1
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Hussein R, Graça A, Forsman J, Aydin AO, Hall M, Gaetcke J, Chernev P, Wendler P, Dobbek H, Messinger J, Zouni A, Schröder WP. Cryo-electron microscopy reveals hydrogen positions and water networks in photosystem II. Science 2024; 384:1349-1355. [PMID: 38900892 DOI: 10.1126/science.adn6541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 05/16/2024] [Indexed: 06/22/2024]
Abstract
Photosystem II starts the photosynthetic electron transport chain that converts solar energy into chemical energy and thus sustains life on Earth. It catalyzes two chemical reactions: water oxidation to molecular oxygen and plastoquinone reduction. Coupling of electron and proton transfer is crucial for efficiency; however, the molecular basis of these processes remains speculative owing to uncertain water binding sites and the lack of experimentally determined hydrogen positions. We thus collected high-resolution cryo-electron microscopy data of fully hydrated photosystem II from the thermophilic cyanobacterium Thermosynechococcus vestitus to a final resolution of 1.71 angstroms. The structure reveals several previously undetected partially occupied water binding sites and more than half of the hydrogen and proton positions. This clarifies the pathways of substrate water binding and plastoquinone B protonation.
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Affiliation(s)
- Rana Hussein
- Humboldt-Universität zu Berlin, Department of Biology, D 10099 Berlin, Germany
| | - André Graça
- Department of Chemistry, Umeå University, SE 90187 Umeå, Sweden
- Molecular Biomimetics, Department of Chemistry- Ångström Laboratory, Uppsala University, SE 75120 Uppsala, Sweden
| | - Jack Forsman
- Department of Chemistry, Umeå University, SE 90187 Umeå, Sweden
| | - A Orkun Aydin
- Molecular Biomimetics, Department of Chemistry- Ångström Laboratory, Uppsala University, SE 75120 Uppsala, Sweden
| | - Michael Hall
- Department of Chemistry, Umeå University, SE 90187 Umeå, Sweden
| | - Julia Gaetcke
- Humboldt-Universität zu Berlin, Department of Biology, D 10099 Berlin, Germany
| | - Petko Chernev
- Molecular Biomimetics, Department of Chemistry- Ångström Laboratory, Uppsala University, SE 75120 Uppsala, Sweden
| | - Petra Wendler
- Institute of Biochemistry and Biology, Department of Biochemistry, University of Potsdam, Karl-Liebknecht Strasse 24-25, D 14476, Potsdam-Golm, Germany
| | - Holger Dobbek
- Humboldt-Universität zu Berlin, Department of Biology, D 10099 Berlin, Germany
| | - Johannes Messinger
- Molecular Biomimetics, Department of Chemistry- Ångström Laboratory, Uppsala University, SE 75120 Uppsala, Sweden
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Sweden
| | - Athina Zouni
- Humboldt-Universität zu Berlin, Department of Biology, D 10099 Berlin, Germany
| | - Wolfgang P Schröder
- Department of Chemistry, Umeå University, SE 90187 Umeå, Sweden
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Sweden
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2
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Nakajima Y, Ugai-Amo N, Tone N, Nakagawa A, Iwai M, Ikeuchi M, Sugiura M, Suga M, Shen JR. Crystal structures of photosystem II from a cyanobacterium expressing psbA 2 in comparison to psbA 3 reveal differences in the D1 subunit. J Biol Chem 2022; 298:102668. [PMID: 36334624 PMCID: PMC9709244 DOI: 10.1016/j.jbc.2022.102668] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/27/2022] [Accepted: 10/30/2022] [Indexed: 11/07/2022] Open
Abstract
Three psbA genes (psbA1, psbA2, and psbA3) encoding the D1 subunit of photosystem II (PSII) are present in the thermophilic cyanobacterium Thermosynechococcus elongatus and are expressed differently in response to changes in the growth environment. To clarify the functional differences of the D1 protein expressed from these psbA genes, PSII dimers from two strains, each expressing only one psbA gene (psbA2 or psbA3), were crystallized, and we analyzed their structures at resolutions comparable to previously studied PsbA1-PSII. Our results showed that the hydrogen bond between pheophytin/D1 (PheoD1) and D1-130 became stronger in PsbA2- and PsbA3-PSII due to change of Gln to Glu, which partially explains the increase in the redox potential of PheoD1 observed in PsbA3. In PsbA2, one hydrogen bond was lost in PheoD1 due to the change of D1-Y147F, which may explain the decrease in stability of PheoD1 in PsbA2. Two water molecules in the Cl-1 channel were lost in PsbA2 due to the change of D1-P173M, leading to the narrowing of the channel, which may explain the lower efficiency of the S-state transition beyond S2 in PsbA2-PSII. In PsbA3-PSII, a hydrogen bond between D1-Ser270 and a sulfoquinovosyl-diacylglycerol molecule near QB disappeared due to the change of D1-Ser270 in PsbA1 and PsbA2 to D1-Ala270. This may result in an easier exchange of bound QB with free plastoquinone, hence an enhancement of oxygen evolution in PsbA3-PSII due to its high QB exchange efficiency. These results provide a structural basis for further functional examination of the three PsbA variants.
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Affiliation(s)
- Yoshiki Nakajima
- Research Institute for Interdisciplinary Science, Okayama University, Okayama, Japan
| | - Natsumi Ugai-Amo
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Naoki Tone
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Akiko Nakagawa
- Proteo-Science Research Center, Ehime University, Matsuyama, Japan
| | - Masako Iwai
- Graduate School and College of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo, Japan
| | - Masahiko Ikeuchi
- Graduate School and College of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo, Japan
| | - Miwa Sugiura
- Proteo-Science Research Center, Ehime University, Matsuyama, Japan
| | - Michihiro Suga
- Research Institute for Interdisciplinary Science, Okayama University, Okayama, Japan,Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan,For correspondence: Michihiro Suga; Jian-Ren Shen
| | - Jian-Ren Shen
- Research Institute for Interdisciplinary Science, Okayama University, Okayama, Japan,Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan,For correspondence: Michihiro Suga; Jian-Ren Shen
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3
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Shimada Y, Sugiyama A, Nagao R, Noguchi T. Role of D1-Glu65 in Proton Transfer during Photosynthetic Water Oxidation in Photosystem II. J Phys Chem B 2022; 126:8202-8213. [PMID: 36199221 DOI: 10.1021/acs.jpcb.2c05869] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Photosynthetic water oxidation takes place at the Mn4CaO5 cluster in photosystem II (PSII) through a light-driven cycle of five intermediates called S states (S0-S4). Although the PSII structures have shown the presence of several channels around the Mn4CaO5 cluster leading to the lumen, the pathways for proton release in the individual S-state transitions remain unidentified. Here, we studied the involvement of the so-called Cl channel in proton transfer during water oxidation by examining the effect of the mutation of D1-Glu65, a key residue in this channel, to Ala using Fourier transform infrared difference and time-resolved infrared spectroscopies together with thermoluminescence and delayed luminescence measurements. It was shown that the structure and the redox property of the catalytic site were little affected by the D1-Glu65Ala mutation. In the S2 → S3 transition, the efficiency was still high and the transition rate was only moderately retarded in the D1-Glu65Ala mutant. In contrast, the S3 → S0 transition was significantly inhibited by this mutation. These results suggest that proton transfer in the S2 → S3 transition occurs through multiple pathways including the Cl channel, whereas this channel likely serves as a single pathway for proton exit in the S3 → S0 transition.
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Affiliation(s)
- Yuichiro Shimada
- Department of Physics, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya464-8602, Japan
| | - Ayane Sugiyama
- Department of Physics, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya464-8602, Japan
| | - Ryo Nagao
- Department of Physics, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya464-8602, Japan.,Research Institute for Interdisciplinary Science, Okayama University, 3-1-1 Tsushima-naka, Okayama700-8530, Japan
| | - Takumi Noguchi
- Department of Physics, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya464-8602, Japan
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4
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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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5
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Kuroda H, Kawashima K, Ueda K, Ikeda T, Saito K, Ninomiya R, Hida C, Takahashi Y, Ishikita H. Proton transfer pathway from the oxygen-evolving complex in photosystem II substantiated by extensive mutagenesis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1862:148329. [PMID: 33069681 DOI: 10.1016/j.bbabio.2020.148329] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 10/07/2020] [Accepted: 10/13/2020] [Indexed: 12/11/2022]
Abstract
We report a structure-based biological approach to identify the proton-transfer pathway in photosystem II. First, molecular dynamics (MD) simulations were conducted to analyze the H-bond network that may serve as a Grotthuss-like proton conduit. MD simulations show that D1-Asp61, the H-bond acceptor of H2O at the Mn4CaO5 cluster (W1), forms an H-bond via one water molecule with D1-Glu65 but not with D2-Glu312. Then, D1-Asp61, D1-Glu65, D2-Glu312, and the adjacent residues, D1-Arg334, D2-Glu302, and D2-Glu323, were thoroughly mutated to the other 19 residues, i.e., 114 Chlamydomonas chloroplast mutant cells were generated. Mutation of D1-Asp61 was most crucial. Only the D61E and D61C cells grew photoautotrophically and exhibit O2-evolving activity. Mutations of D2-Glu312 were less crucial to photosynthetic growth than mutations of D1-Glu65. Quantum mechanical/molecular mechanical calculations indicated that in the PSII crystal structure, the proton is predominantly localized at D1-Glu65 along the H-bond with D2-Glu312, i.e., pKa(D1-Glu65) > pKa(D2-Glu312). The potential-energy profile shows that the release of the proton from D1-Glu65 leads to the formation of the two short H-bonds between D1-Asp61 and D1-Glu65, which facilitates downhill proton transfer along the Grotthuss-like proton conduit in the S2 to S3 transition. It seems possible that D1-Glu65 is involved in the dominant pathway that proceeds from W1 via D1-Asp61 toward the thylakoid lumen, whereas D2-Glu312 and D1-Arg334 may be involved in alternative pathways in some mutants.
