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Ivanov B, Borisova-Mubarakshina M, Vilyanen D, Vetoshkina D, Kozuleva M. Cooperative pathway of O2 reduction to H2O2 in chloroplast thylakoid membrane: new insight into the Mehler reaction. Biophys Rev 2022; 14:857-869. [DOI: 10.1007/s12551-022-00980-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 07/03/2022] [Indexed: 11/30/2022] Open
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2
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Kato Y, Noguchi T. Redox properties and regulatory mechanism of the iron-quinone electron acceptor in photosystem II as revealed by FTIR spectroelectrochemistry. PHOTOSYNTHESIS RESEARCH 2022; 152:135-151. [PMID: 34985636 DOI: 10.1007/s11120-021-00894-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 12/24/2021] [Indexed: 05/09/2023]
Abstract
Photosystem II (PSII) performs oxidation of water and reduction of plastoquinone through light-induced electron transfer. Electron transfer reactions at individual redox cofactors are controlled by their redox potentials, and the forward and backward electron flows in PSII are regulated by tuning them. It is, thus, crucial to accurately estimate the redox potentials of the cofactors and their shifts by environmental changes to understand the regulatory mechanisms in PSII. Fourier-transform infrared (FTIR) spectroelectrochemistry combined with a light-induced difference technique is a powerful method to investigate the mechanisms of the redox reactions in PSII. In this review, we introduce the methodology and the application of this method in the studies of the iron-quinone complex, which consists of two plastoquinone molecules, QA and QB, and the non-heme iron, on the electron-acceptor side of PSII. It is shown that FTIR spectroelectrochemistry is a useful method not only for estimating the redox potentials but also for detecting the reactions of nearby amino-acid residues coupled with the redox reactions.
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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.
| | - Takumi Noguchi
- Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan.
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3
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Kato Y, Noguchi T. Effects of Stromal and Lumenal Side Perturbations on the Redox Potential of the Primary Quinone Electron Acceptor Q A in Photosystem II. Biochemistry 2021; 60:3697-3706. [PMID: 34784184 DOI: 10.1021/acs.biochem.1c00624] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The primary quinone electron acceptor QA is a key component in the electron transfer regulation in photosystem II (PSII), and hence accurate estimation of its redox potential, Em(QA-/QA), is crucial in understanding the regulatory mechanism. Although fluorescence detection has been extensively used for monitoring the redox state of QA, it was recently suggested that this method tends to provide a higher Em(QA-/QA) estimate depending on the sample status due to the effect of measuring light [Kato et al. (2019) Biochim. Biophys. Acta 1860, 148082]. In this study, we applied the Fourier transform infrared (FTIR) spectroelectrochemistry, which uses non-reactive infrared light to monitor the redox state of QA, to investigate the effects of stromal- and lumenal-side perturbations on Em(QA-/QA) in PSII. It was shown that replacement of bicarbonate bound to the non-heme iron with formate upshifted Em(QA-/QA) by ∼55 mV, consistent with the previous fluorescence measurement. In contrast, an Em(QA-/QA) difference between binding of 3-(3,4-dichlorophenyl)-1,1-dimethylurea and bromoxynil was found to be ∼30 mV, which is much smaller than the previous estimate, ∼100 mV, by the fluorescence method. This ∼30 mV difference was verified by the decay kinetics of the S2QA- recombination. On the lumenal side, Mn depletion hardly affected the Em(QA-/QA), confirming the previous FTIR result. However, removal of the extrinsic proteins by NaCl or CaCl2 wash downshifted the Em(QA-/QA) by 14-20 mV. These results suggest that electron flow through QA is regulated by changes both on the stromal and lumenal sides of PSII.
