1
|
Watanabe S, Noguchi T. Intermediate Formation via Proton Release during the Photoassembly of the Water-Oxidizing Mn 4CaO 5 Cluster in Photosystem II. J Phys Chem B 2024. [PMID: 39148348 DOI: 10.1021/acs.jpcb.4c03768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
The early stages of the photoassembly of the water-oxidizing Mn4CaO5 cluster in spinach photosystem II (PSII) were monitored using rapid-scan time-resolved Fourier transform infrared (FTIR) spectroscopy. Carboxylate stretching and the amide I bands, which appeared upon the flash-induced oxidation of a Mn2+ ion, changed their features during the subsequent dark rearrangement process, indicating the relocation of the Mn3+ ion concomitant with protein conformational changes. Monitoring the isotope-edited FTIR signals of a Mes buffer estimated that nearly two protons are released upon the Mn2+ oxidation. Quantum chemical calculations for models of the Mn binding site suggested that the proton of a water ligand is transferred to D1-H332 through a hydrogen bond upon the Mn3+ formation and then released to the bulk as the Mn3+ shifts to bind to this histidine. Another Mn2+ ion may be inserted to form a binuclear Mn3+Mn2+ complex, whose structure was calculated to be stabilized by a μ-hydroxo bridge hydrogen-bonded with deprotonated D1-H337. Nearly one additional proton can thus be released from this histidine, assuming that it is mostly protonated before illumination. Alternatively, a proton could be released by further insertion of Ca2+, forming a Mn3+Mn2+Ca2+ complex with another hydroxo ligand connecting Ca2+ to the Mn3+Mn2+ complex.
Collapse
Affiliation(s)
- Shunya Watanabe
- Department of Physics, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Takumi Noguchi
- Department of Physics, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| |
Collapse
|
2
|
Wheeler TA, Tilley TD. Metal-Metal Redox Exchange to Produce Heterometallic Manganese-Cobalt Oxo Cubanes via a "Dangler" Intermediate. J Am Chem Soc 2024; 146:20279-20290. [PMID: 38978206 PMCID: PMC11273651 DOI: 10.1021/jacs.4c05367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Revised: 06/21/2024] [Accepted: 06/24/2024] [Indexed: 07/10/2024]
Abstract
Pendent metals bound to heterocubanes are components of well-known active sites in enzymes that mediate difficult chemical transformations. Investigations into the specific role of these metal ions, sometimes referred to as "danglers", have been hindered by a paucity of rational synthetic routes to appropriate model structures. To generate pendent metal ions bonded to an oxo cubane through a carboxylate bridge, the cubane Co4(μ3-O)4(OAc)4(t-Bupy)4 (OAc = acetate, t-Bupy = 4-tert-butylpyridine) was exposed to various metal acetate complexes. Reaction with Cu(OAc)2 gave the structurally characterized (by X-ray diffraction) dicopper dangler Cu2Co4(μ4-O)2(μ3-O)2(OAc)6(Cl)2(t-Bupy)4. In contrast, the analogous reaction with Mn(OAc)2 produced the MnIV-containing cubane cation [MnCo3(μ3-O)4(OAc)4(t-Bupy)4]+ by way of a metal-metal exchange that gives Co(OAc)2 and [CoIII(μ-OH)(OAc)]n oligomers as byproducts. Additionally, reaction of the formally CoIV cubane complex [Co4(μ3-O)4(OAc)4(t-Bupy)4][PF6] with Mn(OAc)2 gave the corresponding Mn-containing cubane in 80% yield. A mechanistic examination of the related metal-metal exchange reaction between Co4(μ3-O)4(OBz)4(py)4 (OBz = benzoate) and [Mn(acac)2(py)2][PF6] by ultraviolet-visible (UV-vis) spectroscopy provided support for a process involving rate-determining association of the reactants and electron transfer through a μ-oxo bridge in the adduct intermediate. The rates of exchange correlate with the donor strength of the cubane pyridine and benzoate ligand substituents; more electron-donating pyridine ligands accelerate metal-metal exchange, while both electron-donating and -withdrawing benzoate ligands can accelerate exchange. These experiments suggest that the basicity of the cubane oxo ligands promotes metal-metal exchange reactivity. The redox potentials of the Mn and cubane starting materials and isotopic labeling studies suggest an inner-sphere electron-transfer mechanism in a dangler intermediate.