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Affiliation(s)
- Hiroshi Kuroda
- Research Institute for Interdisciplinary Science, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan
| | - Keisuke Kawashima
- Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo 113-8654, Japan
| | - Kazuyo Ueda
- Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan
| | - Takuya Ikeda
- Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo 113-8654, Japan
| | - Keisuke Saito
- Department of Applied Chemistry, Graduate School of Engineering, 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
| | - Ryo Ninomiya
- Department of Biology, Faculty of Science, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan
| | - Chisato Hida
- Department of Biology, Faculty of Science, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan
| | - Yuichiro Takahashi
- Research Institute for Interdisciplinary Science, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan.
| | - Hiroshi Ishikita
- Department of Applied Chemistry, Graduate School of Engineering, 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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6
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Water-oxidizing complex in Photosystem II: Its structure and relation to manganese-oxide based catalysts. Coord Chem Rev 2020. [DOI: 10.1016/j.ccr.2020.213183] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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7
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Mandal M, Kawashima K, Saito K, Ishikita H. Redox Potential of the Oxygen-Evolving Complex in the Electron Transfer Cascade of Photosystem II. J Phys Chem Lett 2020; 11:249-255. [PMID: 31729876 DOI: 10.1021/acs.jpclett.9b02831] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In photosystem II (PSII), water oxidation occurs in the Mn4CaO5 cluster with the release of electrons via the redox-active tyrosine (TyrZ) to the reaction-center chlorophylls (PD1/PD2). Using a quantum mechanical/molecular mechanical approach, we report the redox potentials (Em) of these cofactors in the PSII protein environment. The Em values suggest that the Mn4CaO5 cluster, TyrZ, and PD1/PD2 form a downhill electron transfer pathway. Em for the first oxidation step, Em(S0/S1), is uniquely low (730 mV) and is ∼100 mV lower than that for the second oxidation step, Em(S1/S2) (830 mV) only when the O4 site of the Mn4CaO5 cluster is protonated in S0. The O4-water chain, which directly forms a low-barrier H-bond with the Mn4CaO5 cluster and mediates proton-coupled electron transfer in the S0 to S1 transition, explains why the second lowest oxidation state, S1, is the most stable and S0 is converted to S1 even in the dark.
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Affiliation(s)
- Manoj Mandal
- Research Center for Advanced Science and Technology , The University of Tokyo , 4-6-1 Komaba , Meguro-ku, Tokyo 153-8904 , Japan
| | - Keisuke Kawashima
- Department of Applied Chemistry , The University of Tokyo , 7-3-1 Hongo , Bunkyo-ku, Tokyo 113-8654 , Japan
| | - Keisuke Saito
- Research Center for Advanced Science and Technology , The University of Tokyo , 4-6-1 Komaba , Meguro-ku, Tokyo 153-8904 , Japan
- Department of Applied Chemistry , The University of Tokyo , 7-3-1 Hongo , Bunkyo-ku, Tokyo 113-8654 , Japan
| | - Hiroshi Ishikita
- Research Center for Advanced Science and Technology , The University of Tokyo , 4-6-1 Komaba , Meguro-ku, Tokyo 153-8904 , Japan
- Department of Applied Chemistry , The University of Tokyo , 7-3-1 Hongo , Bunkyo-ku, Tokyo 113-8654 , Japan
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8
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Ghosh I, Khan S, Banerjee G, Dziarski A, Vinyard DJ, Debus RJ, Brudvig GW. Insights into Proton-Transfer Pathways during Water Oxidation in Photosystem II. J Phys Chem B 2019; 123:8195-8202. [DOI: 10.1021/acs.jpcb.9b06244] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ipsita Ghosh
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Sahr Khan
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Gourab Banerjee
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Alisha Dziarski
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - David J. Vinyard
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Richard J. Debus
- Department of Biochemistry, University of California, Riverside, California 92521, United States
| | - Gary W. Brudvig
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
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9
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Photosystem II oxygen-evolving complex photoassembly displays an inverse H/D solvent isotope effect under chloride-limiting conditions. Proc Natl Acad Sci U S A 2019; 116:18917-18922. [PMID: 31484762 PMCID: PMC6754581 DOI: 10.1073/pnas.1910231116] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Metal clusters play important roles in a wide variety of proteins. In cyanobacteria, algae, and plants, photosystem II uses light energy to oxidize water and release O2 at an active site that contains 1 calcium and 4 manganese atoms. This cluster must be built within the protein environment through a process known as photoassembly. Through experiments and simulations, we found that the efficiency of photoassembly was highly dependent on protons and chloride. Surprisingly, when the solvent was switched from H2O to deuterated water, D2O, the yield of photoassembly was higher. These results provide insights into the stepwise mechanism of photoassembly that can inform synthesis and repair strategies being developed for artificial photosynthesis technologies. Photosystem II (PSII) performs the solar-driven oxidation of water used to fuel oxygenic photosynthesis. The active site of water oxidation is the oxygen-evolving complex (OEC), a Mn4CaO5 cluster. PSII requires degradation of key subunits and reassembly of the OEC as frequently as every 20 to 40 min. The metals for the OEC are assembled within the PSII protein environment via a series of binding events and photochemically induced oxidation events, but the full mechanism is unknown. A role of proton release in this mechanism is suggested here by the observation that the yield of in vitro OEC photoassembly is higher in deuterated water, D2O, compared with H2O when chloride is limiting. In kinetic studies, OEC photoassembly shows a significant lag phase in H2O at limiting chloride concentrations with an apparent H/D solvent isotope effect of 0.14 ± 0.05. The growth phase of OEC photoassembly shows an H/D solvent isotope effect of 1.5 ± 0.2. We analyzed the protonation states of the OEC protein environment using classical Multiconformer Continuum Electrostatics. Combining experiments and simulations leads to a model in which protons are lost from amino acid that will serve as OEC ligands as metals are bound. Chloride and D2O increase the proton affinities of key amino acid residues. These residues tune the binding affinity of Mn2+/3+ and facilitate the deprotonation of water to form a proposed μ-hydroxo bridged Mn2+Mn3+ intermediate.
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10
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Ogata K, Hatakeyama M, Sakamoto Y, Nakamura S. Investigation of a Pathway for Water Delivery in Photosystem II Protein by Molecular Dynamics Simulation. J Phys Chem B 2019; 123:6444-6452. [DOI: 10.1021/acs.jpcb.9b04838] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Koji Ogata
- Nakamura Laboratory, RIKEN Cluster for Science, Technology and Innovation Hub, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Makoto Hatakeyama
- Nakamura Laboratory, RIKEN Cluster for Science, Technology and Innovation Hub, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Yuki Sakamoto
- Nakamura Laboratory, RIKEN Cluster for Science, Technology and Innovation Hub, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Department of Biological Information, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
| | - Shinichiro Nakamura
- Nakamura Laboratory, RIKEN Cluster for Science, Technology and Innovation Hub, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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11
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Chrysina M, de Mendonça Silva JC, Zahariou G, Pantazis DA, Ioannidis N. Proton Translocation via Tautomerization of Asn298 During the S 2-S 3 State Transition in the Oxygen-Evolving Complex of Photosystem II. J Phys Chem B 2019; 123:3068-3078. [PMID: 30888175 PMCID: PMC6727346 DOI: 10.1021/acs.jpcb.9b02317] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
![]()
In biological water oxidation, a
redox-active tyrosine residue
(D1-Tyr161 or YZ) mediates electron transfer between the
Mn4CaO5 cluster of the oxygen-evolving complex
and the charge-separation site of photosystem II (PSII), driving the
cluster through progressively higher oxidation states Si (i = 0–4). In contrast to
lower S-states (S0, S1), in higher S-states
(S2, S3) of the Mn4CaO5 cluster, YZ cannot be oxidized at cryogenic temperatures
due to the accumulation of positive charge in the S1 →
S2 transition. However, oxidation of YZ by illumination
of S2 at 77–190 K followed by rapid freezing and
charge recombination between YZ• and
the plastoquinone radical QA•– allows trapping of an S2 variant, the so-called S2trapped state (S2t), that
is capable of forming YZ• at cryogenic
temperature. To identify the differences between the S2 and S2t states, we used the S2tYZ• intermediate as a probe for
the S2t state and followed the S2tYZ•/QA•– recombination kinetics at 10 K using time-resolved electron paramagnetic
resonance spectroscopy in H2O and D2O. The results
show that while S2tYZ•/QA•– recombination can be described
as pure electron transfer occurring in the Marcus inverted region,
the S2t → S2 reversion depends
on proton rearrangement and exhibits a strong kinetic isotope effect.
