1
|
Pavlou A, Mokvist F, Styring S, Mamedov F. Far-red photosynthesis: Two charge separation pathways exist in plant Photosystem II reaction center. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148994. [PMID: 37355002 DOI: 10.1016/j.bbabio.2023.148994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 06/09/2023] [Accepted: 06/15/2023] [Indexed: 06/26/2023]
Abstract
An alternative charge separation pathway in Photosystem II under the far-red light was proposed by us on the basis of electron transfer properties at 295 K and 5 K. Here we extend these studies to the temperature range of 77-295 K with help of electron paramagnetic resonance spectroscopy. Induction of the S2 state multiline signal, oxidation of Cytochrome b559 and ChlorophyllZ was studied in Photosystem II membrane preparations from spinach after application of a laser flashes in visible (532 nm) or far-red (730-750 nm) spectral regions. Temperature dependence of the S2 state signal induction after single flash at 730-750 nm (Tinhibition ~ 240 K) was found to be different than that at 532 nm (Tinhibition ~ 157 K). No contaminant oxidation of the secondary electron donors cytochrome b559 or chlorophyllZ was observed. Photoaccumulation experiments with extensive flashing at 77 K showed similar results, with no or very little induction of the secondary electron donors. Thus, the partition ratio defined as (yield of YZ/CaMn4O5-cluster oxidation):(yield of Cytb559/ChlZ/CarD2 oxidation) was found to be 0.4 at under visible light and 1.7 at under far-red light at 77 K. Our data indicate that different products of charge separation after far-red light exists in the wide temperature range which further support the model of the different primary photochemistry in Photosystem II with localization of hole on the ChlD1 molecule.
Collapse
Affiliation(s)
- Andrea Pavlou
- Molecular Biomimetics, Department of Chemistry-Ångström, Uppsala University, P.O. Box 523, 751 20 Uppsala, Sweden
| | - Fredrik Mokvist
- Molecular Biomimetics, Department of Chemistry-Ångström, Uppsala University, P.O. Box 523, 751 20 Uppsala, Sweden
| | - Stenbjörn Styring
- Molecular Biomimetics, Department of Chemistry-Ångström, Uppsala University, P.O. Box 523, 751 20 Uppsala, Sweden
| | - Fikret Mamedov
- Molecular Biomimetics, Department of Chemistry-Ångström, Uppsala University, P.O. Box 523, 751 20 Uppsala, Sweden.
| |
Collapse
|
2
|
Han G, Chernev P, Styring S, Messinger J, Mamedov F. Molecular basis for turnover inefficiencies (misses) during water oxidation in photosystem II. Chem Sci 2022; 13:8667-8678. [PMID: 35974765 PMCID: PMC9337725 DOI: 10.1039/d2sc00854h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 07/04/2022] [Indexed: 11/24/2022] Open
Abstract
Photosynthesis stores solar light as chemical energy and efficiency of this process is highly important. The electrons required for CO2 reduction are extracted from water in a reaction driven by light-induced charge separations in the Photosystem II reaction center and catalyzed by the CaMn4O5-cluster. This cyclic process involves five redox intermediates known as the S0–S4 states. In this study, we quantify the flash-induced turnover efficiency of each S state by electron paramagnetic resonance spectroscopy. Measurements were performed in photosystem II membrane preparations from spinach in the presence of an exogenous electron acceptor at selected temperatures between −10 °C and +20 °C and at flash frequencies of 1.25, 5 and 10 Hz. The results show that at optimal conditions the turnover efficiencies are limited by reactions occurring in the water oxidizing complex, allowing the extraction of their S state dependence and correlating low efficiencies to structural changes and chemical events during the reaction cycle. At temperatures 10 °C and below, the highest efficiency (i.e. lowest miss parameter) was found for the S1 → S2 transition, while the S2 → S3 transition was least efficient (highest miss parameter) over the whole temperature range. These electron paramagnetic resonance results were confirmed by measurements of flash-induced oxygen release patterns in thylakoid membranes and are explained on the basis of S state dependent structural changes at the CaMn4O5-cluster that were determined recently by femtosecond X-ray crystallography. Thereby, possible “molecular errors” connected to the e− transfer, H+ transfer, H2O binding and O2 release are identified. Temperature dependence of the transition inefficiencies (misses) for the water oxidation process in photosystem II were studied by EPR spectroscopy and are explained on the basis of S state dependent structural changes at the CaMn4O5-cluster.![]()