Collapse
Affiliation(s)
- T. Alexander Wheeler
- Department
of Chemistry, University of California,
Berkeley, Berkeley, California 94720, United States
- Chemical
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | - T. Don Tilley
- Department
of Chemistry, University of California,
Berkeley, Berkeley, California 94720, United States
- Chemical
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| |
Collapse
|
3
|
Puthiyaveetil S, McKenzie SD. Plant photosystem II assembly: TROL2 to the rescue. MOLECULAR PLANT 2023; 16:1719-1721. [PMID: 37743626 DOI: 10.1016/j.molp.2023.09.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 09/19/2023] [Accepted: 09/20/2023] [Indexed: 09/26/2023]
Affiliation(s)
- Sujith Puthiyaveetil
- Department of Biochemistry and Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA.
| | - Steven D McKenzie
- Department of Biochemistry and Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
| |
Collapse
|
4
|
Khorobrykh A. A possible relationship between the effect of factors on photoactivation of photosystem II depleted of functional Mn and cytochrome b 559. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148997. [PMID: 37506995 DOI: 10.1016/j.bbabio.2023.148997] [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: 05/20/2023] [Revised: 06/27/2023] [Accepted: 07/19/2023] [Indexed: 07/30/2023]
Abstract
The photoassembly of the Mn4CaO5 cluster in Mn-depleted photosystem II preparations (photoactivation) was studied under the influence of oxidants, reductants and pH. New data on the effect of these factors on the photoactivation yield are presented. The presence of the oxidant, ferricyanide, negatively affected the photoactivation yield over the entire concentration range studied (0-1 mM). In contrast to ferricyanide, the addition of the reductant, ferrocyanide, up to 1 mM resulted in an increase in the photoactivation yield. Other reductants either did not significantly affect (diphenylcarbazide) or suppressed (ascorbate) the photoactivation yield. The effect of ferrocyanide on photoactivation were found to be similar dichlorophenolindophenol. Investigation of the photoactivation yield as a function of pH revealed that the maximum yield was observed at pH 6.5 in the presence of ferrocyanide and DCPIP, and at pH 5.5 without additives. In addition, the photoactivation yield at pH 5.5 was the same without and with the addition of ferrocyanide or dichlorophenolindophenol. Although ferricyanide suppressed the photoactivation, the photoactivation yield increased in the presence of ferricyanide by shifting the pH to the acidic region. The samples contained approximately 25 % of the HP cyt b559, which was in the reduced state, as the absorbance at 559 nm was decreased upon addition of ferricyanide and subsequent addition of ferrocyanide returned the spectrum to the baseline. A possible relationship between the effect of factors on the photoactivation and the involvement of cyt b559 in the protection of PSII from oxidative damage on the donor side is discussed.
Collapse
Affiliation(s)
- Andrey Khorobrykh
- Institute of Basic Biological Problems, FRC PSCBR RAS, Pushchino 142290, Moscow Region, Russia.
| |
Collapse
|
5
|
Matsubara T, Shimada Y, Kitajima-Ihara T, Nagao R, Noguchi T. Rapid-Scan Fourier Transform Infrared Monitoring of the Photoactivation Process in Cyanobacterial Photosystem II. J Phys Chem B 2023; 127:8150-8161. [PMID: 37718495 DOI: 10.1021/acs.jpcb.3c04325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/19/2023]
Abstract
The catalytic site of photosynthetic water oxidation, the Mn4CaO5 cluster, in photosystem II (PSII) is known to be formed by a light-induced process called photoactivation. However, details of its molecular mechanism remain unresolved. In this study, we monitored the photoactivation process in cyanobacterial PSII using rapid-scan, time-resolved Fourier transform infrared (FTIR) spectroscopy. The Mn3+/Mn2+ FTIR difference spectra of PSII, in which D1-D170 was specifically 13C labeled, and PSII from the D1-D170A, D1-E189A, and D1-D342A mutants provide strong evidence that the initial Mn2+ is coordinated by D1-D170 and D1-E189. Protein conformational changes and relocation of photo-oxidized Mn3+ in the dark rearrangement process were detected as slow-phase signals in the amide I and carboxylate regions, whereas similar signals were not observed in D1-E189A PSII. It is thus proposed that relocation of Mn3+ via D1-E189 induces the conformational changes of the proteins to form proper Mn binding sites in the mature protein conformation.
