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Vinyard DJ, Govindjee G. Bicarbonate is a key regulator but not a substrate for O 2 evolution in Photosystem II. PHOTOSYNTHESIS RESEARCH 2024; 162:93-99. [PMID: 39037690 DOI: 10.1007/s11120-024-01111-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2024] [Accepted: 07/11/2024] [Indexed: 07/23/2024]
Abstract
Photosystem II (PSII) uses light energy to oxidize water and to reduce plastoquinone in the photosynthetic electron transport chain. O2 is produced as a byproduct. While most members of the PSII research community agree that O2 originates from water molecules, alternative hypotheses involving bicarbonate persist in the literature. In this perspective, we provide an overview of the important roles of bicarbonate in regulating PSII activity and assembly. Further, we emphasize that biochemistry, spectroscopy, and structural biology experiments have all failed to detect bicarbonate near the active site of O2 evolution. While thermodynamic arguments for oxygen-centered bicarbonate oxidation are valid, the claim that bicarbonate is a substrate for photosynthetic O2 evolution is challenged.
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Affiliation(s)
- David J Vinyard
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA.
| | - Govindjee Govindjee
- Department of Biochemistry, Department of Plant Biology, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
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2
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Guo S, Wu Y, Aboueldahab M. Rapid oxygen isotopic exchange between bicarbonate and water during photosynthesis. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2024; 255:112924. [PMID: 38688041 DOI: 10.1016/j.jphotobiol.2024.112924] [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: 02/10/2024] [Revised: 04/14/2024] [Accepted: 04/24/2024] [Indexed: 05/02/2024]
Abstract
Whether rapid oxygen isotopic exchange between bicarbonate and water occurs in photosynthesis is the key to determine the source of oxygen by classic 18O-labeled photosynthetic oxygen evolution experiments. Here we show that both Microcystis aeruginosa and Chlamydomonas reinhardtii utilize a significant proportion (>16%) of added bicarbonate as a carbon source for photosynthesis. However, oxygen isotopic signal in added bicarbonate cannot be traced in the oxygen in organic matter synthesized by these photosynthetic organisms. This contradicts the current photosynthesis theory, which states that photosynthetic oxygen evolution comes only from water, and oxygen in photosynthetic organic matter comes only from carbon dioxide. We conclude that the photosynthetic organisms undergo rapid exchange of oxygen isotope between bicarbonate and water during photosynthesis. At the same time, this study also provides isotopic evidence for a new mechanism that half of the oxygen in photosynthetic oxygen evolution comes from bicarbonate photolysis and half comes from water photolysis, which provides a new explanation for the bicarbonate effect, and suggests that the Kok-Joliot cycle of photosynthetic oxygen evolution, must be modified to include a molecule of bicarbonate in addition to one molecule of water which in turn must be incorporated into the cycle instead of two water molecules. Furthermore, this study provides a theoretical basis for constructing a newer artificial photosynthetic reactor coupling light reactions with the dark reactions.
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Affiliation(s)
- Shaogang Guo
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yanyou Wu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China.
| | - Mohamed Aboueldahab
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; University of Chinese Academy of Sciences, Beijing 100049, China; Department of Botany and Microbiology, Faculty of Science, South Valley University, Qena 83523, Egypt
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3
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Dang K, Mu J, Tian H, Gao D, Zhou H, Guo L, Shao X, Geng Y, Zhang Q. Zinc regulation of chlorophyll fluorescence and carbohydrate metabolism in saline-sodic stressed rice seedlings. BMC PLANT BIOLOGY 2024; 24:464. [PMID: 38802756 PMCID: PMC11129408 DOI: 10.1186/s12870-024-05170-w] [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: 04/01/2024] [Accepted: 05/19/2024] [Indexed: 05/29/2024]
Abstract
Saline-sodic stress can limit the absorption of available zinc in rice, subsequently impacting the normal photosynthesis and carbohydrate metabolism of rice plants. To investigate the impact of exogenous zinc application on photosynthesis and carbohydrate metabolism in rice grown in saline-sodic soil, this study simulated saline-sodic stress conditions using two rice varieties, 'Changbai 9' and 'Tonghe 899', as experimental materials. Rice seedlings at 4 weeks of age underwent various treatments including control (CT), 2 μmol·L-1 zinc treatment alone (Z), 50 mmol·L-1 saline-sodic treatment (S), and 50 mmol·L-1 saline-sodic treatment with 2 μmol·L-1 zinc (Z + S). We utilized JIP-test to analyze the variations in excitation fluorescence and MR820 signal in rice leaves resulting from zinc supplementation under saline-sodic stress, and examined the impact of zinc supplementation on carbohydrate metabolism in both rice leaves and roots under saline-sodic stress. Research shows that zinc increased the chloroplast pigment content, specific energy flow, quantum yield, and performance of active PSII reaction centers (PIABS), as well as the oxidation (VOX) and reduction rate (Vred) of PSI in rice leaves under saline-sodic stress. Additionally, it decreased the relative variable fluorescence (WK and VJ) and quantum energy dissipation yield (φDO) of the rice. Meanwhile, zinc application can reduce the content of soluble sugars and starch in rice leaves and increasing the starch content in the roots. Therefore, the addition of zinc promotes electron and energy transfer in the rice photosystem under saline-sodic stress. It enhances rice carbohydrate metabolism, improving the rice plants' ability to withstand saline-sodic stress and ultimately promoting rice growth and development.
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Affiliation(s)
- Kun Dang
- Agronomy College, Jilin Agricultural University, Changchun, 130118, China
| | - Jinmeng Mu
- Agronomy College, Jilin Agricultural University, Changchun, 130118, China
| | - Hao Tian
- Agronomy College, Jilin Agricultural University, Changchun, 130118, China
| | - Dapeng Gao
- Agronomy College, Jilin Agricultural University, Changchun, 130118, China
| | - Hongxiang Zhou
- Agronomy College, Jilin Agricultural University, Changchun, 130118, China
| | - Liying Guo
- Agronomy College, Jilin Agricultural University, Changchun, 130118, China
| | - Xiwen Shao
- Agronomy College, Jilin Agricultural University, Changchun, 130118, China
| | - Yanqiu Geng
- Agronomy College, Jilin Agricultural University, Changchun, 130118, China.
- Key Laboratory of Germplasm Innovation and Physiological Ecology of Coldland Grain Crops, Ministry of Education, Harbin, 150000, China.
| | - Qiang Zhang
- Agronomy College, Jilin Agricultural University, Changchun, 130118, China.
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Gates C, Williams JM, Ananyev G, Dismukes GC. How chloride functions to enable proton conduction in photosynthetic water oxidation: Time-resolved kinetics of intermediates (S-states) in vivo and bromide substitution. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148998. [PMID: 37499962 DOI: 10.1016/j.bbabio.2023.148998] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 07/11/2023] [Accepted: 07/19/2023] [Indexed: 07/29/2023]
Abstract
Chloride (Cl-) is essential for O2 evolution during photosynthetic water oxidation. Two chlorides near the water-oxidizing complex (WOC) in Photosystem II (PSII) structures from Thermosynechococcus elongatus (and T. vulcanus) have been postulated to transfer protons generated from water oxidation. We monitored four criteria: primary charge separation flash yield (P* → P+QA-), rates of water oxidation steps (S-states), rate of proton evolution, and flash O2 yield oscillations by measuring chlorophyll variable fluorescence (P* quenching), pH-sensitive dye changes, and oximetry. Br-substitution slows and destabilizes cellular growth, resulting from lower light-saturated O2 evolution rate (-20 %) and proton release (-36 % ΔpH gradient). The latter implies less ATP production. In Br- cultures, protonogenic S-state transitions (S2 → S3 → S0') slow with increasing light intensity and during O2/water exchange (S0' → S0 → S1), while the non-protonogenic S1 → S2 transition is kinetically unaffected. As flash rate increases in Cl- cultures, both rate and extent of acidification of the lumen increase, while charge recombination is suppressed relative to Br-. The Cl- advantage in rapid proton escape from the WOC to lumen is attributed to correlated ion-pair movement of H3O+Cl- in dry water channels vs. separated Br- and H+ ion movement through different regions (>200-fold difference in Bronsted acidities). By contrast, at low flash rates a previously unreported reversal occurs that favors Br- cultures for both proton evolution and less PSII charge recombination. In Br- cultures, slower proton transfer rate is attributed to stronger ion-pairing of Br- with AA residues lining the water channels. Both anions charge-neutralize protons and shepherd them to the lumen using dry aqueous channels.
