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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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2
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Bhattarai R, Liu H, Siddique KHM, Yan G. Transcriptomic profiling of near-isogenic lines reveals candidate genes for a significant locus conferring metribuzin resistance in wheat. BMC PLANT BIOLOGY 2023; 23:237. [PMID: 37142987 PMCID: PMC10161546 DOI: 10.1186/s12870-023-04166-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 03/13/2023] [Indexed: 05/06/2023]
Abstract
BACKGROUND Weeds reduce wheat yields in dryland farming systems. Herbicides such as metribuzin are commonly used to control weeds. However, wheat has a narrow safety margin against metribuzin. Standing crops such as wheat with weeds in the same field can also be killed by the same dose of metribuzin. Therefore, it is important to identify metribuzin resistance genes and understand the resistance mechanism in wheat for sustainable crop production. A previous study identified a significant metribuzin resistance wheat QTL, Qsns.uwa.4 A.2, explaining 69% of the phenotypic variance for metribuzin resistance. RESULTS Two NIL pairs with the most contrasting performance in the metribuzin treatment and different in genetic backgrounds were compared using RNA sequence analysis, identifying nine candidate genes underlying Qsns.uwa.4 A.2 responsible for metribuzin resistance. Quantitative RT-qPCR further validated the candidate genes, with TraesCS4A03G1099000 (nitrate excretion transporter), TraesCS4A03G1181300 (aspartyl protease), and TraesCS4A03G0741300 (glycine-rich proteins) identified as key factors for metribuzin resistance. CONCLUSION Identified markers and key candidate genes can be used for selecting metribuzin resistance in wheat.
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Affiliation(s)
- Rudra Bhattarai
- UWA School of Agriculture and Environment, The University of Western Australia, 6009, Perth, WA, Australia
- The UWA Institute of Agriculture, The University of Western Australia, 6009, Perth, WA, Australia
| | - Hui Liu
- UWA School of Agriculture and Environment, The University of Western Australia, 6009, Perth, WA, Australia.
- The UWA Institute of Agriculture, The University of Western Australia, 6009, Perth, WA, Australia.
| | - Kadambot H M Siddique
- UWA School of Agriculture and Environment, The University of Western Australia, 6009, Perth, WA, Australia
- The UWA Institute of Agriculture, The University of Western Australia, 6009, Perth, WA, Australia
| | - Guijun Yan
- UWA School of Agriculture and Environment, The University of Western Australia, 6009, Perth, WA, Australia
- The UWA Institute of Agriculture, The University of Western Australia, 6009, Perth, WA, Australia
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3
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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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4
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Imaizumi K, Ifuku K. Binding and functions of the two chloride ions in the oxygen-evolving center of photosystem II. PHOTOSYNTHESIS RESEARCH 2022; 153:135-156. [PMID: 35698013 DOI: 10.1007/s11120-022-00921-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 05/02/2022] [Indexed: 06/15/2023]
Abstract
Light-driven water oxidation in photosynthesis occurs at the oxygen-evolving center (OEC) of photosystem II (PSII). Chloride ions (Cl-) are essential for oxygen evolution by PSII, and two Cl- ions have been found to specifically bind near the Mn4CaO5 cluster in the OEC. The retention of these Cl- ions within the OEC is critically supported by some of the membrane-extrinsic subunits of PSII. The functions of these two Cl- ions and the mechanisms of their retention both remain to be fully elucidated. However, intensive studies performed recently have advanced our understanding of the functions of these Cl- ions, and PSII structures from various species have been reported, aiding the interpretation of previous findings regarding Cl- retention by extrinsic subunits. In this review, we summarize the findings to date on the roles of the two Cl- ions bound within the OEC. Additionally, together with a short summary of the functions of PSII membrane-extrinsic subunits, we discuss the mechanisms of Cl- retention by these extrinsic subunits.
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Affiliation(s)
- Ko Imaizumi
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, 606-8502, Japan
| | - Kentaro Ifuku
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan.
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5
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Yocum CF. Photosystem 2 and the oxygen evolving complex: a brief overview. PHOTOSYNTHESIS RESEARCH 2022; 152:97-105. [PMID: 35294671 DOI: 10.1007/s11120-022-00910-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 02/28/2022] [Indexed: 06/14/2023]
Abstract
These special issues of photosynthesis research present papers documenting progress in revealing the many aspects of photosystem 2, a unique, one-of-a-kind complex system that can reduce a plastoquinone to a plastoquinol on every second flash of light and oxidize 2 H2O to an O2 on every fourth flash. This overview is a brief personal assessment of the progress observed by the author over a four-decade research career, including a discussion of some remaining unsolved issues. It will come as no surprise to readers that there are remaining questions given the complexity of PS2, and the efforts that have been needed so far to uncover its secrets. In fact, most readers will have their own lists of outstanding questions.
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Affiliation(s)
- Charles F Yocum
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA.
