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Lubitz W, Pantazis DA, Cox N. Water oxidation in oxygenic photosynthesis studied by magnetic resonance techniques. FEBS Lett 2023; 597:6-29. [PMID: 36409002 DOI: 10.1002/1873-3468.14543] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 11/14/2022] [Accepted: 11/15/2022] [Indexed: 11/23/2022]
Abstract
The understanding of light-induced biological water oxidation in oxygenic photosynthesis is of great importance both for biology and (bio)technological applications. The chemically difficult multistep reaction takes place at a unique protein-bound tetra-manganese/calcium cluster in photosystem II whose structure has been elucidated by X-ray crystallography (Umena et al. Nature 2011, 473, 55). The cluster moves through several intermediate states in the catalytic cycle. A detailed understanding of these intermediates requires information about the spatial and electronic structure of the Mn4 Ca complex; the latter is only available from spectroscopic techniques. Here, the important role of Electron Paramagnetic Resonance (EPR) and related double resonance techniques (ENDOR, EDNMR), complemented by quantum chemical calculations, is described. This has led to the elucidation of the cluster's redox and protonation states, the valence and spin states of the manganese ions and the interactions between them, and contributed substantially to the understanding of the role of the protein surrounding, as well as the binding and processing of the substrate water molecules, the O-O bond formation and dioxygen release. Based on these data, models for the water oxidation cycle are developed.
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Affiliation(s)
- Wolfgang Lubitz
- Max-Planck-Institut für Chemische Energiekonversion, Mülheim/Ruhr, Germany
| | | | - Nicholas Cox
- Research School of Chemistry, Australian National University, Canberra, ACT, Australia
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2
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Gao X, Fan H. The Role of Redox-Inactive Metals in Modulating the Redox Potential of the Mn 4CaO 4 Model Complex. Inorg Chem 2022; 61:11539-11549. [PMID: 35839298 DOI: 10.1021/acs.inorgchem.2c00243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Photosynthetic oxygen-evolving center (OEC), the "engine of life", is a unique Mn4CaO5 cluster catalyzing the water oxidation. The role of redox-inactive component Ca2+, which can only be functionally replaced by Sr2+ in a biological environment, has been under debate for a long time. Recently, its modulating effect on the redox potential of native OEC and artificial structural OEC model complex has received great attention, and linear relationship between the potential and the Lewis acidity of the redox-inactive metal has been proposed for the MMn3O4 model complex. In this work, the modulating effect has been studied in detail using the Mn4CaO4 model complex, which is the closest structural model to OEC to date and has a similar redox potential at the S1-S2 transition. We found the redox-inactive metal only has a weak modulating effect on the potential, which is comparable in strength to that of the ligand environments. Meanwhile, the net charge of the complex, which could be changed along with the redox-inactive metal, has a high impact on the potential and can be unified by protonation, deprotonation, or ligand modification. Although the modulating effect of the redox-inactive metal is not very strong, the linear relationship between the potential and the Lewis acidity is still valid for Mn4MO4 complexes. Our results of strong modulating effects for net charge and weak modulating effects for redox-inactive metal fit with the previous experimental observations on Mn4MO4 (M = Ca2+, Y3+, and Gd3+) model complexes, and suggest that Ca2+ can be structurally and electrochemically replaced with other metal cations, together with proper ligand modifications.
