, St. Catharines, Ontario, Canada L2S 3A1
| | - Gary W Brudvig
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Bernard R Brooks
- Laboratory of Computational Biology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
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10
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Chrysina M, Drosou M, Castillo RG, Reus M, Neese F, Krewald V, Pantazis DA, DeBeer S. Nature of S-States in the Oxygen-Evolving Complex Resolved by High-Energy Resolution Fluorescence Detected X-ray Absorption Spectroscopy. J Am Chem Soc 2023; 145:25579-25594. [PMID: 37970825 PMCID: PMC10690802 DOI: 10.1021/jacs.3c06046] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 10/13/2023] [Accepted: 10/13/2023] [Indexed: 11/19/2023]
Abstract
Photosystem II, the water splitting enzyme of photosynthesis, utilizes the energy of sunlight to drive the four-electron oxidation of water to dioxygen at the oxygen-evolving complex (OEC). The OEC harbors a Mn4CaO5 cluster that cycles through five oxidation states Si (i = 0-4). The S3 state is the last metastable state before the O2 evolution. Its electronic structure and nature of the S2 → S3 transition are key topics of persisting controversy. Most spectroscopic studies suggest that the S3 state consists of four Mn(IV) ions, compared to the Mn(III)Mn(IV)3 of the S2 state. However, recent crystallographic data have received conflicting interpretations, suggesting either metal- or ligand-based oxidation, the latter leading to an oxyl radical or a peroxo moiety in the S3 state. Herein, we utilize high-energy resolution fluorescence detected (HERFD) X-ray absorption spectroscopy to obtain a highly resolved description of the Mn K pre-edge region for all S-states, paying special attention to use chemically unperturbed S3 state samples. In combination with quantum chemical calculations, we achieve assignment of specific spectroscopic features to geometric and electronic structures for all S-states. These data are used to confidently discriminate between the various suggestions concerning the electronic structure and the nature of oxidation events in all observable catalytic intermediates of the OEC. Our results do not support the presence of either peroxo or oxyl in the active configuration of the S3 state. This establishes Mn-centered storage of oxidative equivalents in all observable catalytic transitions and constrains the onset of the O-O bond formation until after the final light-driven oxidation event.
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Affiliation(s)
- Maria Chrysina
- Max-Planck-Institut
für Chemische Energiekonversion, Stiftstr. 34-36, Mülheim
an der Ruhr 45470, Germany
- Institute
of Nanoscience & Nanotechnology, NCSR “Demokritos”, Athens 15310, Greece
| | - Maria Drosou
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, Mülheim an der Ruhr 45470, Germany
| | - Rebeca G. Castillo
- Max-Planck-Institut
für Chemische Energiekonversion, Stiftstr. 34-36, Mülheim
an der Ruhr 45470, Germany
- Laboratory
of Ultrafast Spectroscopy (LSU) and Lausanne Centre for Ultrafast
Science, École Polytechnique Fédérale
de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - Michael Reus
- Max-Planck-Institut
für Chemische Energiekonversion, Stiftstr. 34-36, Mülheim
an der Ruhr 45470, Germany
| | - Frank Neese
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, Mülheim an der Ruhr 45470, Germany
| | - Vera Krewald
- Department
of Chemistry, Technical University of Darmstadt, Peter-Grünberg-Str. 4, Darmstadt 64287, Germany
| | - Dimitrios A. Pantazis
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, Mülheim an der Ruhr 45470, Germany
| | - Serena DeBeer
- Max-Planck-Institut
für Chemische Energiekonversion, Stiftstr. 34-36, Mülheim
an der Ruhr 45470, Germany
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11
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Yamaguchi K, Miyagawa K, Shoji M, Kawakami T, Isobe H, Yamanaka S, Nakajima T. Theoretical elucidation of the structure, bonding, and reactivity of the CaMn 4O x clusters in the whole Kok cycle for water oxidation embedded in the oxygen evolving center of photosystem II. New molecular and quantum insights into the mechanism of the O-O bond formation. PHOTOSYNTHESIS RESEARCH 2023:10.1007/s11120-023-01053-7. [PMID: 37945776 DOI: 10.1007/s11120-023-01053-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 09/25/2023] [Indexed: 11/12/2023]
Abstract
This paper reviews our historical developments of broken-symmetry (BS) and beyond BS methods that are applicable for theoretical investigations of metalloenzymes such as OEC in PSII. The BS hybrid DFT (HDFT) calculations starting from high-resolution (HR) XRD structure in the most stable S1 state have been performed to elucidate structure and bonding of whole possible intermediates of the CaMn4Ox cluster (1) in the Si (i = 0 ~ 4) states of the Kok cycle. The large-scale HDFT/MM computations starting from HR XRD have been performed to elucidate biomolecular system structures which are crucial for examination of possible water inlet and proton release pathways for water oxidation in OEC of PSII. DLPNO CCSD(T0) computations have been performed for elucidation of scope and reliability of relative energies among the intermediates by HDFT. These computations combined with EXAFS, XRD, XFEL, and EPR experimental results have elucidated the structure, bonding, and reactivity of the key intermediates, which are indispensable for understanding and explanation of the mechanism of water oxidation in OEC of PSII. Interplay between theory and experiments have elucidated important roles of four degrees of freedom, spin, charge, orbital, and nuclear motion for understanding and explanation of the chemical reactivity of 1 embedded in protein matrix, indicating the participations of the Ca(H2O)n ion and tyrosine(Yz)-O radical as a one-electron acceptor for the O-O bond formation. The Ca-assisted Yz-coupled O-O bond formation mechanisms for water oxidation are consistent with recent XES and very recent time-resolved SFX XFEL and FTIR results.
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Affiliation(s)
- Kizashi Yamaguchi
- Center for Quantum Information and Quantum Biology, Osaka University, Toyonaka, Osaka, 560-0043, Japan.
- RIKEN Center for Computational Science, Kobe, Hyogo, 650-0047, Japan.
- SANKEN, Osaka University, Ibaraki, Osaka, 567-0047, Japan.
| | - Koichi Miyagawa
- Center of Computational Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8577, Japan
| | - Mitsuo Shoji
- Center of Computational Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8577, Japan
| | - Takashi Kawakami
- RIKEN Center for Computational Science, Kobe, Hyogo, 650-0047, Japan
- Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan
| | - Hiroshi Isobe
- Research Institute for Interdisciplinary Science, and Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan
| | - Shusuke Yamanaka
- Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan
| | - Takahito Nakajima
- RIKEN Center for Computational Science, Kobe, Hyogo, 650-0047, Japan
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12
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Kosaki S, Mino H. Molecular Structure Related to an S = 5/2 High-Spin S 2 State Manganese Cluster of Photosystem II Investigated by Q-Band Pulse EPR Spectroscopy. J Phys Chem B 2023. [PMID: 37463845 DOI: 10.1021/acs.jpcb.3c01656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
The high-spin S2 state of the photosynthetic oxygen-evolving cluster Mn4CaO5, corresponding to the g = 4.1 signal for X-band electron paramagnetic resonance (EPR), was investigated using Q-band pulsed EPR, which detected a main peak at g = 3.10 and satellite peaks at 5.25, 4.55, and 2.80. We evaluated the spin state as the zero-field splitting of D = 0.465 cm-1 and E/D = 0.245 with S = 5/2. The temperature dependence of the T1 relaxation time revealed that the excited-state energy was 28.7 cm-1 higher than that of the S = 5/2 ground state. By comparing present quantum mechanical (QM) calculation models, a closed-cubane structure with the protonation state of two oxygens, W1 (= OH-) and W2 (= H2O), was the most probable structure for the S = 5/2 state. The three-pulse electron spin-echo envelope modulation (ESEEM) detected the nuclear signal, which was assigned to nitrogen as His332 ligated to the Mn1 ion. The obtained hyperfine constant for the nitrogen signal was significantly reduced from that in the S = 1/2 low-spin state. These results indicate that the S = 5/2 spin state arises from the closed-cubane structure.