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6
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Oxidation of iodide with a mononuclear manganese(IV) complex ion: Mechanistic investigation of autocatalytic behaviour. Polyhedron 2020. [DOI: 10.1016/j.poly.2020.114664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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7
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Anjum S, Bazai ZA, Rizwan S, Benincasa C, Mehmood K, Siddique N, Shaheen G, Mehmood Z, Azam M, Sajjad A. Elemental Characterization of Medicinal Plants and Soils from Hazarganji Chiltan National Park and Nearby Unprotected Areas of Balochistan, Pakistan. J Oleo Sci 2019; 68:443-461. [PMID: 31061264 DOI: 10.5650/jos.ess19004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The aim of this work was to evaluate the variability in elemental composition of seven medicinal plants and their respective soils belonging to protected and nearby unprotected sites of the Hazarganji Chiltan National Park. The medical plants under study were Achillea wilhelmsii C. Koch, Peganum harmala Linn, Sophora mollis (Royle) Baker, Perovskia atriplicifolia Benth, Seriphidium quettense (Podlech.) Ling, Hertia intermedia (Bioss) O. Ktze, and Nepeta praetervisa Rech. F. Macro (C, H, N, S, K, Ca), micro (Cl, Cu, Fe, Mn, and Zn), beneficial (Al, Co, Na), others (As, Br, Cr, Cs, Hf, Pb, Rb, Sb, Sr, Sn, V and Th) and rare earth elements (Ce, Eu, La, Lu, Nd Sc, Sm, Tb and Yb) were characterized by means of standard organic elemental and instrumental neutron activation methodologies and by flame atomic absorption spectroscopy. Results showed that, among macro nutrients, carbon concentration was the highest element in both plant and soil samples followed by H and K. Elements such as Cl, Na and Fe were detected in considerably good amounts; all the other elements were found in trace quantities. Principal component analysis (PCA) was applied to identify spatial variation in elemental composition of medicinal plants, in which 80-90% of the total variance in whole set of data was found. In particular, the findings highlighted the presence of essential and beneficial elements such as C, H, N, K, Ca, Fe, Mn and Na, in samples from protected sites, while potentially dangerous elements such as Al, As, Br and Cr were detected in samples from unprotected sites. These results emphasized on the need for rational exploitation of valuable medicinal plants and supporting protected areas as an excellent source of biodiversity conservation.
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Affiliation(s)
| | | | - Sabeena Rizwan
- Department of Chemistry, Sardar Bahadur Khan, Women's University
| | | | | | | | | | - Zahid Mehmood
- Institute of Biochemistry, University of Balochistan
| | - Muhammad Azam
- Institute of Biochemistry, University of Balochistan
| | - Ashif Sajjad
- Institute of Biochemistry, University of Balochistan
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8
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Baranov S, Haddy A. An enzyme kinetics study of the pH dependence of chloride activation of oxygen evolution in photosystem II. PHOTOSYNTHESIS RESEARCH 2017; 131:317-332. [PMID: 27896527 DOI: 10.1007/s11120-016-0325-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 11/16/2016] [Indexed: 06/06/2023]
Abstract
Oxygen evolution by photosystem II (PSII) involves activation by Cl- ion, which is regulated by extrinsic subunits PsbQ and PsbP. In this study, the kinetics of chloride activation of oxygen evolution was studied in preparations of PSII depleted of the PsbQ and PsbP subunits (NaCl-washed and Na2SO4/pH 7.5-treated) over a pH range from 5.3 to 8.0. At low pH, activation by chloride was followed by inhibition at chloride concentrations >100 mM, whereas at high pH activation continued as the chloride concentration increased above 100 mM. Both activation and inhibition were more pronounced at lower pH, indicating that Cl- binding depended on protonation events in each case. The simplest kinetic model that could account for the complete data set included binding of Cl- at two sites, one for activation and one for inhibition, and four protonation steps. The intrinsic (pH-independent) dissociation constant for Cl- activation, K S, was found to be 0.9 ± 0.2 mM for both preparations, and three of the four pK as were determined, with the fourth falling below the pH range studied. The intrinsic inhibition constant, K I, was found to be 64 ± 2 and 103 ± 7 mM for the NaCl-washed and Na2SO4/pH7.5-treated preparations, respectively, and is considered in terms of the conditions likely to be present in the thylakoid lumen. This enzyme kinetics analysis provides a more complete characterization of chloride and pH dependence of O2 evolution activity than has been previously presented.
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Affiliation(s)
- Sergei Baranov
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC, 27402, USA
| | - Alice Haddy
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC, 27402, USA.
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9
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Amin M, Pokhrel R, Brudvig GW, Badawi A, Obayya SSA. Effect of Chloride Depletion on the Magnetic Properties and the Redox Leveling of the Oxygen-Evolving Complex in Photosystem II. J Phys Chem B 2016; 120:4243-8. [DOI: 10.1021/acs.jpcb.6b03545] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Muhamed Amin
- Center
for Photonics
and Smart Materials, Zewail City of Science and Technology, Sheikh Zayed District, 6th of October City, 12588 Giza, Egypt
| | - Ravi Pokhrel
- The Dow
Chemical
Company, Marlborough, Massachusetts 01752, United States
| | - Gary W. Brudvig
- Department
of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Ashraf Badawi
- Center
for Photonics
and Smart Materials, Zewail City of Science and Technology, Sheikh Zayed District, 6th of October City, 12588 Giza, Egypt
| | - S. S. A. Obayya
- Center
for Photonics
and Smart Materials, Zewail City of Science and Technology, Sheikh Zayed District, 6th of October City, 12588 Giza, Egypt
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10
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Abdolahzadeh S, de Boer JW, Browne WR. Redox-State Dependent Ligand Exchange in Manganese-Based Oxidation Catalysis. Eur J Inorg Chem 2015. [DOI: 10.1002/ejic.201500134] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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11
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Kato Y, Shibamoto T, Yamamoto S, Watanabe T, Ishida N, Sugiura M, Rappaport F, Boussac A. Influence of the PsbA1/PsbA3, Ca2+/Sr2+ and Cl−/Br− exchanges on the redox potential of the primary quinone QA in Photosystem II from Thermosynechococcus elongatus as revealed by spectroelectrochemistry. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:1998-2004. [PMID: 22721916 DOI: 10.1016/j.bbabio.2012.06.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 06/09/2012] [Accepted: 06/11/2012] [Indexed: 11/30/2022]
Affiliation(s)
- Yuki Kato
- Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan.