This suggests that YZ oxidation in the S2t state is facilitated by favorable proton redistribution in
the vicinity of YZ, most likely within the hydrogen-bonded
YZ–His190–Asn298 triad. Computational models
show that tautomerization of Asn298 to its imidic acid form enables
proton translocation to an adjacent asparagine-rich cavity of water
molecules that functions as a proton reservoir and can further participate
in proton egress to the lumen.
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Affiliation(s)
- Maria Chrysina
- Institute of Nanoscience & Nanotechnology , NCSR "Demokritos" , Athens 15310 , Greece.,Max-Planck-Institut für Chemische Energiekonversion , Stiftstr. 34-36 , 45470 Mülheim an der Ruhr , Germany
| | - Juliana Cecília de Mendonça Silva
- Max-Planck-Institut für Chemische Energiekonversion , Stiftstr. 34-36 , 45470 Mülheim an der Ruhr , Germany.,Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelm-Platz 1 , 45470 Mülheim an der Ruhr , Germany
| | - Georgia Zahariou
- Institute of Nanoscience & Nanotechnology , NCSR "Demokritos" , Athens 15310 , Greece
| | - Dimitrios A Pantazis
- Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelm-Platz 1 , 45470 Mülheim an der Ruhr , Germany
| | - Nikolaos Ioannidis
- Institute of Nanoscience & Nanotechnology , NCSR "Demokritos" , Athens 15310 , Greece
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12
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Ghosh I, Banerjee G, Kim CJ, Reiss K, Batista VS, Debus RJ, Brudvig GW. D1-S169A Substitution of Photosystem II Perturbs Water Oxidation. Biochemistry 2019; 58:1379-1387. [DOI: 10.1021/acs.biochem.8b01184] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Ipsita Ghosh
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Gourab Banerjee
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Christopher J. Kim
- Department of Biochemistry, University of California, Riverside, California 92521, United States
| | - Krystle Reiss
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Victor S. Batista
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Richard J. Debus
- Department of Biochemistry, University of California, Riverside, California 92521, United States
| | - Gary W. Brudvig
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
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13
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Abstract
AbstractCyanobacteria and plants carry out oxygenic photosynthesis. They use water to generate the atmospheric oxygen we breathe and carbon dioxide to produce the biomass serving as food, feed, fibre and fuel. This paper scans the emergence of structural and mechanistic understanding of oxygen evolution over the past 50 years. It reviews speculative concepts and the stepped insight provided by novel experimental and theoretical techniques. Driven by sunlight photosystem II oxidizes the catalyst of water oxidation, a hetero-metallic Mn4CaO5(H2O)4 cluster. Mn3Ca are arranged in cubanoid and one Mn dangles out. By accumulation of four oxidizing equivalents before initiating dioxygen formation it matches the four-electron chemistry from water to dioxygen to the one-electron chemistry of the photo-sensitizer. Potentially harmful intermediates are thereby occluded in space and time. Kinetic signatures of the catalytic cluster and its partners in the photo-reaction centre have been resolved, in the frequency domain ranging from acoustic waves via infra-red to X-ray radiation, and in the time domain from nano- to milli-seconds. X-ray structures to a resolution of 1.9 Å are available. Even time resolved X-ray structures have been obtained by clocking the reaction cycle by flashes of light and diffraction with femtosecond X-ray pulses. The terminal reaction cascade from two molecules of water to dioxygen involves the transfer of four electrons, two protons, one dioxygen and one water. A rigorous mechanistic analysis is challenging because of the kinetic enslaving at millisecond duration of six partial reactions (4e−, 1H+, 1O2). For the time being a peroxide-intermediate in the reaction cascade to dioxygen has been in focus, both experimentally and by quantum chemistry. Homo sapiens has relied on burning the products of oxygenic photosynthesis, recent and fossil. Mankind's total energy consumption amounts to almost one-fourth of the global photosynthetic productivity. If the average power consumption equalled one of those nations with the highest consumption per capita it was four times greater and matched the total productivity. It is obvious that biomass should be harvested for food, feed, fibre and platform chemicals rather than for fuel.
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14
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Probing the role of Valine 185 of the D1 protein in the Photosystem II oxygen evolution. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:1259-1273. [DOI: 10.1016/j.bbabio.2018.10.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 10/03/2018] [Accepted: 10/14/2018] [Indexed: 11/23/2022]
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15
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Kim CJ, Bao H, Burnap RL, Debus RJ. Impact of D1-V185 on the Water Molecules That Facilitate O2 Formation by the Catalytic Mn4CaO5 Cluster in Photosystem II. Biochemistry 2018; 57:4299-4311. [DOI: 10.1021/acs.biochem.8b00630] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Christopher J. Kim
- Department of Biochemistry, University of California, Riverside, California 92521, United States
| | - Han Bao
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Robert L. Burnap
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Richard J. Debus
- Department of Biochemistry, University of California, Riverside, California 92521, United States
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16
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Kawashima K, Takaoka T, Kimura H, Saito K, Ishikita H. O 2 evolution and recovery of the water-oxidizing enzyme. Nat Commun 2018; 9:1247. [PMID: 29593210 PMCID: PMC5871790 DOI: 10.1038/s41467-018-03545-w] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 02/20/2018] [Indexed: 01/14/2023] Open
Abstract
In photosystem II, light-induced water oxidation occurs at the Mn4CaO5 cluster. Here we demonstrate proton releases, dioxygen formation, and substrate water incorporation in response to Mn4CaO5 oxidation in the protein environment, using a quantum mechanical/molecular mechanical approach and molecular dynamics simulations. In S2, H2O at the W1 site forms a low-barrier H-bond with D1-Asp61. In the S2-to-S3 transition, oxidation of OW1H– to OW1•–, concerted proton transfer from OW1H– to D1-Asp61, and binding of a water molecule Wn-W1 at OW1•– are observed. In S4, Wn-W1 facilitates oxo-oxyl radical coupling between OW1•– and corner μ-oxo O4. Deprotonation via D1-Asp61 leads to formation of OW1=O4. As OW1=O4 moves away from Mn, H2O at W539 is incorporated into the vacant O4 site of the O2-evolved Mn4CaO4 cluster, forming a μ-oxo bridge (Mn3–OW539–Mn4) in an exergonic process. Simultaneously, Wn-W1 is incorporated as W1, recovering the Mn4CaO5 cluster. Water splitting during photosynthesis results in the combination of two oxygen atoms to form O2. Here, based on computational simulations, the authors develop a possible mechanism for this reaction, which is different from the mechanisms previous studies have suggested.
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Affiliation(s)
- Keisuke Kawashima
- Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8654, Japan
| | - Tomohiro Takaoka
- Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8654, Japan
| | - Hiroki Kimura
- Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8654, Japan
| | - Keisuke Saito
- Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8654, Japan.,Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8904, Japan
| | - Hiroshi Ishikita
- Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8654, Japan. .,Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8904, Japan.
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17
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Schuth N, Liang Z, Schönborn M, Kussicke A, Assunção R, Zaharieva I, Zilliges Y, Dau H. Inhibitory and Non-Inhibitory NH 3 Binding at the Water-Oxidizing Manganese Complex of Photosystem II Suggests Possible Sites and a Rearrangement Mode of Substrate Water Molecules. Biochemistry 2017; 56:6240-6256. [PMID: 29086556 DOI: 10.1021/acs.biochem.7b00743] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The identity and rearrangements of substrate water molecules in photosystem II (PSII) water oxidation are of great mechanistic interest and addressed herein by comprehensive analysis of NH4+/NH3 binding. Time-resolved detection of O2 formation and recombination fluorescence as well as Fourier transform infrared (FTIR) difference spectroscopy on plant PSII membrane particles reveals the following. (1) Partial inhibition in NH4Cl buffer occurs with a pH-independent binding constant of ∼25 mM, which does not result from decelerated O2 formation, but from complete blockage of a major PSII fraction (∼60%) after reaching the Mn(IV)4 (S3) state. (2) The non-inhibited PSII fraction advances through the reaction cycle, but modified nuclear rearrangements are suggested by FTIR difference spectroscopy. (3) Partial inhibition can be explained by anticooperative (mutually exclusive) NH3 binding to one inhibitory and one non-inhibitory site; these two sites may correspond to two water molecules terminally bound to the "dangling" Mn ion. (4) Unexpectedly strong modifications of the FTIR difference spectra suggest that in the non-inhibited PSII, ammonia binding obliterates the need for some of the nuclear rearrangements occurring in the S2-S3 transition as well as their reversal in the O2 formation transition, in line with the carousel mechanism [Askerka, M., et al. (2015) Biochemistry 54, 5783]. (5) We observe the same partial inhibition of PSII by NH4Cl also for thylakoid membranes prepared from mesophilic and thermophilic cyanobacteria, suggesting that the results described above are valid for plant and cyanobacterial PSII.