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Affiliation(s)
- Shinya Kosaki
- Division of Materials Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, 464-8602 Nagoya, Aichi, Japan
| | - Hiroyuki Mino
- Division of Materials Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, 464-8602 Nagoya, Aichi, Japan
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13
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Shiau AA, Lee HB, Oyala PH, Agapie T. Coordination Number in High-Spin-Low-Spin Equilibrium in Cluster Models of the S 2 State of the Oxygen Evolving Complex. J Am Chem Soc 2023; 145:14592-14598. [PMID: 37366634 PMCID: PMC10575483 DOI: 10.1021/jacs.3c04464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2023]
Abstract
The S2 state of the Oxygen Evolving Complex (OEC) of Photosystem II (PSII) shows high-spin (HS) and low-spin (LS) EPR signals attributed to distinct structures based on computation. Five-coordinate MnIII centers are proposed in these species but are absent in available spectroscopic model complexes. Herein, we report the synthesis, crystal structure, electrochemistry, SQUID magnetometry, and EPR spectroscopy of a MnIIIMnIV3O4 cuboidal complex featuring five-coordinate MnIII. This cluster displays a spin ground state of S = 5/2, while conversion to a six-coordinate Mn upon treatment with water results in a spin state change to S = 1/2. These results demonstrate that coordination number, without dramatic changes within the Mn4O4 core, has a substantial effect on spectroscopy.
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Affiliation(s)
- Angela A Shiau
- Department of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd MC 127-72, Pasadena, California 91125, United States
| | - Heui Beom Lee
- Department of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd MC 127-72, Pasadena, California 91125, United States
| | - Paul H Oyala
- Department of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd MC 127-72, Pasadena, California 91125, United States
| | - Theodor Agapie
- Department of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd MC 127-72, Pasadena, California 91125, United States
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14
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Shevela D, Kern JF, Govindjee G, Messinger J. Solar energy conversion by photosystem II: principles and structures. PHOTOSYNTHESIS RESEARCH 2023; 156:279-307. [PMID: 36826741 PMCID: PMC10203033 DOI: 10.1007/s11120-022-00991-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 12/01/2022] [Indexed: 05/23/2023]
Abstract
Photosynthetic water oxidation by Photosystem II (PSII) is a fascinating process because it sustains life on Earth and serves as a blue print for scalable synthetic catalysts required for renewable energy applications. The biophysical, computational, and structural description of this process, which started more than 50 years ago, has made tremendous progress over the past two decades, with its high-resolution crystal structures being available not only of the dark-stable state of PSII, but of all the semi-stable reaction intermediates and even some transient states. Here, we summarize the current knowledge on PSII with emphasis on the basic principles that govern the conversion of light energy to chemical energy in PSII, as well as on the illustration of the molecular structures that enable these reactions. The important remaining questions regarding the mechanism of biological water oxidation are highlighted, and one possible pathway for this fundamental reaction is described at a molecular level.
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Affiliation(s)
- Dmitry Shevela
- Department of Chemistry, Chemical Biological Centre, Umeå University, 90187, Umeå, Sweden.
| | - Jan F Kern
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Govindjee Govindjee
- Department of Plant Biology, Department of Biochemistry and Center of Biophysics & Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Johannes Messinger
- Department of Chemistry, Chemical Biological Centre, Umeå University, 90187, Umeå, Sweden.
- Molecular Biomimetics, Department of Chemistry - Ångström, Uppsala University, 75120, Uppsala, Sweden.
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15
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Drosou M, Comas-Vilà G, Neese F, Salvador P, Pantazis DA. Does Serial Femtosecond Crystallography Depict State-Specific Catalytic Intermediates of the Oxygen-Evolving Complex? J Am Chem Soc 2023; 145:10604-10621. [PMID: 37137865 DOI: 10.1021/jacs.3c00489] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Recent advances in serial femtosecond crystallography (SFX) of photosystem II (PSII), enabled by X-ray free electron lasers (XFEL), provided the first geometric models of distinct intermediates in the catalytic S-state cycle of the oxygen-evolving complex (OEC). These models are obtained by flash-advancing the OEC from the dark-stable state (S1) to more oxidized intermediates (S2 and S3), eventually cycling back to the most reduced S0. However, the interpretation of these models is controversial because geometric parameters within the Mn4CaO5 cluster of the OEC do not exactly match those expected from coordination chemistry for the spectroscopically verified manganese oxidation states of the distinct S-state intermediates. Here we focus on the first catalytic transition, S1 → S2, which represents a one-electron oxidation of the OEC. Combining geometric and electronic structure criteria, including a novel effective oxidation state approach, we analyze existing 1-flash (1F) SFX-XFEL crystallographic models that should depict the S2 state of the OEC. We show that the 1F/S2 equivalence is not obvious, because the Mn oxidation states and total unpaired electron counts encoded in these models are not fully consistent with those of a pure S2 state and with the nature of the S1 → S2 transition. Furthermore, the oxidation state definition in two-flashed (2F) structural models is practically impossible to elucidate. Our results advise caution in the extraction of electronic structure information solely from the literal interpretation of crystallographic models and call for re-evaluation of structural and mechanistic interpretations that presume exact correspondence of such models to specific catalytic intermediates of the OEC.
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Affiliation(s)
- Maria Drosou
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Gerard Comas-Vilà
- Institute of Computational Chemistry and Catalysis, Chemistry Department, University of Girona, Montilivi Campus, Girona, Catalonia 17003, Spain
| | - Frank Neese
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Pedro Salvador
- Institute of Computational Chemistry and Catalysis, Chemistry Department, University of Girona, Montilivi Campus, Girona, Catalonia 17003, Spain
| | - Dimitrios A Pantazis
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
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16
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Amin M. Predicting the oxidation states of Mn ions in the oxygen-evolving complex of photosystem II using supervised and unsupervised machine learning. PHOTOSYNTHESIS RESEARCH 2023; 156:89-100. [PMID: 35896927 PMCID: PMC10070209 DOI: 10.1007/s11120-022-00941-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 07/13/2022] [Indexed: 05/21/2023]
Abstract
Serial Femtosecond Crystallography at the X-ray Free Electron Laser (XFEL) sources enabled the imaging of the catalytic intermediates of the oxygen evolution reaction of Photosystem II (PSII). However, due to the incoherent transition of the S-states, the resolved structures are a convolution from different catalytic states. Here, we train Decision Tree Classifier and K-means clustering models on Mn compounds obtained from the Cambridge Crystallographic Database to predict the S-state of the X-ray, XFEL, and CryoEM structures by predicting the Mn's oxidation states in the oxygen-evolving complex. The model agrees mostly with the XFEL structures in the dark S1 state. However, significant discrepancies are observed for the excited XFEL states (S2, S3, and S0) and the dark states of the X-ray and CryoEM structures. Furthermore, there is a mismatch between the predicted S-states within the two monomers of the same dimer, mainly in the excited states. We validated our model against other metalloenzymes, the valence bond model and the Mn spin densities calculated using density functional theory for two of the mismatched predictions of PSII. The model suggests designing a more optimized sample delivery and illumiation systems are crucial to precisely resolve the geometry of the advanced S-states to overcome the noncoherent S-state transition. In addition, significant radiation damage is observed in X-ray and CryoEM structures, particularly at the dangler Mn center (Mn4). Our model represents a valuable tool for investigating the electronic structure of the catalytic metal cluster of PSII to understand the water splitting mechanism.