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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
| | - Takumi Noguchi
- Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
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4
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Kalmatskaya OA, Trubitsin BV, Suslichenko IS, Karavaev VA, Tikhonov AN. Electron transport in Tradescantia leaves acclimated to high and low light: thermoluminescence, PAM-fluorometry, and EPR studies. PHOTOSYNTHESIS RESEARCH 2020; 146:123-141. [PMID: 32594291 DOI: 10.1007/s11120-020-00767-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 06/10/2020] [Indexed: 06/11/2023]
Abstract
Using thermoluminescence, PAM-fluorometry, and electron paramagnetic resonance (EPR) for assaying electron transport processes in chloroplasts in situ, we have compared photosynthetic characteristics in Tradescantia fluminensis leaves grown under low light (LL, 50-125 µmol photons m-2 s-1) or high light (HL, 875-1000 µmol photons m-2 s-1) condition. We found differences in the thermoluminescence (TL) spectra of LL- and HL-acclimated leaves. The LL and HL leaves show different proportions of the Q (~ 0 °C) and B (~ 25-30 °C) bands in their TL spectra; the ratios of the "light sums" of the Q and B bands being SQ/SB ≈ 1/1 (LL) and SQ/SB ≈ 1/3 (HL). This suggests the existence of different redox states of electron carriers on the acceptor side of PSII in LL and HL leaves, which may be affected, in particular, by different capacities of their photo-reducible PQ pools. Enhanced content of PQ in chloroplasts of LL leaves may be the reason for an efficient performance of photosynthesis at low irradiance. Kinetic studies of slow induction of Chl a fluorescence and measurements of P700 photooxidation by EPR demonstrate that HL leaves have faster (about 2 times) response to switching on actinic light as compared to LL leaves grown at moderate irradiation. HL leaves also show higher non-photochemical quenching (NPQ) of Chl a fluorescence. These properties of HL leaves (faster response to light and generation of enhanced NPQ) reflect the flexibility of their photosynthetic apparatus, providing sustainability and rapid response to fluctuations of environmental light intensity and solar stress resistance. Analysis of time-courses of the EPR signals of [Formula: see text] induced by far-red (λmax = 707 nm), exciting predominantly PSI, and white light, exciting both PSI and PSII, suggests that there is a contribution of cyclic electron flow around PSI to electron flow through PSI in HL leaves. The data obtained are discussed in terms of photosynthetic apparatus sustainability of HL and LL leaves under variable irradiation conditions.
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Affiliation(s)
| | - Boris V Trubitsin
- Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Igor S Suslichenko
- Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow, Russia
| | | | - Alexander N Tikhonov
- Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow, Russia.
- N.M. Emanuel Institute of Biochemical Physics of Russian Academy of Sciences, Moscow, Russia.
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5
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Kato Y, Ohira A, Nagao R, Noguchi T. Does the water-oxidizing Mn4CaO5 cluster regulate the redox potential of the primary quinone electron acceptor QA in photosystem II? A study by Fourier transform infrared spectroelectrochemistry. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:148082. [DOI: 10.1016/j.bbabio.2019.148082] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 08/31/2019] [Accepted: 09/08/2019] [Indexed: 10/25/2022]
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6
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Khorobrykh A. Hydrogen Peroxide and Superoxide Anion Radical Photoproduction in PSII Preparations at Various Modifications of the Water-Oxidizing Complex. PLANTS 2019; 8:plants8090329. [PMID: 31491946 PMCID: PMC6784185 DOI: 10.3390/plants8090329] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 08/25/2019] [Accepted: 08/29/2019] [Indexed: 11/24/2022]
Abstract
The photoproduction of superoxide anion radical (O2−•) and hydrogen peroxide (H2O2) in photosystem II (PSII) preparations depending on the damage to the water-oxidizing complex (WOC) was investigated. The light-induced formation of O2−• and H2O2 in the PSII preparations rose with the increased destruction of the WOC. The photoproduction of superoxide both in the PSII preparations holding intact WOC and the samples with damage to the WOC was approximately two times higher than H2O2. The rise of O2−• and H2O2 photoproduction in the PSII preparations in the course of the disassembly of the WOC correlated with the increase in the fraction of the low-potential (LP) Cyt b559. The restoration of electron flow in the Mn-depleted PSII preparations by exogenous electron donors (diphenylcarbazide, Mn2+) suppressed the light-induced formation of O2−• and H2O2. The decrease of O2−• and H2O2 photoproduction upon the restoration of electron transport in the Mn-depleted PSII preparations could be due to the re-conversion of the LP Cyt b559 into higher potential forms. It is supposed that the conversion of the high potential Cyt b559 into its LP form upon damage to the WOC leads to the increase of photoproduction of O2−• and H2O2 in PSII.
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Affiliation(s)
- Andrey Khorobrykh
- Institute of Basic Biological Problems, FRC PSCBR RAS, Pushchino 142290, Moscow Region, Russia.