Collapse
Affiliation(s)
- Guangye Han
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University, Box 523, 751 20 Uppsala, Sweden
| | - Petko Chernev
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University, Box 523, 751 20 Uppsala, Sweden
| | - Stenbjörn Styring
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University, Box 523, 751 20 Uppsala, Sweden
| | - Johannes Messinger
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University, Box 523, 751 20 Uppsala, Sweden
- Department of Chemistry, Umeå University, 901 87 Umeå, Sweden
| | - Fikret Mamedov
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University, Box 523, 751 20 Uppsala, Sweden
| |
Collapse
|
3
|
Takatsuka K. Electron Dynamics in Molecular Elementary Processes and Chemical Reactions. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2021. [DOI: 10.1246/bcsj.20200388] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Kazuo Takatsuka
- Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103, Japan
| |
Collapse
|
4
|
Ghosh I, Banerjee G, Reiss K, Kim CJ, Debus RJ, Batista VS, Brudvig GW. D1-S169A substitution of photosystem II reveals a novel S 2-state structure. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148301. [PMID: 32860756 DOI: 10.1016/j.bbabio.2020.148301] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 08/18/2020] [Accepted: 08/22/2020] [Indexed: 10/23/2022]
Abstract
In photosystem II (PSII), photosynthetic water oxidation occurs at the O2-evolving complex (OEC), a tetramanganese-calcium cluster that cycles through light-induced redox intermediates (S0-S4) to produce oxygen from two substrate water molecules. The OEC is surrounded by a hydrogen-bonded network of amino-acid residues that plays a crucial role in proton transfer and substrate water delivery. Previously, we found that D1-S169 was crucial for water oxidation and its mutation to alanine perturbed the hydrogen-bonding network. In this study, we demonstrate that the activation energy for the S2 to S1 transition of D1-S169A PSII is higher than wild-type PSII with a ~1.7-2.7× slower rate of charge recombination with QA- relative to wild-type PSII. Arrhenius analysis of the decay kinetics shows an Ea of 5.87 ± 1.15 kcal mol-1 for decay back to the S1 state, compared to 0.80 ± 0.13 kcal mol-1 for the wild-type S2 state. In addition, we find that ammonia does not affect the S2-state EPR signal, indicating that ammonia does not bind to the Mn cluster in D1-S169A PSII. Finally, a QM/MM analysis indicates that an additional water molecule binds to the Mn4 ion in place of an oxo ligand O5 in the S2 state of D1-S169A PSII. The altered S2 state of D1-S169A PSII provides insight into the S2➔S3 state transition.
Collapse
Affiliation(s)
- Ipsita Ghosh
- Department of Chemistry, Yale University, New Haven, CT 06520-8107, USA
| | - Gourab Banerjee
- Department of Chemistry, Yale University, New Haven, CT 06520-8107, USA
| | - Krystle Reiss
- Department of Chemistry, Yale University, New Haven, CT 06520-8107, USA
| | - Christopher J Kim
- Department of Biochemistry, University of California, Riverside, CA 92521, USA
| | - Richard J Debus
- Department of Biochemistry, University of California, Riverside, CA 92521, USA.
| | - Victor S Batista
- Department of Chemistry, Yale University, New Haven, CT 06520-8107, USA
| | - Gary W Brudvig
- Department of Chemistry, Yale University, New Haven, CT 06520-8107, USA.
| |
Collapse
|
5
|
Yamamoto K, Takatsuka K. Collision induced charge separation in ground-state water splitting dynamics. Phys Chem Chem Phys 2018; 20:12229-12240. [DOI: 10.1039/c8cp00520f] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The pathway of one-way electron–hole transfer induced by proton reciprocating motions, thereby realizing the collision induced ground-state charge separation.