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12
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Commet A, Boswell N, Yocum CF, Popelka H. pH optimum of the photosystem II H₂O oxidation reaction: effects of PsbO, the manganese-stabilizing protein, Cl- retention, and deprotonation of a component required for O₂ evolution activity. Biochemistry 2012; 51:3808-18. [PMID: 22512418 DOI: 10.1021/bi201678m] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hydroxide ion inhibits Photosystem II (PSII) activity by extracting Cl(-) from its binding site in the O(2)-evolving complex (OEC) under continuous illumination [Critchley, C., et al. (1982) Biochim. Biophys. Acta 682, 436]. The experiments reported here examine whether two subunits of PsbO, the manganese-stabilizing protein, bound to eukaryotic PSII play a role in protecting the OEC against OH(-) inhibition. The data show that the PSII binding properties of PsbO affect the pH optimum for O(2) evolution activity as well as the Cl(-) affinity of the OEC that decreases with an increasing pH. These results suggest that PsbO functions as a barrier against inhibition of the OEC by OH(-). Through facilitation of efficient retention of Cl(-) in PSII [Popelkova, H., et al. (2008) Biochemistry 47, 12593], PsbO influences the ability of Cl(-) to resist OH(-)-induced release from its site in the OEC. Preventing inhibition by OH(-) allows for normal (short) lifetimes of the S(2) and S(3) states in darkness [Roose, J. L., et al. (2011) Biochemistry 50, 5988] and for maximal steady-state activity by PSII. The data presented here indicate that activation of H(2)O oxidation occurs with a pK(a) of ∼6.5, which could be a function of deprotonation of one or more amino acid residues that reside near the OEC active site on the D1 and CP43 intrinsic subunits of the PSII reaction center.
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Affiliation(s)
- Alan Commet
- Department of Molecular, Cellular and Developmental Biology, The University of Michigan, Ann Arbor, Michigan 48109, USA
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13
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Baianu IC, Critchley C, Gutowsky HS. NMR study of chloride ion interactions with thylakoid membranes. Proc Natl Acad Sci U S A 2010; 81:3713-7. [PMID: 16593474 PMCID: PMC345289 DOI: 10.1073/pnas.81.12.3713] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The role of Cl(-) in photosynthetic O(2) evolution has been investigated by observing the (35)Cl NMR linewidth under a variety of conditions in aqueous suspensions of chloroplasts, primarily for the halophytes Avicennia germinans, Avicennia marina, and Aster tripolium but also for spinach. The line broadening shows there is weak, ionic binding of Cl(-) to thylakoids, the bound Cl(-) exchanging rapidly (>>10(4) sec(-1)) with free Cl(-) in solution. The binding is necessary for O(2) evolution to occur. Michaelis-Menten constants obtained from the Cl(-) dependence of the O(2) evolution rate are approximately 15-70 mM for the halophytes compared with 0.6 mM for spinach (0.5 mM with Br(-)). There appear to be two types of Cl(-) binding sites in halophytes, of which the stronger is the activator, at lower [Cl(-)], of O(2) evolution. The (35)Cl line broadening includes a nonspecific interaction, which becomes apparent at high Cl(-) concentrations (>/=0.5 M).
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Affiliation(s)
- I C Baianu
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
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14
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Location of chloride and its possible functions in oxygen-evolving photosystem II revealed by X-ray crystallography. Proc Natl Acad Sci U S A 2009; 106:8567-72. [PMID: 19433803 PMCID: PMC2688974 DOI: 10.1073/pnas.0812797106] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The chloride ion, Cl(-), is an essential cofactor for oxygen evolution of photosystem II (PSII) and is closely associated with the Mn(4)Ca cluster. Its detailed location and function have not been identified, however. We substituted Cl(-) with a bromide ion (Br(-)) or an iodide ion (I(-)) in PSII and analyzed the crystal structures of PSII with Br(-) and I(-) substitutions. Substitution of Cl(-) with Br(-) did not inhibit oxygen evolution, whereas substitution of Cl(-) with I(-) completely inhibited oxygen evolution, indicating the efficient replacement of Cl(-) by I(-). PSII with Br(-) and I(-) substitutions were crystallized, and their structures were analyzed. The results showed that there are 2 anion-binding sites in each PSII monomer; they are located on 2 sides of the Mn(4)Ca cluster at equal distances from the metal cluster. Anion-binding site 1 is close to the main chain of D1-Glu-333, and site 2 is close to the main chain of CP43-Glu-354; these 2 residues are coordinated directly with the Mn(4)Ca cluster. In addition, site 1 is located in the entrance of a proton exit channel. These results indicate that these 2 Cl(-) anions are required to maintain the coordination structure of the Mn(4)Ca cluster as well as the proposed proton channel, thereby keeping the oxygen-evolving complex fully active.