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Affiliation(s)
- Nils Schuth
- Freie Universität Berlin , Department of Physics, 14195 Berlin, Germany
| | - Zhiyong Liang
- Freie Universität Berlin , Department of Physics, 14195 Berlin, Germany
| | | | - André Kussicke
- Freie Universität Berlin , Department of Physics, 14195 Berlin, Germany
| | - Ricardo Assunção
- Freie Universität Berlin , Department of Physics, 14195 Berlin, Germany
| | - Ivelina Zaharieva
- Freie Universität Berlin , Department of Physics, 14195 Berlin, Germany
| | - Yvonne Zilliges
- Freie Universität Berlin , Department of Physics, 14195 Berlin, Germany
| | - Holger Dau
- Freie Universität Berlin , Department of Physics, 14195 Berlin, Germany
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18
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Nagao R, Ueoka-Nakanishi H, Noguchi T. D1-Asn-298 in photosystem II is involved in a hydrogen-bond network near the redox-active tyrosine Y Z for proton exit during water oxidation. J Biol Chem 2017; 292:20046-20057. [PMID: 29046348 DOI: 10.1074/jbc.m117.815183] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 10/04/2017] [Indexed: 01/19/2023] Open
Abstract
In photosynthetic water oxidation, two water molecules are converted into one oxygen molecule and four protons at the Mn4CaO5 cluster in photosystem II (PSII) via the S-state cycle. Efficient proton exit from the catalytic site to the lumen is essential for this process. However, the exit pathways of individual protons through the PSII proteins remain to be identified. In this study, we examined the involvement of a hydrogen-bond network near the redox-active tyrosine YZ in proton transfer during the S-state cycle. We focused on spectroscopic analyses of a site-directed variant of D1-Asn-298, a residue involved in a hydrogen-bond network near YZ We found that the D1-N298A mutant of Synechocystis sp. PCC 6803 exhibits an O2 evolution activity of ∼10% of the wild-type. D1-N298A and the wild-type D1 had very similar features of thermoluminescence glow curves and of an FTIR difference spectrum upon YZ oxidation, suggesting that the hydrogen-bonded structure of YZ and electron transfer from the Mn4CaO5 cluster to YZ were little affected by substitution. In the D1-N298A mutant, however, the flash-number dependence of delayed luminescence showed a monotonic increase without oscillation, and FTIR difference spectra of the S-state cycle indicated partial and significant inhibition of the S2 → S3 and S3 → S0 transitions, respectively. These results suggest that the D1-N298A substitution inhibits the proton transfer processes in the S2 → S3 and S3 → S0 transitions. This in turn indicates that the hydrogen-bond network near YZ can be functional as a proton transfer pathway during photosynthetic water oxidation.
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Affiliation(s)
- Ryo Nagao
- Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
| | - Hanayo Ueoka-Nakanishi
- Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Takumi Noguchi
- Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
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19
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Najafpour MM, Renger G, Hołyńska M, Moghaddam AN, Aro EM, Carpentier R, Nishihara H, Eaton-Rye JJ, Shen JR, Allakhverdiev SI. Manganese Compounds as Water-Oxidizing Catalysts: From the Natural Water-Oxidizing Complex to Nanosized Manganese Oxide Structures. Chem Rev 2016; 116:2886-936. [PMID: 26812090 DOI: 10.1021/acs.chemrev.5b00340] [Citation(s) in RCA: 337] [Impact Index Per Article: 42.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
All cyanobacteria, algae, and plants use a similar water-oxidizing catalyst for water oxidation. This catalyst is housed in Photosystem II, a membrane-protein complex that functions as a light-driven water oxidase in oxygenic photosynthesis. Water oxidation is also an important reaction in artificial photosynthesis because it has the potential to provide cheap electrons from water for hydrogen production or for the reduction of carbon dioxide on an industrial scale. The water-oxidizing complex of Photosystem II is a Mn-Ca cluster that oxidizes water with a low overpotential and high turnover frequency number of up to 25-90 molecules of O2 released per second. In this Review, we discuss the atomic structure of the Mn-Ca cluster of the Photosystem II water-oxidizing complex from the viewpoint that the underlying mechanism can be informative when designing artificial water-oxidizing catalysts. This is followed by consideration of functional Mn-based model complexes for water oxidation and the issue of Mn complexes decomposing to Mn oxide. We then provide a detailed assessment of the chemistry of Mn oxides by considering how their bulk and nanoscale properties contribute to their effectiveness as water-oxidizing catalysts.
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Affiliation(s)
| | - Gernot Renger
- Institute of Chemistry, Max-Volmer-Laboratory of Biophysical Chemistry, Technical University Berlin , Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Małgorzata Hołyńska
- Fachbereich Chemie und Wissenschaftliches Zentrum für Materialwissenschaften (WZMW), Philipps-Universität Marburg , Hans-Meerwein-Straße, D-35032 Marburg, Germany
| | | | - Eva-Mari Aro
- Department of Biochemistry and Food Chemistry, University of Turku , 20014 Turku, Finland
| | - Robert Carpentier
- Groupe de Recherche en Biologie Végétale (GRBV), Université du Québec à Trois-Rivières , C.P. 500, Trois-Rivières, Québec G9A 5H7, Canada
| | - Hiroshi Nishihara
- Department of Chemistry, School of Science, The University of Tokyo , 7-3-1, Hongo, Bunkyo-Ku, Tokyo 113-0033, Japan
| | - Julian J Eaton-Rye
- Department of Biochemistry, University of Otago , P.O. Box 56, Dunedin 9054, New Zealand
| | - Jian-Ren Shen
- Photosynthesis Research Center, Graduate School of Natural Science and Technology, Faculty of Science, Okayama University , Okayama 700-8530, Japan.,Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences , Beijing 100093, China
| | - Suleyman I Allakhverdiev
- Controlled Photobiosynthesis Laboratory, Institute of Plant Physiology, Russian Academy of Sciences , Botanicheskaya Street 35, Moscow 127276, Russia.,Institute of Basic Biological Problems, Russian Academy of Sciences , Pushchino, Moscow Region 142290, Russia.,Department of Plant Physiology, Faculty of Biology, M.V. Lomonosov Moscow State University , Leninskie Gory 1-12, Moscow 119991, Russia
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20
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Nakamura S, Ota K, Shibuya Y, Noguchi T. Role of a Water Network around the Mn4CaO5 Cluster in Photosynthetic Water Oxidation: A Fourier Transform Infrared Spectroscopy and Quantum Mechanics/Molecular Mechanics Calculation Study. Biochemistry 2016; 55:597-607. [DOI: 10.1021/acs.biochem.5b01120] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Shin Nakamura
- Division
of Material Science,
Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Kai Ota
- Division
of Material Science,
Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Yuichi Shibuya
- Division
of Material Science,
Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Takumi Noguchi
- Division
of Material Science,
Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
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21
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Estimation of the driving force for dioxygen formation in photosynthesis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:23-33. [DOI: 10.1016/j.bbabio.2015.09.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 09/10/2015] [Accepted: 09/30/2015] [Indexed: 11/22/2022]
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22
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Structural rearrangements preceding dioxygen formation by the water oxidation complex of photosystem II. Proc Natl Acad Sci U S A 2015; 112:E6139-47. [PMID: 26508637 DOI: 10.1073/pnas.1512008112] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Photosynthetic water oxidation is catalyzed by the Mn4CaO5 cluster of photosystem II. Recent studies implicate an oxo bridge atom, O5, of the Mn4CaO5 cluster, as the "slowly exchanging" substrate water molecule. The D1-V185N mutant is in close vicinity of O5 and known to extend the lag phase and retard the O2 release phase (slow phase) in this critical last [Formula: see text] transition of water oxidation. The pH dependence, hydrogen/deuterium (H/D) isotope effect, and temperature dependence on the O2 release kinetics for this mutant were studied using time-resolved O2 polarography, and comparisons were made with WT and two mutants of the putative proton gate D1-D61. Both kinetic phases in V185N are independent of pH and buffer concentration and have weaker H/D kinetic isotope effects. Each phase is characterized by a parallel or even lower activation enthalpy but a less favorable activation entropy than the WT. The results indicate new rate-determining steps for both phases. It is concluded that the lag does not represent inhibition of proton release but rather, slowing of a previously unrecognized kinetic phase involving a structural rearrangement or tautomerism of the S3 (+) ground state as it approaches a configuration conducive to dioxygen formation. The parallel impacts on both the lag and O2 formation phases suggest a common origin for the defects surmised to be perturbations of the H-bond network and the water cluster adjacent to O5.
