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Guo Y, Messinger J, Kloo L, Sun L. Alternative Mechanism for O 2 Formation in Natural Photosynthesis via Nucleophilic Oxo-Oxo Coupling. J Am Chem Soc 2023; 145:4129-4141. [PMID: 36763485 DOI: 10.1021/jacs.2c12174] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
O2 formation in photosystem II (PSII) is a vital event on Earth, but the exact mechanism remains unclear. The presently prevailing theoretical model is "radical coupling" (RC) involving a Mn(IV)-oxyl unit in an "open-cubane" Mn4CaO6 cluster, which is supported experimentally by the S3 state of cyanobacterial PSII featuring an additional Mn-bound oxygenic ligand. However, it was recently proposed that the major structural form of the S3 state of higher plants lacks this extra ligand, and that the resulting S4 state would feature instead a penta-coordinate dangler Mn(V)=oxo, covalently linked to a "closed-cubane" Mn3CaO4 cluster. For this proposal, we explore here a large number of possible pathways of O-O bond formation and demonstrate that the "nucleophilic oxo-oxo coupling" (NOOC) between Mn(V)=oxo and μ3-oxo is the only eligible mechanism in such a system. The reaction is facilitated by a specific conformation of the cluster and concomitant water binding, which is delayed compared to the RC mechanism. An energetically feasible process is described starting from the valid S4 state through the sequential formation of peroxide and superoxide, followed by O2 release and a second water insertion. The newly found mechanism is consistent with available experimental thermodynamic and kinetic data and thus a viable alternative pathway for O2 formation in natural photosynthesis, in particular for higher plants.
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Affiliation(s)
- Yu Guo
- Center of Artificial Photosynthesis for Solar Fuels and Department of Chemistry, School of Science, Westlake University, Hangzhou 310024, China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou 310024, China
| | - Johannes Messinger
- Department of Chemistry, Umeå University, Linnaeus väg 6 (KBC huset), Umeå SE-90187, Sweden
- Molecular Biomimetics, Department of Chemistry─Ångström Laboratory, Uppsala University, Uppsala SE-75120, Sweden
| | - Lars Kloo
- Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Stockholm SE-10044, Sweden
| | - Licheng Sun
- Center of Artificial Photosynthesis for Solar Fuels and Department of Chemistry, School of Science, Westlake University, Hangzhou 310024, China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou 310024, China
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2
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Guo Y, Messinger J, Kloo L, Sun L. Reversible Structural Isomerization of Nature's Water Oxidation Catalyst Prior to O-O Bond Formation. J Am Chem Soc 2022; 144:11736-11747. [PMID: 35748306 PMCID: PMC9264352 DOI: 10.1021/jacs.2c03528] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
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Photosynthetic water
oxidation is catalyzed by a manganese–calcium
oxide cluster, which experiences five “S-states” during
a light-driven reaction cycle. The unique “distorted chair”-like
geometry of the Mn4CaO5(6) cluster shows structural
flexibility that has been frequently proposed to involve “open”
and “closed”-cubane forms from the S1 to
S3 states. The isomers are interconvertible in the S1 and S2 states, while in the S3 state,
the open-cubane structure is observed to dominate inThermosynechococcus elongatus (cyanobacteria) samples.
In this work, using density functional theory calculations, we go
beyond the S3+Yz state to the S3nYz• → S4+Yz step, and report for the first time
that the reversible isomerism, which is suppressed in the S3+Yz state, is fully recovered
in the ensuing S3nYz• state due to the proton release
from a manganese-bound water ligand. The altered coordination strength
of the manganese–ligand facilitates formation of the closed-cubane
form, in a dynamic equilibrium with the open-cubane form. This tautomerism
immediately preceding dioxygen formation may constitute the rate limiting
step for O2 formation, and exert a significant influence
on the water oxidation mechanism in photosystem II.
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Affiliation(s)
- Yu Guo
- Center of Artificial Photosynthesis for Solar Fuels and Department of Chemistry, School of Science, Westlake University, Hangzhou 310024, China.,Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou 310024, China
| | - Johannes Messinger
- Department of Chemistry, Umeå University, Linnaeus väg 6 (KBC huset), SE-90187 Umeå, Sweden.,Molecular Biomimetics, Department of Chemistry─Ångström Laboratory, Uppsala University, SE-75120 Uppsala, Sweden
| | - Lars Kloo
- Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden
| | - Licheng Sun
- Center of Artificial Photosynthesis for Solar Fuels and Department of Chemistry, School of Science, Westlake University, Hangzhou 310024, China.,Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou 310024, China
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3
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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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4
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de Lichtenberg C, Avramov AP, Zhang M, Mamedov F, Burnap RL, Messinger J. The D1-V185N mutation alters substrate water exchange by stabilizing alternative structures of the Mn 4Ca-cluster in photosystem II. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1862:148319. [PMID: 32979346 DOI: 10.1016/j.bbabio.2020.148319] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 09/15/2020] [Accepted: 09/19/2020] [Indexed: 11/30/2022]
Abstract
In photosynthesis, the oxygen-evolving complex (OEC) of the pigment-protein complex photosystem II (PSII) orchestrates the oxidation of water. Introduction of the V185N mutation into the D1 protein was previously reported to drastically slow O2-release and strongly perturb the water network surrounding the Mn4Ca cluster. Employing time-resolved membrane inlet mass spectrometry, we measured here the H218O/H216O-exchange kinetics of the fast (Wf) and slow (Ws) exchanging substrate waters bound in the S1, S2 and S3 states to the Mn4Ca cluster of PSII core complexes isolated from wild type and D1-V185N strains of Synechocystis sp. PCC 6803. We found that the rate of exchange for Ws was increased in the S1 and S2 states, while both Wf and Ws exchange rates were decreased in the S3 state. Additionally, we used EPR spectroscopy to characterize the Mn4Ca cluster and its interaction with the redox active D1-Tyr161 (YZ). In the S2 state, we observed a greatly diminished multiline signal in the V185N-PSII that could be recovered by addition of ammonia. The split signal in the S1 state was not affected, while the split signal in the S3 state was absent in the D1-V185N mutant. These findings are rationalized by the proposal that the N185 residue stabilizes the binding of an additional water-derived ligand at the Mn1 site of the Mn4Ca cluster via hydrogen bonding. Implications for the sites of substrate water binding are discussed.