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15
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Affiliation(s)
- My Hang V Huynh
- DE-1: High Explosive Science and Technology Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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16
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Meyer TJ, Huynh MHV, Thorp HH. The Possible Role of Proton-Coupled Electron Transfer (PCET) in Water Oxidation by Photosystem II. Angew Chem Int Ed Engl 2007; 46:5284-304. [PMID: 17604381 DOI: 10.1002/anie.200600917] [Citation(s) in RCA: 410] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
All higher life forms use oxygen and respiration as their primary energy source. The oxygen comes from water by solar-energy conversion in photosynthetic membranes. In green plants, light absorption in photosystem II (PSII) drives electron-transfer activation of the oxygen-evolving complex (OEC). The mechanism of water oxidation by the OEC has long been a subject of great interest to biologists and chemists. With the availability of new molecular-level protein structures from X-ray crystallography and EXAFS, as well as the accumulated results from numerous experiments and theoretical studies, it is possible to suggest how water may be oxidized at the OEC. An integrated sequence of light-driven reactions that exploit coupled electron-proton transfer (EPT) could be the key to water oxidation. When these reactions are combined with long-range proton transfer (by sequential local proton transfers), it may be possible to view the OEC as an intricate structure that is "wired for protons".
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Affiliation(s)
- Thomas J Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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17
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Meyer T, Huynh M, Thorp H. Zur möglichen Rolle des protonengekoppelten Elektronentransfers (PCET) bei der Oxidation von Wasser durch das Photosystem II. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200600917] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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18
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Popelková H, Yocum CF. Current status of the role of Cl(-) ion in the oxygen-evolving complex. PHOTOSYNTHESIS RESEARCH 2007; 93:111-21. [PMID: 17200880 DOI: 10.1007/s11120-006-9121-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2006] [Accepted: 12/04/2006] [Indexed: 05/07/2023]
Abstract
This minireview summarizes the current state of knowledge concerning the role of Cl(-) in the oxygen-evolving complex (OEC) of photosystem II (PSII). The model that proposes that Cl(-) is a Mn ligand is discussed in light of more recent work. Studies of Cl(-) specificity, stoichiometry, kinetics, and retention by extrinsic polypeptides are discussed, as are the results that fail to detect Cl(-) ligation to Mn and results that show a lack of a requirement for Cl(-) in PSII-catalyzed H(2)O oxidation. Mutagenesis experiments in cyanobacteria and higher plants that produce evidence for a correlation between Cl(-) retention and stable interactions among intrinsic and extrinsic polypeptides are summarized, and spectroscopic data on the interaction between PSII and Cl(-) are discussed. Lastly, the question of the site of Cl(-) action in PSII is discussed in connection with the current crystal structures of the enzyme.
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Affiliation(s)
- Hana Popelková
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA
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19
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Lu YK, Stemler AJ. Differing responses of the two forms of photosystem II carbonic anhydrase to chloride, cations, and pH. BIOCHIMICA ET BIOPHYSICA ACTA 2007; 1767:633-8. [PMID: 17320812 DOI: 10.1016/j.bbabio.2006.12.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2006] [Revised: 11/25/2006] [Accepted: 12/14/2006] [Indexed: 10/23/2022]
Abstract
The effects of Cl(-), Mn(2+), Ca(2+), and pH on extrinsic and intrinsic photosystem II carbonic anhydrase activity were compared. Under the conditions of our in vitro experiments, extrinsic CA activity, located on the OEC33 protein, was optimum at about 30 mM Cl(-), and strongly inhibited above this concentration. This enzyme is activated by Mn(2+) and stimulated somewhat by Ca(2+). The OEC33 showed dehydration activity that is optimum at pH 6 or below. In contrast, intrinsic CA activity found in the PSII complex after removal of extrinsic proteins was stimulated by Cl(-) up to 0.4 M. Ca(2+) appears to be the required cofactor, which implies that the location of the intrinsic CA activity is in the immediate vicinity of the CaMn(4) complex. Up to now, intrinsic CA has shown only hydration activity that is nearly pH independent.
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Affiliation(s)
- Yih-Kuang Lu
- Section of Plant Biology, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA.
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20
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Brudvig GW, Crabtree RH. Bioinorganic Chemistry of Manganese Related to Photosynthetic Oxygen Evolution. PROGRESS IN INORGANIC CHEMISTRY 2007. [DOI: 10.1002/9780470166383.ch2] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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21
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Affiliation(s)
- James P McEvoy
- Department of Chemistry, Yale University, P.O. Box 208107, New Haven, Connecticut 06520-8107, USA
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22
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Kobayashi M, Katoh H, Ikeuchi M. Mutations in a Putative Chloride Efflux Transporter Gene Suppress the Chloride Requirement of Photosystem II in the Cytochrome c550-deficient Mutant. ACTA ACUST UNITED AC 2006; 47:799-804. [PMID: 16621843 DOI: 10.1093/pcp/pcj052] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The cytochrome c550-deficient mutant (psbV-disruptant) of Synechocystis requires a high concentration of Cl(-) in the culture medium to support photosynthetic oxygen evolution. From this disruptant, we isolated spontaneous suppressor mutants that are able to grow photoautotrophically in the absence of Cl(-). Three independent mutations were identified: one was a deletion in slr0753 and two were a transposition of related insertion sequences in the same slr0753. The deduced product of slr0753 belongs to a novel group of the superfamily of ion efflux pumps and ion transporters. These results suggest that Slr0753 exports Cl(-) or a related anion, which is essential for PSII oxygen evolution.