Collapse
Affiliation(s)
- Takumi Matsubara
- Department of Physics, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan
| | - Yuichiro Shimada
- Department of Physics, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan
| | - Tomomi Kitajima-Ihara
- Department of Physics, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan
| | - Ryo Nagao
- Faculty of Agriculture, Shizuoka University, Shizuoka 422-8529, Japan
| | - Takumi Noguchi
- Department of Physics, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan
| |
Collapse
|
6
|
Sorce C, Bellini E, Bacchi F, Sanità di Toppi L. Photosynthetic Efficiency of Marchantia polymorpha L. in Response to Copper, Iron, and Zinc. PLANTS (BASEL, SWITZERLAND) 2023; 12:2776. [PMID: 37570930 PMCID: PMC10420882 DOI: 10.3390/plants12152776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 07/14/2023] [Accepted: 07/17/2023] [Indexed: 08/13/2023]
Abstract
Metal micronutrients are essential for plant nutrition, but their toxicity threshold is low. In-depth studies on the response of light-dependent reactions of photosynthesis to metal micronutrients are needed, and the analysis of chlorophyll a fluorescence transients is a suitable technique. The liverwort Marchantia polymorpha L., a model organism also used in biomonitoring, allowed us to accurately study the effects of metal micronutrients in vivo, particularly the early responses. Gametophytes were treated with copper (Cu), iron (Fe) or zinc (Zn) for up to 120 h. Copper showed the strongest effects, negatively affecting almost the entire light phase of photosynthesis. Iron was detrimental to the flux of energy around photosystem II (PSII), while the acceptor side of PSI was unaltered. The impact of Fe was milder than that of Cu and in both cases the structures of the photosynthetic apparatus that resisted the treatments were still able to operate efficiently. The susceptibility of M. polymorpha to Zn was low: although the metal affected a large part of the electron transport chain, its effects were modest and short-lived. Our results may provide a contribution towards achieving a more comprehensive understanding of response mechanisms to metals and their evolution in plants, and may be useful for supporting the development of biomonitoring techniques.
Collapse
Affiliation(s)
- Carlo Sorce
- Department of Biology, University of Pisa, via L. Ghini, 13, 56126 Pisa, Italy; (C.S.)
| | - Erika Bellini
- Department of Biology, University of Pisa, via L. Ghini, 13, 56126 Pisa, Italy; (C.S.)
- Department of Biology and Biotechnology “Charles Darwin”, Sapienza University of Rome, Piazzale A. Moro, 5, 00185 Rome, Italy
| | - Florinda Bacchi
- Department of Biology, University of Pisa, via L. Ghini, 13, 56126 Pisa, Italy; (C.S.)
| | - Luigi Sanità di Toppi
- Department of Biology, University of Pisa, via L. Ghini, 13, 56126 Pisa, Italy; (C.S.)
| |
Collapse
|
7
|
Smythers AL, Crislip JR, Slone DR, Flinn BB, Chaffins JE, Camp KA, McFeeley EW, Kolling DRJ. Excess manganese increases photosynthetic activity via enhanced reducing center and antenna plasticity in Chlorella vulgaris. Sci Rep 2023; 13:11301. [PMID: 37438371 DOI: 10.1038/s41598-023-35895-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 05/25/2023] [Indexed: 07/14/2023] Open
Abstract
Photosynthesis relies on many easily oxidizable/reducible transition metals found in the metalloenzymes that make up much of the photosynthetic electron transport chain (ETC). One of these is manganese, an essential cofactor of photosystem II (PSII) and a component of the oxygen-evolving complex, the only biological entity capable of oxidizing water. Additionally, manganese is a cofactor in enzymatic antioxidants, notably the superoxide dismutases-which are localized to the chloroplastic membrane. However, unlike other metals found in the photosynthetic ETC, previous research has shown exposure to excess manganese enhances photosynthetic activity rather than diminishing it. In this study, the impact of PSII heterogeneity on overall performance was investigated using chlorophyll fluorescence, a rapid, non-invasive technique that probed for overall photosynthetic efficiency, reducing site activity, and antenna size and distribution. These measurements unveiled an enhanced plasticity of PSII following excess manganese exposure, in which overall performance and reducing center activity increased while antenna size and proportion of PSIIβ centers decreased. This enhanced activity suggests manganese may hold the key to improving photosynthetic efficiency beyond that which is observed in nature.
Collapse
Affiliation(s)
- Amanda L Smythers
- Department of Chemistry, Marshall University, Huntington, WV, USA
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | | | - Danielle R Slone
- Department of Chemistry, Marshall University, Huntington, WV, USA
| | - Brendin B Flinn
- Department of Chemistry, Marshall University, Huntington, WV, USA
| | | | - Kristen A Camp
- Department of Chemistry, Marshall University, Huntington, WV, USA
| | - Eli W McFeeley
- Department of Chemistry, Marshall University, Huntington, WV, USA
| | | |
Collapse
|
8
|
Drosou M, Comas-Vilà G, Neese F, Salvador P, Pantazis DA. Does Serial Femtosecond Crystallography Depict State-Specific Catalytic Intermediates of the Oxygen-Evolving Complex? J Am Chem Soc 2023; 145:10604-10621. [PMID: 37137865 DOI: 10.1021/jacs.3c00489] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Recent advances in serial femtosecond crystallography (SFX) of photosystem II (PSII), enabled by X-ray free electron lasers (XFEL), provided the first geometric models of distinct intermediates in the catalytic S-state cycle of the oxygen-evolving complex (OEC). These models are obtained by flash-advancing the OEC from the dark-stable state (S1) to more oxidized intermediates (S2 and S3), eventually cycling back to the most reduced S0. However, the interpretation of these models is controversial because geometric parameters within the Mn4CaO5 cluster of the OEC do not exactly match those expected from coordination chemistry for the spectroscopically verified manganese oxidation states of the distinct S-state intermediates. Here we focus on the first catalytic transition, S1 → S2, which represents a one-electron oxidation of the OEC. Combining geometric and electronic structure criteria, including a novel effective oxidation state approach, we analyze existing 1-flash (1F) SFX-XFEL crystallographic models that should depict the S2 state of the OEC. We show that the 1F/S2 equivalence is not obvious, because the Mn oxidation states and total unpaired electron counts encoded in these models are not fully consistent with those of a pure S2 state and with the nature of the S1 → S2 transition. Furthermore, the oxidation state definition in two-flashed (2F) structural models is practically impossible to elucidate. Our results advise caution in the extraction of electronic structure information solely from the literal interpretation of crystallographic models and call for re-evaluation of structural and mechanistic interpretations that presume exact correspondence of such models to specific catalytic intermediates of the OEC.