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Affiliation(s)
- Xianrui Gao
- Shenyang University of Chemical Technology, Shenyang 110142, China.,State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, China
| | - Hongjun Fan
- Shenyang University of Chemical Technology, Shenyang 110142, China.,State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, China
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3
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Oliver N, Avramov AP, Nürnberg DJ, Dau H, Burnap RL. From manganese oxidation to water oxidation: assembly and evolution of the water-splitting complex in photosystem II. PHOTOSYNTHESIS RESEARCH 2022; 152:107-133. [PMID: 35397059 DOI: 10.1007/s11120-022-00912-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 03/03/2022] [Indexed: 06/14/2023]
Abstract
The manganese cluster of photosystem II has been the focus of intense research aiming to understand the mechanism of H2O-oxidation. Great effort has also been applied to investigating its oxidative photoassembly process, termed photoactivation that involves the light-driven incorporation of metal ions into the active Mn4CaO5 cluster. The knowledge gained on these topics has fundamental scientific significance, but may also provide the blueprints for the development of biomimetic devices capable of splitting water for solar energy applications. Accordingly, synthetic chemical approaches inspired by the native Mn cluster are actively being explored, for which the native catalyst is a useful benchmark. For both the natural and artificial catalysts, the assembly process of incorporating Mn ions into catalytically active Mn oxide complexes is an oxidative process. In both cases this process appears to share certain chemical features, such as producing an optimal fraction of open coordination sites on the metals to facilitate the binding of substrate water, as well as the involvement of alkali metals (e.g., Ca2+) to facilitate assembly and activate water-splitting catalysis. This review discusses the structure and formation of the metal cluster of the PSII H2O-oxidizing complex in the context of what is known about the formation and chemical properties of different Mn oxides. Additionally, the evolutionary origin of the Mn4CaO5 is considered in light of hypotheses that soluble Mn2+ was an ancient source of reductant for some early photosynthetic reaction centers ('photomanganotrophy'), and recent evidence that PSII can form Mn oxides with structural resemblance to the geologically abundant birnessite class of minerals. A new functional role for Ca2+ to facilitate sustained Mn2+ oxidation during photomanganotrophy is proposed, which may explain proposed physiological intermediates during the likely evolutionary transition from anoxygenic to oxygenic photosynthesis.
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Affiliation(s)
- Nicholas Oliver
- Physics Department, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Anton P Avramov
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Dennis J Nürnberg
- Physics Department, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Holger Dau
- Physics Department, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Robert L Burnap
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, 74078, USA.
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4
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The role of Ca 2+ and protein scaffolding in the formation of nature's water oxidizing complex. Proc Natl Acad Sci U S A 2020; 117:28036-28045. [PMID: 33106422 PMCID: PMC7668025 DOI: 10.1073/pnas.2011315117] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Photosynthetic O2 evolution is catalyzed by the Mn4CaO5 cluster of the water oxidation complex of the photosystem II (PSII) complex. The photooxidative self-assembly of the Mn4CaO5 cluster, termed photoactivation, utilizes the same highly oxidizing species that drive the water oxidation in order to drive the incorporation of Mn2+ into the high-valence Mn4CaO5 cluster. This multistep process proceeds with low quantum efficiency, involves a molecular rearrangement between light-activated steps, and is prone to photoinactivation and misassembly. A sensitive polarographic technique was used to track the assembly process under flash illumination as a function of the constituent Mn2+ and Ca2+ ions in genetically engineered membranes of the cyanobacterium Synechocystis sp. PCC6803 to elucidate the action of Ca2+ and peripheral proteins. We show that the protein scaffolding organizing this process is allosterically modulated by the assembly protein Psb27, which together with Ca2+ stabilizes the intermediates of photoactivation, a feature especially evident at long intervals between photoactivating flashes. The results indicate three critical metal-binding sites: two Mn and one Ca, with occupation of the Ca site by Ca2+ critical for the suppression of photoinactivation. The long-observed competition between Mn2+ and Ca2+ occurs at the second Mn site, and its occupation by competing Ca2+ slows the rearrangement. The relatively low overall quantum efficiency of photoactivation is explained by the requirement of correct occupancy of these metal-binding sites coupled to a slow restructuring of the protein ligation environment, which are jointly necessary for the photooxidative trapping of the first stable assembly intermediate.