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7
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Chen J, Chen J, Liu Y, Zheng Y, Zhu Q, Han G, Shen JR. Proton-Coupled Electron Transfer of Plastoquinone Redox Reactions in Photosystem II: A Pump-Probe Ultraviolet Resonance Raman Study. J Phys Chem Lett 2019; 10:3240-3247. [PMID: 31117681 DOI: 10.1021/acs.jpclett.9b00959] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Plastoquinones (PQs) act as electron and proton mediators in photosystem II (PSII) for solar-to-chemical energy conversion. It is known that the redox potential of PQ varies in a wide range spanning hundreds of millivolts; however, its structural origin is not known yet. Here, by developing a pump-probe ultraviolet resonance Raman technique, we measured the vibrational structures of PQs including QA and QB in cyanobacterial PSII directly. The conversion of QA to QA•- in the Mn-depleted PSII is verified by direct observation of the distinct QA•- vibrational bands. A frequency upshift of the ring C=O/C=C stretch band at 1565 cm-1 for QA•- was observed, which suggests a π-π interaction between the quinone ring and Trp253. In contrast, proton-coupled reduction of QA to QAH upon light-driven electron transfer is demonstrated in PSII without QB bound. The H-bond between QA and His214 is likely the proton origin of this proton-coupled electron transfer.
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Affiliation(s)
- Jun Chen
- Science and Technology on Surface Physics and Chemistry Laboratory , Jiangyou 621908 , China
- State Key Laboratory of Catalysis , Dalian Institute of Chemical Physics, Chinese Academy of Sciences , Dalian 116023 , China
| | - Jinfan Chen
- Science and Technology on Surface Physics and Chemistry Laboratory , Jiangyou 621908 , China
| | - Ying Liu
- Institute of Materials , China Academy of Engineering Physics , Mianyang 621907 , China
| | - Yang Zheng
- State Key Laboratory of Catalysis , Dalian Institute of Chemical Physics, Chinese Academy of Sciences , Dalian 116023 , China
| | - Qingjun Zhu
- Photosynthesis Research Center, Key Laboratory of Photobiology , Institute of Botany, Chinese Academy of Sciences , No. 20, Nanxincun , Xiangshan, Beijing , 100093 , China
| | - Guangye Han
- Photosynthesis Research Center, Key Laboratory of Photobiology , Institute of Botany, Chinese Academy of Sciences , No. 20, Nanxincun , Xiangshan, Beijing , 100093 , China
| | - Jian-Ren Shen
- Photosynthesis Research Center, Key Laboratory of Photobiology , Institute of Botany, Chinese Academy of Sciences , No. 20, Nanxincun , Xiangshan, Beijing , 100093 , China
- Research Institute of Interdisciplinary Science, Graduate School of Natural Science and Technology , Okayama University , Tsushima Naka 3-1-1 , Okayama 700-8530 , Japan
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8
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Suslichenko IS, Tikhonov AN. Photo-reducible plastoquinone pools in chloroplasts of Tradescentia plants acclimated to high and low light. FEBS Lett 2019; 593:788-798. [PMID: 30896038 DOI: 10.1002/1873-3468.13366] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 02/28/2019] [Accepted: 03/19/2019] [Indexed: 11/09/2022]
Abstract
In photosynthetic systems of oxygenic type, plastoquinone (PQ) molecules are reduced by photosystem II (PSII). The turnover of PQ determines the rate of PSII operation. PQ molecules are present in surplus with respect to PSII. In this work, using the pulse amplitude modulation-fluorometry technique, we quantified photo-reducible PQ pools in chloroplasts of two contrasting ecotypes of Tradescantia, acclimated either to low light (~ 100 μmol photons·m-2 ·s-1 , LL) or to high light (~ 1000 μmol photons·m-2 ·s-1 , HL). The LL-grown plants are characterized by higher capacity of rapidly reducible PQ pool ([PQ]0 /[PSII] ≈ 8) as compared to HL-grown plants of both species ([PQ]0 /[PSII] ≈ 4). The elevated content of PQ in LL plants favours photosynthetic electron flow at low-solar irradiance.