Collapse
Affiliation(s)
- Maria Drosou
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Gerard Comas-Vilà
- Institute of Computational Chemistry and Catalysis, Chemistry Department, University of Girona, Montilivi Campus, Girona, Catalonia 17003, Spain
| | - Frank Neese
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Pedro Salvador
- Institute of Computational Chemistry and Catalysis, Chemistry Department, University of Girona, Montilivi Campus, Girona, Catalonia 17003, Spain
| | - Dimitrios A Pantazis
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| |
Collapse
|
9
|
Isobe H, Shoji M, Suzuki T, Shen JR, Yamaguchi K. Roles of the Flexible Primary Coordination Sphere of the Mn 4CaO x Cluster: What Are the Immediate Decay Products of the S3 State? J Phys Chem B 2022; 126:7212-7228. [DOI: 10.1021/acs.jpcb.2c02596] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hiroshi Isobe
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Mitsuo Shoji
- Center for Computational Science, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
| | - Takayoshi Suzuki
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Jian-Ren Shen
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Kizashi Yamaguchi
- Institute for NanoScience Design, Osaka University, Toyonaka, Osaka 560-0043, Japan
| |
Collapse
|
10
|
Post-translational amino acid conversion in photosystem II as a possible origin of photosynthetic oxygen evolution. Nat Commun 2022; 13:4211. [PMID: 35864123 PMCID: PMC9304363 DOI: 10.1038/s41467-022-31931-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 07/08/2022] [Indexed: 12/18/2022] Open
Abstract
Photosynthetic oxygen evolution is performed at the Mn cluster in photosystem II (PSII). The advent of this reaction on ancient Earth changed its environment by generating an oxygenic atmosphere. However, how oxygen evolution originated during the PSII evolution remains unknown. Here, we characterize the site-directed mutants at the carboxylate ligands to the Mn cluster in cyanobacterial PSII. A His residue replaced for D1-D170 is found to be post-translationally converted to the original Asp to recover oxygen evolution. Gln/Asn residues in the mutants at D1-E189/D1-D342 are also converted to Glu/Asp, suggesting that amino-acid conversion is a common phenomenon at the ligand sites of the Mn cluster. We hypothesize that post-translational generation of carboxylate ligands in ancestral PSII could have led to the formation of a primitive form of the Mn cluster capable of partial water oxidation, which could have played a crucial role in the evolutionary process of photosynthetic oxygen evolution. How photosynthetic oxygen evolution is originated on ancient Earth is unknown. Here, the authors find that some amino acid residues at the ligand sites of the Mn cluster can be posttranslationally converted to the original carboxylate residues, which could have contributed to the evolutionary process of photosynthetic oxygen evolution.
Collapse
|
11
|
Chen Y, Xu B, Yao R, Chen C, Zhang C. Mimicking the Oxygen-Evolving Center in Photosynthesis. FRONTIERS IN PLANT SCIENCE 2022; 13:929532. [PMID: 35874004 PMCID: PMC9302449 DOI: 10.3389/fpls.2022.929532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 06/20/2022] [Indexed: 06/15/2023]
Abstract
The oxygen-evolving center (OEC) in photosystem II (PSII) of oxygenic photosynthetic organisms is a unique heterometallic-oxide Mn4CaO5-cluster that catalyzes water splitting into electrons, protons, and molecular oxygen through a five-state cycle (Sn, n = 0 ~ 4). It serves as the blueprint for the developing of the man-made water-splitting catalysts to generate solar fuel in artificial photosynthesis. Understanding the structure-function relationship of this natural catalyst is a great challenge and a long-standing issue, which is severely restricted by the lack of a precise chemical model for this heterometallic-oxide cluster. However, it is a great challenge for chemists to precisely mimic the OEC in a laboratory. Recently, significant advances have been achieved and a series of artificial Mn4XO4-clusters (X = Ca/Y/Gd) have been reported, which closely mimic both the geometric structure and the electronic structure, as well as the redox property of the OEC. These new advances provide a structurally well-defined molecular platform to study the structure-function relationship of the OEC and shed new light on the design of efficient catalysts for the water-splitting reaction in artificial photosynthesis.