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23
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Oyala PH, Stich TA, Debus RJ, Britt RD. Ammonia Binds to the Dangler Manganese of the Photosystem II Oxygen-Evolving Complex. J Am Chem Soc 2015; 137:8829-37. [DOI: 10.1021/jacs.5b04768] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Paul H. Oyala
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - Troy A. Stich
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - Richard J. Debus
- Department of Biochemistry, University of California, Riverside, Riverside, California 92521, United States
| | - R. David Britt
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
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24
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Pokhrel R, Debus RJ, Brudvig GW. Probing the Effect of Mutations of Asparagine 181 in the D1 Subunit of Photosystem II. Biochemistry 2015; 54:1663-72. [DOI: 10.1021/bi501468h] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Ravi Pokhrel
- Department
of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Richard J. Debus
- Department
of Biochemistry, University of California, Riverside, California 92521, United States
| | - Gary W. Brudvig
- Department
of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
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25
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Debus RJ. FTIR studies of metal ligands, networks of hydrogen bonds, and water molecules near the active site Mn₄CaO₅ cluster in Photosystem II. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1847:19-34. [PMID: 25038513 DOI: 10.1016/j.bbabio.2014.07.007] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 07/09/2014] [Accepted: 07/10/2014] [Indexed: 11/26/2022]
Abstract
The photosynthetic conversion of water to molecular oxygen is catalyzed by the Mn₄CaO₅ cluster in Photosystem II and provides nearly our entire supply of atmospheric oxygen. The Mn₄CaO₅ cluster accumulates oxidizing equivalents in response to light-driven photochemical events within Photosystem II and then oxidizes two molecules of water to oxygen. The Mn₄CaO₅ cluster converts water to oxygen much more efficiently than any synthetic catalyst because its protein environment carefully controls the cluster's reactivity at each step in its catalytic cycle. This control is achieved by precise choreography of the proton and electron transfer reactions associated with water oxidation and by careful management of substrate (water) access and proton egress. This review describes the FTIR studies undertaken over the past two decades to identify the amino acid residues that are responsible for this control and to determine the role of each. In particular, this review describes the FTIR studies undertaken to characterize the influence of the cluster's metal ligands on its activity, to delineate the proton egress pathways that link the Mn₄CaO₅ cluster with the thylakoid lumen, and to characterize the influence of specific residues on the water molecules that serve as substrate or as participants in the networks of hydrogen bonds that make up the water access and proton egress pathways. This information will improve our understanding of water oxidation by the Mn₄CaO₅ catalyst in Photosystem II and will provide insight into the design of new generations of synthetic catalysts that convert sunlight into useful forms of storable energy. This article is part of a Special Issue entitled: Vibrational spectroscopies and bioenergetic systems.
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Affiliation(s)
- Richard J Debus
- Department of Biochemistry, University of California, Riverside, Riverside, CA 92521-0129, USA.
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26
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Serial time-resolved crystallography of photosystem II using a femtosecond X-ray laser. Nature 2014; 513:261-5. [PMID: 25043005 DOI: 10.1038/nature13453] [Citation(s) in RCA: 315] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 05/04/2014] [Indexed: 01/17/2023]
Abstract
Photosynthesis, a process catalysed by plants, algae and cyanobacteria converts sunlight to energy thus sustaining all higher life on Earth. Two large membrane protein complexes, photosystem I and II (PSI and PSII), act in series to catalyse the light-driven reactions in photosynthesis. PSII catalyses the light-driven water splitting process, which maintains the Earth's oxygenic atmosphere. In this process, the oxygen-evolving complex (OEC) of PSII cycles through five states, S0 to S4, in which four electrons are sequentially extracted from the OEC in four light-driven charge-separation events. Here we describe time resolved experiments on PSII nano/microcrystals from Thermosynechococcus elongatus performed with the recently developed technique of serial femtosecond crystallography. Structures have been determined from PSII in the dark S1 state and after double laser excitation (putative S3 state) at 5 and 5.5 Å resolution, respectively. The results provide evidence that PSII undergoes significant conformational changes at the electron acceptor side and at the Mn4CaO5 core of the OEC. These include an elongation of the metal cluster, accompanied by changes in the protein environment, which could allow for binding of the second substrate water molecule between the more distant protruding Mn (referred to as the 'dangler' Mn) and the Mn3CaOx cubane in the S2 to S3 transition, as predicted by spectroscopic and computational studies. This work shows the great potential for time-resolved serial femtosecond crystallography for investigation of catalytic processes in biomolecules.
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27
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Noguchi T. Fourier transform infrared difference and time-resolved infrared detection of the electron and proton transfer dynamics in photosynthetic water oxidation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1847:35-45. [PMID: 24998309 DOI: 10.1016/j.bbabio.2014.06.009] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 06/25/2014] [Accepted: 06/26/2014] [Indexed: 01/15/2023]
Abstract
Photosynthetic water oxidation, which provides the electrons necessary for CO₂ reduction and releases O₂ and protons, is performed at the Mn₄CaO₅ cluster in photosystem II (PSII). In this review, studies that assessed the mechanism of water oxidation using infrared spectroscopy are summarized focusing on electron and proton transfer dynamics. Structural changes in proteins and water molecules between intermediates known as Si states (i=0-3) were detected using flash-induced Fourier transform infrared (FTIR) difference spectroscopy. Electron flow in PSII and proton release from substrate water were monitored using the infrared changes in ferricyanide as an exogenous electron acceptor and Mes buffer as a proton acceptor. Time-resolved infrared (TRIR) spectroscopy provided information on the dynamics of proton-coupled electron transfer during the S-state transitions. In particular, a drastic proton movement during the lag phase (~200μs) before electron transfer in the S3→S0 transition was detected directly by monitoring the infrared absorption of a polarizable proton in a hydrogen bond network. Furthermore, the proton release pathways in the PSII proteins were analyzed by FTIR difference measurements in combination with site-directed mutagenesis, isotopic substitutions, and quantum chemical calculations. Therefore, infrared spectroscopy is a powerful tool for understanding the molecular mechanism of photosynthetic water oxidation. This article is part of a Special Issue entitled: Vibrational spectroscopies and bioenergetic systems.
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Affiliation(s)
- Takumi Noguchi
- Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan.
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28
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Nakamura S, Nagao R, Takahashi R, Noguchi T. Fourier transform infrared detection of a polarizable proton trapped between photooxidized tyrosine YZ and a coupled histidine in photosystem II: relevance to the proton transfer mechanism of water oxidation. Biochemistry 2014; 53:3131-44. [PMID: 24786306 DOI: 10.1021/bi500237y] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The redox-active tyrosine YZ (D1-Tyr161) in photosystem II (PSII) functions as an immediate electron acceptor of the Mn4Ca cluster, which is the catalytic center of photosynthetic water oxidation. YZ is also located in the hydrogen bond network that connects the Mn4Ca cluster to the lumen and hence is possibly related to the proton transfer process during water oxidation. To understand the role of YZ in the water oxidation mechanism, we have studied the hydrogen bonding interactions of YZ and its photooxidized neutral radical YZ(•) together with the interaction of the coupled His residue, D1-His190, using light-induced Fourier transform infrared (FTIR) difference spectroscopy. The YZ(•)-minus-YZ FTIR difference spectrum of Mn-depleted PSII core complexes exhibited a broad positive feature around 2800 cm(-1), which was absent in the corresponding spectrum of another redox-active tyrosine YD (D2-Tyr160). Analyses by (15)N and H/D substitutions, examination of the pH dependence, and density functional theory and quantum mechanics/molecular mechanics (QM/MM) calculations showed that this band arises from the N-H stretching vibration of the protonated cation of D1-His190 forming a charge-assisted strong hydrogen bond with YZ(•). This result provides strong evidence that the proton released from YZ upon its oxidation is trapped in D1-His190 and a positive charge remains on this His. The broad feature of the ~2800 cm(-1) band reflects a large proton polarizability in the hydrogen bond between YZ(•) and HisH(+). QM/MM calculations further showed that upon YZ oxidation the hydrogen bond network is rearranged and one water molecule moves toward D1-His190. From these data, a novel proton transfer mechanism via YZ(•)-HisH(+) is proposed, in which hopping of the polarizable proton of HisH(+) to this water triggers the transfer of the proton from substrate water to the luminal side. This proton transfer mechanism could be functional in the S2 → S3 transition, which requires proton release before electron transfer because of an excess positive charge on the Mn4Ca cluster.
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Affiliation(s)
- Shin Nakamura
- Division of Material Science, Graduate School of Science, Nagoya University , Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
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29
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Debus RJ. Evidence from FTIR Difference Spectroscopy That D1-Asp61 Influences the Water Reactions of the Oxygen-Evolving Mn4CaO5 Cluster of Photosystem II. Biochemistry 2014; 53:2941-55. [DOI: 10.1021/bi500309f] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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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Service RJ, Hillier W, Debus RJ. Network of Hydrogen Bonds near the Oxygen-Evolving Mn4CaO5 Cluster of Photosystem II Probed with FTIR Difference Spectroscopy. Biochemistry 2014; 53:1001-17. [DOI: 10.1021/bi401450y] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Rachel J. Service
- Department
of Biochemistry, University of California, Riverside, California 92521, United States
| | - Warwick Hillier
- Research
School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - Richard J. Debus
- Department
of Biochemistry, University of California, Riverside, California 92521, United States
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Linke K, Ho FM. Water in Photosystem II: Structural, functional and mechanistic considerations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:14-32. [DOI: 10.1016/j.bbabio.2013.08.003] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 08/08/2013] [Accepted: 08/13/2013] [Indexed: 12/30/2022]
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Bao H, Dilbeck PL, Burnap RL. Proton transport facilitating water-oxidation: the role of second sphere ligands surrounding the catalytic metal cluster. PHOTOSYNTHESIS RESEARCH 2013; 116:215-229. [PMID: 23975203 DOI: 10.1007/s11120-013-9907-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 08/03/2013] [Indexed: 06/02/2023]
Abstract
The ability of PSII to extract electrons from water, with molecular oxygen as a by-product, is a remarkable biochemical and evolutionary innovation. From an evolutionary perspective, the invention of PSII approximately 2.7 Ga led to the accelerated accumulation of biomass in the biosphere and the accumulation of oxygen in the atmosphere, a combination that allowed for the evolution of a much more complex and extensive biosphere than would otherwise have been possible. From the biochemical and enzymatic perspective, PSII is remarkable because of the thermodynamic and kinetic obstacles that needed to have been overcome to oxidize water as the ultimate photosynthetic electron donor. This article focuses on how proton release is an integral part of how these kinetic and thermodynamic obstacles have been overcome: the sequential removal of protons from the active site of H2O-oxidation facilitates the multistep oxidation of the substrate water at the Mn4CaOx, the catalytic heart of the H2O-oxidation reaction. As noted previously, the facilitated deprotonation of the Mn4CaOx cluster exerts a redox-leveling function preventing the accumulation of excess positive charge on the cluster, which might otherwise hinder the already energetically difficult oxidation of water. Using recent results, including the characteristics of site-directed mutants, the role of the second sphere of amino acid ligands and the associated network of water molecules surrounding the Mn4CaOx is discussed in relation to proton transport in other systems. In addition to the redox-leveling function, a trapping function is assigned to the proton release step occurring immediately prior to the dioxygen chemistry. This trapping appears to involve a yet-to-be clarified gating mechanism that facilitates to coordinated release of a proton from the neighborhood of the active site thereby insuring that the backward charge-recombination reaction does not out-compete the forward reaction of dioxygen chemistry during this final step of H2O-oxidation.