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Affiliation(s)
- Mari Kobayashi
- Department of Life Sciences (Biology), The University of Tokyo, Komaba 3-8-1, Meguro, Tokyo, 153-8902 Japan.
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23
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van Gorkom HJ, Yocum CF. The Calcium and Chloride Cofactors. ADVANCES IN PHOTOSYNTHESIS AND RESPIRATION 2005. [DOI: 10.1007/1-4020-4254-x_14] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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24
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McEvoy JP, Brudvig GW. Structure-based mechanism of photosynthetic water oxidation. Phys Chem Chem Phys 2004. [DOI: 10.1039/b407500e] [Citation(s) in RCA: 174] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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25
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Mavankal G, McCain DC, Bricker TM. Effects of chloride on paramagnetic coupling of manganese in calcium chloride-washed photosystem II preparations. FEBS Lett 2001. [DOI: 10.1016/0014-5793(86)80693-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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26
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Andersson B, Critchley C, Ryrie IJ, Jansson C, Larsson C, Anderson JM. Modification of the chloride requirement for photosynthetic O2
evolution. FEBS Lett 2001. [DOI: 10.1016/0014-5793(84)80217-3] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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27
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Muallem A, Izawa S. Inactivation of the O2
evolving mechanism by exogenous Mn2+
in Cl−
-depleted chloroplasts. FEBS Lett 2001. [DOI: 10.1016/0014-5793(80)80724-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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28
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CaCl2
inhibition of H2
O2
electron donation to photosystem II in submembrane preparations depleted in extrinsic polypeptides. FEBS Lett 2001. [DOI: 10.1016/0014-5793(89)81686-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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29
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Miyao M, Murata N. Role of the 33-kDa polypeptide in preserving Mn in the photosynthetic oxygen-evolution system and its replacement by chloride ions. FEBS Lett 2001. [DOI: 10.1016/0014-5793(84)81342-3] [Citation(s) in RCA: 233] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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30
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31
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Theg SM, Johnson JD, Homann PH. Proton efflux from thylakoids induced in darkness and its effect on photosystem II. FEBS Lett 2001. [DOI: 10.1016/0014-5793(82)81199-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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32
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Wincencjusz H, Yocum CF, van Gorkom HJ. S-state dependence of chloride binding affinities and exchange dynamics in the intact and polypeptide-depleted O2 evolving complex of photosystem II. Biochemistry 1998; 37:8595-604. [PMID: 9622511 DOI: 10.1021/bi972660v] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The Cl- binding properties in the successive oxidation states of the O2 evolving complex of photosystem II were investigated by measurements of UV absorbance changes, induced by a series of saturating flashes, that monitor manganese oxidation state transitions. In dark-adapted, intact photosystem II, Cl- can be replaced by NO3- in minutes, in an exchange reaction that depends on the NO3- concentration and that is not rate-limited by dissociation of Cl- from its binding site. Preillumination of dark-adapted photosystem II by one or two flashes accelerated the NO3- substitution reaction by an order of magnitude. A quantitative analysis of the Cl- concentration dependence of UV absorbance changes, measured in photosystem II preparations depleted of extrinsic 17 and 23 kDa polypeptides, shows that the Cl- binding properties of photosystem II change with the oxidation state of the oxygen evolving complex. Although the affinity for the individual S-states could not be determined with precision, it is shown that the affinity is an order of magnitude lower in the S2 state than in the S1 state. Comparison of the results obtained using intact photosystem II and preparations depleted of the 17 and 23 kDa extrinsic polypeptides suggests that these proteins constitute a diffusion barrier, which prevents fast equilibration of the Cl- binding site with the medium, but does not change the Cl- affinity of the binding site.