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5
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Lubitz W, Chrysina M, Cox N. Water oxidation in photosystem II. PHOTOSYNTHESIS RESEARCH 2019; 142:105-125. [PMID: 31187340 PMCID: PMC6763417 DOI: 10.1007/s11120-019-00648-3] [Citation(s) in RCA: 120] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 05/20/2019] [Indexed: 05/18/2023]
Abstract
Biological water oxidation, performed by a single enzyme, photosystem II, is a central research topic not only in understanding the photosynthetic apparatus but also for the development of water splitting catalysts for technological applications. Great progress has been made in this endeavor following the report of a high-resolution X-ray crystallographic structure in 2011 resolving the cofactor site (Umena et al. in Nature 473:55-60, 2011), a tetra-manganese calcium complex. The electronic properties of the protein-bound water oxidizing Mn4OxCa complex are crucial to understand its catalytic activity. These properties include: its redox state(s) which are tuned by the protein matrix, the distribution of the manganese valence and spin states and the complex interactions that exist between the four manganese ions. In this short review we describe how magnetic resonance techniques, particularly EPR, complemented by quantum chemical calculations, have played an important role in understanding the electronic structure of the cofactor. Together with isotope labeling, these techniques have also been instrumental in deciphering the binding of the two substrate water molecules to the cluster. These results are briefly described in the context of the history of biological water oxidation with special emphasis on recent work using time resolved X-ray diffraction with free electron lasers. It is shown that these data are instrumental for developing a model of the biological water oxidation cycle.
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Affiliation(s)
- Wolfgang Lubitz
- Max-Planck-Institut für Chemische Energiekonversion, Mülheim/Ruhr, Germany
| | - Maria Chrysina
- Max-Planck-Institut für Chemische Energiekonversion, Mülheim/Ruhr, Germany
| | - Nicholas Cox
- Research School of Chemistry, The Australian National University, Canberra, Australia
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6
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Lee HB, Agapie T. Redox Tuning via Ligand-Induced Geometric Distortions at a YMn 3O 4 Cubane Model of the Biological Oxygen Evolving Complex. Inorg Chem 2019; 58:14998-15003. [PMID: 31095368 PMCID: PMC6876925 DOI: 10.1021/acs.inorgchem.9b00510] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
![]()
The function of proteins
involved in electron transfer is dependent
on cofactors attaining the necessary reduction potentials. We establish
a mode of cluster redox tuning through steric pressure on a synthetic
model related to Photosystem II. Resembling the cuboidal [CaMn3O4] subsite of the biological oxygen evolving complex
(OEC), [Mn4O4] and [YMn3O4] complexes featuring ligands of different basicity and chelating
properties were characterized by cyclic voltammetry. In the absence
of ligand-induced distortions, increasing the basicity of the ligands
results in a decrease of cluster reduction potential. Contraction
of Y-oxo/Y–Mn distances by 0.1/0.15 Å enforced by a chelating
ligand results in an increase of cluster reduction potential even
in the presence of strongly basic donors. Related protein-induced
changes in Ca-oxo/Ca–Mn distances may have similar effects
in tuning the redox potential of the OEC through entatic states and
may explain the cation size dependence on the progression of the S-state
cycle. The redox properties of [YMn3O4] and
[Mn4O4] complexes featuring bridging ligands
of different basicity and chelating properties are reported. In the
absence of ligand-induced geometric distortions, increasing the basicity
of the ligands results in a decrease of cluster reduction potential.
A chelating ligand results in contractions of Y-oxo distances by ∼0.1
Å, which correlates with an increase of cluster reduction potential
even in the presence of strongly basic donors.
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Affiliation(s)
- Heui Beom Lee
- Department of Chemistry and Chemical Engineering , California Institute of Technology , 1200 E. California Blvd MC 127-72 , Pasadena , California 91125 , United States
| | - Theodor Agapie
- Department of Chemistry and Chemical Engineering , California Institute of Technology , 1200 E. California Blvd MC 127-72 , Pasadena , California 91125 , United States
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7
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The Significance of Calcium in Photosynthesis. Int J Mol Sci 2019; 20:ijms20061353. [PMID: 30889814 PMCID: PMC6471148 DOI: 10.3390/ijms20061353] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 02/23/2019] [Accepted: 03/01/2019] [Indexed: 01/12/2023] Open
Abstract
As a secondary messenger, calcium participates in various physiological and biochemical reactions in plants. Photosynthesis is the most extensive biosynthesis process on Earth. To date, researchers have found that some chloroplast proteins have Ca2+-binding sites, and the structure and function of some of these proteins have been discussed in detail. Although the roles of Ca2+ signal transduction related to photosynthesis have been discussed, the relationship between calcium and photosynthesis is seldom systematically summarized. In this review, we provide an overview of current knowledge of calcium’s role in photosynthesis.