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Affiliation(s)
- Han Bao
- Department of Microbiology and Molecular Genetics, Oklahoma State University, 307 Life Sciences East, Stillwater, OK, 74078, USA
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Dilbeck PL, Bao H, Neveu CL, Burnap RL. Perturbing the Water Cavity Surrounding the Manganese Cluster by Mutating the Residue D1-Valine 185 Has a Strong Effect on the Water Oxidation Mechanism of Photosystem II. Biochemistry 2013; 52:6824-33. [DOI: 10.1021/bi400930g] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Preston L. Dilbeck
- Department of Microbiology and Molecular
Genetics, Oklahoma State University, 307 Life Sciences East, Stillwater, Oklahoma 74078, United States
| | - Han Bao
- Department of Microbiology and Molecular
Genetics, Oklahoma State University, 307 Life Sciences East, Stillwater, Oklahoma 74078, United States
| | - Curtis L. Neveu
- Department of Microbiology and Molecular
Genetics, Oklahoma State University, 307 Life Sciences East, Stillwater, Oklahoma 74078, United States
| | - Robert L. Burnap
- Department of Microbiology and Molecular
Genetics, Oklahoma State University, 307 Life Sciences East, Stillwater, Oklahoma 74078, United States
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Pokhrel R, Service RJ, Debus RJ, Brudvig GW. Mutation of Lysine 317 in the D2 Subunit of Photosystem II Alters Chloride Binding and Proton Transport. Biochemistry 2013; 52:4758-73. [DOI: 10.1021/bi301700u] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Ravi Pokhrel
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107,
United States
| | - Rachel J. Service
- 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
| | - Gary W. Brudvig
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107,
United States
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35
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Alternating electron and proton transfer steps in photosynthetic water oxidation. Proc Natl Acad Sci U S A 2012; 109:16035-40. [PMID: 22988080 DOI: 10.1073/pnas.1206266109] [Citation(s) in RCA: 146] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Water oxidation by cyanobacteria, algae, and plants is pivotal in oxygenic photosynthesis, the process that powers life on Earth, and is the paradigm for engineering solar fuel-production systems. Each complete reaction cycle of photosynthetic water oxidation requires the removal of four electrons and four protons from the catalytic site, a manganese-calcium complex and its protein environment in photosystem II. In time-resolved photothermal beam deflection experiments, we monitored apparent volume changes of the photosystem II protein associated with charge creation by light-induced electron transfer (contraction) and charge-compensating proton relocation (expansion). Two previously invisible proton removal steps were detected, thereby filling two gaps in the basic reaction-cycle model of photosynthetic water oxidation. In the S(2) → S(3) transition of the classical S-state cycle, an intermediate is formed by deprotonation clearly before electron transfer to the oxidant (Y Z OX). The rate-determining elementary step (τ, approximately 30 µs at 20 °C) in the long-distance proton relocation toward the protein-water interface is characterized by a high activation energy (E(a) = 0.46 ± 0.05 eV) and strong H/D kinetic isotope effect (approximately 6). The characteristics of a proton transfer step during the S(0) → S(1) transition are similar (τ, approximately 100 µs; E(a) = 0.34 ± 0.08 eV; kinetic isotope effect, approximately 3); however, the proton removal from the Mn complex proceeds after electron transfer to . By discovery of the transient formation of two further intermediate states in the reaction cycle of photosynthetic water oxidation, a temporal sequence of strictly alternating removal of electrons and protons from the catalytic site is established.
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36
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Boussac A, Ishida N, Sugiura M, Rappaport F. Probing the role of chloride in Photosystem II from Thermosynechococcus elongatus by exchanging chloride for iodide. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:802-10. [DOI: 10.1016/j.bbabio.2012.02.031] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Revised: 02/21/2012] [Accepted: 02/24/2012] [Indexed: 11/29/2022]
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Extended protein/water H-bond networks in photosynthetic water oxidation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:1177-90. [PMID: 22503827 DOI: 10.1016/j.bbabio.2012.03.031] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 03/19/2012] [Accepted: 03/28/2012] [Indexed: 11/23/2022]
Abstract
Oxidation of water molecules in the photosystem II (PSII) protein complex proceeds at the manganese-calcium complex, which is buried deeply in the lumenal part of PSII. Understanding the PSII function requires knowledge of the intricate coupling between the water-oxidation chemistry and the dynamic proton management by the PSII protein matrix. Here we assess the structural basis for long-distance proton transfer in the interior of PSII and for proton management at its surface. Using the recent high-resolution crystal structure of PSII, we investigate prominent hydrogen-bonded networks of the lumenal side of PSII. This analysis leads to the identification of clusters of polar groups and hydrogen-bonded networks consisting of amino acid residues and water molecules. We suggest that long-distance proton transfer and conformational coupling is facilitated by hydrogen-bonded networks that often involve more than one protein subunit. Proton-storing Asp/Glu dyads, such as the D1-E65/D2-E312 dyad connected to a complex water-wire network, may be particularly important for coupling protonation states to the protein conformation. Clusters of carboxylic amino acids could participate in proton management at the lumenal surface of PSII. We propose that rather than having a classical hydrophobic protein interior, the lumenal side of PSII resembles a complex polyelectrolyte with evolutionary optimized hydrogen-bonding networks. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.
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Renger G. Mechanism of light induced water splitting in Photosystem II of oxygen evolving photosynthetic organisms. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:1164-76. [PMID: 22353626 DOI: 10.1016/j.bbabio.2012.02.005] [Citation(s) in RCA: 121] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 01/27/2012] [Accepted: 02/05/2012] [Indexed: 11/24/2022]
Abstract
The reactions of light induced oxidative water splitting were analyzed within the framework of the empirical rate constant-distance relationship of non-adiabatic electron transfer in biological systems (C. C. Page, C. C. Moser, X. Chen , P. L. Dutton, Nature 402 (1999) 47-52) on the basis of structure information on Photosystem II (PS II) (A. Guskov, A. Gabdulkhakov, M. Broser, C. Glöckner, J. Hellmich, J. Kern, J. Frank, W. Saenger, A. Zouni, Chem. Phys. Chem. 11 (2010) 1160-1171, Y. Umena, K. Kawakami, J-R Shen, N. Kamiya, Crystal structure of oxygen-evolving photosystem II at a resolution of 1.9Å. Nature 47 (2011) 55-60). Comparison of these results with experimental data leads to the following conclusions: 1) The oxidation of tyrosine Y(z) by the cation radical P680(+·) in systems with an intact water oxidizing complex (WOC) is kinetically limited by the non-adiabatic electron transfer step and the extent of this reaction is thermodynamically determined by relaxation processes in the environment including rearrangements of hydrogen bond network(s). In marked contrast, all Y(z)(ox) induced oxidation steps in the WOC up to redox state S(3) are kinetically limited by trigger reactions which are slower by orders of magnitude than the rates calculated for non-adiabatic electron transfer. 3) The overall rate of the triggered reaction sequence of Y(z)(ox) reduction by the WOC in redox state S(3) eventually leading to formation and release of O(2) is kinetically limited by an uphill electron transfer step. Alternative models are discussed for this reaction. The protein matrix of the WOC and bound water molecules provide an optimized dynamic landscape of hydrogen bonded protons for catalyzing oxidative water splitting energetically driven by light induced formation of the cation radical P680(+·). In this way the PS II core acts as a molecular machine formed during a long evolutionary process. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.