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Affiliation(s)
| | - Alexander N Tikhonov
- Faculty of Physics, M.V.Lomonosov Moscow State University, Russia.,N.M.Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia
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9
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Pham LV, Janna Olmos JD, Chernev P, Kargul J, Messinger J. Unequal misses during the flash-induced advancement of photosystem II: effects of the S state and acceptor side cycles. PHOTOSYNTHESIS RESEARCH 2019; 139:93-106. [PMID: 30191436 PMCID: PMC6373315 DOI: 10.1007/s11120-018-0574-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 08/03/2018] [Indexed: 05/17/2023]
Abstract
Photosynthetic water oxidation is catalyzed by the oxygen-evolving complex (OEC) in photosystem II (PSII). This process is energetically driven by light-induced charge separation in the reaction center of PSII, which leads to a stepwise accumulation of oxidizing equivalents in the OEC (Si states, i = 0-4) resulting in O2 evolution after each fourth flash, and to the reduction of plastoquinone to plastoquinol on the acceptor side of PSII. However, the Si-state advancement is not perfect, which according to the Kok model is described by miss-hits (misses). These may be caused by redox equilibria or kinetic limitations on the donor (OEC) or the acceptor side. In this study, we investigate the effects of individual S state transitions and of the quinone acceptor side on the miss parameter by analyzing the flash-induced oxygen evolution patterns and the S2, S3 and S0 state lifetimes in thylakoid samples of the extremophilic red alga Cyanidioschyzon merolae. The data are analyzed employing a global fit analysis and the results are compared to the data obtained previously for spinach thylakoids. These two organisms were selected, because the redox potential of QA/QA- in PSII is significantly less negative in C. merolae (Em = - 104 mV) than in spinach (Em = - 163 mV). This significant difference in redox potential was expected to allow the disentanglement of acceptor and donor side effects on the miss parameter. Our data indicate that, at slightly acidic and neutral pH values, the Em of QA-/QA plays only a minor role for the miss parameter. By contrast, the increased energy gap for the backward electron transfer from QA- to Pheo slows down the charge recombination reaction with the S3 and S2 states considerably. In addition, our data support the concept that the S2 → S3 transition is the least efficient step during the oxidation of water to molecular oxygen in the Kok cycle of PSII.
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Affiliation(s)
- Long Vo Pham
- Department of Chemistry - Ångström, Uppsala University, Lägerhyddsvägen 1, 75120, Uppsala, Sweden
| | - Julian David Janna Olmos
- Solar Fuels Lab, Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097, Warsaw, Poland
- Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland
| | - Petko Chernev
- Department of Chemistry - Ångström, Uppsala University, Lägerhyddsvägen 1, 75120, Uppsala, Sweden
| | - Joanna Kargul
- Solar Fuels Lab, Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097, Warsaw, Poland.
| | - Johannes Messinger
- Department of Chemistry - Ångström, Uppsala University, Lägerhyddsvägen 1, 75120, Uppsala, Sweden.
- Department of Chemistry, Chemistry Biology Center (KBC), Umeå University, Linnaeus väg 6, 901 87, Umeå, Sweden.
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10
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Schulz CE, Dutta AK, Izsák R, Pantazis DA. Systematic High-Accuracy Prediction of Electron Affinities for Biological Quinones. J Comput Chem 2018; 39:2439-2451. [PMID: 30281169 DOI: 10.1002/jcc.25570] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Revised: 08/06/2018] [Accepted: 08/07/2018] [Indexed: 11/07/2022]
Abstract
Quinones play vital roles as electron carriers in fundamental biological processes; therefore, the ability to accurately predict their electron affinities is crucial for understanding their properties and function. The increasing availability of cost-effective implementations of correlated wave function methods for both closed-shell and open-shell systems offers an alternative to density functional theory approaches that have traditionally dominated the field despite their shortcomings. Here, we define a benchmark set of quinones with experimentally available electron affinities and evaluate a range of electronic structure methods, setting a target accuracy of 0.1 eV. Among wave function methods, we test various implementations of coupled cluster (CC) theory, including local pair natural orbital (LPNO) approaches to canonical and parameterized CCSD, the domain-based DLPNO approximation, and the equations-of-motion approach for electron affinities, EA-EOM-CCSD. In addition, several variants of canonical, spin-component-scaled, orbital-optimized, and explicitly correlated (F12) Møller-Plesset perturbation theory are benchmarked. Achieving systematically the target level of accuracy is challenging and a composite scheme that combines canonical CCSD(T) with large basis set LPNO-based extrapolation of correlation energy proves to be the most accurate approach. Methods that offer comparable performance are the parameterized LPNO-pCCSD, the DLPNO-CCSD(T0 ), and the orbital optimized OO-SCS-MP2. Among DFT methods, viable practical alternatives are only the M06 and the double hybrids, but the latter should be employed with caution because of significant basis set sensitivity. A highly accurate yet cost-effective DLPNO-based coupled cluster approach is used to investigate the methoxy conformation effect on the electron affinities of ubiquinones found in photosynthetic bacterial reaction centers. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Christine E Schulz
- Fakultät für Chemie und Biochemie, Ruhr-Universität Bochum, 44780, Bochum, Germany
- 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
| | - Achintya Kumar Dutta
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstr. 34-36, 45470, Mülheim an der Ruhr, Germany
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Róbert Izsák
- 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
| | - Dimitrios A Pantazis
- 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
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11
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Allen JF, Nield J. Redox Tuning in Photosystem II. TRENDS IN PLANT SCIENCE 2017; 22:97-99. [PMID: 27979715 DOI: 10.1016/j.tplants.2016.11.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 11/10/2016] [Accepted: 11/14/2016] [Indexed: 06/06/2023]
Abstract
In photosynthesis, oxygen is liberated from water, not from CO2; however, this model has been silent on why photosynthesis requires bicarbonate. Rutherford and colleagues solve this problem elegantly: bicarbonate tunes water-oxidising photosystem II to make onward electron transfer efficient; an absence of bicarbonate retunes, redirects, and safely shuts down energy flow.