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8
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Affiliation(s)
- Dimitrios A. Pantazis
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
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9
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Calcium, conformational selection, and redox-active tyrosine YZ in the photosynthetic oxygen-evolving cluster. Proc Natl Acad Sci U S A 2018; 115:5658-5663. [PMID: 29752381 DOI: 10.1073/pnas.1800758115] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In Photosystem II (PSII), YZ (Tyr161D1) participates in radical transfer between the chlorophyll donor and the Mn4CaO5 cluster. Under flashing illumination, the metal cluster cycles among five Sn states, and oxygen is evolved from water. The essential YZ is transiently oxidized and reduced on each flash in a proton-coupled electron transfer (PCET) reaction. Calcium is required for function. Of reconstituted divalent ions, only strontium restores oxygen evolution. YZ is predicted to hydrogen bond to calcium-bound water and to His190D1 in PSII structures. Here, we report a vibrational spectroscopic study of YZ radical and singlet in the presence of the metal cluster. The S2 state is trapped by illumination at 190 K; flash illumination then generates the S2YZ radical. Using reaction-induced FTIR spectroscopy and divalent ion depletion/substitution, we identify calcium-sensitive tyrosyl radical and tyrosine singlet bands in the S2 state. In calcium-containing PSII, two CO stretching bands are detected at 1,503 and 1,478 cm-1 These bands are assigned to two different radical conformers in calcium-containing PSII. At pH 6.0, the 1,503-cm-1 band shifts to 1,507 cm-1 in strontium-containing PSII, and the band is reduced in intensity in calcium-depleted PSII. These effects are consistent with a hydrogen-bonding interaction between the calcium site and one conformer of radical YZ. Analysis of the amide I region indicates that calcium selects for a PCET reaction in a subset of the YZ conformers, which are trapped in the S2 state. These results support the interpretation that YZ undergoes a redox-coupled conformational change, which is calcium dependent.
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10
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Guo Z, Barry BA. Calcium, Ammonia, Redox-Active Tyrosine YZ, and Proton-Coupled Electron Transfer in the Photosynthetic Oxygen-Evolving Complex. J Phys Chem B 2017; 121:3987-3996. [DOI: 10.1021/acs.jpcb.7b01802] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Zhanjun Guo
- School of Chemistry and Biochemistry and Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Bridgette A. Barry
- School of Chemistry and Biochemistry and Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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11
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Tiwari A, Singh P, Asthana RK. Role of calcium in the mitigation of heat stress in the cyanobacterium Anabaena PCC 7120. JOURNAL OF PLANT PHYSIOLOGY 2016; 199:67-75. [PMID: 27302007 DOI: 10.1016/j.jplph.2016.05.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 05/09/2016] [Accepted: 05/18/2016] [Indexed: 05/08/2023]
Abstract
The effects of exogenously added CaCl2 (0.25mM) on photopigments, photosynthetic O2-evolution, antioxidative enzyme activity, membrane damage, expression of two heat shock genes (groEL and groES) and apoptotic features in Anabaena 7120 under heat stress (45°C) for up to 24h were investigated. Heat stress lowered the level of photopigments; however, Ca2+--supplemented cultures showed a low level reduction in Chl a but induced accumulation of carotenoids and phycocyanin under heat stress. Photosynthetic O2-evolving capacity was maintained at a higher level in cells from Ca2+-supplemented medium. Among the antioxidative enzymes, superoxide dismutase activity was unaffected by the presence or absence of Ca2+ in contrast to increases in catalase, ascorbate peroxidase and glutathione reductase activities in cells grown in Ca2+-supplemented medium. Lower levels of lipid peroxidation were recorded in Anabaena cells grown in Ca2+-supplemented medium in comparison to cells from Ca2+--deprived medium. Target cells grown in Ca2+-deprived medium developed apoptotic features in the early stages of heat shock, while Ca2+ application seemed to interfere with apoptosis because only a few cells showed such features after 24 h of heat exposure, indicating a role for Ca2+ in maintaining cell viability under heat stress. There was also continuous up regulation of two important heat shock genes (groEL and groES) in Ca2+-supplemented cultures, exposed to heat shock, again indicating a role for Ca2+ in stress management.