Collapse
Affiliation(s)
- Kentaro Yamamoto
- Fukui Institute for Fundamental Chemistry
- Kyoto University
- Kyoto 606-8103
- Japan
| | - Kazuo Takatsuka
- Fukui Institute for Fundamental Chemistry
- Kyoto University
- Kyoto 606-8103
- Japan
| |
Collapse
|
6
|
Ahmadova N, Ho FM, Styring S, Mamedov F. Tyrozine D oxidation and redox equilibrium in photosystem II. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:407-417. [DOI: 10.1016/j.bbabio.2017.02.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 02/17/2017] [Accepted: 02/20/2017] [Indexed: 10/20/2022]
|
7
|
Retegan M, Pantazis DA. Interaction of methanol with the oxygen-evolving complex: atomistic models, channel identification, species dependence, and mechanistic implications. Chem Sci 2016; 7:6463-6476. [PMID: 28451104 PMCID: PMC5355959 DOI: 10.1039/c6sc02340a] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 06/28/2016] [Indexed: 12/29/2022] Open
Abstract
Methanol has long being used as a substrate analogue to probe access pathways and investigate water delivery at the oxygen-evolving complex (OEC) of photosystem-II. In this contribution we study the interaction of methanol with the OEC by assembling available spectroscopic data into a quantum mechanical treatment that takes into account the local channel architecture of the active site. The effect on the magnetic energy levels of the Mn4Ca cluster in the S2 state of the catalytic cycle can be explained equally well by two models that involve either methanol binding to the calcium ion of the cluster, or a second-sphere interaction in the vicinity of the "dangler" Mn4 ion. However, consideration of the latest 13C hyperfine interaction data shows that only one model is fully consistent with experiment. In contrast to previous hypotheses, methanol is not a direct ligand to the OEC, but is situated at the end-point of a water channel associated with the O4 bridge. Its effect on magnetic properties of plant PS-II results from disruption of hydrogen bonding between O4 and proximal channel water molecules, thus enhancing superexchange (antiferromagnetic coupling) between the Mn3 and Mn4 ions. The same interaction mode applies to the dark-stable S1 state and possibly to all other states of the complex. Comparison of protein sequences from cyanobacteria and plants reveals a channel-altering substitution (D1-Asn87 versus D1-Ala87) in the proximity of the methanol binding pocket, explaining the species-dependence of the methanol effect. The water channel established as the methanol access pathway is the same that delivers ammonia to the Mn4 ion, supporting the notion that this is the only directly solvent-accessible manganese site of the OEC. The results support the pivot mechanism for water binding at a component of the S3 state and would be consistent with partial inhibition of water delivery by methanol. Mechanistic implications for enzymatic regulation and catalytic progression are discussed.
Collapse
Affiliation(s)
- Marius Retegan
- Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36 , 45470 Mülheim an der Ruhr , Germany .
| | - Dimitrios A Pantazis
- Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36 , 45470 Mülheim an der Ruhr , Germany .
| |
Collapse
|
8
|
Ananyev G, Gates C, Dismukes GC. The Oxygen quantum yield in diverse algae and cyanobacteria is controlled by partitioning of flux between linear and cyclic electron flow within photosystem II. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1380-1391. [PMID: 27117512 DOI: 10.1016/j.bbabio.2016.04.056] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 04/20/2016] [Accepted: 04/21/2016] [Indexed: 01/07/2023]
Abstract
We have measured flash-induced oxygen quantum yields (O2-QYs) and primary charge separation (Chl variable fluorescence yield, Fv/Fm) in vivo among phylogenetically diverse microalgae and cyanobacteria. Higher O2-QYs can be attained in cells by releasing constraints on charge transfer at the Photosystem II (PSII) acceptor side by adding membrane-permeable benzoquinone (BQ) derivatives that oxidize plastosemiquinone QB(-) and QBH2. This method allows uncoupling PSII turnover from its natural regulation in living cells, without artifacts of isolating PSII complexes. This approach reveals different extents of regulation across species, controlled at the QB(-) acceptor site. Arthrospira maxima is confirmed as the most efficient PSII-WOC (water oxidizing complex) and exhibits the least regulation of flux. Thermosynechococcus elongatus exhibits an O2-QY of 30%, suggesting strong downregulation. WOC cycle simulations with the most accurate model (VZAD) show that a light-driven backward transition (net addition of an electron to the WOC, distinct from recombination) occurs in up to 25% of native PSIIs in the S2 and S3 states, while adding BQ prevents backward transitions and increases the lifetime of S2 and S3 by 10-fold. Backward transitions occur in PSIIs that have plastosemiquinone radicals in the QB site and are postulated to be physiologically regulated pathways for storing light energy as proton gradient through direct PSII-cyclic electron flow (PSII-CEF). PSII-CEF is independent of classical PSI/cyt-b6f-CEF and provides an alternative proton translocation pathway for energy conversion. PSII-CEF enables variable fluxes between linear and cyclic electron pathways, thus accommodating species-dependent needs for redox and ion-gradient energy sources powered by a single photosystem.