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Affiliation(s)
- H Wincencjusz
- Biophysics Department, Huygens Laboratory, Leiden University, The Netherlands
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33
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Wang S, Tsai HL, Libby E, Folting K, Streib WE, Hendrickson DN, Christou G. Modeling the Photosynthetic Water Oxidation Center: Chloride/Bromide Incorporation and Reversible Redox Processes in the Complexes Mn4O3X(OAc)3(dbm)3 (X = Cl, Br) and (pyH)3[Mn4O3Cl7(OAc)3]. Inorg Chem 1996. [DOI: 10.1021/ic9601347] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sheyi Wang
- Department of Chemistry and Molecular Structure Center, Indiana University, Bloomington, Indiana 47405-4001, and Department of Chemistry 0358, University of California at San Diego, La Jolla, California 92093-0358
| | - Hui-Lien Tsai
- Department of Chemistry and Molecular Structure Center, Indiana University, Bloomington, Indiana 47405-4001, and Department of Chemistry 0358, University of California at San Diego, La Jolla, California 92093-0358
| | - Eduardo Libby
- Department of Chemistry and Molecular Structure Center, Indiana University, Bloomington, Indiana 47405-4001, and Department of Chemistry 0358, University of California at San Diego, La Jolla, California 92093-0358
| | - Kirsten Folting
- Department of Chemistry and Molecular Structure Center, Indiana University, Bloomington, Indiana 47405-4001, and Department of Chemistry 0358, University of California at San Diego, La Jolla, California 92093-0358
| | - William E. Streib
- Department of Chemistry and Molecular Structure Center, Indiana University, Bloomington, Indiana 47405-4001, and Department of Chemistry 0358, University of California at San Diego, La Jolla, California 92093-0358
| | - David N. Hendrickson
- Department of Chemistry and Molecular Structure Center, Indiana University, Bloomington, Indiana 47405-4001, and Department of Chemistry 0358, University of California at San Diego, La Jolla, California 92093-0358
| | - George Christou
- Department of Chemistry and Molecular Structure Center, Indiana University, Bloomington, Indiana 47405-4001, and Department of Chemistry 0358, University of California at San Diego, La Jolla, California 92093-0358
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34
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Schnackenberg J, Ikemoto H, Miyachi S. Photosynthesis and hydrogen evolution under stress conditions in a CO2-tolerant marine green alga, Chlorococcum littorale. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 1996. [DOI: 10.1016/1011-1344(95)07270-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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35
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Moubarak-Milad M, Stemler A. Oxidation-reduction potential dependence of photosystem II carbonic anhydrase in maize thylakoids. Biochemistry 1994; 33:4432-8. [PMID: 8155662 DOI: 10.1021/bi00180a042] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In characterizing the carbonic anhydrase (CA) found in maize thylakoid membranes, it was observed that the enzyme's activity was inhibited somewhat when the Hill oxidant, ferricyanide, was given in the dark [Stemler, A. (1986) Biochim. Biophys. Acta 850, 97-107]. In the present work, a redox titration of this effect shows that the CA activity is mediated by a component that has a midpoint potential (Em) of about 485 mV at pH 6.5 and a pH dependence of 60 mV/pH. These redox titration characteristics are identical to those of the redox mediator "D480", which modulates formate and bicarbonate binding affinity to photosystem II (PS II). Bicarbonate binds to PS II more readily, and CA activity is higher, when D480 is reduced, whereas both bicarbonate binding and thylakoid-bound CA activity are low when D480 is oxidized in the dark by ferricyanide. Both the low bicarbonate binding affinity and the low CA activity induced by the presence of ferricyanide are reversed by a single saturating flash of light. In contrast, the activity of soluble CA, which is extracted from maize mesophyll cytosol, does not exhibit any redox dependence in the range 400-550 mV. Furthermore, thylakoid-bound CA activity is inhibited by 5 mM ZnCl2 by as much as 75%, whereas the activity of soluble CA shows no significant decrease induced by ZnCl2. Also, at a medium potential of 400 mV, ferricyanide (1 mM) inhibits soluble CA activity by 88% and thylakoid-bound CA activity by only 18%. It is concluded from these results that CA activity observed in thylakoids arises from CA inherent to PS II and is not some form of contamination by soluble CA. Possible roles of CA in PS II reaction mechanisms are discussed.
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36
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MacLachlan DJ, Nugent JH. Investigation of the S3 electron paramagnetic resonance signal from the oxygen-evolving complex of photosystem 2: effect of inhibition of oxygen evolution by acetate. Biochemistry 1993; 32:9772-80. [PMID: 8396970 DOI: 10.1021/bi00088a032] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
An S3 electron paramagnetic resonance (EPR) signal is observed in a variety of photosystem 2 (PS2) samples in which the oxygen-evolving complex (OEC) has been inhibited. These signals have been proposed to be due to an interaction, S2X+, between the manganese cluster in an oxidation state equivalent to S2 and an organic radical, either oxidized histidine [Boussac et al. (1990) Nature 347, 303-306] or the tyrosine radical Yz+ [Hallahan et al. (1992) Biochemistry 31, 4562-4573]. We report that treatment of PS2 with acetate at pH 5.5 leads to a slowing of the reduction of Yz+ and allows the trapping of an S3-type state on freezing to 77 K following illumination at 277 K. The S3 EPR signal in acetate-treated PS2 has a broader and more complex line shape but otherwise has similar properties to other S3 signals. The addition to acetate-treated samples in the S1 state of the herbicide 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), which allows only a single turnover of the reaction center, causes a large reduction in the yield of the S3 signal. Various anion and cation treatments change the S3 signal line shape and are used to show that acetate probably acts by binding and displacing chloride. We propose that a variety of treatments which affect calcium and chloride cofactor binding cause a modification of the S2 state of the manganese cluster, slow the reduction of Yz+, and allow an S3 EPR signal to be observed following illumination.(ABSTRACT TRUNCATED AT 250 WORDS)
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37
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Mohanty P, Hayashi H, Papageorgiou G, Murata N. Stabilization of the Mn-cluster of the oxygen-evolving complex by glycinebetaine. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1993. [DOI: 10.1016/0005-2728(93)90035-e] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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38
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Lindberg K, Vänngård T, Andréasson LE. Studies of the slowly exchanging chloride in Photosystem II of higher plants. PHOTOSYNTHESIS RESEARCH 1993; 38:401-408. [PMID: 24317996 DOI: 10.1007/bf00046767] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/1993] [Accepted: 09/09/1993] [Indexed: 06/02/2023]
Abstract
(36)Cl(-) was used to study the slow exchange of chloride at a binding site associated with Photosystem II (PS II). When PS II membranes were labeled with different concentrations of (36)Cl(-), saturation of binding at about I chloride/PS II was observed. The rate of binding showed a clear dependence on the concentration of chloride approaching a limiting value of about 3·10(-4) s(-1) at high concentrations, similar to the rate of release of chloride from labeled membranes. These rates were close to that found earlier for the release of chloride from PS II membranes isolated from spinach grown on (36)Cl(-), which suggests that we are observing the same site for chloride binding. The similarity between the limiting rate of binding and the rate of release of chloride suggests that the exchange of chloride with the surrounding medium is controlled by an intramolecular process. The binding of chloride showed a pH-dependence with an apparent pKa of 7.5 and was very sensitive to the presence of the extrinsic polypeptides at the PS II donor side. The binding of chloride was competitively inhibited by a few other anions, notably Br(-) and NO3 (-). The slowly exchanging Cl(-) did not show any significant correlation with oxygen evolution rate or yield of EPR signals from the S2 state. Our studies indicate that removal of the slowly exchanging chloride lowers the stability of PS II as indicated by the loss of oxygen evolution activity and S2 state EPR signals.