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Affiliation(s)
- Anupam Tiwari
- R.N. Singh Memorial Lab, Centre of Advanced study in Botany, Banaras Hindu University, Varanasi 221005, India
| | - Priyanka Singh
- R.N. Singh Memorial Lab, Centre of Advanced study in Botany, Banaras Hindu University, Varanasi 221005, India
| | - Ravi Kumar Asthana
- R.N. Singh Memorial Lab, Centre of Advanced study in Botany, Banaras Hindu University, Varanasi 221005, India.
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12
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Redox-coupled substrate water reorganization in the active site of Photosystem II-The role of calcium in substrate water delivery. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:740-8. [PMID: 26826591 DOI: 10.1016/j.bbabio.2016.01.015] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 12/10/2015] [Accepted: 01/26/2016] [Indexed: 01/08/2023]
Abstract
Photosystem II (PSII) catalyzes light-driven water splitting in nature and is the key enzyme for energy input into the biosphere. Important details of its mechanism are not well understood. In order to understand the mechanism of water splitting, we perform here large-scale density functional theory (DFT) calculations on the active site of PSII in different oxidation, spin and ligand states. Prior to formation of the O-O bond, we find that all manganese atoms are oxidized to Mn(IV) in the S3 state, consistent with earlier studies. We find here, however, that the formation of the S3 state is coupled to the movement of a calcium-bound hydroxide (W3) from the Ca to a Mn (Mn1 or Mn4) in a process that is triggered by the formation of a tyrosyl radical (Tyr-161) and its protonated base, His-190. We find that subsequent oxidation and deprotonation of this hydroxide on Mn1 result in formation of an oxyl-radical that can exergonically couple with one of the oxo-bridges (O5), forming an O-O bond. When O(2) leaves the active site, a second Ca-bound water molecule reorients to bridge the gap between the manganese ions Mn1 and Mn4, forming a new oxo-bridge for the next reaction cycle. Our findings are consistent with experimental data, and suggest that the calcium ion may control substrate water access to the water oxidation sites.
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Krewald V, Neese F, Pantazis DA. Redox potential tuning by redox-inactive cations in nature's water oxidizing catalyst and synthetic analogues. Phys Chem Chem Phys 2016; 18:10739-50. [DOI: 10.1039/c5cp07213a] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Fundamental differences between synthetic manganese clusters and the biological water oxidizing catalyst are demonstrated in the modulation of their redox potential by redox-inactive cations.
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Affiliation(s)
- Vera Krewald
- Max Planck Institute for Chemical Energy Conversion
- 45470 Mülheim an der Ruhr
- Germany
| | - Frank Neese
- Max Planck Institute for Chemical Energy Conversion
- 45470 Mülheim an der Ruhr
- Germany
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14
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Zhang Z, Coats KL, Chen Z, Hubin TJ, Yin G. Influence of Calcium(II) and Chloride on the Oxidative Reactivity of a Manganese(II) Complex of a Cross-Bridged Cyclen Ligand. Inorg Chem 2014; 53:11937-47. [DOI: 10.1021/ic501342c] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Zhan Zhang
- Key
Laboratory for Large-Format Battery Materials and System, Ministry
of Education, School of Chemistry and Chemical Engineering, Hubei
Key Laboratory of Material Chemistry and Service Failure, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| | - Katherine L. Coats
- Department
of Chemistry and Physics, Southwestern Oklahoma State University, 100
Campus Drive, Weatherford, Oklahoma 73096, United States
| | - Zhuqi Chen
- Key
Laboratory for Large-Format Battery Materials and System, Ministry
of Education, School of Chemistry and Chemical Engineering, Hubei
Key Laboratory of Material Chemistry and Service Failure, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| | - Timothy J. Hubin
- Department
of Chemistry and Physics, Southwestern Oklahoma State University, 100
Campus Drive, Weatherford, Oklahoma 73096, United States
| | - Guochuan Yin
- Key
Laboratory for Large-Format Battery Materials and System, Ministry
of Education, School of Chemistry and Chemical Engineering, Hubei
Key Laboratory of Material Chemistry and Service Failure, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
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15
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Yano J, Yachandra V. Mn4Ca cluster in photosynthesis: where and how water is oxidized to dioxygen. Chem Rev 2014; 114:4175-205. [PMID: 24684576 PMCID: PMC4002066 DOI: 10.1021/cr4004874] [Citation(s) in RCA: 468] [Impact Index Per Article: 46.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Indexed: 12/25/2022]
Affiliation(s)
- Junko Yano
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Vittal Yachandra
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