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Affiliation(s)
- Colin Gates
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, NJ 08854, USA; Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, NJ 08854, USA; Department of Computational Biology and Molecular Biophysics, Rutgers, The State University of New Jersey, NJ 08854, USA; Department of Chemistry and Biochemistry, Loyola University Chicago, IL 60660, USA
| | - Jonah M Williams
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, NJ 08854, USA; Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, NJ 08854, USA
| | - Gennady Ananyev
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, NJ 08854, USA; Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, NJ 08854, USA
| | - G Charles Dismukes
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, NJ 08854, USA; Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, NJ 08854, USA.
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Zhao X, Wu Y, Xing D, Li H, Zhang F. Water Metabolism of Lonicera japonica and Parthenocissus quinquefolia in Response to Heterogeneous Simulated Rock Outcrop Habitats. PLANTS (BASEL, SWITZERLAND) 2023; 12:2279. [PMID: 37375904 DOI: 10.3390/plants12122279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 06/08/2023] [Accepted: 06/08/2023] [Indexed: 06/29/2023]
Abstract
The karst carbon sink caused by rock outcrops results in enrichment of the bicarbonate in soil, affecting the physiological process of plants in an all-round way. Water is the basis of plant growth and metabolic activities. In heterogeneous rock outcrop habitats, the impact of bicarbonate enrichment on the intracellular water metabolism of plant leaf is still unclear, which needs to be revealed. In this paper, the Lonicera japonica and Parthenocissus quinquefolia plants were selected as experimental materials, and electrophysiological indices were used to study their water holding, transfer and use efficiency under three simulated rock outcrop habitats, i.e., rock/soil ratio as 1, 1/4 and 0. By synchronously determining and analyzing the leaf water content, photosynthetic and chlorophyll fluorescence parameters, the response characteristics of water metabolism within leaf cells to the heterogeneous rock outcrop habitats were revealed. The results showed that the soil bicarbonate content in rock outcrop habitats increased with increasing rock/soil ratio. Under the treatment of a higher concentration of bicarbonate, the leaf intra- and intercellular water acquisition and transfer efficiency as well as the photosynthetic utilization capacity of P. quinquefolia decreased, the leaf water content was lower, and those plants had low bicarbonate utilization efficiency, which greatly weakened their drought resistance. However, the Lonicera japonica had a high bicarbonate use capacity when facing the enrichment of bicarbonate within cells, the above-mentioned capacity could significantly improve the water status of the leaves, and the water content and intracellular water-holding capacity of plant leaves in large rock outcrop habitats were significantly better than in non-rock outcrop habitats. In addition, the higher intracellular water-holding capacity was likely to maintain the stability of the intra- and intercellular water environment, thus ensuring the full development of its photosynthetic metabolic capacity, and the stable intracellular water-use efficiency also made itself more vigorous under karstic drought. Taken together, the results suggested that the water metabolic traits of Lonicera japonica made it more adaptable to karst environments.
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Affiliation(s)
- Xiaopan Zhao
- School of Agricultural Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Yanyou Wu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Deke Xing
- School of Agricultural Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Haitao Li
- Department of Agricultural Engineering, Guizhou Vocational College of Agriculture, Qingzhen 551400, China
| | - Furong Zhang
- School of Agricultural Engineering, Jiangsu University, Zhenjiang 212013, China
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Shevela D, Kern JF, Govindjee G, Messinger J. Solar energy conversion by photosystem II: principles and structures. PHOTOSYNTHESIS RESEARCH 2023; 156:279-307. [PMID: 36826741 PMCID: PMC10203033 DOI: 10.1007/s11120-022-00991-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 12/01/2022] [Indexed: 05/23/2023]
Abstract
Photosynthetic water oxidation by Photosystem II (PSII) is a fascinating process because it sustains life on Earth and serves as a blue print for scalable synthetic catalysts required for renewable energy applications. The biophysical, computational, and structural description of this process, which started more than 50 years ago, has made tremendous progress over the past two decades, with its high-resolution crystal structures being available not only of the dark-stable state of PSII, but of all the semi-stable reaction intermediates and even some transient states. Here, we summarize the current knowledge on PSII with emphasis on the basic principles that govern the conversion of light energy to chemical energy in PSII, as well as on the illustration of the molecular structures that enable these reactions. The important remaining questions regarding the mechanism of biological water oxidation are highlighted, and one possible pathway for this fundamental reaction is described at a molecular level.
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Affiliation(s)
- Dmitry Shevela
- Department of Chemistry, Chemical Biological Centre, Umeå University, 90187, Umeå, Sweden.
| | - Jan F Kern
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Govindjee Govindjee
- Department of Plant Biology, Department of Biochemistry and Center of Biophysics & Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Johannes Messinger
- Department of Chemistry, Chemical Biological Centre, Umeå University, 90187, Umeå, Sweden.
- Molecular Biomimetics, Department of Chemistry - Ångström, Uppsala University, 75120, Uppsala, Sweden.
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7
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Murali Manoj K, Bazhin N, Parashar A, Manekkathodi A, Wu Y. Comprehensive Analyses of the Enhancement of Oxygenesis in Photosynthesis by Bicarbonate and Effects of Diverse Additives: Z-scheme Explanation Versus Murburn Model. Physiology (Bethesda) 2022. [DOI: 10.5772/intechopen.106996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
The Z-scheme electron transport chain (ETC) explanation for photosynthesis starts with the serial/sequential transfer of electrons sourced from water molecules bound at Photosystem II via a deterministic array of redox centers (of various stationary/mobile proteins), before \"sinking\" via the reduction of NADP+ bound at flavin-enzyme reductase. Several research groups’ finding that additives (like bicarbonate) enhance the light reaction had divided the research community because it violated the Z-scheme. The untenable aspects of the Z-scheme perception were demonstrated earlier and a murburn bioenergetics (a stochastic/parallel paradigm of ion-radical equilibriums) model was proposed to explain photophosphorylation and Emerson effect. Herein, we further support the murburn model with accurate thermodynamic calculations, which show that the cost of one-electron abstraction from bicarbonate [491 kJ/mol] is lower than water [527 kJ/mol]. Further, copious thioredoxin enables the capture of photoactivated electrons in milieu, which aid in the reduction of nicotinamide nucleotides. The diffusible reactive species (DRS) generated in milieu sponsor phosphorylations and oxygenic reactions. With structural analysis of Photosystems and interacting molecules, we chart out the equations of reactions that explain the loss of labeled O-atom traces in delocalized oxygenesis. Thus, this essay discredits the Z-scheme and explains key outstanding observations in the field.
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Allophycocyanin A is a carbon dioxide receptor in the cyanobacterial phycobilisome. Nat Commun 2022; 13:5289. [PMID: 36075935 PMCID: PMC9458709 DOI: 10.1038/s41467-022-32925-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 08/24/2022] [Indexed: 11/10/2022] Open
Abstract
Light harvesting is fundamental for production of ATP and reducing equivalents for CO2 fixation during photosynthesis. However, electronic energy transfer (EET) through a photosystem can harm the photosynthetic apparatus when not balanced with CO2. Here, we show that CO2 binding to the light-harvesting complex modulates EET in photosynthetic cyanobacteria. More specifically, CO2 binding to the allophycocyanin alpha subunit of the light-harvesting complex regulates EET and its fluorescence quantum yield in the cyanobacterium Synechocystis sp. PCC 6803. CO2 binding decreases the inter-chromophore distance in the allophycocyanin trimer. The result is enhanced EET in vitro and in live cells. Our work identifies a direct target for CO2 in the cyanobacterial light-harvesting apparatus and provides insights into photosynthesis regulation. The transfer of electronic energy through a photosystem can harm the photosynthetic apparatus when not balanced with CO2 fixation. Here, the authors show that CO2 modulates electronic energy transfer in cyanobacteria by binding to and enhancing the activity of the light-harvesting complex.