Collapse
Affiliation(s)
- Gennady Ananyev
- The Waksman Institute of Microbiology and the Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, United States
| | - Colin Gates
- The Waksman Institute of Microbiology and the Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, United States
| | - G Charles Dismukes
- The Waksman Institute of Microbiology and the Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, United States.
| |
Collapse
|
9
|
Rhodes CJ. The Role of ESR Spectroscopy in Advancing Catalytic Science: Some Recent Developments. PROGRESS IN REACTION KINETICS AND MECHANISM 2015. [DOI: 10.3184/146867815x14297237081532] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Recent progress is surveyed in regard to the importance of molecular species containing unpaired electrons in catalytic systems, as revealed using ESR spectroscopy. The review begins with studies of enzymes and their role directly in biological systems, and then discusses investigations of various artificially created catalysts with potential human and environmental significance, including zeolites. Among the specific types of catalytic media considered are those for photocatalysis, water splitting, the degradation of environmental pollutants, hydrocarbon conversions, fuel cells, ionic liquids and sensor devices employing graphene. Studies of muonium-labelled radicals in zeolites are also reviewed, as a means for determining the dynamics of transient radicals in these nanoporous materials.
Collapse
|
10
|
Vinyard DJ, Brudvig GW. Insights into substrate binding to the oxygen-evolving complex of photosystem II from ammonia inhibition studies. Biochemistry 2015; 54:622-8. [PMID: 25531753 DOI: 10.1021/bi5014134] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Water oxidation in Photosystem II occurs at the oxygen-evolving complex (OEC), which cycles through distinct intermediates, S0-S4. The inhibitor ammonia selectively binds to the S2 state at an unresolved site that is not competitive with substrate water. By monitoring the yields of flash-induced oxygen production, we show that ammonia decreases the net efficiency of OEC turnover and slows the decay kinetics of S2 to S1. The temperature dependence of biphasic S2 decay kinetics provides activation energies that do not vary in control and ammonia conditions. We interpret our data in the broader context of previous studies by introducing a kinetic model for both the formation and decay of ammonia-bound S2. The model predicts ammonia binds to S2 rapidly (t1/2 = 1 ms) with a large equilibrium constant. This finding implies that ammonia decreases the reduction potential of S2 by at least 2.7 kcal mol(-1) (>120 mV), which is not consistent with ammonia substitution of a terminal water ligand of Mn(IV). Instead, these data support the proposal that ammonia binds as a bridging ligand between two Mn atoms. Implications for the mechanism of O-O bond formation are discussed.
Collapse
Affiliation(s)
- David J Vinyard
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | | |
Collapse
|
11
|
Mokvist F, Sjöholm J, Mamedov F, Styring S. The Photochemistry in Photosystem II at 5 K Is Different in Visible and Far-Red Light. Biochemistry 2014; 53:4228-38. [DOI: 10.1021/bi5006392] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Fredrik Mokvist
- Molecular Biomimetics, Department
of Chemistry-Ångström, Uppsala University, Ångström Laboratory, P.O. Box 523, S-751 20 Uppsala, Sweden
| | - Johannes Sjöholm
- Molecular Biomimetics, Department
of Chemistry-Ångström, Uppsala University, Ångström Laboratory, P.O. Box 523, S-751 20 Uppsala, Sweden
| | - Fikret Mamedov
- Molecular Biomimetics, Department
of Chemistry-Ångström, Uppsala University, Ångström Laboratory, P.O. Box 523, S-751 20 Uppsala, Sweden
| | - Stenbjörn Styring
- Molecular Biomimetics, Department
of Chemistry-Ångström, Uppsala University, Ångström Laboratory, P.O. Box 523, S-751 20 Uppsala, Sweden
| |
Collapse
|
12
|
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.
Collapse
Affiliation(s)
- Yun Zhang
- Department of Chemistry, University of Connecticut, Storrs, CT, 06269-3060, USA
| | | | | | | |
Collapse
|
13
|
Migliore A, Polizzi NF, Therien M, Beratan DN. Biochemistry and theory of proton-coupled electron transfer. Chem Rev 2014; 114:3381-465. [PMID: 24684625 PMCID: PMC4317057 DOI: 10.1021/cr4006654] [Citation(s) in RCA: 345] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Indexed: 02/01/2023]
Affiliation(s)
- Agostino Migliore
- Department
of Chemistry, Department of Biochemistry, and Department of Physics, Duke University, Durham, North Carolina 27708, United States
| | - Nicholas F. Polizzi
- Department
of Chemistry, Department of Biochemistry, and Department of Physics, Duke University, Durham, North Carolina 27708, United States
| | - Michael
J. Therien
- Department
of Chemistry, Department of Biochemistry, and Department of Physics, Duke University, Durham, North Carolina 27708, United States
| | - David N. Beratan
- Department
of Chemistry, Department of Biochemistry, and Department of Physics, Duke University, Durham, North Carolina 27708, United States
| |
Collapse
|
14
|
Abstract
An overview is provided of the importance of molecular species containing unpaired electrons in catalytic systems, as revealed using ESR spectroscopy. The review aims to demonstrate the considerable extent of scientific progress that has been made in this broad topic during the past few decades. Studies of catalytically active surfaces, including zeolites, are surveyed, and the detection of radical species, formed as intermediates in their reactions, using matrix isolation and spin-trapping techniques. Radical cation formation in zeolites is discussed, and the employment of muon spin rotation and relaxation techniques to study the mobility of labelled radicals in various porous and catalytic media. Among the specific types of catalytic media considered are those for photocatalysis, water splitting, degradation of environmental pollutants, hydrocarbon conversions, fuel cells and sensor devices employing graphene. The review concludes with recent developments in the study of enzymes and their reactions, using ESR-based methods.