Collapse
Affiliation(s)
- Yang Chen
- Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Boran Xu
- Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ruoqing Yao
- Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Changhui Chen
- Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China
| | - Chunxi Zhang
- Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China
| |
Collapse
|
12
|
Russell BP, Vinyard DJ. Chloride facilitates Mn(III) formation during photoassembly of the Photosystem II oxygen-evolving complex. PHOTOSYNTHESIS RESEARCH 2022; 152:283-288. [PMID: 34817779 DOI: 10.1007/s11120-021-00886-4] [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: 07/06/2021] [Accepted: 11/12/2021] [Indexed: 06/13/2023]
Abstract
The Mn4Ca oxygen-evolving complex (OEC) in Photosystem II (PSII) is assembled in situ from free Mn2+, Ca2+, and water. In an early light-driven step, Mn2+ in a protein high-affinity site is oxidized to Mn3+. Using dual-mode electron paramagnetic resonance spectroscopy, we observed that Mn3+ accumulation increases as chloride concentration increases in spinach PSII membranes depleted of all extrinsic subunits. At physiologically relevant pH values, this effect requires the presence of calcium. When combined with pH studies, we conclude that the first Mn2+ oxidation event in OEC assembly requires a deprotonation that is facilitated by chloride.
Collapse
Affiliation(s)
- Brandon P Russell
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - David J Vinyard
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA.
| |
Collapse
|
13
|
Solution Equilibria Formation of Manganese(II) Complexes with Ethylenediamine, 1,3-Propanediamine and 1,4-ButanediaMine in Methanol. MOLBANK 2022. [DOI: 10.3390/m1367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Manganese is an abundant element that plays critical roles and is at the reaction center of several enzymes. In order to promote an understanding of the behavior of manganese(II) ion with several aliphatic ligands, in this work, the stability and spectral behavior of the complexes with manganese(II) and ethylenediamine, 1,3-propanediamine or 1,4-butanediamine were explored. A spectrophotometric study of its speciation in methanol was performed at 293 K. The formation constants obtained for these systems were: manganese(II)-ethylenediamine log β110 = 3.98 and log β120 = 7.51; for the manganese(II)-1,3-propanediamine log β110 = 5.08 and log β120 = 8.66; and for manganese(II)-1,4-butanediamine log β110 = 4.36 and log β120 = 8.46. These results were obtained by fitting the experimental spectrophotometric data using the HypSpec software. The complexes reported in this study show a spectral pattern that could be related to a chelate effect in which the molar absorbance is not directly related to the increase in the carbon chain of the ligands.
Collapse
|
14
|
Sarath NG, Manzil SA, Ali S, Alsahli AA, Puthur JT. Physio-anatomical modifications and elemental allocation pattern in Acanthus ilicifolius L. subjected to zinc stress. PLoS One 2022; 17:e0263753. [PMID: 35580091 PMCID: PMC9113579 DOI: 10.1371/journal.pone.0263753] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Accepted: 01/25/2022] [Indexed: 11/18/2022] Open
Abstract
Physio-anatomical modifications and elemental distribution pattern in Acanthus ilicifolius subjected to Zn stress were analysed in this study. Survival of A. ilicifolius plants under a high concentration of ZnSO4 was compensated by the reduction in the photosynthetic efficacy. Micro and macro-elemental distribution pattern in the root tissues was significantly influenced by heavy metal exposure. Tolerance towards the excess toxic metal ions in the tissue of A. ilicifolius was aided by the modified anatomical features. Moreover, the increased deposition of Zn around the central vasculature of the root confirms the complexation of Zn2+ in the xylem vessels. Metal induced molecular level changes of root and leaf samples indicate the presence of OH, NH2, and CH3 deformation as well as C-O-H and C-O-C stretch. A prominent band corresponding to CH3 deformation, pointing hemicellulose fortification, occurs in the cell walls of the xylem, aiding in Zn localization. The phytostabilisation potential of A. ilicifolius is dependent on the coordinated responses which endow with phenotypic plasticity necessary to cope with Zn toxicity.