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Affiliation(s)
- Muhamed Amin
- Department of Sciences, University College Groningen, University of Groningen, Hoendiepskade 23/24, 9718 BG, Groningen, The Netherlands.
- Rijksuniversiteit Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands.
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607, Hamburg, Germany.
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17
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Guo Y, Messinger J, Kloo L, Sun L. Alternative Mechanism for O 2 Formation in Natural Photosynthesis via Nucleophilic Oxo-Oxo Coupling. J Am Chem Soc 2023; 145:4129-4141. [PMID: 36763485 DOI: 10.1021/jacs.2c12174] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
O2 formation in photosystem II (PSII) is a vital event on Earth, but the exact mechanism remains unclear. The presently prevailing theoretical model is "radical coupling" (RC) involving a Mn(IV)-oxyl unit in an "open-cubane" Mn4CaO6 cluster, which is supported experimentally by the S3 state of cyanobacterial PSII featuring an additional Mn-bound oxygenic ligand. However, it was recently proposed that the major structural form of the S3 state of higher plants lacks this extra ligand, and that the resulting S4 state would feature instead a penta-coordinate dangler Mn(V)=oxo, covalently linked to a "closed-cubane" Mn3CaO4 cluster. For this proposal, we explore here a large number of possible pathways of O-O bond formation and demonstrate that the "nucleophilic oxo-oxo coupling" (NOOC) between Mn(V)=oxo and μ3-oxo is the only eligible mechanism in such a system. The reaction is facilitated by a specific conformation of the cluster and concomitant water binding, which is delayed compared to the RC mechanism. An energetically feasible process is described starting from the valid S4 state through the sequential formation of peroxide and superoxide, followed by O2 release and a second water insertion. The newly found mechanism is consistent with available experimental thermodynamic and kinetic data and thus a viable alternative pathway for O2 formation in natural photosynthesis, in particular for higher plants.
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Affiliation(s)
- Yu Guo
- Center of Artificial Photosynthesis for Solar Fuels and Department of Chemistry, School of Science, Westlake University, Hangzhou 310024, China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou 310024, China
| | - Johannes Messinger
- Department of Chemistry, Umeå University, Linnaeus väg 6 (KBC huset), Umeå SE-90187, Sweden
- Molecular Biomimetics, Department of Chemistry─Ångström Laboratory, Uppsala University, Uppsala SE-75120, Sweden
| | - Lars Kloo
- Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Stockholm SE-10044, Sweden
| | - Licheng Sun
- Center of Artificial Photosynthesis for Solar Fuels and Department of Chemistry, School of Science, Westlake University, Hangzhou 310024, China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou 310024, China
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18
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Simon PS, Makita H, Bogacz I, Fuller F, Bhowmick A, Hussein R, Ibrahim M, Zhang M, Chatterjee R, Cheah MH, Chernev P, Doyle MD, Brewster AS, Alonso-Mori R, Sauter NK, Bergmann U, Dobbek H, Zouni A, Messinger J, Kern J, Yachandra VK, Yano J. Capturing the sequence of events during the water oxidation reaction in photosynthesis using XFELs. FEBS Lett 2023; 597:30-37. [PMID: 36310373 PMCID: PMC9839502 DOI: 10.1002/1873-3468.14527] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Revised: 10/13/2022] [Accepted: 10/17/2022] [Indexed: 01/17/2023]
Abstract
Ever since the discovery that Mn was required for oxygen evolution in plants by Pirson in 1937 and the period-four oscillation in flash-induced oxygen evolution by Joliot and Kok in the 1970s, understanding of this process has advanced enormously using state-of-the-art methods. The most recent in this series of innovative techniques was the introduction of X-ray free-electron lasers (XFELs) a decade ago, which led to another quantum leap in the understanding in this field, by enabling operando X-ray structural and X-ray spectroscopy studies at room temperature. This review summarizes the current understanding of the structure of Photosystem II (PS II) and its catalytic centre, the Mn4 CaO5 complex, in the intermediate Si (i = 0-4)-states of the Kok cycle, obtained using XFELs.
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Affiliation(s)
- Philipp S Simon
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Hiroki Makita
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Isabel Bogacz
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Franklin Fuller
- Pulse Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Asmit Bhowmick
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Rana Hussein
- Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Mohamed Ibrahim
- Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Miao Zhang
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Ruchira Chatterjee
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Mun Hon Cheah
- Molecular Biomimetics, Department of Chemistry - Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Petko Chernev
- Molecular Biomimetics, Department of Chemistry - Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Margaret D Doyle
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Aaron S Brewster
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Roberto Alonso-Mori
- LINAC Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Nicholas K Sauter
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Uwe Bergmann
- Department of Physics, University of Wisconsin-Madison, Madison, WI, USA
| | - Holger Dobbek
- Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Athina Zouni
- Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Johannes Messinger
- Molecular Biomimetics, Department of Chemistry - Ångström Laboratory, Uppsala University, Uppsala, Sweden
- Department of Chemistry, Umeå University, Umeå, Sweden
| | - Jan Kern
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Vittal K Yachandra
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Junko Yano
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
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19
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Lubitz W, Pantazis DA, Cox N. Water oxidation in oxygenic photosynthesis studied by magnetic resonance techniques. FEBS Lett 2023; 597:6-29. [PMID: 36409002 DOI: 10.1002/1873-3468.14543] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 11/14/2022] [Accepted: 11/15/2022] [Indexed: 11/23/2022]
Abstract
The understanding of light-induced biological water oxidation in oxygenic photosynthesis is of great importance both for biology and (bio)technological applications. The chemically difficult multistep reaction takes place at a unique protein-bound tetra-manganese/calcium cluster in photosystem II whose structure has been elucidated by X-ray crystallography (Umena et al. Nature 2011, 473, 55). The cluster moves through several intermediate states in the catalytic cycle. A detailed understanding of these intermediates requires information about the spatial and electronic structure of the Mn4 Ca complex; the latter is only available from spectroscopic techniques. Here, the important role of Electron Paramagnetic Resonance (EPR) and related double resonance techniques (ENDOR, EDNMR), complemented by quantum chemical calculations, is described. This has led to the elucidation of the cluster's redox and protonation states, the valence and spin states of the manganese ions and the interactions between them, and contributed substantially to the understanding of the role of the protein surrounding, as well as the binding and processing of the substrate water molecules, the O-O bond formation and dioxygen release. Based on these data, models for the water oxidation cycle are developed.
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Affiliation(s)
- Wolfgang Lubitz
- Max-Planck-Institut für Chemische Energiekonversion, Mülheim/Ruhr, Germany
| | | | - Nicholas Cox
- Research School of Chemistry, Australian National University, Canberra, ACT, Australia
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20
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Rogers C, Hardwick O, Corry TA, Rummel F, Collison D, Bowen AM, O’Malley PJ. Magnetic and Electronic Structural Properties of the S 3 State of Nature's Water Oxidizing Complex: A Combined Study in ELDOR-Detected Nuclear Magnetic Resonance Spectral Simulation and Broken-Symmetry Density Functional Theory. ACS OMEGA 2022; 7:41783-41788. [PMID: 36406523 PMCID: PMC9670293 DOI: 10.1021/acsomega.2c06151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 10/24/2022] [Indexed: 06/16/2023]
Abstract
ELDOR-detected nuclear magnetic resonance (EDNMR) spectral simulations combined with broken-symmetry density functional theory (BS-DFT) calculations are used to obtain and to assign the 55Mn hyperfine coupling constants (hfcs) for modified forms of the water oxidizing complex in the penultimate S3 state of the water oxidation cycle. The study shows that an open cubane form of the core Mn4CaO6 cluster explains the magnetic properties of the dominant S = 3 species in all cases studied experimentally with no need to invoke a closed cubane intermediate possessing a distorted pentacoordinate Mn4 ion as recently suggested. EDNMR simulations found that both the experimental bandwidth and multinuclear transitions may alter relative EDNMR peak intensities, potentially leading to incorrect assignment of hfcs. The implications of these findings for the water oxidation mechanism are discussed.