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16
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Mass spectroscopy locates the extrinsic proteins of photosystem II. Proc Natl Acad Sci U S A 2014; 111:4359-60. [DOI: 10.1073/pnas.1402022111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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17
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Polander BC, Barry BA. Calcium and the Hydrogen-Bonded Water Network in the Photosynthetic Oxygen-Evolving Complex. J Phys Chem Lett 2013; 4:786-791. [PMID: 26281933 DOI: 10.1021/jz400071k] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In photosynthesis, photosystem II evolves oxygen from water at a Mn4CaO5 cluster (OEC). Calcium is required for biological oxygen evolution. In the OEC, a water network, extending from the calcium to four peptide carbonyl groups, has recently been predicted by a high-resolution crystal structure. Here, we use carbonyl vibrational frequencies as reporters of electrostatic changes to test the presence of this water network. A single flash, oxidizing Mn(III) to Mn(IV) (the S1 to S2 transition), upshifted the frequencies of peptide C═O bands. The spectral change was attributable to a decrease in C═O hydrogen bonding. Strontium, which supports a lower level of steady state activity, also led to an oxidation-induced shift in C═O frequencies, but treatment with barium and magnesium, which do not support activity, did not. This work provides evidence that calcium maintains an electrostatically responsive water network in the OEC and shows that OEC peptide carbonyl groups can be used as solvatochromic markers.
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Affiliation(s)
- Brandon C Polander
- Department of Chemistry and Biochemistry and the Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Bridgette A Barry
- Department of Chemistry and Biochemistry and the Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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18
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Najafpour MM, Moghaddam AN, Allakhverdiev SI, Govindjee. Biological water oxidation: lessons from nature. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:1110-21. [PMID: 22507946 DOI: 10.1016/j.bbabio.2012.04.002] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 04/02/2012] [Accepted: 04/04/2012] [Indexed: 01/03/2023]
Abstract
Hydrogen production by water splitting may be an appealing solution for future energy needs. To evolve hydrogen efficiently in a sustainable manner, it is necessary first to synthesize what we may call a 'super catalyst' for water oxidation, which is the more challenging half reaction of water splitting. An efficient system for water oxidation exists in the water oxidizing complex in cyanobacteria, algae and plants; further, recently published data on the Manganese-calcium cluster have provided details on the mechanism and structure of the water oxidizing complex. Here, we have briefly reviewed the characteristics of the natural system from the standpoint of what we could learn from it to produce an efficient artificial system. In short, to design an efficient water oxidizing complex for artificial photosynthesis, we must learn and use wisely the knowledge about water oxidation and the water oxidizing complex in the natural system. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.
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19
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Popelkova H, Boswell N, Yocum C. Probing the topography of the photosystem II oxygen evolving complex: PsbO is required for efficient calcium protection of the manganese cluster against dark-inhibition by an artificial reductant. PHOTOSYNTHESIS RESEARCH 2011; 110:111-121. [PMID: 22042330 DOI: 10.1007/s11120-011-9703-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Accepted: 10/17/2011] [Indexed: 05/31/2023]
Abstract
The photosystem II (PSII) manganese-stabilizing protein (PsbO) is known to be the essential PSII extrinsic subunit for stabilization and retention of the Mn and Cl(-) cofactors in the oxygen evolving complex (OEC) of PSII, but its function relative to Ca(2+) is less clear. To obtain a better insight into the relationship, if any, between PsbO and Ca(2+) binding in the OEC, samples with altered PsbO-PSII binding properties were probed for their potential to promote the ability of Ca(2+) to protect the Mn cluster against dark-inhibition by an exogenous artificial reductant, N,N-dimethylhydroxylamine. In the absence of the PsbP and PsbQ extrinsic subunits, Ca(2+) and its surrogates (Sr(2+), Cd(2+)) shield Mn atoms from inhibitory reduction (Kuntzleman et al., Phys Chem Chem Phys 6:4897, 2004). The results presented here show that PsbO exhibits a positive effect on Ca(2+) binding in the OEC by facilitating the ability of the metal to prevent inhibition of activity by the reductant. The data presented here suggest that PsbO may have a role in the formation of the OEC-associated Ca(2+) binding site by promoting the equilibrium between bound and free Ca(2+) that favors the bound metal.