Collapse
Affiliation(s)
- Nair G. Sarath
- Department of Botany, Plant Physiology and Biochemistry Division, University of Calicut, Thenhipalam, Kerala, India
| | - Shackira A. Manzil
- Department of Botany, Sir Syed College, Taliparamba, Kannur, Kerala, India
| | - Sajad Ali
- Department of Biotechnology, Yeungnam University, Gyeongsan, South Korea
| | | | - Jos T. Puthur
- Department of Botany, Plant Physiology and Biochemistry Division, University of Calicut, Thenhipalam, Kerala, India
| |
Collapse
|
15
|
Gates C, Ananyev G, Roy-Chowdhury S, Cullinane B, Miller M, Fromme P, Dismukes GC. Why Did Nature Choose Manganese over Cobalt to Make Oxygen Photosynthetically on the Earth? J Phys Chem B 2022; 126:3257-3268. [PMID: 35446582 DOI: 10.1021/acs.jpcb.2c00749] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
All contemporary oxygenic phototrophs─from primitive cyanobacteria to complex multicellular plants─split water using a single invariant cluster comprising Mn4CaO5 (the water oxidation catalyst) as the catalyst within photosystem II, the universal oxygenic reaction center of natural photosynthesis. This cluster is unstable outside of PSII and can be reconstituted, both in vivo and in vitro, using elemental aqueous ions and light, via photoassembly. Here, we demonstrate the first functional substitution of manganese in any oxygenic reaction center by in vitro photoassembly. Following complete removal of inorganic cofactors from cyanobacterial photosystem II microcrystal (PSIIX), photoassembly with free cobalt (Co2+), calcium (Ca2+), and water (OH-) restores O2 evolution activity. Photoassembly occurs at least threefold faster using Co2+ versus Mn2+ due to a higher quantum yield for PSIIX-mediated charge separation (P*): Co2+ → P* → Co3+QA-. However, this kinetic preference for Co2+ over native Mn2+ during photoassembly is offset by significantly poorer catalytic activity (∼25% of the activity with Mn2+) and ∼3- to 30-fold faster photoinactivation rate. The resulting reconstituted Co-PSIIX oxidizes water by the standard four-flash photocycle, although they produce 4-fold less O2 per PSII, suggested to arise from faster charge recombination (Co3+QA ← Co4+QA-) in the catalytic cycle. The faster photoinactivation of reconstituted Co-PSIIX occurs under anaerobic conditions during the catalytic cycle, suggesting direct photodamage without the involvement of O2. Manganese offers two advantages for oxygenic phototrophs, which may explain its exclusive retention throughout Darwinian evolution: significantly slower charge recombination (Mn3+QA ← Mn4+QA-) permits more water oxidation at low and fluctuating solar irradiation (greater net energy conversion) and much greater tolerance to photodamage at high light intensities (Mn4+ is less oxidizing than Co4+). Future work to identify the chemical nature of the intermediates will be needed for further interpretation.
Collapse
Affiliation(s)
- Colin Gates
- Waksman Institute of Microbiology, Rutgers University, Piscataway, New Jersey 08854, United States.,Department of Chemistry & Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, United States.,Department of Computational Biology & Molecular Biophysics, Rutgers University, Piscataway, New Jersey 08854, United States.,Department of Chemistry & Biochemistry, Loyola University Chicago, Chicago, Illinois 60660, United States
| | - Gennady Ananyev
- Waksman Institute of Microbiology, Rutgers University, Piscataway, New Jersey 08854, United States.,Department of Chemistry & Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Shatabdi Roy-Chowdhury
- Biodesign Center for Applied Structural Discovery and School of Molecular Sciences, Arizona State University, Tempe, Arizona 85281, United States
| | - Brendan Cullinane
- Waksman Institute of Microbiology, Rutgers University, Piscataway, New Jersey 08854, United States.,Department of Molecular Biology & Biochemistry, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Mathias Miller
- Waksman Institute of Microbiology, Rutgers University, Piscataway, New Jersey 08854, United States.,Department of Molecular Biology & Biochemistry, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Petra Fromme
- Biodesign Center for Applied Structural Discovery and School of Molecular Sciences, Arizona State University, Tempe, Arizona 85281, United States
| | - G Charles Dismukes
- Waksman Institute of Microbiology, Rutgers University, Piscataway, New Jersey 08854, United States.,Department of Chemistry & Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, United States
| |
Collapse
|
16
|
Advances in the Understanding of the Lifecycle of Photosystem II. Microorganisms 2022; 10:microorganisms10050836. [PMID: 35630282 PMCID: PMC9145668 DOI: 10.3390/microorganisms10050836] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 04/14/2022] [Accepted: 04/16/2022] [Indexed: 02/04/2023] Open
Abstract
Photosystem II is a light-driven water-plastoquinone oxidoreductase present in cyanobacteria, algae and plants. It produces molecular oxygen and protons to drive ATP synthesis, fueling life on Earth. As a multi-subunit membrane-protein-pigment complex, Photosystem II undergoes a dynamic cycle of synthesis, damage, and repair known as the Photosystem II lifecycle, to maintain a high level of photosynthetic activity at the cellular level. Cyanobacteria, oxygenic photosynthetic bacteria, are frequently used as model organisms to study oxygenic photosynthetic processes due to their ease of growth and genetic manipulation. The cyanobacterial PSII structure and function have been well-characterized, but its lifecycle is under active investigation. In this review, advances in studying the lifecycle of Photosystem II in cyanobacteria will be discussed, with a particular emphasis on new structural findings enabled by cryo-electron microscopy. These structural findings complement a rich and growing body of biochemical and molecular biology research into Photosystem II assembly and repair.