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Affiliation(s)
- John F Allen
- Research Department of Genetics, Evolution, and Environment, Darwin Building, University College London, Gower Street, London WC1E 6BT, UK.
| | - Jon Nield
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK.
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12
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Kato Y, Ishii R, Noguchi T. Comparative Analysis of the Interaction of the Primary Quinone QA in Intact and Mn-Depleted Photosystem II Membranes Using Light-Induced ATR-FTIR Spectroscopy. Biochemistry 2016; 55:6355-6358. [DOI: 10.1021/acs.biochem.6b01052] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yuki Kato
- Division of Material
Science,
Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Rina Ishii
- 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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13
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Bicarbonate-induced redox tuning in Photosystem II for regulation and protection. Proc Natl Acad Sci U S A 2016; 113:12144-12149. [PMID: 27791001 DOI: 10.1073/pnas.1608862113] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The midpoint potential (Em) of [Formula: see text], the one-electron acceptor quinone of Photosystem II (PSII), provides the thermodynamic reference for calibrating PSII bioenergetics. Uncertainty exists in the literature, with two values differing by ∼80 mV. Here, we have resolved this discrepancy by using spectroelectrochemistry on plant PSII-enriched membranes. Removal of bicarbonate (HCO3-) shifts the Em from ∼-145 mV to -70 mV. The higher values reported earlier are attributed to the loss of HCO3- during the titrations (pH 6.5, stirred under argon gassing). These findings mean that HCO3- binds less strongly when QA-• is present. Light-induced QA-• formation triggered HCO3- loss as manifest by the slowed electron transfer and the upshift in the Em of QA HCO3--depleted PSII also showed diminished light-induced 1O2 formation. This finding is consistent with a model in which the increase in the Em of [Formula: see text] promotes safe, direct [Formula: see text] charge recombination at the expense of the damaging back-reaction route that involves chlorophyll triplet-mediated 1O2 formation [Johnson GN, et al. (1995) Biochim Biophys Acta 1229:202-207]. These findings provide a redox tuning mechanism, in which the interdependence of the redox state of QA and the binding by HCO3- regulates and protects PSII. The potential for a sink (CO2) to source (PSII) feedback mechanism is discussed.
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14
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Zhang JZ, Sokol KP, Paul N, Romero E, van Grondelle R, Reisner E. Competing charge transfer pathways at the photosystem II-electrode interface. Nat Chem Biol 2016; 12:1046-1052. [PMID: 27723748 PMCID: PMC5113757 DOI: 10.1038/nchembio.2192] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 08/01/2016] [Indexed: 12/22/2022]
Abstract
The integration of the water-oxidation enzyme, photosystem II (PSII), into electrodes allows the electrons extracted from water-oxidation to be harnessed for enzyme characterization and driving novel endergonic reactions. However, PSII continues to underperform in integrated photoelectrochemical systems despite extensive optimization efforts. Here, we performed protein-film photoelectrochemistry on spinach and Thermosynechococcus elongatus PSII, and identified a competing charge transfer pathway at the enzyme-electrode interface that short-circuits the known water-oxidation pathway: photo-induced O2 reduction occurring at the chlorophyll pigments. This undesirable pathway is promoted by the embedment of PSII in an electron-conducting matrix, a common strategy of enzyme immobilization. Anaerobicity helps to recover the PSII photoresponses, and unmasked the onset potentials relating to the QA/QB charge transfer process. These findings have imparted a fuller understanding of the charge transfer pathways within PSII and at photosystem-electrode interfaces, which will lead to more rational design of pigment-containing photoelectrodes in general.