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Dilbeck PL, Hwang HJ, Zaharieva I, Gerencser L, Dau H, Burnap RL. The D1-D61N Mutation in Synechocystis sp. PCC 6803 Allows the Observation of pH-Sensitive Intermediates in the Formation and Release of O2 from Photosystem II. Biochemistry 2012; 51:1079-91. [DOI: 10.1021/bi201659f] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Preston L. Dilbeck
- Department of Microbiology and
Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma 74078-4034, United States
| | - Hong Jin Hwang
- Department of Microbiology and
Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma 74078-4034, United States
| | | | | | - Holger Dau
- Department of Physics, Free University Berlin, Berlin, Germany
| | - Robert L. Burnap
- Department of Microbiology and
Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma 74078-4034, United States
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40
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Rivalta I, Amin M, Luber S, Vassiliev S, Pokhrel R, Umena Y, Kawakami K, Shen JR, Kamiya N, Bruce D, Brudvig GW, Gunner MR, Batista VS. Structural-functional role of chloride in photosystem II. Biochemistry 2011; 50:6312-5. [PMID: 21678923 DOI: 10.1021/bi200685w] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Chloride binding in photosystem II (PSII) is essential for photosynthetic water oxidation. However, the functional roles of chloride and possible binding sites, during oxygen evolution, remain controversial. This paper examines the functions of chloride based on its binding site revealed in the X-ray crystal structure of PSII at 1.9 Å resolution. We find that chloride depletion induces formation of a salt bridge between D2-K317 and D1-D61 that could suppress the transfer of protons to the lumen.
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Affiliation(s)
- Ivan Rivalta
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, USA.
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41
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Membrane-inlet mass spectrometry reveals a high driving force for oxygen production by photosystem II. Proc Natl Acad Sci U S A 2011; 108:3602-7. [PMID: 21321223 DOI: 10.1073/pnas.1014249108] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Oxygenic photosynthesis is the basis for aerobic life on earth. The catalytic Mn(4)O(x)CaY(Z) center of photosystem II (PSII), after fourfold oxidation, extracts four electrons from two water molecules to yield dioxygen. This reaction cascade has appeared as a single four-electron transfer that occurs in typically 1 ms. Inevitable redox intermediates have so far escaped detection, probably because of very short lifetime. Previous attempts to stabilize intermediates by high O(2)-back pressure have revealed controversial results. Here we monitored by membrane-inlet mass spectrometry (MIMS) the production of from (18)O-labeled water against a high background of in a suspension of PSII-core complexes. We found neither an inhibition nor an altered pattern of O(2) production by up to 50-fold increased concentration of dissolved O(2). Lack of inhibition is in line with results from previous X-ray absorption and visible-fluorescence experiments, but contradictory to the interpretation of previous UV-absorption data. Because we used essentially identical experimental conditions in MIMS as had been used in the UV work, the contradiction was serious, and we found it was not to be resolved by assuming a significant slowdown of the O(2) release kinetics or a subsequent slow conformational relaxation. This calls for reevaluation of the less direct UV experiments. The direct detection of O(2) release by MIMS shows unequivocally that O(2) release in PSII is highly exothermic. Under the likely assumption that one H(+) is released in the S(4) → S(0) transition, the driving force at pH 6.5 and atmospheric O(2) pressure is at least 220 meV, otherwise 160 meV.
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42
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Service RJ, Hillier W, Debus RJ. Evidence from FTIR difference spectroscopy of an extensive network of hydrogen bonds near the oxygen-evolving Mn(4)Ca cluster of photosystem II involving D1-Glu65, D2-Glu312, and D1-Glu329. Biochemistry 2010; 49:6655-69. [PMID: 20593803 DOI: 10.1021/bi100730d] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Analyses of the refined X-ray crystallographic structures of photosystem II (PSII) at 2.9-3.5 A have revealed the presence of possible channels for the removal of protons from the catalytic Mn(4)Ca cluster during the water-splitting reaction. As an initial attempt to verify these channels experimentally, the presence of a network of hydrogen bonds near the Mn(4)Ca cluster was probed with FTIR difference spectroscopy in a spectral region sensitive to the protonation states of carboxylate residues and, in particular, with a negative band at 1747 cm(-1) that is often observed in the S(2)-minus-S(1) FTIR difference spectrum of PSII from the cyanobacterium Synechocystis sp. PCC 6803. On the basis of its 4 cm(-1) downshift in D(2)O, this band was assigned to the carbonyl stretching vibration (C horizontal lineO) of a protonated carboxylate group whose pK(a) decreases during the S(1) to S(2) transition. The positive charge that forms on the Mn(4)Ca cluster during the S(1) to S(2) transition presumably causes structural perturbations that are transmitted to this carboxylate group via electrostatic interactions and/or an extended network of hydrogen bonds. In an attempt to identify the carboxylate group that gives rise to this band, the FTIR difference spectra of PSII core complexes from the mutants D1-Asp61Ala, D1-Glu65Ala, D1-Glu329Gln, and D2-Glu312Ala were examined. In the X-ray crystallographic models, these are the closest carboxylate residues to the Mn(4)Ca cluster that do not ligate Mn or Ca and all are highly conserved. The 1747 cm(-1) band is present in the S(2)-minus-S(1) FTIR difference spectrum of D1-Asp61Ala but absent from the corresponding spectra of D1-Glu65Ala, D2-Glu312Ala, and D1-Glu329Gln. The band is also sharply diminished in magnitude in the wild type when samples are maintained at a relative humidity of </=85%. It is proposed that D1-Glu65, D2-Glu312, and D1-Glu329 participate in a common network of hydrogen bonds that includes water molecules and the carboxylate group that gives rise to the 1747 cm(-1) band. It is further proposed that the mutation of any of these three residues, or partial dehydration caused by maintaining samples at a relative humidity of <or=85%, disrupts the network sufficiently that the structural perturbations associated with the S(1) to S(2) transition are no longer transmitted to the carboxylate group that gives rise to the 1747 cm(-1) band. Because D1-Glu329 is located approximately 20 A from D1-Glu65 and D2-Glu312, the postulated network of hydrogen bonds must extend for at least 20 A across the lumenal face of the Mn(4)Ca cluster. The D1-Asp61Ala, D1-Glu65Ala, and D2-Glu312Ala mutations also appear to substantially decrease the fraction of PSII reaction centers that undergo the S(3) to S(0) transition in response to a saturating flash. This behavior is consistent with D1-Asp61, D1-Glu65, and D2-Glu312 participating in a dominant proton egress channel that links the Mn(4)Ca cluster with the thylakoid lumen.
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Affiliation(s)
- Rachel J Service
- Department of Biochemistry, University of California, Riverside, California 92521, USA
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43
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Sugiura M, Rappaport F, Hillier W, Dorlet P, Ohno Y, Hayashi H, Boussac A. Evidence that D1-His332 in photosystem II from Thermosynechococcus elongatus interacts with the S3-state and not with the S2-state. Biochemistry 2009; 48:7856-66. [PMID: 19624137 DOI: 10.1021/bi901067b] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Oxygen evolution by Photosystem II (PSII) is catalyzed by a Mn(4)Ca cluster. Thus far, from the crystallographic three-dimensional (3D) structures, seven amino acid residues have been identified as possible ligands of the Mn(4)Ca cluster. Among them, there is only one histidine, His332, which belongs to the D1 polypeptide. The relationships of the D1-His332 amino acid with kinetics and thermodynamic properties of the Mn(4)Ca cluster in the S(2)- and S(3)-states of the catalytic cycle were investigated in purified PSII from Thermosynechococcus elongatus. This was done by examining site-directed D1-His332Gln and D1-His332Ser mutants by a variety of spectroscopic techniques such as time-resolved UV-visible absorption change spectroscopy, cw- and pulse-EPR, thermoluminescence, and measurement of substrate water exchange. Both mutants grew photo-autotrophically and active PSII could be purified. On the basis of the parameters assessed in this work, the D1-His332(Gln, Ser) mutations had no effect in the S(2)-state. Electron spin-echo envelope modulation (ESEEM) spectroscopy also showed that possible interactions between the nuclear spin of the nitrogen(s) of D1-His332 with the electronic spin S = 1/2 of the Mn(4)Ca cluster in the S(2)-state were not detectable and that the D1-His332Ser mutation did not affect the detected hyperfine couplings. In contrast, the following changes were observed in the S(3)-state of the D1-His332 mutants: (1) The redox potential of the S(3)/S(2) couple was slightly increased by < or = 20 meV, (2) The S(3)-EPR spectrum was slightly modified, (3) The D1-His332Gln mutation resulted in a approximately 3 fold decrease of the slow (tightly bound) exchange rate and a approximately 2 fold increase of the fast exchange rate of the water substrate molecules. All these results suggest that the D1-His332 would be more involved in S(3) than in S(2). This could be one element of the conformational changes put forward in the S(2) to S(3) transition.
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Affiliation(s)
- Miwa Sugiura
- Cell-Free Science and Technology Research Center, Ehime University, Bunkyo-cho, Matsuyama Ehime, 790-8577, Japan.