Collapse
|
17
|
Chen C, Xu B, Yao R, Chen Y, Zhang C. Synthesizing Mechanism of the Mn 4 Ca Cluster Mimicking the Oxygen-Evolving Center in Photosynthesis. CHEMSUSCHEM 2022; 15:e202102661. [PMID: 35075776 DOI: 10.1002/cssc.202102661] [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: 12/17/2021] [Revised: 01/19/2022] [Indexed: 06/14/2023]
Abstract
The photosynthetic oxygen-evolving center (OEC) is a unique Mn4 CaO5 cluster that serves as a blueprint to develop superior water-splitting catalysts for the generation of solar fuels in artificial photosynthesis. It is a great challenge and long-standing issue to reveal the synthesizing mechanism of this Mn4 CaO5 cluster in both natural and artificial photosynthesis. Herein, efforts were made to reveal the synthesizing mechanism of an artificial Mn4 CaO4 cluster, a close mimic of the OEC. Four key intermediates were successfully isolated and structurally characterized for the first time. It was demonstrated that the Mn4 CaO4 cluster could be formed through a reaction between a thermodynamically stable Mn3 CaO4 cluster and an unusual four-coordinated MnIII ion, followed by stabilization process through binding an organic base (e.g., pyridine) on the "dangling" Mn ion. These findings shed new light on the synthesizing mechanism of the OEC and rational design of new artificial water-splitting catalysts.
Collapse
Affiliation(s)
- Changhui Chen
- Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Boran Xu
- Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Ruoqing Yao
- Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Yang Chen
- Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Chunxi Zhang
- Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| |
Collapse
|
18
|
Bigness A, Vaddypally S, Zdilla MJ, Mendoza-Cortes JL. Ubiquity of cubanes in bioinorganic relevant compounds. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2021.214168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
19
|
Narzi D, Guidoni L. Structural and dynamic insights into Mn 4Ca cluster-depleted Photosystem II. Phys Chem Chem Phys 2021; 23:27428-27436. [PMID: 34860219 DOI: 10.1039/d1cp02367e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In the first steps of natural oxygenic photosynthesis, sunlight is used to oxidize water molecules to protons, electrons and molecular oxygen. This reaction takes place on the Mn4Ca cluster located in the reaction centre of Photosystem II (PSII), where the cluster is assembled and continuously repaired through a process known as photoactivation. Understanding the molecular details of such a process has important implications in different fields, in particular inspiring synthesis and repair strategies for artificial photosynthesis devices. In this regard, a detailed structural and dynamic characterization of Photosystem II lacking a Mn4Ca cluster, namely apo PSII, is a prerequisite for the full comprehension of the photoactivation. Recently, the structure of the apo PSII was resolved at 2.55 Å resolution [Zhang et al., eLife, 2017, 6, e26933], suggesting a pre-organized structure of the protein cavity hosting the cluster. Anyway, the question of whether these findings are a feature of the method used remains open. Here, by means of classical Molecular Dynamics simulations, we characterized the structural and dynamic features of the apo PSII for different protonation states of the cluster cavity. Albeit an overall conformational stability common to all investigated systems, we found significant deviations in the conformation of the side chains of the active site with respect to the X-ray positions. Our findings suggest that not all residues acting as Mn ligands are pre-organized prior to the Mn4Ca formation and previous local conformational changes are required in order to bind the first Mn ion in the high-affinity binding site.
Collapse
Affiliation(s)
- Daniele Narzi
- Department of Physical and Chemical Science, Università dellAquila, LAquila, Italy.
| | - Leonardo Guidoni
- Department of Physical and Chemical Science, Università dellAquila, LAquila, Italy.