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Affiliation(s)
- Jenny Z Zhang
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | | | - Nicholas Paul
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Elisabet Romero
- Department of Physics and Astronomy, VU Amsterdam, Amsterdam, The Netherlands
| | - Rienk van Grondelle
- Department of Physics and Astronomy, VU Amsterdam, Amsterdam, The Netherlands
| | - Erwin Reisner
- Department of Chemistry, University of Cambridge, Cambridge, UK
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15
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Brinkert K, Le Formal F, Li X, Durrant J, Rutherford AW, Fantuzzi A. Photocurrents from photosystem II in a metal oxide hybrid system: Electron transfer pathways. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1857:1497-1505. [PMID: 26946088 PMCID: PMC4990130 DOI: 10.1016/j.bbabio.2016.03.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 02/19/2016] [Accepted: 03/01/2016] [Indexed: 12/21/2022]
Abstract
We have investigated the nature of the photocurrent generated by Photosystem II (PSII), the water oxidizing enzyme, isolated from Thermosynechococcus elongatus, when immobilized on nanostructured titanium dioxide on an indium tin oxide electrode (TiO2/ITO). We investigated the properties of the photocurrent from PSII when immobilized as a monolayer versus multilayers, in the presence and absence of an inhibitor that binds to the site of the exchangeable quinone (QB) and in the presence and absence of exogenous mobile electron carriers (mediators). The findings indicate that electron transfer occurs from the first quinone (QA) directly to the electrode surface but that the electron transfer through the nanostructured metal oxide is the rate-limiting step. Redox mediators enhance the photocurrent by taking electrons from the nanostructured semiconductor surface to the ITO electrode surface not from PSII. This is demonstrated by photocurrent enhancement using a mediator incapable of accepting electrons from PSII. This model for electron transfer also explains anomalies reported in the literature using similar and related systems. The slow rate of the electron transfer step in the TiO2 is due to the energy level of electron injection into the semiconducting material being below the conduction band. This limits the usefulness of the present hybrid electrode. Strategies to overcome this kinetic limitation are discussed.
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Affiliation(s)
- Katharina Brinkert
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Florian Le Formal
- Department of Chemistry, Imperial College London, London SW7 2AZ, UK
| | - Xiaoe Li
- Department of Chemistry, Imperial College London, London SW7 2AZ, UK
| | - James Durrant
- Department of Chemistry, Imperial College London, London SW7 2AZ, UK
| | | | - Andrea Fantuzzi
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK.
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Kozuleva MA, Ivanov BN. The Mechanisms of Oxygen Reduction in the Terminal Reducing Segment of the Chloroplast Photosynthetic Electron Transport Chain. PLANT & CELL PHYSIOLOGY 2016; 57:1397-1404. [PMID: 27016099 DOI: 10.1093/pcp/pcw035] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Accepted: 02/10/2016] [Indexed: 05/25/2023]
Abstract
The review is dedicated to ascertainment of the roles of the electron transfer cofactors of the pigment-protein complex of PSI, ferredoxin (Fd) and ferredoxin-NADP reductase in oxygen reduction in the photosynthetic electron transport chain (PETC) in the light. The data regarding oxygen reduction in other segments of the PETC are briefly analyzed, and it is concluded that their participation in the overall process in the PETC under unstressful conditions should be insignificant. Data concerning the contribution of Fd to the oxygen reduction in the PETC are examined. A set of collateral evidence as well as results of direct measurements of the involvement of Fd in this process in the presence of isolated thylakoids led to the inference that this contribution in vivo is negligible. The increase in oxygen reduction rate in the isolated thylakoids in the presence of either Fd or Fd plus NADP+ under increasing light intensity was attributed to the increase in oxygen reduction executed by the membrane-bound oxygen reductants. Data are presented which imply that a main reductant of the O2 molecule in the terminal reducing segment of the PETC is the electron transfer cofactor of PSI, phylloquinone. The physiological significance of characteristic properties of oxygen reductants in this segment of the PETC is discussed.