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21
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Yamaguchi K, Shoji M, Isobe H, Kawakami T, Miyagawa K, Suga M, Akita F, Shen JR. Geometric, electronic and spin structures of the CaMn4O5 catalyst for water oxidation in oxygen-evolving photosystem II. Interplay between experiments and theoretical computations. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2022.214742] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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22
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Isobe H, Shoji M, Suzuki T, Shen JR, Yamaguchi K. Roles of the Flexible Primary Coordination Sphere of the Mn 4CaO x Cluster: What Are the Immediate Decay Products of the S3 State? J Phys Chem B 2022; 126:7212-7228. [DOI: 10.1021/acs.jpcb.2c02596] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hiroshi Isobe
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Mitsuo Shoji
- Center for Computational Science, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
| | - Takayoshi Suzuki
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Jian-Ren Shen
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Kizashi Yamaguchi
- Institute for NanoScience Design, Osaka University, Toyonaka, Osaka 560-0043, Japan
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23
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Gao X, Fan H. The Role of Redox-Inactive Metals in Modulating the Redox Potential of the Mn 4CaO 4 Model Complex. Inorg Chem 2022; 61:11539-11549. [PMID: 35839298 DOI: 10.1021/acs.inorgchem.2c00243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Photosynthetic oxygen-evolving center (OEC), the "engine of life", is a unique Mn4CaO5 cluster catalyzing the water oxidation. The role of redox-inactive component Ca2+, which can only be functionally replaced by Sr2+ in a biological environment, has been under debate for a long time. Recently, its modulating effect on the redox potential of native OEC and artificial structural OEC model complex has received great attention, and linear relationship between the potential and the Lewis acidity of the redox-inactive metal has been proposed for the MMn3O4 model complex. In this work, the modulating effect has been studied in detail using the Mn4CaO4 model complex, which is the closest structural model to OEC to date and has a similar redox potential at the S1-S2 transition. We found the redox-inactive metal only has a weak modulating effect on the potential, which is comparable in strength to that of the ligand environments. Meanwhile, the net charge of the complex, which could be changed along with the redox-inactive metal, has a high impact on the potential and can be unified by protonation, deprotonation, or ligand modification. Although the modulating effect of the redox-inactive metal is not very strong, the linear relationship between the potential and the Lewis acidity is still valid for Mn4MO4 complexes. Our results of strong modulating effects for net charge and weak modulating effects for redox-inactive metal fit with the previous experimental observations on Mn4MO4 (M = Ca2+, Y3+, and Gd3+) model complexes, and suggest that Ca2+ can be structurally and electrochemically replaced with other metal cations, together with proper ligand modifications.
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Affiliation(s)
- Xianrui Gao
- Shenyang University of Chemical Technology, Shenyang 110142, China.,State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, China
| | - Hongjun Fan
- Shenyang University of Chemical Technology, Shenyang 110142, China.,State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, China
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24
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Guo Y, Messinger J, Kloo L, Sun L. Reversible Structural Isomerization of Nature's Water Oxidation Catalyst Prior to O-O Bond Formation. J Am Chem Soc 2022; 144:11736-11747. [PMID: 35748306 PMCID: PMC9264352 DOI: 10.1021/jacs.2c03528] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
![]()
Photosynthetic water
oxidation is catalyzed by a manganese–calcium
oxide cluster, which experiences five “S-states” during
a light-driven reaction cycle. The unique “distorted chair”-like
geometry of the Mn4CaO5(6) cluster shows structural
flexibility that has been frequently proposed to involve “open”
and “closed”-cubane forms from the S1 to
S3 states. The isomers are interconvertible in the S1 and S2 states, while in the S3 state,
the open-cubane structure is observed to dominate inThermosynechococcus elongatus (cyanobacteria) samples.
In this work, using density functional theory calculations, we go
beyond the S3+Yz state to the S3nYz• → S4+Yz step, and report for the first time
that the reversible isomerism, which is suppressed in the S3+Yz state, is fully recovered
in the ensuing S3nYz• state due to the proton release
from a manganese-bound water ligand. The altered coordination strength
of the manganese–ligand facilitates formation of the closed-cubane
form, in a dynamic equilibrium with the open-cubane form. This tautomerism
immediately preceding dioxygen formation may constitute the rate limiting
step for O2 formation, and exert a significant influence
on the water oxidation mechanism in photosystem II.
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Affiliation(s)
- Yu Guo
- Center of Artificial Photosynthesis for Solar Fuels and Department of Chemistry, School of Science, Westlake University, Hangzhou 310024, China.,Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou 310024, China
| | - Johannes Messinger
- Department of Chemistry, Umeå University, Linnaeus väg 6 (KBC huset), SE-90187 Umeå, Sweden.,Molecular Biomimetics, Department of Chemistry─Ångström Laboratory, Uppsala University, SE-75120 Uppsala, Sweden
| | - Lars Kloo
- Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden
| | - Licheng Sun
- Center of Artificial Photosynthesis for Solar Fuels and Department of Chemistry, School of Science, Westlake University, Hangzhou 310024, China.,Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou 310024, China
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25
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Boussac A, Sugiura M, Sellés J. Probing the proton release by Photosystem II in the S 1 to S 2 high-spin transition. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148546. [PMID: 35337840 DOI: 10.1016/j.bbabio.2022.148546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 02/24/2022] [Accepted: 03/17/2022] [Indexed: 06/14/2023]
Abstract
The stoichiometry and kinetics of the proton release were investigated during each transition of the S-state cycle in Photosystem II (PSII) from Thermosynechococcus elongatus containing either a Mn4CaO5 (PSII/Ca) or a Mn4SrO5 (PSII/Sr) cluster. The measurements were done at pH 6.0 and pH 7.0 knowing that, in PSII/Ca at pH 6.0 and pH 7.0 and in PSII/Sr at pH 6.0, the flash-induced S2-state is in a low-spin configuration (S2LS) whereas in PSII/Sr at pH 7.0, the S2-state is in a high-spin configuration (S2HS) in half of the centers. Two measurements were done; the time-resolved flash dependent i) absorption of either bromocresol purple at pH 6.0 or neutral red at pH 7.0 and ii) electrochromism in the Soret band of PD1 at 440 nm. The fittings of the oscillations with a period of four indicate that one proton is released in the S1 to S2HS transition in PSII/Sr at pH 7.0. It has previously been suggested that the proton released in the S2LS to S3 transition would be released in a S2LSTyrZ• → S2HSTyrZ• transition before the electron transfer from the cluster to TyrZ• occurs. The release of a proton in the S1TyrZ• → S2HSTyrZ transition would logically imply that this proton release is missing in the S2HSTyrZ• to S3TyrZ transition. Instead, the proton release in the S1 to S2HS transition in PSII/Sr at pH 7.0 was mainly done at the expense of the proton release in the S3 to S0 and S0 to S1 transitions. However, at pH 7.0, the electrochromism of PD1 seems larger in PSII/Sr when compared to PSII/Ca in the S3 state. This points to the complex link between proton movements in and immediately around the Mn4 cluster and the mechanism leading to the release of protons into the bulk.