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Affiliation(s)
- K Lindberg
- Department of Biochemistry and Biophysics, Chalmers University of Technology, S-412 96, Göteborg, Sweden
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39
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Debus RJ. The manganese and calcium ions of photosynthetic oxygen evolution. BIOCHIMICA ET BIOPHYSICA ACTA 1992; 1102:269-352. [PMID: 1390827 DOI: 10.1016/0005-2728(92)90133-m] [Citation(s) in RCA: 970] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- R J Debus
- Department of Biochemistry, University of California Riverside 92521-0129
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40
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Pauly S, Schlodder E, Witt H. The influence of salts on charge separation (P6804QA) and water oxidation of photosystem II complexes from thermophilic cyanobacteria. Active and inactive conformational states of photosystem II. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1992. [DOI: 10.1016/0005-2728(92)90028-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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41
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Rickert KW, Sears J, Beck WF, Brudvig GW. Mechanism of irreversible inhibition of O2 evolution in photosystem II by Tris(hydroxymethyl)aminomethane. Biochemistry 1991; 30:7888-94. [PMID: 1651110 DOI: 10.1021/bi00246a003] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The dark reaction of tris(hydroxymethyl)aminomethane (Tris) with the O2-evolving center of photosystem II (PSII) in the S1 state causes irreversible inhibition of O2 evolution. Similar inhibition is observed for several other amines: NH3, CH3NH2, (CH3)2NH, ethanolamine, and 2-amino-2-ethyl-1,3-propanediol. In PSII membranes, both depleted of the 17- and 23-kDa polypeptides and undepleted, the rate of reaction of Tris depends inversely upon the Cl- concentration. However, the rate of reaction of Tris is about 2-fold greater with PSII membranes depleted of the 17- and 23-kDa polypeptides than with undepleted PSII membranes. We have used low-temperature electron paramagnetic resonance (EPR) spectroscopy to study the effect of Tris on the oxidation state of the Mn complex in the O2-evolving center, to monitor the electron-donation reactions in Tris-treated samples, and to observe any loss of the Mn complex (forming Mn2+ ions) after Tris treatment. We find that Tris treatment causes loss of electron-donation ability from the Mn complex at the same rate as inhibition of O2 evolution and that Mn2+ ions are released. We conclude that Tris reduces the Mn complex to labile Mn2+ ions, without generating any kinetically stable, partially reduced intermediates, and that the reaction occurs at the Cl(-)-sensitive site previously characterized in studies of the reversible inhibition of O2 evolution by amines.
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Affiliation(s)
- K W Rickert
- Department of Chemistry, Yale University, New Haven, Connecticut 06511
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42
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Philbrick J, Diner B, Zilinskas B. Construction and characterization of cyanobacterial mutants lacking the manganese-stabilizing polypeptide of photosystem II. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)98849-6] [Citation(s) in RCA: 130] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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43
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Papageorgiou GC, Lagoyanni T. Interactions of iodide ions with isolated photosystem 2 particles. Arch Biochem Biophys 1991; 285:339-43. [PMID: 1897936 DOI: 10.1016/0003-9861(91)90369-t] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The effects of I- ions on O2 evolution by photosystem 2 particles, which were depleted of the 18-kDa and the 23-kDa extrinsic proteins of the O2 evolution complex by NaCl washing (dPS2 particles) were examined. In the absence of Cl- (incompetent dPS2) I- stimulated O2 evolution up to 3-6 mM, depending on the associated cation, and inhibited it at higher concentrations. In the presence of Cl- (competent dPS2), I- was inhibitory at all concentrations. The inhibition was reversible, it occurred at a site preceding Tyrz (Tyr residue mediating electron transfer from H2O to photosystem 2), and it interfered noncompetitively with the reactivation of incompetent dPS2 with Cl-. Furthermore, the organic salts tetrabutyl ammonium iodide and tetraphenyl phosphonium iodide proved to be stronger inhibitors than the inorganic NaI. This is interpreted as an indication of a negatively charged surface, situated behind a hydrophobic permeability barrier. Permeant organic cations, being better compensators of the inner surface charge than Na+, are also more apt in facilitating access of the I- ions to the inhibitory site in the vicinity of Tyrz.