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Affiliation(s)
- Marina A Kozuleva
- Photosynthetic Electron Transport lab., Institute of Basic Biological Problems, Pushchino, 142290, Russia
| | - Boris N Ivanov
- Photosynthetic Electron Transport lab., Institute of Basic Biological Problems, Pushchino, 142290, Russia
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Redox potential of the terminal quinone electron acceptor QB in photosystem II reveals the mechanism of electron transfer regulation. Proc Natl Acad Sci U S A 2015; 113:620-5. [PMID: 26715751 DOI: 10.1073/pnas.1520211113] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Photosystem II (PSII) extracts electrons from water at a Mn4CaO5 cluster using light energy and then transfers them to two plastoquinones, the primary quinone electron acceptor QA and the secondary quinone electron acceptor QB. This forward electron transfer is an essential process in light energy conversion. Meanwhile, backward electron transfer is also significant in photoprotection of PSII proteins. Modulation of the redox potential (Em) gap of QA and QB mainly regulates the forward and backward electron transfers in PSII. However, the full scheme of electron transfer regulation remains unresolved due to the unknown Em value of QB. Here, for the first time (to our knowledge), the Em value of QB reduction was measured directly using spectroelectrochemistry in combination with light-induced Fourier transform infrared difference spectroscopy. The Em(QB (-)/QB) was determined to be approximately +90 mV and was virtually unaffected by depletion of the Mn4CaO5 cluster. This insensitivity of Em(QB (-)/QB), in combination with the known large upshift of Em(QA (-)/QA), explains the mechanism of PSII photoprotection with an impaired Mn4CaO5 cluster, in which a large decrease in the Em gap between QA and QB promotes rapid charge recombination via QA (-).
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Fisher N, Kramer DM. Non-photochemical reduction of thylakoid photosynthetic redox carriers in vitro: relevance to cyclic electron flow around photosystem I? BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1837:1944-1954. [PMID: 25251244 DOI: 10.1016/j.bbabio.2014.09.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 09/07/2014] [Accepted: 09/14/2014] [Indexed: 01/17/2023]
Abstract
UNLABELLED Non-photochemical (dark) increases in chlorophyll a fluorescence yield associated with non-photochemical reduction of redox carriers (Fnpr) have been attributed to the reduction of plastoquinone (PQ) related to cyclic electron flow (CEF) around photosystem I. In vivo, this rise in fluorescence is associated with activity of the chloroplast plastoquinone reductase (plastid NAD(P)H plastoquinone oxidoreductase) complex. In contrast, this signal measured in isolated thylakoids has been attributed to the activity of the protein gradient regulation-5 (PGR5)/PGR5-like (PGRL1)-associated CEF pathway. Here, we report a systematic experimentation on the origin of Fnpr in isolated thylakoids. Addition of NADPH and ferredoxin to isolated spinach thylakoids resulted in the reduction of the PQ pool, but neither its kinetics nor its inhibitor sensitivities matched those of Fnpr. Notably, Fnpr was more rapid than PQ reduction, and completely insensitive to inhibitors of the PSII QB site and oxygen evolving complex as well as inhibitors of the cytochrome b6f complex. We thus conclude that Fnpr in isolated thylakoids is not a result of redox equilibrium with bulk PQ. Redox titrations and fluorescence emission spectra imply that Fnpr is dependent on the reduction of a low potential redox component (Em about − 340 mV) within photosystem II (PSII), and is likely related to earlier observations of low potential variants of QA within a subpopulation of PSII that is directly reducible by ferredoxin. The implications of these results for our understanding of CEF and other photosynthetic processes are discussed.
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Affiliation(s)
- Nicholas Fisher
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
| | - David M Kramer
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA; Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA.
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Kato Y, Noguchi T. Long-Range Interaction between the Mn4CaO5 Cluster and the Non-heme Iron Center in Photosystem II as Revealed by FTIR Spectroelectrochemistry. Biochemistry 2014; 53:4914-23. [DOI: 10.1021/bi500549b] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Yuki Kato
- 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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Zhang Y, Magdaong N, Frank HA, Rusling JF. Protein film voltammetry and co-factor electron transfer dynamics in spinach photosystem II core complex. PHOTOSYNTHESIS RESEARCH 2014; 120:153-167. [PMID: 23625504 DOI: 10.1007/s11120-013-9831-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 04/15/2013] [Indexed: 06/02/2023]
Abstract
Direct protein film voltammetry (PFV) was used to investigate the redox properties of the photosystem II (PSII) core complex from spinach. The complex was isolated using an improved protocol not used previously for PFV. The PSII core complex had high oxygen-evolving capacity and was incorporated into thin lipid and polyion films. Three well-defined reversible pairs of reduction and oxidation voltammetry peaks were observed at 4 °C in the dark. Results were similar in both types of films, indicating that the environment of the PSII-bound cofactors was not influenced by film type. Based on comparison with various control samples including Mn-depleted PSII, peaks were assigned to chlorophyll a (Chl a) (Em = -0.47 V, all vs. NHE, at pH 6), quinones (-0.12 V), and the manganese (Mn) cluster (Em = 0.18 V). PFV of purified iron heme protein cytochrome b-559 (Cyt b-559), a component of PSII, gave a partly reversible peak pair at 0.004 V that did not have a potential similar to any peaks observed from the intact PSII core complex. The closest peak in PSII to 0.004 V is the 0.18 V peak that was found to be associated with a two-electron process, and thus is inconsistent with iron heme protein voltammetry. The -0.47 V peak had a peak potential and peak potential-pH dependence similar to that found for purified Chl a incorporated into DMPC films. The midpoint potentials reported here may differ to various extents from previously reported redox titration data due to the influence of electrode double-layer effects. Heterogeneous electron transfer (hET) rate constants were estimated by theoretical fitting and digital simulations for the -0.47 and 0.18 V peaks. Data for the Chl a peaks were best fit to a one-electron model, while the peak assigned to the Mn cluster was best fit by a two-electron/one-proton model.