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Rudenko NN, Ivanov BN. Unsolved Problems of Carbonic Anhydrases Functioning in Photosynthetic Cells of Higher C3 Plants. BIOCHEMISTRY. BIOKHIMIIA 2021; 86:1243-1255. [PMID: 34903154 DOI: 10.1134/s0006297921100072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The review presents current data on carbonic anhydrases found in various compartments of photosynthetic cells of higher plants. The available data on expression of genes some of carbonic anhydrases and its dependence on environmental factors and plant age are considered. The existing hypotheses on the functions of carbonic anhydrases of plasma membrane, cytoplasm, as well as of stroma and thylakoids of chloroplast, first of all, the hypothesis on participation of these enzymes in supplying carbon dioxide molecules to ribulose-bisphosphate carboxylase (Rubisco) are analyzed. Difficulties of establishing physiological role of the plant cell carbonic anhydrase are discussed in detail.
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Affiliation(s)
- Natalia N Rudenko
- Institute of Basic Biological Problems, Pushchino Scientific Center for Biological Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
| | - Boris N Ivanov
- Institute of Basic Biological Problems, Pushchino Scientific Center for Biological Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
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10
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Abstract
In neutral medium (pH 7.0) [RuIIIRuII(µ-CO3)4(OH)]4− undergoes one electron oxidation to form [RuIIIRuIII(µ-CO3)4(OH)2]4− at an E1/2 of 0.85 V vs. NHE followed by electro-catalytic water oxidation at a potential ≥1.5 V. When the same electrochemical measurements are performed in bicarbonate medium (pH 8.3), the complex first undergoes one electron oxidation at an Epa of 0.86 V to form [RuIIIRuIII(µ-CO3)4(OH)2]4−. This complex further undergoes two step one electron oxidations to form RuIVRuIII and RuIVRuIV species at potentials (Epa) 1.18 and 1.35 V, respectively. The RuIVRuIII and RuIVRuIV species in bicarbonate solutions are [RuIVRuIII(µ-CO3)4(OH)(CO3)]4− and [RuIVRuIV(µ-CO3)4(O)(CO3)]4− based on density functional theory (DFT) calculations. The formation of HCO4− in the course of the oxidation has been demonstrated by DFT. The catalyst acts as homogeneous water oxidation catalyst, and after long term chronoamperometry, the absorption spectra does not change significantly. Each step has been found to follow a proton coupled electron transfer process (PCET) as obtained from the pH dependent studies. The catalytic current is found to follow linear relation with the concentration of the catalyst and bicarbonate. Thus, bicarbonate is involved in the catalytic process that is also evident from the generation of higher oxidation peaks in cyclic voltammetry. The detailed mechanism has been derived by DFT. A catalyst with no organic ligands has the advantage of long-time stability.
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Lin JY, Xue C, Tan SI, Ng IS. Pyridoxal kinase PdxY mediated carbon dioxide assimilation to enhance the biomass in Chlamydomonas reinhardtii CC-400. BIORESOURCE TECHNOLOGY 2021; 322:124530. [PMID: 33340949 DOI: 10.1016/j.biortech.2020.124530] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 12/06/2020] [Accepted: 12/07/2020] [Indexed: 06/12/2023]
Abstract
Microalga served as the promising bioresources due to the high efficiency of carbon dioxide conversion. However, the application of microalga is still restricted by low biomass, easier contamination, and high cost of production. To overcome the challenge, engineered Chlamydomonas reinhardtii CC-400 with pyridoxal kinase gene (pdxY) has demonstrated in this study. The results indicated CC-400 with pdxY reached enhanced algal biomass in three different systems, including flask, Two-layer Photo-Reactor (TPR) and airlift Photo-Bioreactor (PBR). The genetic strain PY9 cultured with 1% CO2 in the PBR showed a significant enhancement of biomass up to 1.442 g/L, a 2-times of that of the wild type. We also found the transcriptional levels of carbonic anhydrase (CA) dropped down in PY9 while higher levels of RuBisCo and pdxY occurred, thus the carbon dioxide assimilation under mixotrophic culture dramatically increased. We proofed that pdxY successfully mediated carbon dioxide utilization in CC-400.
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Affiliation(s)
- Jia-Yi Lin
- Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan
| | - Chengfeng Xue
- Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan
| | - Shih-I Tan
- Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan
| | - I-Son Ng
- Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan.
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12
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Water oxidation by photosystem II is the primary source of electrons for sustained H 2 photoproduction in nutrient-replete green algae. Proc Natl Acad Sci U S A 2020; 117:29629-29636. [PMID: 33168746 PMCID: PMC7703569 DOI: 10.1073/pnas.2009210117] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Photosynthetic H2 production in the green alga Chlamydomonas reinhardtii is catalyzed by O2-sensitive [FeFe]-hydrogenases, which accept electrons from photosynthetically reduced ferredoxin and reduce protons to H2. Since the process occurs downstream of photosystem I, the contribution of photosystem II (PSII) in H2 photoproduction has long been a subject of debate. Indeed, water oxidation by PSII results in O2 accumulation in chloroplasts, which inhibits H2 evolution. Therefore, clear evidence for direct water biophotolysis resulting in simultaneous H2 and O2 releases in algae has never been presented. This paper demonstrates that sustained H2 photoproduction in C. reinhardtii is directly linked to PSII-dependent water oxidation and brings insights into regulation of PSII activity and H2 production by CO2/HCO3– under microoxic conditions. The unicellular green alga Chlamydomonas reinhardtii is capable of photosynthetic H2 production. H2 evolution occurs under anaerobic conditions and is difficult to sustain due to 1) competition between [FeFe]-hydrogenase (H2ase), the key enzyme responsible for H2 metabolism in algae, and the Calvin–Benson–Bassham (CBB) cycle for photosynthetic reductants and 2) inactivation of H2ase by O2 coevolved in photosynthesis. Recently, we achieved sustainable H2 photoproduction by shifting algae from continuous illumination to a train of short (1 s) light pulses, interrupted by longer (9 s) dark periods. This illumination regime prevents activation of the CBB cycle and redirects photosynthetic electrons to H2ase. Employing membrane-inlet mass spectrometry and H218O, we now present clear evidence that efficient H2 photoproduction in pulse-illuminated algae depends primarily on direct water biophotolysis, where water oxidation at the donor side of photosystem II (PSII) provides electrons for the reduction of protons by H2ase downstream of photosystem I. This occurs exclusively in the absence of CO2 fixation, while with the activation of the CBB cycle by longer (8 s) light pulses the H2 photoproduction ceases and instead a slow overall H2 uptake is observed. We also demonstrate that the loss of PSII activity in DCMU-treated algae or in PSII-deficient mutant cells can be partly compensated for by the indirect (PSII-independent) H2 photoproduction pathway, but only for a short (<1 h) period. Thus, PSII activity is indispensable for a sustained process, where it is responsible for more than 92% of the final H2 yield.
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Abstract
CO2, HCO3-, and CO32- are present in all aqueous media at pH > 4 if no major effort is made to remove them. Usually the presence of CO2/HCO3-/CO32- is either forgotten or considered only as a buffer or proton transfer catalyst. Results obtained in the last decades point out that carbonates are key participants in a variety of oxidation processes. This was first attributed to the formation of carbonate anion radicals via the reaction OH• + CO32- → CO3•- + OH-. However, recent studies point out that the involvement of carbonates in oxidation processes is more fundamental. Thus, the presence of HCO3-/CO32- changes the mechanisms of Fenton and Fenton-like reactions to yield CO3•- directly even at very low HCO3-/CO32- concentrations. CO3•- is a considerably weaker oxidizing agent than the hydroxyl radical and therefore a considerably more selective oxidizing agent. This requires reconsideration of the sources of oxidative stress in biological systems and might explain the selective damage induced during oxidative stress. The lower oxidation potential of CO3•- probably also explains why not all pollutants are eliminated in many advanced oxidation technologies and requires rethinking of the optimal choice of the technologies applied. The role of percarbonate in Fenton-like processes and in advanced oxidation processes is discussed and has to be re-evaluated. Carbonate as a ligand stabilizes transition metal complexes in uncommon high oxidation states. These high-valent complexes are intermediates in electrochemical water oxidation processes that are of importance in the development of new water splitting technologies. HCO3- and CO32- are also very good hole scavengers in photochemical processes of semiconductors and may thus become key participants in the development of new processes for solar energy conversion. In this Account, an attempt to correlate these observations with the properties of carbonates is made. Clearly, further studies are essential to fully uncover the potential of HCO3-/CO32- in desired oxidation processes.