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Affiliation(s)
- G C Papageorgiou
- National Research Center Demokritos, Institute of Biology, Athens, Greece
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44
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Coleman WJ. Chloride binding proteins: mechanistic implications for the oxygen-evolving complex of Photosystem II. PHOTOSYNTHESIS RESEARCH 1990; 23:1-27. [PMID: 24420988 DOI: 10.1007/bf00030059] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/1987] [Accepted: 12/09/1988] [Indexed: 05/13/2023]
Abstract
Chloride plays a key role in activating the photosynethetic oxygen-evolving complex (OEC) of Photosystem II, but the OEC is only one of many enzymes affected by this anion. Some of the mechanistic features of Cl(-) involvement in water-splitting resemble those of other proteins whose structure and chemistry are known in detail. An overview of the similarities and differences between these Cl(-)-binding systems is presented.
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Affiliation(s)
- W J Coleman
- Department of Chemistry, Massachusetts Institute of Technology, 02139, Cambridge, MA, USA
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45
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Abstract
We have studied the 35Cl- NMR line broadening in the presence of photosystem II (PS II) membranes from spinach in the dark. In the presence of NH3 (which other work has shown to competitively inhibit chloride binding to PS II) we observed no decrease in 35 Cl- linewidths. We conclude that binding of Cl- to the O2 evolving center in PS II in the dark (previously demonstrated by EPR) is in slow exchange on the NMR timescale. We assign the observed line broadening to interaction with non-specific binding sites and with free paramagnetics.
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46
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Oxidation of exogenous substrates by the O2-evolving center of photosystem II and related catalytic air oxidation of secondary alcohols via a tetranuclear manganese(IV) complex. Tetrahedron 1989. [DOI: 10.1016/s0040-4020(01)85159-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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47
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Sandusky P, Yocum C. Hydrogen peroxide oxidation catalyzed by chloride-depleted thylakoid membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1988. [DOI: 10.1016/0005-2728(88)90231-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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48
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Homann PH. The chloride and calcium requirement of photosynthetic water oxidation: Effects of pH. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1988. [DOI: 10.1016/0005-2728(88)90113-2] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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49
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Homann PH. Chloride relations of photosystem II membrane preparations depleted of, and resupplied with, their 17 and 23 kDa extrinsic polypeptides. PHOTOSYNTHESIS RESEARCH 1988; 15:205-220. [PMID: 24430923 DOI: 10.1007/bf00047353] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/1987] [Accepted: 10/14/1987] [Indexed: 06/03/2023]
Abstract
Photosystem II membranes prepared from thylakoids of Phytolacca americana chloroplasts were depleted of their intrinsic 17 and 23 kDa polypeptides, and the effects of a reconstitution of these polypeptides on the Cl(-) requirements of O2 evolution activity were analyzed. It was found that the activating effectiveness of limiting amounts of added Cl(-) was increased several fold by an addition of the 23 kDa polypeptide. When it was supplemented by the 17 kDa species, only a small additional increase occurred, but Cl(-) retention in Cl(-) free media was enhanced greatly. Addition of the 17 kDa polypeptide alone was without effect because it is known that it cannot bind to its native site unless the 23 kDa polypeptide is in place.Optimal enhancements of the effectiveness of activating added Cl(-) were observed when the assays were done in the presence of the reconstituting polypeptides. When the reconstituting treatment with the polypeptides, and the assay of the Cl(-) relations, were separated, it was advantageous to have Cl(-) present in the reconstituting medium, and not to add Ca(2+), another cofactor of photosynthetic water oxidation. Those requirements are attributed to the labilizing effects Cl(-) free conditions and divalent cations have on the association of especially the 23 kDa polypeptides with the water oxidizing complex, and to a possible aggregation of the membranes under the influence of Ca(2+) which might have impeded proper polypeptide binding.
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Affiliation(s)
- P H Homann
- Institute of Molecular Biophysics, Florida State University, 32306-3015, Tallahassee, Florida, USA
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50
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Critchley C, Chopra RK. Protection of photosynthetic O2 evolution against heat inactivation: the role of chloride, pH and coupling status. PHOTOSYNTHESIS RESEARCH 1988; 15:143-152. [PMID: 24430859 DOI: 10.1007/bf00035258] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/1987] [Accepted: 10/01/1987] [Indexed: 06/03/2023]
Abstract
Heat inactivation of photosynthetic O2 evolution was studied in isolated thylakoids from spinach (Spinacia oleracea) and mangrove (Avicennia marina) leaves. Different temperatures, salt, pH and uncoupler effects were investigated. From these results and others in the literature it was concluced that chloride loss from the membrane and, more specifically, the oxygen-evolving complex of photosystem II, may be the cause of inhibition of oxygen evolution during heat inactivation.
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Affiliation(s)
- C Critchley
- Botany Department, The Faculties, Australian National University, GPO Box 4, 2601, Canberra, ACT, Australia
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