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Affiliation(s)
- Alain Boussac
- I(2)BC, UMR CNRS 9198, CEA Saclay, 91191 Gif-sur-Yvette, France.
| | - Miwa Sugiura
- Proteo-Science Research Center, Department of Chemistry, Graduate School of Science and Technology, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
| | - Julien Sellés
- Institut de Biologie Physico-Chimique, UMR CNRS 7141 and Sorbonne Université, 13 rue Pierre et Marie Curie, 75005 Paris, France
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26
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Flesher DA, Liu J, Wiwczar JM, Reiss K, Yang KR, Wang J, Askerka M, Gisriel CJ, Batista VS, Brudvig GW. Glycerol binding at the narrow channel of photosystem II stabilizes the low-spin S 2 state of the oxygen-evolving complex. PHOTOSYNTHESIS RESEARCH 2022; 152:167-175. [PMID: 35322325 PMCID: PMC9427693 DOI: 10.1007/s11120-022-00911-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Accepted: 03/02/2022] [Indexed: 05/11/2023]
Abstract
The oxygen-evolving complex (OEC) of photosystem II (PSII) cycles through redox intermediate states Si (i = 0-4) during the photochemical oxidation of water. The S2 state involves an equilibrium of two isomers including the low-spin S2 (LS-S2) state with its characteristic electron paramagnetic resonance (EPR) multiline signal centered at g = 2.0, and a high-spin S2 (HS-S2) state with its g = 4.1 EPR signal. The relative intensities of the two EPR signals change under experimental conditions that shift the HS-S2/LS-S2 state equilibrium. Here, we analyze the effect of glycerol on the relative stability of the LS-S2 and HS-S2 states when bound at the narrow channel of PSII, as reported in an X-ray crystal structure of cyanobacterial PSII. Our quantum mechanics/molecular mechanics (QM/MM) hybrid models of cyanobacterial PSII show that the glycerol molecule perturbs the hydrogen-bond network in the narrow channel, increasing the pKa of D1-Asp61 and stabilizing the LS-S2 state relative to the HS-S2 state. The reported results are consistent with the absence of the HS-S2 state EPR signal in native cyanobacterial PSII EPR spectra and suggest that the narrow water channel hydrogen-bond network regulates the relative stability of OEC catalytic intermediates during water oxidation.
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Affiliation(s)
- David A Flesher
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Jinchan Liu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Jessica M Wiwczar
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Krystle Reiss
- Department of Chemistry, Yale University, New Haven, CT, 05620, USA
| | - Ke R Yang
- Department of Chemistry, Yale University, New Haven, CT, 05620, USA
| | - Jimin Wang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Mikhail Askerka
- Department of Chemistry, Yale University, New Haven, CT, 05620, USA
| | | | - Victor S Batista
- Department of Chemistry, Yale University, New Haven, CT, 05620, USA
| | - Gary W Brudvig
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA.
- Department of Chemistry, Yale University, New Haven, CT, 05620, USA.
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27
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Mino H. Temperature dependence of the formation of the g ~ 5 EPR signal in the oxygen evolving complex of photosystem II. PHOTOSYNTHESIS RESEARCH 2022; 152:207-212. [PMID: 35437616 DOI: 10.1007/s11120-022-00916-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 03/15/2022] [Indexed: 06/14/2023]
Abstract
The temperature dependence of the formation of the g ~ 5 S2 state electron paramagnetic resonance (EPR) signal in photosystem II (PSII) was investigated. The g ~ 5 signal was produced at an illumination above 200 K. The half inhibition temperature of the formation of the g ~ 5 EPR signal was approximately 215 K. The half inhibition temperature is close to that of the transition from the S2 state-to-S3 state in the untreated PSII, and not to that of the transition from S1 state -to-S2 state in the untreated PSII. The upshift of the half inhibition temperature of the transition from the S1 state -to-S2 state (g ~ 5) reflects the structural change upon transition from the S1 state to the S2 state. The activation energy of the g ~ 5 state formation was estimated as 40.7 ± 4.4 kJ/mol, which is comparable to the reported activation energy for the S2 formation in the untreated PSII. The activation enthalpy and entropy were estimated to be 39.0 ± 4.4 kJ/mol and - 103 ± 19 J/mol K at 210 K, respectively. Based on these parameters, the formation process of the g ~ 5 state is discussed in this study.
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Affiliation(s)
- Hiroyuki Mino
- Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8602, Japan.
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28
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Miyagawa K, Shoji M, Isobe H, Kawakami T, Nakajima T, Yamaguchi K. Relative energies among proton-shifted S2 isomers in the photosystem II revealed by DLPNO coupled cluster and hybrid DFT calculations. Proton transfer coupled spin transitions of the CaMn4Ox cluster in OEC of PSII. Chem Phys Lett 2022. [DOI: 10.1016/j.cplett.2022.139357] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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29
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Debus RJ. Alteration of the O 2-Producing Mn 4Ca Cluster in Photosystem II by the Mutation of a Metal Ligand. Biochemistry 2021; 60:3841-3855. [PMID: 34898175 DOI: 10.1021/acs.biochem.1c00504] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The O2-evolving Mn4Ca cluster in photosystem II (PSII) is arranged as a distorted Mn3Ca cube that is linked to a fourth Mn ion (denoted as Mn4) by two oxo bridges. The Mn4 and Ca ions are bridged by residue D1-D170. This is also the only residue known to participate in the high-affinity Mn(II) site that participates in the light-driven assembly of the Mn4Ca cluster. In this study, we use Fourier transform infrared difference spectroscopy to characterize the impact of the D1-D170E mutation. On the basis of analyses of carboxylate and carbonyl stretching modes and the O-H stretching modes of hydrogen-bonded water molecules, we show that this mutation alters the extensive network of hydrogen bonds that surrounds the Mn4Ca cluster in the same manner as that of many other mutations. It also alters the equilibrium between conformers of the Mn4Ca cluster in the dark-stable S1 state so that a high-spin form of the S2 state is produced during the S1-to-S2 transition instead of the low-spin form that gives rise to the S2 state multiline electron paramagnetic resonance signal. The mutation may also change the coordination mode of the carboxylate group at position 170 to unidentate ligation of Mn4. This is the first mutation of a metal ligand in PSII that substantially impacts the spectroscopic signatures of the Mn4Ca cluster without substantially eliminating O2 evolution. The results have significant implications for our understanding of the roles of alternate active/inactive conformers of the Mn4Ca cluster in the mechanism of O2 formation.
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Affiliation(s)
- Richard J Debus
- Department of Biochemistry, University of California, Riverside, California 92521, United States
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30
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Amin M, Kaur D, Gunner M, Brudvig G. Toward understanding the S2-S3 transition in the Kok cycle of Photosystem II: Lessons from Sr-substituted structure. INORG CHEM COMMUN 2021. [DOI: 10.1016/j.inoche.2021.108890] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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31
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de Lichtenberg C, Kim CJ, Chernev P, Debus RJ, Messinger J. The exchange of the fast substrate water in the S 2 state of photosystem II is limited by diffusion of bulk water through channels - implications for the water oxidation mechanism. Chem Sci 2021; 12:12763-12775. [PMID: 34703563 PMCID: PMC8494045 DOI: 10.1039/d1sc02265b] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 08/31/2021] [Indexed: 12/02/2022] Open
Abstract
The molecular oxygen we breathe is produced from water-derived oxygen species bound to the Mn4CaO5 cluster in photosystem II (PSII). Present research points to the central oxo-bridge O5 as the 'slow exchanging substrate water (Ws)', while, in the S2 state, the terminal water ligands W2 and W3 are both discussed as the 'fast exchanging substrate water (Wf)'. A critical point for the assignment of Wf is whether or not its exchange with bulk water is limited by barriers in the channels leading to the Mn4CaO5 cluster. In this study, we measured the rates of H2 16O/H2 18O substrate water exchange in the S2 and S3 states of PSII core complexes from wild-type (WT) Synechocystis sp. PCC 6803, and from two mutants, D1-D61A and D1-E189Q, that are expected to alter water access via the Cl1/O4 channels and the O1 channel, respectively. We found that the exchange rates of Wf and Ws were unaffected by the E189Q mutation (O1 channel), but strongly perturbed by the D61A mutation (Cl1/O4 channel). It is concluded that all channels have restrictions limiting the isotopic equilibration of the inner water pool near the Mn4CaO5 cluster, and that D61 participates in one such barrier. In the D61A mutant this barrier is lowered so that Wf exchange occurs more rapidly. This finding removes the main argument against Ca-bound W3 as fast substrate water in the S2 state, namely the indifference of the rate of Wf exchange towards Ca/Sr substitution.