Collapse
|
15
|
Vinyard DJ, Gimpel J, Ananyev GM, Cornejo MA, Golden SS, Mayfield SP, Dismukes GC. Natural variants of photosystem II subunit D1 tune photochemical fitness to solar intensity. J Biol Chem 2012; 288:5451-62. [PMID: 23271739 DOI: 10.1074/jbc.m112.394668] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Photosystem II (PSII) is composed of six core polypeptides that make up the minimal unit capable of performing the primary photochemistry of light-driven charge separation and water oxidation in all oxygenic phototrophs. The D1 subunit of this complex contains most of the ligating amino acid residues for the Mn(4)CaO(5) core of the water-oxidizing complex (WOC). Most cyanobacteria have 3-5 copies of the psbA gene coding for at least two isoforms of D1, whereas algae and plants have only one isoform. Synechococcus elongatus PCC 7942 contains two D1 isoforms; D1:1 is expressed under low light conditions, and D1:2 is up-regulated in high light or stress conditions. Using a heterologous psbA expression system in the green alga Chlamydomonas reinhardtii, we have measured growth rate, WOC cycle efficiency, and O(2) yield as a function of D1:1, D1:2, or the native algal D1 isoform. D1:1-PSII cells outcompete D1:2-PSII cells and accumulate more biomass in light-limiting conditions. However, D1:2-PSII cells easily outcompete D1:1-PSII cells at high light intensities. The native C. reinhardtii-PSII WOC cycles less efficiently at all light intensities and produces less O(2) than either cyanobacterial D1 isoform. D1:2-PSII makes more O(2) per saturating flash than D1:1-PSII, but it exhibits lower WOC cycling efficiency at low light intensities due to a 40% faster charge recombination rate in the S(3) state. These functional advantages of D1:1-PSII and D1:2-PSII at low and high light regimes, respectively, can be explained by differences in predicted redox potentials of PSII electron acceptors that control kinetic performance.
Collapse
Affiliation(s)
- David J Vinyard
- Department of Chemistry and Chemical Biology, State University of New Jersey, Piscataway, New Jersey 08854, USA
| | | | | | | | | | | | | |
Collapse
|
16
|
Han G, Mamedov F, Styring S. Misses during water oxidation in photosystem II are S state-dependent. J Biol Chem 2012; 287:13422-9. [PMID: 22374999 DOI: 10.1074/jbc.m112.342543] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The period of four oscillation of the S state intermediates of the water oxidizing complex in Photosystem II (PSII) is commonly analyzed by the Kok parameters. The important miss factor determines the efficiency for each S transition. Commonly, an equal miss factor has been used in the analysis. We have used EPR signals which probe all S states in the same sample during S cycle advancement. This allows, for the first time, to measure directly the miss parameter for each S state transition. Experiments were performed in PSII membrane preparations from spinach in the presence of electron acceptor at 1 °C and 20 °C. The data show that the miss parameter is different in different transitions and shows different temperature dependence. We found no misses at 1 °C and 10% misses at 20 °C during the S(1)→S(2) transition. The highest miss factor was found in the S(2)→S(3) transition which decreased from 23% to 16% with increasing temperature. For the S(3)→S(0) transition the miss parameter was found to be 7% at 1 °C and decreased to 3% at 20 °C. For the S(0)→S(1) transition the miss parameter was found to be approximately 10% at both temperatures. The contribution from the acceptor side in the form of recombination reactions as well as from the donor side of PSII to the uneven misses is discussed. It is suggested that the different transition efficiency in each S transition partly reflects the chemistry at the CaMn(4)O(5) cluster. That consequently contributes to the uneven misses during S cycle turnover in PSII.
Collapse
Affiliation(s)
- Guangye Han
- Photochemistry and Molecular Science, the Department of Chemistry-Ångström, Box 523, Uppsala University, 751 20 Uppsala, Sweden
| | | | | |
Collapse
|
17
|
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.
Collapse
|