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Affiliation(s)
- Yun Zhang
- Department of Chemistry, University of Connecticut, Storrs, CT, 06269-3060, USA
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Vinyard DJ, Ananyev GM, Charles Dismukes G. Photosystem II: The Reaction Center of Oxygenic Photosynthesis. Annu Rev Biochem 2013; 82:577-606. [DOI: 10.1146/annurev-biochem-070511-100425] [Citation(s) in RCA: 279] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- David J. Vinyard
- Department of Chemistry and Chemical Biology and the Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854; ,
- Department of Chemistry, Princeton University, Princeton, New Jersey 08540;
| | - Gennady M. Ananyev
- Department of Chemistry and Chemical Biology and the Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854; ,
| | - G. Charles Dismukes
- Department of Chemistry and Chemical Biology and the Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854; ,
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Kato Y, Shibamoto T, Yamamoto S, Watanabe T, Ishida N, Sugiura M, Rappaport F, Boussac A. Influence of the PsbA1/PsbA3, Ca2+/Sr2+ and Cl−/Br− exchanges on the redox potential of the primary quinone QA in Photosystem II from Thermosynechococcus elongatus as revealed by spectroelectrochemistry. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:1998-2004. [PMID: 22721916 DOI: 10.1016/j.bbabio.2012.06.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 06/09/2012] [Accepted: 06/11/2012] [Indexed: 11/30/2022]
Affiliation(s)
- Yuki Kato
- Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan.
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High and low potential forms of the QA quinone electron acceptor in Photosystem II of Thermosynechococcus elongatus and spinach. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2011; 104:154-7. [PMID: 21393014 DOI: 10.1016/j.jphotobiol.2011.02.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2010] [Revised: 02/08/2011] [Accepted: 02/09/2011] [Indexed: 12/21/2022]
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Redox potentials of primary electron acceptor quinone molecule (QA)- and conserved energetics of photosystem II in cyanobacteria with chlorophyll a and chlorophyll d. Proc Natl Acad Sci U S A 2011; 108:8054-8. [PMID: 21521792 DOI: 10.1073/pnas.1100173108] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In a previous study, we measured the redox potential of the primary electron acceptor pheophytin (Phe) a of photosystem (PS) II in the chlorophyll d-dominated cyanobacterium Acaryochloris marina and a chlorophyll a-containing cyanobacterium, Synechocystis. We obtained the midpoint redox potential (E(m)) values of -478 mV for A. marina and -536 mV for Synechocystis. In this study, we measured the redox potentials of the primary electron acceptor quinone molecule (Q(A)), i.e., E(m)(Q(A)/Q(A)(-)), of PS II and the energy difference between [P680·Phe a(-)·Q(A)] and [P680·Phe a·Q(A)(-)], i.e., ΔG(PhQ). The E(m)(Q(A)/Q(A)(-)) of A. marina was determined to be +64 mV without the Mn cluster and was estimated to be -66 to -86 mV with a Mn-depletion shift (130-150 mV), as observed with other organisms. The E(m)(Phe a/Phe a(-)) in Synechocystis was measured to be -525 mV with the Mn cluster, which is consistent with our previous report. The Mn-depleted downshift of the potential was measured to be approximately -77 mV in Synechocystis, and this value was applied to A. marina (-478 mV); the E(m)(Phe a/Phe a(-)) was estimated to be approximately -401 mV. These values gave rise to a ΔG(PhQ) of -325 mV for A. marina and -383 mV for Synechocystis. In the two cyanobacteria, the energetics in PS II were conserved, even though the potentials of Q(A)(-) and Phe a(-) were relatively shifted depending on the special pair, indicating a common strategy for electron transfer in oxygenic photosynthetic organisms.
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