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Affiliation(s)
- Casper de Lichtenberg
- Department of Chemistry, Umeå University Linnaeus väg 6 (KBC huset), SE-901 87 Umeå Sweden
- Molecular Biomimetics, Department of Chemistry - Ångström Laboratory, Uppsala University POB 523 SE-75120 Uppsala Sweden
| | - Christopher J Kim
- Department of Biochemistry, University of California Riverside California 92521 USA
| | - Petko Chernev
- Molecular Biomimetics, Department of Chemistry - Ångström Laboratory, Uppsala University POB 523 SE-75120 Uppsala Sweden
| | - Richard J Debus
- Department of Biochemistry, University of California Riverside California 92521 USA
| | - Johannes Messinger
- Department of Chemistry, Umeå University Linnaeus väg 6 (KBC huset), SE-901 87 Umeå Sweden
- Molecular Biomimetics, Department of Chemistry - Ångström Laboratory, Uppsala University POB 523 SE-75120 Uppsala Sweden
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32
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Corry TA, O'Malley PJ. S 3 State Models of Nature's Water Oxidizing Complex: Analysis of Bonding and Magnetic Exchange Pathways, Assessment of Experimental Electron Paramagnetic Resonance Data, and Implications for the Water Oxidation Mechanism. J Phys Chem B 2021; 125:10097-10107. [PMID: 34463499 DOI: 10.1021/acs.jpcb.1c04459] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Broken symmetry density functional theory (BS-DFT) calculations on large models of Nature's water oxidizing complex (WOC) are used to investigate the electronic structure and associated magnetic interactions of this key intermediate state. The electronic origins of the ferromagnetic and antiferromagnetic couplings between neighboring Mn ions are investigated and illustrated by using corresponding orbital transformations. Protonation of the O4 and/or O6 atoms leads to large variation in the distribution of spin around the complex with associated changes in its magnetic resonance properties. Models for Sr2+ exchange and methanol addition indicate minor perturbations reflected in slightly altered spin projection coefficients for the Mn1 and Mn2 ions. These are shown to account for the observed changes observed experimentally via electron paramagnetic resonance methods and suggest a reinterpretation of the experimental findings. By comparison with experimental determinations, we show that the spin projections and resulting calculated 55Mn hyperfine couplings support the open cubane form of an oxo (O5)-hydroxo (O6) cluster in all cases with no need to invoke a closed cubane intermediate. The implications of these findings for the water oxidation mechanism are discussed.
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Affiliation(s)
- Thomas A Corry
- Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester M13 9PL, U.K
| | - Patrick J O'Malley
- Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester M13 9PL, U.K
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33
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Corry TA, Rummel F, O'Malley PJ. Bonding and Magnetic Exchange Pathways in Nature's Water-Oxidizing Complex. J Phys Chem B 2021; 125:7147-7154. [PMID: 34180671 DOI: 10.1021/acs.jpcb.1c03864] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The nature of the bonding and magnetic exchange pathways of the water-oxidizing complex of photosystem 2 is explored using broken symmetry density functional theory. The electronic structure and superexchange pathways are illustrated and analyzed using corresponding orbitals and intrinsic bond orbitals. These demonstrate a dominating influence on the bonding and magnetic interactions by both the geometrical structure of the Mn4CaO5 core complex and the ionic interactions of the oxo bridges with the neighboring Ca2+ ion. The demonstrated ionic nature of the Ca2+ bonds is proposed to contribute to the stabilization of the oxygen atoms participating in O-O bond formation.
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Affiliation(s)
- Thomas A Corry
- Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester M13 9PL, U.K
| | - Felix Rummel
- Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester M13 9PL, U.K
| | - Patrick J O'Malley
- Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester M13 9PL, U.K
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34
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Orio M, Pantazis DA. Successes, challenges, and opportunities for quantum chemistry in understanding metalloenzymes for solar fuels research. Chem Commun (Camb) 2021; 57:3952-3974. [DOI: 10.1039/d1cc00705j] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Overview of the rich and diverse contributions of quantum chemistry to understanding the structure and function of the biological archetypes for solar fuel research, photosystem II and hydrogenases.
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Affiliation(s)
- Maylis Orio
- Aix-Marseille Université
- CNRS
- iSm2
- Marseille
- France
| | - Dimitrios A. Pantazis
- Max-Planck-Institut für Kohlenforschung
- Kaiser-Wilhelm-Platz 1
- 45470 Mülheim an der Ruhr
- Germany
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35
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Abstract
We derive a model that provides an exact solution to the substrate-water exchange kinetics in a double-conformation system and use this model to interpret recently published data for Ca2+- and Sr2+-containing PSII in the S2 state, in which the g = 2.0 and g = 4.1 conformations coexist. The component concentrations derived from the kinetic model provide an analytic description of the substrate-water exchange kinetics, allowing us to more accurately interpret the results. Based on this model and the previously reported data on the S2 state g = 2.0 conformation, we obtain the substrate-water exchange rates of the g = 4.1 conformation and the conformational change rates. Two conclusions are made from the analyses. First, contrary to previous reports, there is no significant effect of substituting Sr2+ for Ca2+ on any of the exchange rate constants. Second, the exchange rate of the slowly-exchanging water (Ws) in the S2 state g = 4.1 conformation is much faster than that in the S2 state g = 2.0 conformation. The second conclusion is consistent with the assignment of Ws to W1 or W2 bound as terminal ligands to Mn4; Mn4 has been proposed to undergo an oxidation state change from Mn(IV) in the g = 2.0 conformation to Mn(III) in the g = 4.1 conformation.
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36
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Yamaguchi K, Miyagawa K, Isobe H, Shoji M, Kawakami T, Yamanaka S. Isolobal and isospin analogy between organic and inorganic open-shell molecules—Application to oxygenation reactions by active oxygen and oxy-radicals and water oxidation in the native and artificial photosynthesis. ADVANCES IN QUANTUM CHEMISTRY 2021. [DOI: 10.1016/bs.aiq.2021.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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37
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Taguchi S, Shen L, Han G, Umena Y, Shen JR, Noguchi T, Mino H. Formation of the High-Spin S 2 State Related to the Extrinsic Proteins in the Oxygen Evolving Complex of Photosystem II. J Phys Chem Lett 2020; 11:8908-8913. [PMID: 32990440 DOI: 10.1021/acs.jpclett.0c02411] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The high-spin S2 state was investigated with photosystem II (PSII) from spinach, Thermosynechococcus vulcanus, and Cyanidioschyzon merolae. In extrinsic protein-depleted PSII, high-spin electron paramagnetic resonance (EPR) signals were not detected in either species, whereas all species showed g ∼ 5 signals in the presence of a high concentration of Ca2+ instead of the multiline signal. In the intact and PsbP/Q-depleted PSII from spinach, the g = 4.1 EPR signal was detected. These results show that formation of the high-spin S2 state of the manganese cluster is regulated by the extrinsic proteins through a charge located near the Mn4 atom in the Mn4CaO5 cluster but is independent of the intrinsic proteins. The shift to the g ∼ 5 state is caused by tilting of the z-axis in the Mn4 coordinates through hydrogen bonds or external divalent cations. The structural modification may allow insertion of an oxygen atom during the S2-to-S3 transition.