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Affiliation(s)
- Hana Popelkova
- Department of Molecular, Cellular, and Developmental Biology, The University of Michigan, Ann Arbor, MI 48109-1048, USA.
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Yachandra VK, Yano J. Calcium in the oxygen-evolving complex: structural and mechanistic role determined by X-ray spectroscopy. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2011; 104:51-9. [PMID: 21524917 DOI: 10.1016/j.jphotobiol.2011.02.019] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 02/22/2011] [Accepted: 02/24/2011] [Indexed: 11/25/2022]
Abstract
This review describes the results from X-ray Absorption Spectroscopy studies that have contributed to an understanding of the role of Ca in the photosynthetic water-oxidation reaction. The results include the first Mn, Ca and Sr X-ray spectroscopy studies using Ca or Sr-substituted PS II samples that established the presence of a MnCa heteronuclear structure and its orientation, and the most recent Sr X-ray spectroscopy study using biosynthetically prepared Sr-containing PS II in the various S-states that provide important insights into the requirement for Ca in the mechanism of the Mn(4)Ca catalytic center.
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Affiliation(s)
- Vittal K Yachandra
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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Renger G, Renger T. Photosystem II: The machinery of photosynthetic water splitting. PHOTOSYNTHESIS RESEARCH 2008; 98:53-80. [PMID: 18830685 DOI: 10.1007/s11120-008-9345-7] [Citation(s) in RCA: 192] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Accepted: 07/29/2008] [Indexed: 05/26/2023]
Abstract
This review summarizes our current state of knowledge on the structural organization and functional pattern of photosynthetic water splitting in the multimeric Photosystem II (PS II) complex, which acts as a light-driven water: plastoquinone-oxidoreductase. The overall process comprises three types of reaction sequences: (1) photon absorption and excited singlet state trapping by charge separation leading to the ion radical pair [Formula: see text] formation, (2) oxidative water splitting into four protons and molecular dioxygen at the water oxidizing complex (WOC) with P680+* as driving force and tyrosine Y(Z) as intermediary redox carrier, and (3) reduction of plastoquinone to plastoquinol at the special Q(B) binding site with Q(A)-* acting as reductant. Based on recent progress in structure analysis and using new theoretical approaches the mechanism of reaction sequence (1) is discussed with special emphasis on the excited energy transfer pathways and the sequence of charge transfer steps: [Formula: see text] where (1)(RC-PC)* denotes the excited singlet state (1)P680* of the reaction centre pigment complex. The structure of the catalytic Mn(4)O(X)Ca cluster of the WOC and the four step reaction sequence leading to oxidative water splitting are described and problems arising for the electronic configuration, in particular for the nature of redox state S(3), are discussed. The unravelling of the mode of O-O bond formation is of key relevance for understanding the mechanism of the process. This problem is not yet solved. A multistate model is proposed for S(3) and the functional role of proton shifts and hydrogen bond network(s) is emphasized. Analogously, the structure of the Q(B) site for PQ reduction to PQH(2) and the energetic and kinetics of the two step redox reaction sequence are described. Furthermore, the relevance of the protein dynamics and the role of water molecules for its flexibility are briefly outlined. We end this review by presenting future perspectives on the water oxidation process.
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Affiliation(s)
- Gernot Renger
- Max Volmer Laboratory for Biophysical Chemistry, Berlin Institute of Technology, Berlin, Germany.
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