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Affiliation(s)
- Shanti Gopal Patra
- Department of Chemical Sciences, The Center for Radical Reactions and the Schlesinger Family Center for Compact Accelerators, Radiation Sources and Applications, Ariel University, Ramat HaGolan Street, Ariel 40700, Israel
| | - Amir Mizrahi
- Department of Chemistry, Nuclear Research Centre Negev, Beer-Sheva 84190, Israel
| | - Dan Meyerstein
- Department of Chemical Sciences, The Center for Radical Reactions and the Schlesinger Family Center for Compact Accelerators, Radiation Sources and Applications, Ariel University, Ramat HaGolan Street, Ariel 40700, Israel
- Department of Chemistry, Ben-Gurion University, Beer-Sheva 8410501, Israel
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Burlacot A, Burlacot F, Li-Beisson Y, Peltier G. Membrane Inlet Mass Spectrometry: A Powerful Tool for Algal Research. FRONTIERS IN PLANT SCIENCE 2020; 11:1302. [PMID: 33013952 PMCID: PMC7500362 DOI: 10.3389/fpls.2020.01302] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 08/11/2020] [Indexed: 05/15/2023]
Abstract
Since the first great oxygenation event, photosynthetic microorganisms have continuously shaped the Earth's atmosphere. Studying biological mechanisms involved in the interaction between microalgae and cyanobacteria with the Earth's atmosphere requires the monitoring of gas exchange. Membrane inlet mass spectrometry (MIMS) has been developed in the early 1960s to study gas exchange mechanisms of photosynthetic cells. It has since played an important role in investigating various cellular processes that involve gaseous compounds (O2, CO2, NO, or H2) and in characterizing enzymatic activities in vitro or in vivo. With the development of affordable mass spectrometers, MIMS is gaining wide popularity and is now used by an increasing number of laboratories. However, it still requires an important theory and practical considerations to be used. Here, we provide a practical guide describing the current technical basis of a MIMS setup and the general principles of data processing. We further review how MIMS can be used to study various aspects of algal research and discuss how MIMS will be useful in addressing future scientific challenges.
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Shevela D, Do HN, Fantuzzi A, Rutherford AW, Messinger J. Bicarbonate-Mediated CO 2 Formation on Both Sides of Photosystem II. Biochemistry 2020; 59:2442-2449. [PMID: 32574489 PMCID: PMC7467574 DOI: 10.1021/acs.biochem.0c00208] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 06/10/2020] [Indexed: 01/25/2023]
Abstract
The effect of bicarbonate (HCO3-) on photosystem II (PSII) activity was discovered in the 1950s, but only recently have its molecular mechanisms begun to be clarified. Two chemical mechanisms have been proposed. One is for the electron-donor side, in which mobile HCO3- enhances and possibly regulates water oxidation by acting as proton acceptor, after which it dissociates into CO2 and H2O. The other is for the electron-acceptor side, in which (i) reduction of the QA quinone leads to the release of HCO3- from its binding site on the non-heme iron and (ii) the Em potential of the QA/QA•- couple increases when HCO3- dissociates. This suggested a protective/regulatory role of HCO3- as it is known that increasing the Em of QA decreases the extent of back-reaction-associated photodamage. Here we demonstrate, using plant thylakoids, that time-resolved membrane-inlet mass spectrometry together with 13C isotope labeling of HCO3- allows donor- and acceptor-side formation of CO2 by PSII to be demonstrated and distinguished, which opens the door for future studies of the importance of both mechanisms under in vivo conditions.
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Affiliation(s)
- Dmitry Shevela
- Department
of Chemistry, Chemical Biological Centre, Umeå University, 90187 Umeå, Sweden
| | - Hoang-Nguyen Do
- Department
of Chemistry, Chemical Biological Centre, Umeå University, 90187 Umeå, Sweden
| | - Andrea Fantuzzi
- Department
of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - A. William Rutherford
- Department
of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Johannes Messinger
- Department
of Chemistry, Chemical Biological Centre, Umeå University, 90187 Umeå, Sweden
- Molecular
Biomimetics, Department of Chemistry-Ångström Laboratory, Uppsala University, 75120 Uppsala, Sweden
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Meng ZH, Wu SH, Sun SW, Xu Z, Zhang XC, Wang XM, Liu Y, Ren HT, Jia SY, Bai H, Han X. Formation and Oxidation Reactivity of MnO2+(HCO3–)n in the MnII(HCO3–)–H2O2 System. Inorg Chem 2020; 59:3171-3180. [DOI: 10.1021/acs.inorgchem.9b03524] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zi-He Meng
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, P.R. China
| | - Song-Hai Wu
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, P.R. China
| | - Shi-Wei Sun
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, P.R. China
| | - Zhi Xu
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, P.R. China
| | - Xiao-Cong Zhang
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, P.R. China
| | - Xiang-Ming Wang
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, P.R. China
| | - Yong Liu
- School of Chemistry and Chemical Engineering, Tianjin University of Technology, Tianjin, P.R. China
| | - Hai-Tao Ren
- School of Textile Science and Engineering, Tiangong University, Tianjin, P.R. China
| | - Shao-Yi Jia
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, P.R. China
| | - He Bai
- China Offshore Environmental Service Ltd., Tianjin, P.R. China
| | - Xu Han
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, P.R. China
- School of Environmental Science and Engineering, Tianjin University, Tianjin, P.R. China
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Banerjee G, Ghosh I, Kim CJ, Debus RJ, Brudvig GW. Bicarbonate rescues damaged proton-transfer pathway in photosystem II. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:611-617. [DOI: 10.1016/j.bbabio.2019.06.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 06/18/2019] [Accepted: 06/21/2019] [Indexed: 01/04/2023]
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Conlan B, Messinger J. Thomas John Wydrzynski (8 July 1947-16 March 2018). PHOTOSYNTHESIS RESEARCH 2019; 140:253-261. [PMID: 30478710 PMCID: PMC6509086 DOI: 10.1007/s11120-018-0606-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 11/12/2018] [Indexed: 06/09/2023]
Abstract
With this Tribute, we remember and honor Thomas John (Tom) Wydrzynski. Tom was a highly innovative, independent and committed researcher, who had, early in his career, defined his life-long research goal. He was committed to understand how Photosystem II produces molecular oxygen from water, using the energy of sunlight, and to apply this knowledge towards making artificial systems. In this tribute, we summarize his research journey, which involved working on 'soft money' in several laboratories around the world for many years, as well as his research achievements. We also reflect upon his approach to life, science and student supervision, as we perceive it. Tom was not only a thoughtful scientist that inspired many to enter this field of research, but also a wonderful supervisor and friend, who is deeply missed (see footnote*).
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Affiliation(s)
- Brendon Conlan
- Research School of Biological Sciences, Australian Capital Territory, Australian National University, Acton, ACT, 0200, Australia
| | - Johannes Messinger
- Department of Chemistry - Ångström, Uppsala University, Lägerhyddsvägen 1, 75120, Uppsala, Sweden.
- Department of Chemistry, Umeå University, Linnaeus väg 6, 90187, Umeå, Sweden.
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Kuttassery F, Sebastian A, Mathew S, Tachibana H, Inoue H. Promotive Effect of Bicarbonate Ion on Two-Electron Water Oxidation to Form H 2 O 2 Catalyzed by Aluminum Porphyrins. CHEMSUSCHEM 2019; 12:1939-1948. [PMID: 30963704 DOI: 10.1002/cssc.201900560] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 04/08/2019] [Indexed: 06/09/2023]
Abstract
Two-electron water oxidation initiated by one-electron oxidation of aluminum porphyrins (AlTMPyP) is an alternative water oxidation to the conventional four-electron pathway and could help to avoid the bottleneck subject of photon-flux density in artificial photosynthesis. Here, a dramatic enhancement of the reactivity by bicarbonate ion in the two-electron water oxidation to form H2 O2 is reported. An addition of sodium carbonate (Na2 CO3 ) controlled both catalytic current and product selectivity of the two-electron water oxidation to enhance the activity of AlTMPyP at pH≈10-11. Controlled potential electrolysis experiments at different concentrations of Na2 CO3 (10-100 mm) showed that peroxide selectivity was improved up to approximately 73 % by the increase of [Na2 CO3 ] added to the system. The promotion of the reaction cycle was induced by an enhanced dynamic capturing of H2 O2 from the hydroperoxy complex of AlTMPyP through an attack of a bicarbonate ion. The detailed electrochemical studies and product selectivity indicated that the bicarbonate ion served as a good cofactor for producing H2 O2 from water. At stronger alkaline conditions (pH 12.5), however, a retardative effect of the addition of Na2 CO3 on the catalytic reactivity was observed.