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Affiliation(s)
- Shota Taguchi
- Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, 464-8602 Nagoya, Aichi, Japan
| | - Liangliang Shen
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Guangye Han
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Yasufumi Umena
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Jian-Ren Shen
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Takumi Noguchi
- Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, 464-8602 Nagoya, Aichi, Japan
| | - Hiroyuki Mino
- Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, 464-8602 Nagoya, Aichi, Japan
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38
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Li XC, Li J, Siegbahn PEM. A Theoretical Study of the Recently Suggested Mn VII Mechanism for O-O Bond Formation in Photosystem II. J Phys Chem A 2020; 124:8011-8018. [PMID: 32877196 PMCID: PMC7586388 DOI: 10.1021/acs.jpca.0c05135] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The mechanism for water oxidation in photosystem II has been a major topic for several decades. The active catalyst has four manganese atoms connected by bridging oxo bonds, in a complex termed the oxygen-evolving complex (OEC), which also includes a calcium atom. The O-O bond of oxygen is formed after absorption of four photons in a state of the OEC termed S4. There has been essential consensus that in the S4 state, all manganese atoms are in the Mn(IV) oxidation state. However, recently there has been a suggestion that one of the atoms is in the Mn(VII) state. In the present computational study, the feasibility of that proposal has been investigated. It is here shown that the mechanism involving Mn(VII) has a much higher barrier for forming O2 than the previous proposal with four Mn(IV) atoms.
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Affiliation(s)
- Xi-Chen Li
- College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Jing Li
- College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Per E M Siegbahn
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
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39
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de Lichtenberg C, Avramov AP, Zhang M, Mamedov F, Burnap RL, Messinger J. The D1-V185N mutation alters substrate water exchange by stabilizing alternative structures of the Mn 4Ca-cluster in photosystem II. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1862:148319. [PMID: 32979346 DOI: 10.1016/j.bbabio.2020.148319] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 09/15/2020] [Accepted: 09/19/2020] [Indexed: 11/30/2022]
Abstract
In photosynthesis, the oxygen-evolving complex (OEC) of the pigment-protein complex photosystem II (PSII) orchestrates the oxidation of water. Introduction of the V185N mutation into the D1 protein was previously reported to drastically slow O2-release and strongly perturb the water network surrounding the Mn4Ca cluster. Employing time-resolved membrane inlet mass spectrometry, we measured here the H218O/H216O-exchange kinetics of the fast (Wf) and slow (Ws) exchanging substrate waters bound in the S1, S2 and S3 states to the Mn4Ca cluster of PSII core complexes isolated from wild type and D1-V185N strains of Synechocystis sp. PCC 6803. We found that the rate of exchange for Ws was increased in the S1 and S2 states, while both Wf and Ws exchange rates were decreased in the S3 state. Additionally, we used EPR spectroscopy to characterize the Mn4Ca cluster and its interaction with the redox active D1-Tyr161 (YZ). In the S2 state, we observed a greatly diminished multiline signal in the V185N-PSII that could be recovered by addition of ammonia. The split signal in the S1 state was not affected, while the split signal in the S3 state was absent in the D1-V185N mutant. These findings are rationalized by the proposal that the N185 residue stabilizes the binding of an additional water-derived ligand at the Mn1 site of the Mn4Ca cluster via hydrogen bonding. Implications for the sites of substrate water binding are discussed.
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Affiliation(s)
- Casper de Lichtenberg
- Department of Chemistry, Umeå University, Linnaeus väg 6 (KBC huset), SE-901 87 Umeå, Sweden; Molecular Biomimetics, Department of Chemistry - Ångström, Uppsala University, POB 523, SE-75120 Uppsala, Sweden
| | - Anton P Avramov
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, United States
| | - Minquan Zhang
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, United States
| | - Fikret Mamedov
- Molecular Biomimetics, Department of Chemistry - Ångström, Uppsala University, POB 523, SE-75120 Uppsala, Sweden
| | - Robert L Burnap
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, United States
| | - Johannes Messinger
- Department of Chemistry, Umeå University, Linnaeus väg 6 (KBC huset), SE-901 87 Umeå, Sweden; Molecular Biomimetics, Department of Chemistry - Ångström, Uppsala University, POB 523, SE-75120 Uppsala, Sweden.
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40
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Kim CJ, Debus RJ. Roles of D1-Glu189 and D1-Glu329 in O2 Formation by the Water-Splitting Mn4Ca Cluster in Photosystem II. Biochemistry 2020; 59:3902-3917. [DOI: 10.1021/acs.biochem.0c00541] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Christopher J. Kim
- Department of Biochemistry, University of California, Riverside, California 92521, United States
| | - Richard J. Debus
- Department of Biochemistry, University of California, Riverside, California 92521, United States
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41
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Ibrahim M, Fransson T, Chatterjee R, Cheah MH, Hussein R, Lassalle L, Sutherlin KD, Young ID, Fuller FD, Gul S, Kim IS, Simon PS, de Lichtenberg C, Chernev P, Bogacz I, Pham CC, Orville AM, Saichek N, Northen T, Batyuk A, Carbajo S, Alonso-Mori R, Tono K, Owada S, Bhowmick A, Bolotovsky R, Mendez D, Moriarty NW, Holton JM, Dobbek H, Brewster AS, Adams PD, Sauter NK, Bergmann U, Zouni A, Messinger J, Kern J, Yachandra VK, Yano J. Untangling the sequence of events during the S 2 → S 3 transition in photosystem II and implications for the water oxidation mechanism. Proc Natl Acad Sci U S A 2020; 117:12624-12635. [PMID: 32434915 PMCID: PMC7293653 DOI: 10.1073/pnas.2000529117] [Citation(s) in RCA: 140] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
In oxygenic photosynthesis, light-driven oxidation of water to molecular oxygen is carried out by the oxygen-evolving complex (OEC) in photosystem II (PS II). Recently, we reported the room-temperature structures of PS II in the four (semi)stable S-states, S1, S2, S3, and S0, showing that a water molecule is inserted during the S2 → S3 transition, as a new bridging O(H)-ligand between Mn1 and Ca. To understand the sequence of events leading to the formation of this last stable intermediate state before O2 formation, we recorded diffraction and Mn X-ray emission spectroscopy (XES) data at several time points during the S2 → S3 transition. At the electron acceptor site, changes due to the two-electron redox chemistry at the quinones, QA and QB, are observed. At the donor site, tyrosine YZ and His190 H-bonded to it move by 50 µs after the second flash, and Glu189 moves away from Ca. This is followed by Mn1 and Mn4 moving apart, and the insertion of OX(H) at the open coordination site of Mn1. This water, possibly a ligand of Ca, could be supplied via a "water wheel"-like arrangement of five waters next to the OEC that is connected by a large channel to the bulk solvent. XES spectra show that Mn oxidation (τ of ∼350 µs) during the S2 → S3 transition mirrors the appearance of OX electron density. This indicates that the oxidation state change and the insertion of water as a bridging atom between Mn1 and Ca are highly correlated.