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44
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Renger G, Renger T. Photosystem II: The machinery of photosynthetic water splitting. PHOTOSYNTHESIS RESEARCH 2008; 98:53-80. [PMID: 18830685 DOI: 10.1007/s11120-008-9345-7] [Citation(s) in RCA: 192] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Accepted: 07/29/2008] [Indexed: 05/26/2023]
Abstract
This review summarizes our current state of knowledge on the structural organization and functional pattern of photosynthetic water splitting in the multimeric Photosystem II (PS II) complex, which acts as a light-driven water: plastoquinone-oxidoreductase. The overall process comprises three types of reaction sequences: (1) photon absorption and excited singlet state trapping by charge separation leading to the ion radical pair [Formula: see text] formation, (2) oxidative water splitting into four protons and molecular dioxygen at the water oxidizing complex (WOC) with P680+* as driving force and tyrosine Y(Z) as intermediary redox carrier, and (3) reduction of plastoquinone to plastoquinol at the special Q(B) binding site with Q(A)-* acting as reductant. Based on recent progress in structure analysis and using new theoretical approaches the mechanism of reaction sequence (1) is discussed with special emphasis on the excited energy transfer pathways and the sequence of charge transfer steps: [Formula: see text] where (1)(RC-PC)* denotes the excited singlet state (1)P680* of the reaction centre pigment complex. The structure of the catalytic Mn(4)O(X)Ca cluster of the WOC and the four step reaction sequence leading to oxidative water splitting are described and problems arising for the electronic configuration, in particular for the nature of redox state S(3), are discussed. The unravelling of the mode of O-O bond formation is of key relevance for understanding the mechanism of the process. This problem is not yet solved. A multistate model is proposed for S(3) and the functional role of proton shifts and hydrogen bond network(s) is emphasized. Analogously, the structure of the Q(B) site for PQ reduction to PQH(2) and the energetic and kinetics of the two step redox reaction sequence are described. Furthermore, the relevance of the protein dynamics and the role of water molecules for its flexibility are briefly outlined. We end this review by presenting future perspectives on the water oxidation process.
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Affiliation(s)
- Gernot Renger
- Max Volmer Laboratory for Biophysical Chemistry, Berlin Institute of Technology, Berlin, Germany.
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45
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Clausen J, Junge W. The terminal reaction cascade of water oxidation: proton and oxygen release. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2008; 1777:1311-8. [PMID: 18640091 DOI: 10.1016/j.bbabio.2008.06.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Revised: 06/09/2008] [Accepted: 06/12/2008] [Indexed: 10/21/2022]
Abstract
In cyanobacteria, algae and plants Photosystem II produces the oxygen we breathe. Driven and clocked by light quanta, the catalytic Mn(4)Ca-tyrosine centre accumulates four oxidising equivalents before it abstracts four electrons from water, liberating dioxygen and protons. Aiming at intermediates of the terminal four-electron cascade, we previously have suppressed this reaction by elevating the oxygen pressure, thereby stabilising one redox intermediate. Here, we established a similar suppression by increasing the proton concentration. Data were analysed in terms of only one (peroxy) redox intermediate between the fourfold oxidised Mn(4)Ca-tyrosine centre and oxygen release. The surprising result was that the release into the bulk of one proton per dioxygen is linked to the first and rate-limiting electron transfer in the cascade rather than to the second which produces free oxygen. The penultimate intermediate might thus be conceived as a fully deprotonated peroxy-moiety.
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Affiliation(s)
- Juergen Clausen
- Abteilung Biophysik, Fachbereich Biologie/Chemie, Universität Osnabrück, Osnabrück, Germany
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46
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Singh S, Debus RJ, Wydrzynski T, Hillier W. Investigation of substrate water interactions at the high-affinity Mn site in the photosystem II oxygen-evolving complex. Philos Trans R Soc Lond B Biol Sci 2008; 363:1229-34; discussion 1234-5. [PMID: 17954434 DOI: 10.1098/rstb.2007.2219] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
18 O isotope exchange measurements of photosystem II (PSII) in thylakoids from wild-type and mutant Synechocystis have been performed to investigate binding of substrate water to the high-affinity Mn4 site in the oxygen-evolving complex (OEC). The mutants investigated were D1-D170H, a mutation of a direct ligand to the Mn4 ion, and D1-D61N, a mutation in the second coordination sphere. The substrate water 18 O exchange rates for D61N were found to be 0.16+/-0.02 s(-1) and 3.03+/-0.32 s(-1) for the slow and fast phases of exchange, respectively, compared with 0.47+/-0.04 s(-1) and 19.7+/-1.3 s(-1) for the wild-type. The D1-D170H rates were found to be 0.70+/-0.16 s(-1) and 24.4+/-4.6 s(-1) and thus are almost within the error limits for the wild-type rates. The results from the D1-D170H mutant indicate that the high-affinity Mn4 site does not directly bind to the substrate water molecule in slow exchange, but the binding of non-substrate water to this Mn ion cannot be excluded. The results from the D61N mutation show an interaction with both substrate water molecules, which could be an indication that D61 is involved in a hydrogen bonding network with the substrate water. Our results provide limitations as to where the two substrate water molecules bind in the OEC of PSII.
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Affiliation(s)
- Sonita Singh
- Photobioenergetics Group, Research School of Biological Sciences, The Australian National University, Canberra, Australian Capital Territory 0200, Australia
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47
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Abstract
Photosynthetic water oxidation is catalyzed by a unique Mn(4)Ca cluster in Photosystem II. The ligation environment of the Mn(4)Ca cluster optimizes the cluster's reactivity at each step in the catalytic cycle and minimizes the release of toxic, partly oxidized intermediates. However, our understanding of the cluster's ligation environment remains incomplete. Although the recent X-ray crystallographic structural models have provided great insight and are consistent with most conclusions of earlier site-directed mutagenesis studies, the ligation environments of the Mn(4)Ca cluster in the two available structural models differ in important respects. Furthermore, while these structural models and the earlier mutagenesis studies agree on the identity of most of the Mn(4)Ca cluster's amino acid ligands, they disagree on the identity of others. This review describes mutant characterizations that have been undertaken to probe the ligation environment of the Mn(4)Ca cluster, some of which have been inspired by the recent X-ray crystallographic structural models. Many of these characterizations have involved Fourier Transform Infrared (FTIR) difference spectroscopy because of the extreme sensitivity of this form of spectroscopy to the dynamic structural changes that occur during an enzyme's catalytic cycle.
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Affiliation(s)
- Richard J. Debus
- Department of Biochemistry, University of California at Riverside, Riverside, CA 92521-0129
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48
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Affiliation(s)
- My Hang V Huynh
- DE-1: High Explosive Science and Technology Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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49
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Meyer TJ, Huynh MHV, Thorp HH. The Possible Role of Proton-Coupled Electron Transfer (PCET) in Water Oxidation by Photosystem II. Angew Chem Int Ed Engl 2007; 46:5284-304. [PMID: 17604381 DOI: 10.1002/anie.200600917] [Citation(s) in RCA: 410] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
All higher life forms use oxygen and respiration as their primary energy source. The oxygen comes from water by solar-energy conversion in photosynthetic membranes. In green plants, light absorption in photosystem II (PSII) drives electron-transfer activation of the oxygen-evolving complex (OEC). The mechanism of water oxidation by the OEC has long been a subject of great interest to biologists and chemists. With the availability of new molecular-level protein structures from X-ray crystallography and EXAFS, as well as the accumulated results from numerous experiments and theoretical studies, it is possible to suggest how water may be oxidized at the OEC. An integrated sequence of light-driven reactions that exploit coupled electron-proton transfer (EPT) could be the key to water oxidation. When these reactions are combined with long-range proton transfer (by sequential local proton transfers), it may be possible to view the OEC as an intricate structure that is "wired for protons".
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Affiliation(s)
- Thomas J Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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50
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Renger G. Oxidative photosynthetic water splitting: energetics, kinetics and mechanism. PHOTOSYNTHESIS RESEARCH 2007; 92:407-25. [PMID: 17647091 DOI: 10.1007/s11120-007-9185-x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2006] [Accepted: 04/19/2007] [Indexed: 05/16/2023]
Abstract
This minireview is an attempt to summarize our current knowledge on oxidative water splitting in photosynthesis. Based on the extended Kok model (Kok, Forbush, McGloin (1970) Photochem Photobiol 11:457-476) as a framework, the energetics and kinetics of two different types of reactions comprising the overall process are discussed: (i) P680+* reduction by the redox active tyrosine YZ of polypeptide D1 and (ii) Yz (ox) induced oxidation of the four step sequence in the water oxidizing complex (WOC) leading to the formation of molecular oxygen. The mode of coupling between electron transport (ET) and proton transfer (PT) is of key mechanistic relevance for the redox turnover of YZ and the reactions within the WOC. The peculiar energetics of the oxidation steps in the WOC assure that redox state S1 is thermodynamically most stable. This is a general feature in all oxygen evolving photosynthetic organisms and assumed to be of physiological relevance. The reaction coordinate of oxidative water splitting is discussed on the basis of the available information about the Gibbs energy differences between the individual redox states Si+1 and Si and the data reported for the activation energies of the individual oxidation steps in the WOC. Finally, an attempt is made to cast our current state of knowledge into a mechanism of oxidative water splitting with special emphasis on the formation of the essential O-O bond and on the active role of the protein in tuning the local proton activity that depends on time and redox state Si. The O-O linkage is assumed to take place at the level of a complexed peroxide.
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Affiliation(s)
- Gernot Renger
- Technische Universität Berlin, Institut für Chemie, Max-Volmer-Laboratorium für Biophysikalische Chemie, Strasse des 17. Juni 135, D-10623 Berlin, Germany.
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