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Affiliation(s)
- Fazalurahman Kuttassery
- Department of Applied Chemistry for Environment, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachiohji, Tokyo, 192-0397, Japan
| | - Abin Sebastian
- Department of Applied Chemistry for Environment, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachiohji, Tokyo, 192-0397, Japan
| | - Siby Mathew
- Department of Applied Chemistry for Environment, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachiohji, Tokyo, 192-0397, Japan
| | - Hiroshi Tachibana
- Department of Applied Chemistry for Environment, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachiohji, Tokyo, 192-0397, Japan
| | - Haruo Inoue
- Department of Applied Chemistry for Environment, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachiohji, Tokyo, 192-0397, Japan
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Govindjee. A sixty-year tryst with photosynthesis and related processes: an informal personal perspective. PHOTOSYNTHESIS RESEARCH 2019; 139:15-43. [PMID: 30343396 DOI: 10.1007/s11120-018-0590-0] [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: 08/02/2018] [Accepted: 10/01/2018] [Indexed: 06/08/2023]
Abstract
After briefly describing my early collaborative work at the University of Allahabad, that had laid the foundation of my research life, I present here some of our research on photosynthesis at the University of Illinois at Urbana-Champaign, randomly selected from light absorption to NADP+ reduction in plants, algae, and cyanobacteria. These include the fact that (i) both the light reactions I and II are powered by light absorbed by chlorophyll (Chl) a of different spectral forms; (ii) light emission (fluorescence, delayed fluorescence, and thermoluminescence) by plants, algae, and cyanobacteria provides detailed information on these reactions and beyond; (iii) primary photochemistry in both the photosystems I (PS I) and II (PS II) occurs within a few picoseconds; and (iv) most importantly, bicarbonate plays a unique role on the electron acceptor side of PS II, specifically at the two-electron gate of PS II. Currently, the ongoing research around the world is, and should be, directed towards making photosynthesis better able to deal with the global issues (such as increasing population, dwindling resources, and rising temperature) particularly through genetic modification. However, basic research is necessary to continue to provide us with an understanding of the molecular mechanism of the process and to guide us in reaching our goals of increasing food production and other chemicals we need for our lives.
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Nölke G, Barsoum M, Houdelet M, Arcalís E, Kreuzaler F, Fischer R, Schillberg S. The Integration of Algal Carbon Concentration Mechanism Components into Tobacco Chloroplasts Increases Photosynthetic Efficiency and Biomass. Biotechnol J 2019; 14:e1800170. [PMID: 29888874 DOI: 10.1002/biot.201800170] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 06/04/2018] [Indexed: 12/14/2022]
Abstract
Increasing the productivity of crops is a major challenge in agricultural research. Given that photosynthetic carbon assimilation is necessary for plant growth, enhancing the efficiency of photosynthesis is one strategy to boost agricultural productivity. The authors attempted to increase the photosynthetic efficiency and biomass of tobacco plants by expressing individual components of the Chlamydomonas reinhardtii carbon concentration mechanism (CCM) and integrating them into the chloroplast. Independent transgenic varieties are generated accumulating the carbonic anhydrase CAH3 in the thylakoid lumen or the bicarbonate transporter LCIA in the inner chloroplast membrane. Independent homozygous transgenic lines showed enhanced CO2 uptake rates (up to 15%), increased photosystem II efficiency (by up to 18%), and chlorophyll content (up to 19%). Transgenic lines produced more shoot biomass than wild-type and azygous controls, and accumulated more carbohydrate and amino acids, reflecting the higher rate of photosynthetic CO2 fixation. These data demonstrate that individual algal CCM components can be integrated into C3 plants to increase biomass, suggesting that transgenic lines combining multiple CCM components could further increase the productivity and yield of C3 crops.
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Affiliation(s)
- Greta Nölke
- Department of Plant Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstrasse 6, 52074 Aachen, Germany
| | - Mirna Barsoum
- Department of Plant Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstrasse 6, 52074 Aachen, Germany
| | - Marcel Houdelet
- Department of Plant Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstrasse 6, 52074 Aachen, Germany
| | - Elsa Arcalís
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Fritz Kreuzaler
- Department of Plant Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstrasse 6, 52074 Aachen, Germany
| | - Rainer Fischer
- Department of Plant Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstrasse 6, 52074 Aachen, Germany
| | - Stefan Schillberg
- Department of Plant Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstrasse 6, 52074 Aachen, Germany
- Justus-Liebig University Giessen, Institute for Phytopathology and Applied Zoology, Phytopathology Department, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany
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Abstract
AbstractCyanobacteria and plants carry out oxygenic photosynthesis. They use water to generate the atmospheric oxygen we breathe and carbon dioxide to produce the biomass serving as food, feed, fibre and fuel. This paper scans the emergence of structural and mechanistic understanding of oxygen evolution over the past 50 years. It reviews speculative concepts and the stepped insight provided by novel experimental and theoretical techniques. Driven by sunlight photosystem II oxidizes the catalyst of water oxidation, a hetero-metallic Mn4CaO5(H2O)4 cluster. Mn3Ca are arranged in cubanoid and one Mn dangles out. By accumulation of four oxidizing equivalents before initiating dioxygen formation it matches the four-electron chemistry from water to dioxygen to the one-electron chemistry of the photo-sensitizer. Potentially harmful intermediates are thereby occluded in space and time. Kinetic signatures of the catalytic cluster and its partners in the photo-reaction centre have been resolved, in the frequency domain ranging from acoustic waves via infra-red to X-ray radiation, and in the time domain from nano- to milli-seconds. X-ray structures to a resolution of 1.9 Å are available. Even time resolved X-ray structures have been obtained by clocking the reaction cycle by flashes of light and diffraction with femtosecond X-ray pulses. The terminal reaction cascade from two molecules of water to dioxygen involves the transfer of four electrons, two protons, one dioxygen and one water. A rigorous mechanistic analysis is challenging because of the kinetic enslaving at millisecond duration of six partial reactions (4e−, 1H+, 1O2). For the time being a peroxide-intermediate in the reaction cascade to dioxygen has been in focus, both experimentally and by quantum chemistry. Homo sapiens has relied on burning the products of oxygenic photosynthesis, recent and fossil. Mankind's total energy consumption amounts to almost one-fourth of the global photosynthetic productivity. If the average power consumption equalled one of those nations with the highest consumption per capita it was four times greater and matched the total productivity. It is obvious that biomass should be harvested for food, feed, fibre and platform chemicals rather than for fuel.
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Mizrahi A, Meyerstein D. Plausible roles of carbonate in catalytic water oxidation. ADVANCES IN INORGANIC CHEMISTRY 2019. [DOI: 10.1016/bs.adioch.2019.03.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Tsaplev YB. Photochemical Oxidation of MnSO4 in Dimethyl Sulfoxide in the Presence of Water. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2018. [DOI: 10.1134/s0036024418110432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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25
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Shitov AV, Terentyev VV, Zharmukhamedov SK, Rodionova MV, Karacan M, Karacan N, Klimov VV, Allakhverdiev SI. Is carbonic anhydrase activity of photosystem II required for its maximum electron transport rate? BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2018; 1859:292-299. [PMID: 29410217 DOI: 10.1016/j.bbabio.2018.01.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 01/26/2018] [Indexed: 01/05/2023]
Abstract
It is known, that the multi-subunit complex of photosystem II (PSII) and some of its single proteins exhibit carbonic anhydrase activity. Previously, we have shown that PSII depletion of HCO3-/CO2 as well as the suppression of carbonic anhydrase activity of PSII by a known inhibitor of α‑carbonic anhydrases, acetazolamide (AZM), was accompanied by a decrease of electron transport rate on the PSII donor side. It was concluded that carbonic anhydrase activity was required for maximum photosynthetic activity of PSII but it was not excluded that AZM may have two independent mechanisms of action on PSII: specific and nonspecific. To investigate directly the specific influence of carbonic anhydrase inhibition on the photosynthetic activity in PSII we used another known inhibitor of α‑carbonic anhydrase, trifluoromethanesulfonamide (TFMSA), which molecular structure and physicochemical properties are quite different from those of AZM. In this work, we show for the first time that TFMSA inhibits PSII carbonic anhydrase activity and decreases rates of both the photo-induced changes of chlorophyll fluorescence yield and the photosynthetic oxygen evolution. The inhibitory effect of TFMSA on PSII photosynthetic activity was revealed only in the medium depleted of HCO3-/CO2. Addition of exogenous HCO3- or PSII electron donors led to disappearance of the TFMSA inhibitory effect on the electron transport in PSII, indicating that TFMSA inhibition site was located on the PSII donor side. These results show the specificity of TFMSA action on carbonic anhydrase and photosynthetic activities of PSII. In this work, we discuss the necessity of carbonic anhydrase activity for the maximum effectiveness of electron transport on the donor side of PSII.