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Affiliation(s)
- Mohamed Ibrahim
- Institut für Biologie, Humboldt-Universität zu Berlin, D-10115 Berlin, Germany
| | - Thomas Fransson
- Interdisciplinary Center for Scientific Computing, University of Heidelberg, 69120 Heidelberg, Germany
| | - Ruchira Chatterjee
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Mun Hon Cheah
- Department of Chemistry - Ångström, Molecular Biomimetics, Uppsala University, SE 75120 Uppsala, Sweden
| | - Rana Hussein
- Institut für Biologie, Humboldt-Universität zu Berlin, D-10115 Berlin, Germany
| | - Louise Lassalle
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Kyle D Sutherlin
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Iris D Young
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Franklin D Fuller
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025
| | - Sheraz Gul
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - In-Sik Kim
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Philipp S Simon
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Casper de Lichtenberg
- Department of Chemistry - Ångström, Molecular Biomimetics, Uppsala University, SE 75120 Uppsala, Sweden
- Institutionen för Kemi, Kemiskt Biologiskt Centrum, Umeå Universitet, SE 90187 Umeå, Sweden
| | - Petko Chernev
- Department of Chemistry - Ångström, Molecular Biomimetics, Uppsala University, SE 75120 Uppsala, Sweden
| | - Isabel Bogacz
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Cindy C Pham
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Allen M Orville
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, OX11 0DE Didcot, United Kingdom
- Research Complex at Harwell, Rutherford Appleton Laboratory, OX11 0FA Didcot, United Kingdom
| | - Nicholas Saichek
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Trent Northen
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Alexander Batyuk
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025
| | - Sergio Carbajo
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025
| | - Roberto Alonso-Mori
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025
| | - Kensuke Tono
- Japan Synchrotron Radiation Research Institute, Sayo-cho, Sayo-gun, 679-5198 Hyogo, Japan
- RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, 679-5148 Hyogo, Japan
| | - Shigeki Owada
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
- Japan Synchrotron Radiation Research Institute, Sayo-cho, Sayo-gun, 679-5198 Hyogo, Japan
| | - Asmit Bhowmick
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Robert Bolotovsky
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Derek Mendez
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Nigel W Moriarty
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - James M Holton
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158
| | - Holger Dobbek
- Institut für Biologie, Humboldt-Universität zu Berlin, D-10115 Berlin, Germany
| | - Aaron S Brewster
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Paul D Adams
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
- Department of Bioengineering, University of California, Berkeley, CA 94720
| | - Nicholas K Sauter
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Uwe Bergmann
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA 94025
| | - Athina Zouni
- Institut für Biologie, Humboldt-Universität zu Berlin, D-10115 Berlin, Germany;
| | - Johannes Messinger
- Department of Chemistry - Ångström, Molecular Biomimetics, Uppsala University, SE 75120 Uppsala, Sweden;
- Institutionen för Kemi, Kemiskt Biologiskt Centrum, Umeå Universitet, SE 90187 Umeå, Sweden
| | - Jan Kern
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Vittal K Yachandra
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720;
| | - Junko Yano
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720;
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Boussac A, Sellés J, Sugiura M. What can we still learn from the electrochromic band-shifts in Photosystem II? BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148176. [PMID: 32061653 DOI: 10.1016/j.bbabio.2020.148176] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 01/29/2020] [Accepted: 02/10/2020] [Indexed: 11/17/2022]
Abstract
Electrochromic band-shifts have been investigated in Photosystem II (PSII) from Thermosynechoccocus elongatus. Firstly, by using Mn-depleted PsbA1-PSII and PsbA3-PSII in which the QX absorption of PheD1 differs, a band-shift in the QX region of PheD2 centered at ~ 544 nm has been identified upon the oxidation, at pH 8.6, of TyrD. In contrast, a band-shift due to the formation of either QA•- or TyrZ• is observed in PsbA3-PSII at ~ 546 nm, as expected with E130 H-bonded to PheD1 and at ~ 544 nm as expected with Q130 H-bonded to PheD1. Secondly, electrochromic band-shifts in the Chla Soret region have been measured in O2-evolving PSII in PsbA3-PSII, in the PsbA3/H198Q mutant in which the Soret band of PD1 is blue shifted and in the PsbA3/T179H mutant. Upon TyrZ•QA•- formation the Soret band of PD1 is red shifted and the Soret band of ChlD1 is blue shifted. In contrast, only PD1 undergoes a detectable S-state dependent electrochromism. Thirdly, the time resolved S-state dependent electrochromism attributed to PD1 is biphasic for all the S-state transitions except for S1 to S2, and shows that: i) the proton release in S0 to S1 occurs after the electron transfer and ii) the proton release and the electron transfer kinetics in S2 to S3, in T. elongatus, are significantly faster than often considered. The nature of S2TyrZ• is discussed in view of the models in the literature involving intermediate states in the S2 to S3 transition.
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Affiliation(s)
- Alain Boussac
- I(2)BC, CNRS UMR 9198, CEA Saclay, 91191 Gif-sur-Yvette, France.
| | - Julien Sellés
- Institut de Biologie Physico-Chimique, CNRS UMR 7141 and Sorbonne Université, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Miwa Sugiura
- Proteo-Science Research Center and Graduate School of Science and Technology, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
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Corry TA, O'Malley PJ. Molecular Identification of a High-Spin Deprotonated Intermediate during the S 2 to S 3 Transition of Nature's Water-Oxidizing Complex. J Am Chem Soc 2020; 142:10240-10243. [PMID: 32431144 DOI: 10.1021/jacs.0c01351] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The identity of a key intermediate in the S2 to S3 transition of nature's water-oxidizing complex (WOC) in Photosystem 2 is presented. Broken-symmetry density functional theory (BS-DFT) calculations and Heisenberg-Dirac-van Vleck (HDvV) spin ladder calculations show that an S2 state open cubane model of the WOC containing a μ-hydroxo O4 changes from an S = 5/2 form to an S = 7/2, form upon deprotonation of W1. Combined with X-band electron paramagnetic resonance (EPR) spectral analysis, this indicates that the g = 4.1 EPR signal corresponds to an S = 5/2 form of the WOC with W1 present as a water ligand to Mn4, while the g = 4.8/4.9 form observed at high pH values corresponds to an S = 7/2 form, with W1 as a hydroxo ligand. The latter is also likely to represent the form needed to progress to S3 in the functioning enzyme.
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Affiliation(s)
- Thomas A Corry
- Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester M13 9PL, U.K
| | - Patrick J O'Malley
- Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester M13 9PL, U.K
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Abstract
The oxygen-evolving center (OEC) in photosystem II (PSII) of plants, algae and cyanobacteria is a unique natural catalyst that splits water into electrons, protons and dioxygen. The crystallographic studies of PSII have revealed that the OEC is an asymmetric Mn4CaO5-cluster. The understanding of the structure-function relationship of this natural Mn4CaO5-cluster is impeded mainly due to the complexity of the protein environment and lack of a rational chemical model as a reference. Although it has been a great challenge for chemists to synthesize the OEC in the laboratory, significant advances have been achieved recently. Different artificial complexes have been reported, especially a series of artificial Mn4CaO4-clusters that closely mimic both the geometric and electronic structures of the OEC in PSII, which provides a structurally well-defined chemical model to investigate the structure-function relationship of the natural Mn4CaO5-cluster. The deep investigations on this artificial Mn4CaO4-cluster could provide new insights into the mechanism of the water-splitting reaction in natural photosynthesis and may help the development of efficient catalysts for the water-splitting reaction in artificial photosynthesis.
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de Lichtenberg C, Messinger J. Substrate water exchange in the S2 state of photosystem II is dependent on the conformation of the Mn4Ca cluster. Phys Chem Chem Phys 2020; 22:12894-12908. [DOI: 10.1039/d0cp01380c] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The structural flexibility of the Mn4Ca cluster in photosystem II supports the exchange of the central O5 bridge.
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46
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Mino H, Nagashima H. Orientation of Ligand Field for Dangling Manganese in Photosynthetic Oxygen-Evolving Complex of Photosystem II. J Phys Chem B 2019; 124:128-133. [DOI: 10.1021/acs.jpcb.9b10817] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Hiroyuki Mino
- Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, 464-8602 Nagoya, Aichi, Japan
| | - Hiroki Nagashima
- Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, 464-8602 Nagoya, Aichi, Japan
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