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Affiliation(s)
- Casper de Lichtenberg
- Department of Chemistry, Umeå University, Linnaeus väg 6 (KBC huset), SE-901 87 Umeå, Sweden; Molecular Biomimetics, Department of Chemistry - Ångström, Uppsala University, POB 523, SE-75120 Uppsala, Sweden
| | - Anton P Avramov
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, United States
| | - Minquan Zhang
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, United States
| | - Fikret Mamedov
- Molecular Biomimetics, Department of Chemistry - Ångström, Uppsala University, POB 523, SE-75120 Uppsala, Sweden
| | - Robert L Burnap
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, United States
| | - Johannes Messinger
- Department of Chemistry, Umeå University, Linnaeus väg 6 (KBC huset), SE-901 87 Umeå, Sweden; Molecular Biomimetics, Department of Chemistry - Ångström, Uppsala University, POB 523, SE-75120 Uppsala, Sweden.
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5
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Boussac A. Temperature dependence of the high-spin S2 to S3 transition in Photosystem II: Mechanistic consequences. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:508-518. [DOI: 10.1016/j.bbabio.2019.05.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 12/20/2018] [Accepted: 01/06/2019] [Indexed: 02/08/2023]
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6
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Amin M, Kaur D, Yang KR, Wang J, Mohamed Z, Brudvig GW, Gunner MR, Batista V. Thermodynamics of the S2-to-S3 state transition of the oxygen-evolving complex of photosystem II. Phys Chem Chem Phys 2019; 21:20840-20848. [DOI: 10.1039/c9cp02308a] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The S2 to S3 transition in the OEC of PSII changes the structure of the Mn cluster. Monte Carlo sampling finds a Ca terminal water moves to form a bridge to Mn4 and the Mn1 ligand E189 can be replaced with a hydroxyl as a proton is lost.
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Affiliation(s)
- Muhamed Amin
- Center for Free-Electron Laser Science
- Deutsches Elektronen-Synchrotron DESY
- 22607 Hamburg
- Germany
- Department of Sciences
| | - Divya Kaur
- Department of Physics
- City College of New York
- 160 Convent Avenue
- New York
- USA
| | - Ke R. Yang
- Department of Chemistry, Yale University
- New Haven
- USA
| | - Jimin Wang
- Department of Molecular Biophysics and Biochemistry
- Yale University
- New Haven
- USA
| | - Zainab Mohamed
- Zewail City of Science and Technology
- Sheikh Zayed
- 12588 Giza
- Egypt
| | | | - M. R. Gunner
- Department of Physics
- City College of New York
- 160 Convent Avenue
- New York
- USA
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7
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Kato Y, Akita F, Nakajima Y, Suga M, Umena Y, Shen JR, Noguchi T. Fourier Transform Infrared Analysis of the S-State Cycle of Water Oxidation in the Microcrystals of Photosystem II. J Phys Chem Lett 2018; 9:2121-2126. [PMID: 29620370 DOI: 10.1021/acs.jpclett.8b00638] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Photosynthetic water oxidation is performed in photosystem II (PSII) through a light-driven cycle of intermediates called S states (S0-S4) at the water oxidizing center. Time-resolved serial femtosecond crystallography (SFX) has recently been applied to the microcrystals of PSII to obtain the structural information on these intermediates. However, it remains unanswered whether the reactions efficiently proceed throughout the S-state cycle retaining the native structures of the intermediates in PSII crystals. We investigated the water oxidation reactions in the PSII microcrystals using flash-induced Fourier transform infrared (FTIR) difference spectroscopy. In comparison with the FTIR spectra in solution, it was shown that all of the metastable intermediates in the microcrystals retained their native structures, and the efficiencies of the S-state transitions remained relatively high, although those of the S2 → S3 and S3 → S0 transitions were slightly lowered possibly due to some restriction of water movement in the crystals.
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Affiliation(s)
- Yuki Kato
- Division of Material Science, Graduate School of Science , Nagoya University , Furo-cho , Chikusa-ku, Nagoya 464-8602 , Japan
| | - Fusamichi Akita
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology , Okayama University , 3-1-1 Tsushima-naka , Kita-ku, Okayama 700-8530 , Japan
- Japan Science and Technology Agency, PRESTO , 4-1-8 Honcho , Kawaguchi, Saitama 332-0012 , Japan
| | - Yoshiki Nakajima
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology , Okayama University , 3-1-1 Tsushima-naka , Kita-ku, Okayama 700-8530 , Japan
| | - Michihiro Suga
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology , Okayama University , 3-1-1 Tsushima-naka , Kita-ku, Okayama 700-8530 , Japan
| | - Yasufumi Umena
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology , Okayama University , 3-1-1 Tsushima-naka , Kita-ku, Okayama 700-8530 , Japan
| | - Jian-Ren Shen
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology , Okayama University , 3-1-1 Tsushima-naka , Kita-ku, Okayama 700-8530 , 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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