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Affiliation(s)
- Alexandr V Shitov
- Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya Street 2, Pushchino, Moscow Region 142290, Russia.
| | - Vasily V Terentyev
- Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya Street 2, Pushchino, Moscow Region 142290, Russia
| | - Sergey K Zharmukhamedov
- Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya Street 2, Pushchino, Moscow Region 142290, Russia; Controlled Photobiosynthesis Laboratory, Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow 127276, Russia
| | - Margarita V Rodionova
- Controlled Photobiosynthesis Laboratory, Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow 127276, Russia
| | - Mehmet Karacan
- Gazi University, Science Faculty, Department of Chemistry, 06500 Ankara, Turkey
| | - Nurcan Karacan
- Gazi University, Science Faculty, Department of Chemistry, 06500 Ankara, Turkey
| | - Vyacheslav V Klimov
- Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya Street 2, Pushchino, Moscow Region 142290, Russia
| | - Suleyman I Allakhverdiev
- Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya Street 2, Pushchino, Moscow Region 142290, Russia; Controlled Photobiosynthesis Laboratory, Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow 127276, Russia; Department of Plant Physiology, Faculty of Biology, M.V. Lomonosov Moscow State University, Leninskie Gory 1-12, Moscow 119991, Russia; Moscow Institute of Physics and Technology, Institutsky lane 9, Dolgoprudny, Moscow Region 141700, Russia; Institute of Molecular Biology and Biotechnology, Azerbaijan National Academy of Sciences, Matbuat Avenue 2a, Baku 1073, Azerbaijan.
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Allakhverdiev SI, Zharmukhamedov SK, Rodionova MV, Shuvalov VA, Dismukes C, Shen JR, Barber J, Samuelsson G. Vyacheslav (Slava) Klimov (1945-2017): A scientist par excellence, a great human being, a friend, and a Renaissance man. PHOTOSYNTHESIS RESEARCH 2018; 136:1-16. [PMID: 28921410 DOI: 10.1007/s11120-017-0440-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 08/15/2017] [Indexed: 06/07/2023]
Abstract
Vyacheslav Vasilevich (V.V.) Klimov (or Slava, as most of us called him) was born on January 12, 1945 and passed away on May 9, 2017. He began his scientific career at the Bach Institute of Biochemistry of the USSR Academy of Sciences (Akademy Nauk (AN) SSSR), Moscow, Russia, and then, he was associated with the Institute of Photosynthesis, Pushchino, Moscow Region, for about 50 years. He worked in the field of biochemistry and biophysics of photosynthesis. He is known for his studies on the molecular organization of photosystem II (PSII). He was an eminent scientist in the field of photobiology, a well-respected professor, and, above all, an outstanding researcher. Further, he was one of the founding members of the Institute of Photosynthesis in Pushchino, Russia. To most, Slava Klimov was a great human being. He was one of the pioneers of research on the understanding of the mechanism of light energy conversion and of water oxidation in photosynthesis. Slava had many collaborations all over the world, and he is (and will be) very much missed by the scientific community and friends in Russia as well as around the World. We present here a brief biography and some comments on his research in photosynthesis. We remember him as a friendly and enthusiastic person who had an unflagging curiosity and energy to conduct outstanding research in many aspects of photosynthesis, especially that related to PSII.
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Affiliation(s)
- Suleyman I Allakhverdiev
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region, Russia, 142290.
- Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow, Russia, 127276.
- Bionanotechnology Laboratory, Institute of Molecular Biology and Biotechnology, Azerbaijan National Academy of Sciences, Baku, Azerbaijan.
- Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia, 119991.
| | - Sergey K Zharmukhamedov
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region, Russia, 142290
- Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow, Russia, 127276
| | - Margarita V Rodionova
- Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow, Russia, 127276
| | - Vladimir A Shuvalov
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region, Russia, 142290
- Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia, 119991
| | - Charles Dismukes
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, 08854, USA
| | - Jian-Ren Shen
- Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University, Okayama, 7008530, Japan
| | - James Barber
- Department of Life Sciences, Imperial College, London, SW7 2AZ, UK
| | - Göran Samuelsson
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, 90736, Umeå, Sweden
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Shevela D, Björn LO. Evolution of the Z-scheme of photosynthesis: a perspective. PHOTOSYNTHESIS RESEARCH 2017; 133:5-15. [PMID: 28160125 DOI: 10.1007/s11120-016-0333-z] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 12/29/2016] [Indexed: 05/08/2023]
Abstract
The concept of the Z-scheme of oxygenic photosynthesis is in all the textbooks. However, its evolution is not. We focus here mainly on some of the history of its biophysical aspects. We have arbitrarily divided here the 1941-2016 period into three sub-periods: (a) Origin of the concept of two light reactions: first hinted at, in 1941, by James Franck and Karl Herzfeld; described and explained, in 1945, by Eugene Rabinowitch; and a clear hypothesis, given in 1956 by Rabinowitch, of the then available cytochrome experiments: one light oxidizing it and another reducing it; (b) Experimental discovery of the two light reactions and two pigment systems and the Z-scheme of photosynthesis: Robert Emerson's discovery, in 1957, of enhancement in photosynthesis when two light beams (one in the far-red region, and the other of shorter wavelengths) are given together than when given separately; and the 1960 scheme of Robin Hill & Fay Bendall; and
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Affiliation(s)
- Dmitriy Shevela
- Department of Chemistry, Chemical Biological Centre, Umeå University, 90187, Umeå, Sweden
| | - Lars Olof Björn
- Department of Biology, Molecular Cell Biology, Lund University, Sölvegatan 35, 22362, Lund, Sweden
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28
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Kadassery KJ, Dey SK, Friedman AE, Lacy DC. Exploring the Role of Carbonate in the Formation of an Organomanganese Tetramer. Inorg Chem 2017; 56:8748-8751. [DOI: 10.1021/acs.inorgchem.7b01438] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Karthika J. Kadassery
- Department of Chemistry, University at Buffalo, SUNY, Buffalo, New York 14260-3000, United States
| | - Suman Kr Dey
- Department of Chemistry, University at Buffalo, SUNY, Buffalo, New York 14260-3000, United States
| | - Alan E. Friedman
- Department of Chemistry, University at Buffalo, SUNY, Buffalo, New York 14260-3000, United States
| | - David C. Lacy
- Department of Chemistry, University at Buffalo, SUNY, Buffalo, New York 14260-3000, United States
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Aiso K, Takeuchi R, Masaki T, Chandra D, Saito K, Yui T, Yagi M. Carbonate Ions Induce Highly Efficient Electrocatalytic Water Oxidation by Cobalt Oxyhydroxide Nanoparticles. CHEMSUSCHEM 2017; 10:687-692. [PMID: 27987267 DOI: 10.1002/cssc.201601494] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Indexed: 06/06/2023]
Abstract
Synthetic models of oxygen evolving complex (OEC) are used not only to gain better understanding of the mechanism and the roles of cofactors for water oxidation in photosynthesis, but also as water oxidation catalysts to realize artificial photosynthesis, which is anticipated as a promising solar fuel production system. However, although much attention has been paid to the composition and structure of active sites for development of heterogeneous OEC models, the cofactors, which are essential for water oxidation by the photosynthetic OEC, remain little studied. The high activity of CoO(OH) nanoparticles for electrocatalytic water oxidation is shown to be induced by a CO32- cofactor. The possibility of CO32- ions acting as proton acceptors for O-O bond formation based on the proton-concerted oxygen atom transfer mechanism is proposed. The O-O bond formation is supposed to be accelerated due to effective proton acceptance by adjacent CO32- ions coordinated on the CoIV center in the intermediate, which is consistent with Michaelis-Menten-type kinetics and the significant H/D isotope effect observed in electrocatalysis.
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Affiliation(s)
- Kaoru Aiso
- Department of Materials Science and Technology, Faculty of Engineering, Niigata University, 8050 Ikarashi-2, Niigata, 950-2181, Japan
| | - Ryouchi Takeuchi
- Department of Materials Science and Technology, Faculty of Engineering, Niigata University, 8050 Ikarashi-2, Niigata, 950-2181, Japan
| | - Takeshi Masaki
- Department of Materials Science and Technology, Faculty of Engineering, Niigata University, 8050 Ikarashi-2, Niigata, 950-2181, Japan
| | - Debraj Chandra
- Department of Materials Science and Technology, Faculty of Engineering, Niigata University, 8050 Ikarashi-2, Niigata, 950-2181, Japan
| | - Kenji Saito
- Department of Materials Science and Technology, Faculty of Engineering, Niigata University, 8050 Ikarashi-2, Niigata, 950-2181, Japan
| | - Tatsuto Yui
- Department of Materials Science and Technology, Faculty of Engineering, Niigata University, 8050 Ikarashi-2, Niigata, 950-2181, Japan
| | - Masayuki Yagi
- Department of Materials Science and Technology, Faculty of Engineering, Niigata University, 8050 Ikarashi-2, Niigata, 950-2181, Japan
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Zhurikova EM, Ignatova LK, Rudenko NN, Mudrik VA, Vetoshkina DV, Ivanov BN. Participation of two carbonic anhydrases of the alpha family in photosynthetic reactions in Arabidopsis thaliana. BIOCHEMISTRY (MOSCOW) 2016; 81:1182-1187. [DOI: 10.1134/s0006297916100151] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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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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Semenikhin A, Vodka M, Polishchuk O. Cofactor and structural role of СО2 in chloroplasts. UKRAINIAN BOTANICAL JOURNAL 2016. [DOI: 10.15407/ukrbotj73.03.290] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Bao H, Burnap RL. Photoactivation: The Light-Driven Assembly of the Water Oxidation Complex of Photosystem II. FRONTIERS IN PLANT SCIENCE 2016; 7:578. [PMID: 27200051 PMCID: PMC4853684 DOI: 10.3389/fpls.2016.00578] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 04/14/2016] [Indexed: 05/10/2023]
Abstract
Photosynthetic water oxidation is catalyzed by the Mn4CaO5 cluster of photosystem II. The assembly of the Mn4O5Ca requires light and involves a sequential process called photoactivation. This process harnesses the charge-separation of the photochemical reaction center and the coordination environment provided by the amino acid side chains of the protein to oxidize and organize the incoming manganese ions to form the oxo-bridged metal cluster capable of H2O-oxidation. Although most aspects of this assembly process remain poorly understood, recent advances in the elucidation of the crystal structure of the fully assembled cyanobacterial PSII complex help in the interpretation of the rich history of experiments designed to understand this process. Moreover, recent insights on the structure and stability of the constituent ions of the Mn4CaO5 cluster may guide future experiments. Here we consider the literature and suggest possible models of assembly including one involving single Mn(2+) oxidation site for all Mn but requiring ion relocation.
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Affiliation(s)
| | - Robert L. Burnap
- Department of Microbiology and Molecular Genetics, Oklahoma State UniversityStillwater, OK, USA
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Darus L, Ledezma P, Keller J, Freguia S. Marine phototrophic consortia transfer electrons to electrodes in response to reductive stress. PHOTOSYNTHESIS RESEARCH 2016; 127:347-354. [PMID: 26407568 DOI: 10.1007/s11120-015-0193-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 09/17/2015] [Indexed: 06/05/2023]
Abstract
This work studies how extracellular electron transfer (EET) from cyanobacteria-dominated marine microbial biofilms to solid electrodes is affected by the availability of inorganic carbon (Ci). The EET was recorded chronoamperometrically in the form of electrical current by a potentiostat in two identical photo-electrochemical cells using carbon electrodes poised at a potential of +0.6 V versus standard hydrogen electrode under 12/12 h illumination/dark cycles. The Ci was supplied by the addition of NaHCO3 to the medium and/or by sparging CO2 gas. At high Ci conditions, EET from the microbial biofilm to the electrodes was observed only during the dark phase, indicating the occurrence of a form of night-time respiration that can use insoluble electrodes as the terminal electron acceptor. At low or no Ci conditions, however, EET also occurred during illumination suggesting that, in the absence of their natural electron acceptor, some cyanobacteria are able to utilise solid electrodes as an electron sink. This may be a natural survival mechanism for cyanobacteria to maintain redox balance in environments with limiting CO2 and/or high light intensity.
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Affiliation(s)
- Libertus Darus
- Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Pablo Ledezma
- Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Jürg Keller
- Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Stefano Freguia
- Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD, 4072, Australia.
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Joya KS, de Groot HJM. Controlled Surface-Assembly of Nanoscale Leaf-Type Cu-Oxide Electrocatalyst for High Activity Water Oxidation. ACS Catal 2016. [DOI: 10.1021/acscatal.5b02950] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Khurram S. Joya
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, P.O. Box 9502, 2300 RA Leiden, The Netherlands
- Department of Chemistry, University of Engineering and Technology (UET), GT Road, 54890 Lahore, Punjab, Pakistan
| | - Huub J. M. de Groot
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, P.O. Box 9502, 2300 RA Leiden, The Netherlands
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Benlloch R, Shevela D, Hainzl T, Grundström C, Shutova T, Messinger J, Samuelsson G, Sauer-Eriksson AE. Crystal structure and functional characterization of photosystem II-associated carbonic anhydrase CAH3 in Chlamydomonas reinhardtii. PLANT PHYSIOLOGY 2015; 167:950-62. [PMID: 25617045 PMCID: PMC4348767 DOI: 10.1104/pp.114.253591] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 01/16/2015] [Indexed: 05/22/2023]
Abstract
In oxygenic photosynthesis, light energy is stored in the form of chemical energy by converting CO2 and water into carbohydrates. The light-driven oxidation of water that provides the electrons and protons for the subsequent CO2 fixation takes place in photosystem II (PSII). Recent studies show that in higher plants, HCO3 (-) increases PSII activity by acting as a mobile acceptor of the protons produced by PSII. In the green alga Chlamydomonas reinhardtii, a luminal carbonic anhydrase, CrCAH3, was suggested to improve proton removal from PSII, possibly by rapid reformation of HCO3 (-) from CO2. In this study, we investigated the interplay between PSII and CrCAH3 by membrane inlet mass spectrometry and x-ray crystallography. Membrane inlet mass spectrometry measurements showed that CrCAH3 was most active at the slightly acidic pH values prevalent in the thylakoid lumen under illumination. Two crystal structures of CrCAH3 in complex with either acetazolamide or phosphate ions were determined at 2.6- and 2.7-Å resolution, respectively. CrCAH3 is a dimer at pH 4.1 that is stabilized by swapping of the N-terminal arms, a feature not previously observed in α-type carbonic anhydrases. The structure contains a disulfide bond, and redox titration of CrCAH3 function with dithiothreitol suggested a possible redox regulation of the enzyme. The stimulating effect of CrCAH3 and CO2/HCO3 (-) on PSII activity was demonstrated by comparing the flash-induced oxygen evolution pattern of wild-type and CrCAH3-less PSII preparations. We showed that CrCAH3 has unique structural features that allow this enzyme to maximize PSII activity at low pH and CO2 concentration.
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Affiliation(s)
- Reyes Benlloch
- Department of Forest Genetics and Plant Physiology (R.B) and Department of Plant Physiology (T.S., G.S.), Umeå Plant Science Centre, and Department of Chemistry, Chemistry Biology Centre (D.S., T.H., C.G., J.M., A.E.S.-E.), Umeå University, SE-90187 Umea, Sweden
| | - Dmitriy Shevela
- Department of Forest Genetics and Plant Physiology (R.B) and Department of Plant Physiology (T.S., G.S.), Umeå Plant Science Centre, and Department of Chemistry, Chemistry Biology Centre (D.S., T.H., C.G., J.M., A.E.S.-E.), Umeå University, SE-90187 Umea, Sweden
| | - Tobias Hainzl
- Department of Forest Genetics and Plant Physiology (R.B) and Department of Plant Physiology (T.S., G.S.), Umeå Plant Science Centre, and Department of Chemistry, Chemistry Biology Centre (D.S., T.H., C.G., J.M., A.E.S.-E.), Umeå University, SE-90187 Umea, Sweden
| | - Christin Grundström
- Department of Forest Genetics and Plant Physiology (R.B) and Department of Plant Physiology (T.S., G.S.), Umeå Plant Science Centre, and Department of Chemistry, Chemistry Biology Centre (D.S., T.H., C.G., J.M., A.E.S.-E.), Umeå University, SE-90187 Umea, Sweden
| | - Tatyana Shutova
- Department of Forest Genetics and Plant Physiology (R.B) and Department of Plant Physiology (T.S., G.S.), Umeå Plant Science Centre, and Department of Chemistry, Chemistry Biology Centre (D.S., T.H., C.G., J.M., A.E.S.-E.), Umeå University, SE-90187 Umea, Sweden
| | - Johannes Messinger
- Department of Forest Genetics and Plant Physiology (R.B) and Department of Plant Physiology (T.S., G.S.), Umeå Plant Science Centre, and Department of Chemistry, Chemistry Biology Centre (D.S., T.H., C.G., J.M., A.E.S.-E.), Umeå University, SE-90187 Umea, Sweden
| | - Göran Samuelsson
- Department of Forest Genetics and Plant Physiology (R.B) and Department of Plant Physiology (T.S., G.S.), Umeå Plant Science Centre, and Department of Chemistry, Chemistry Biology Centre (D.S., T.H., C.G., J.M., A.E.S.-E.), Umeå University, SE-90187 Umea, Sweden
| | - A Elisabeth Sauer-Eriksson
- Department of Forest Genetics and Plant Physiology (R.B) and Department of Plant Physiology (T.S., G.S.), Umeå Plant Science Centre, and Department of Chemistry, Chemistry Biology Centre (D.S., T.H., C.G., J.M., A.E.S.-E.), Umeå University, SE-90187 Umea, Sweden
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Mohapatra PK, Singh NR. Teaching the Z-Scheme of electron transport in photosynthesis: a perspective. PHOTOSYNTHESIS RESEARCH 2015; 123:105-114. [PMID: 25209177 DOI: 10.1007/s11120-014-0034-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2014] [Accepted: 08/01/2014] [Indexed: 06/03/2023]
Abstract
This paper deals with how Govindjee taught the Z-Scheme of electron transport in oxygenic photosynthesis at Ravenshaw University, Cuttack, Odisha, India, in 2014, in a unique and highly effective fashion-using students to act as molecules, representing the entire electron transport chain from water to nicotinamide adenine dinucleotide phosphate (NADP(+)). It culminated in a show by B.Sc. students in the garden of the Department of Botany, Ravenshaw University. The first author (PKM) personally acted as Ferredoxin NADP Reductase (FNR) catalyzing the reduction of NADP(+) to NADPH, taking electrons from reduced ferredoxin at the end of Photosystem I. On the other hand, the Q-cycle was played by M.Sc. students, who acted as molecules running this ingenious cycle that produces extra protons. An interesting event was when a student, acting as a herbicide, who was dressed like a devil (fierce looking, in black clothes with a sword; "Yamaraj: The God of Death", as he called himself), stopped all reactions by throwing out QB, the second plastoquinone molecule of Photosystem II, and that too aggressively, taking its position instead. The second author was the major organizer of the Z-scheme show. We provide here a basic background on the process, a bit on Govindjee's teaching, and some selected pictures from the drama played in March, 2014 at Ravenshaw University. Here, we also recognize the teacher Govindjee for his ingenious and fun-filled teaching methods that touched the hearts and the souls of the students as well as the teachers of Ravenshaw University. He was rated as one of the most-admired teachers of plant biology at our university.
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Igamberdiev AU. Control of Rubisco function via homeostatic equilibration of CO2 supply. FRONTIERS IN PLANT SCIENCE 2015; 6:106. [PMID: 25767475 PMCID: PMC4341507 DOI: 10.3389/fpls.2015.00106] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 02/09/2015] [Indexed: 05/09/2023]
Abstract
Rubisco is the most abundant protein on Earth that serves as the primary engine of carbon assimilation. It is characterized by a slow rate and low specificity for CO2 leading to photorespiration. We analyze here the challenges of operation of this enzyme as the main carbon fixation engine. The high concentration of Rubisco exceeds that of its substrate CO2 by 2-3 orders of magnitude; however, the total pool of available carbon in chloroplast, i.e., mainly bicarbonate, is comparable to the concentration of Rubisco active sites. This makes the reactant stationary assumption (RSA), which is essential as a condition of satisfying the Michaelis-Menten (MM) kinetics, valid if we assume that the delivery of CO2 from this pool is not limiting. The RSA is supported by active carbonic anhydrases (CA) that quickly equilibrate bicarbonate and CO2 pools and supply CO2 to Rubisco. While the operation of stromal CA is independent of light reactions, the thylakoidal CA associated with PSII and pumping CO2 from the thylakoid lumen is coordinated with the rate of electron transport, water splitting and proton gradient across the thylakoid membrane. At high CO2 concentrations, CA becomes less efficient (the equilibrium becomes unfavorable), so a deviation from the MM kinetics is observed, consistent with Rubisco reaching its Vmax at approximately 50% lower level than expected from the classical MM curve. Previously, this deviation was controversially explained by the limitation of RuBP regeneration. At low ambient CO2 and correspondingly limited capacity of the bicarbonate pool, its depletion at Rubisco sites is relieved in that the enzyme utilizes O2 instead of CO2, i.e., by photorespiration. In this process, CO2 is supplied back to Rubisco, and the chloroplastic redox state and energy level are maintained. It is concluded that the optimal performance of photosynthesis is achieved via the provision of continuous CO2 supply to Rubisco by carbonic anhydrases and photorespiration.
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Affiliation(s)
- Abir U. Igamberdiev
- *Correspondence: Abir U. Igamberdiev, Department of Biology, Memorial University of Newfoundland, 232 Elizabeth Avenue, St. John’s, NL A1B 3X9, Canada
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Messinger J, Debus R, Dismukes GC. Warwick Hillier: a tribute. PHOTOSYNTHESIS RESEARCH 2014; 122:1-11. [PMID: 25038923 DOI: 10.1007/s11120-014-0025-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 06/30/2014] [Indexed: 06/03/2023]
Abstract
Warwick Hillier (October 18, 1967-January 10, 2014) made seminal contributions to our understanding of photosynthetic water oxidation employing membrane inlet mass spectrometry and FTIR spectroscopy. This article offers a collection of historical perspectives on the scientific impact of Warwick Hillier's work and tributes to the personal impact his life and ideas had on his collaborators and colleagues.
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Affiliation(s)
- Johannes Messinger
- Department of Chemistry, Chemical Biological Centre (KBC), Umeå University, Linnaeus väg 6, 90187, Umeå, Sweden
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Hill JF. The controversy over the minimum quantum requirement for oxygen evolution. PHOTOSYNTHESIS RESEARCH 2014; 122:97-112. [PMID: 24925628 DOI: 10.1007/s11120-014-0014-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 05/07/2014] [Indexed: 06/03/2023]
Abstract
During the early- to mid-twentieth century, a bitter controversy raged among researchers on photosynthesis regarding the minimum number of light quanta required for the evolution of one molecule of oxygen. From 1923 until his death in 1970, Otto Warburg insisted that this value was about three or four quanta. Beginning in the late 1930s, Robert Emerson and others on the opposing side consistently obtained a value of 8-12 quanta. Warburg changed the protocols of his experiments, sometimes in unexplained ways, yet he almost always arrived at a value of four or less, except eight in carbonate/bicarbonate buffer, which he dismissed as "unphysiological". This paper is largely an abbreviated form of the detailed story on the minimum quantum requirement of photosynthesis, as told by Nickelsen and Govindjee (The maximum quantum yield controversy: Otto Warburg and the "Midwest-Gang", 2011); we provide here a scientific thread, leaving out the voluminous private correspondence among the principal players that Nickelsen and Govindjee (2011) examined in conjunction with their analysis of the principals' published papers. We explore the development and course of the controversy and the ultimate resolution in favor of Emerson's result as the phenomenon of the two-light-reaction, two-pigment-system scheme of photosynthesis came to be understood. In addition, we include a brief discussion of the discovery by Otto Warburg of the requirement for bicarbonate in the Hill reaction.
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Affiliation(s)
- Jane F Hill
- , 8211 Hawthorne Road, Bethesda, MD, 20817-3102, USA,
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