| |
Collapse
|
20
|
Sato A, Nakano Y, Nakamura S, Noguchi T. Rapid-Scan Time-Resolved ATR-FTIR Study on the Photoassembly of the Water-Oxidizing Mn4CaO5 Cluster in Photosystem II. J Phys Chem B 2021; 125:4031-4045. [DOI: 10.1021/acs.jpcb.1c01624] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Akihiko Sato
- Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Yuki Nakano
- Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Shin Nakamura
- Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Takumi Noguchi
- Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| |
Collapse
|
21
|
Zabret J, Bohn S, Schuller SK, Arnolds O, Möller M, Meier-Credo J, Liauw P, Chan A, Tajkhorshid E, Langer JD, Stoll R, Krieger-Liszkay A, Engel BD, Rudack T, Schuller JM, Nowaczyk MM. Structural insights into photosystem II assembly. NATURE PLANTS 2021; 7:524-538. [PMID: 33846594 PMCID: PMC8094115 DOI: 10.1038/s41477-021-00895-0] [Citation(s) in RCA: 84] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 03/04/2021] [Indexed: 05/07/2023]
Abstract
Biogenesis of photosystem II (PSII), nature's water-splitting catalyst, is assisted by auxiliary proteins that form transient complexes with PSII components to facilitate stepwise assembly events. Using cryo-electron microscopy, we solved the structure of such a PSII assembly intermediate from Thermosynechococcus elongatus at 2.94 Å resolution. It contains three assembly factors (Psb27, Psb28 and Psb34) and provides detailed insights into their molecular function. Binding of Psb28 induces large conformational changes at the PSII acceptor side, which distort the binding pocket of the mobile quinone (QB) and replace the bicarbonate ligand of non-haem iron with glutamate, a structural motif found in reaction centres of non-oxygenic photosynthetic bacteria. These results reveal mechanisms that protect PSII from damage during biogenesis until water splitting is activated. Our structure further demonstrates how the PSII active site is prepared for the incorporation of the Mn4CaO5 cluster, which performs the unique water-splitting reaction.
Collapse
Affiliation(s)
- Jure Zabret
- Department of Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Stefan Bohn
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Sandra K Schuller
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
- CryoEM of Molecular Machines, SYNMIKRO Research Center and Department of Chemistry, Philipps University of Marburg, Marburg, Germany
| | - Oliver Arnolds
- Biomolecular Spectroscopy and RUBiospek|NMR, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Madeline Möller
- Department of Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | | | - Pasqual Liauw
- Department of Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Aaron Chan
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Emad Tajkhorshid
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Julian D Langer
- Proteomics, Max Planck Institute of Biophysics, Frankfurt, Germany
- Proteomics, Max Planck Institute for Brain Research, Frankfurt, Germany
| | - Raphael Stoll
- Biomolecular Spectroscopy and RUBiospek|NMR, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Anja Krieger-Liszkay
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Benjamin D Engel
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
- Helmholtz Pioneer Campus, Helmholtz Zentrum München, Neuherberg, Germany
- Department of Chemistry, Technical University of Munich, Garching, Germany
| | - Till Rudack
- Biospectroscopy, Center for Protein Diagnostics (ProDi), Ruhr University Bochum, Bochum, Germany.
- Department of Biophysics, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany.
| | - Jan M Schuller
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Martinsried, Germany.
- CryoEM of Molecular Machines, SYNMIKRO Research Center and Department of Chemistry, Philipps University of Marburg, Marburg, Germany.
| | - Marc M Nowaczyk
- Department of Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany.
| |
Collapse
|
22
|
Light-driven formation of manganese oxide by today's photosystem II supports evolutionarily ancient manganese-oxidizing photosynthesis. Nat Commun 2020; 11:6110. [PMID: 33257675 PMCID: PMC7705724 DOI: 10.1038/s41467-020-19852-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 11/02/2020] [Indexed: 11/10/2022] Open
Abstract
Water oxidation and concomitant dioxygen formation by the manganese-calcium cluster of oxygenic photosynthesis has shaped the biosphere, atmosphere, and geosphere. It has been hypothesized that at an early stage of evolution, before photosynthetic water oxidation became prominent, light-driven formation of manganese oxides from dissolved Mn(2+) ions may have played a key role in bioenergetics and possibly facilitated early geological manganese deposits. Here we report the biochemical evidence for the ability of photosystems to form extended manganese oxide particles. The photochemical redox processes in spinach photosystem-II particles devoid of the manganese-calcium cluster are tracked by visible-light and X-ray spectroscopy. Oxidation of dissolved manganese ions results in high-valent Mn(III,IV)-oxide nanoparticles of the birnessite type bound to photosystem II, with 50-100 manganese ions per photosystem. Having shown that even today’s photosystem II can form birnessite-type oxide particles efficiently, we propose an evolutionary scenario, which involves manganese-oxide production by ancestral photosystems, later followed by down-sizing of protein-bound manganese-oxide nanoparticles to finally yield today’s catalyst of photosynthetic water oxidation. Photosynthetic formation of manganese (Mn) oxides from dissolved Mn ions was proposed to occur in ancestral photosystems before oxygenic photosynthesis evolved. Here, the authors provide evidence for this hypothesis by showing that photosystem II devoid of the Mn cluster oxidises Mn ions leading to formation of Mn-oxide nanoparticles.
Collapse
|
23
|
Tokano T, Kato Y, Sugiyama S, Uchihashi T, Noguchi T. Structural Dynamics of a Protein Domain Relevant to the Water-Oxidizing Complex in Photosystem II as Visualized by High-Speed Atomic Force Microscopy. J Phys Chem B 2020; 124:5847-5857. [PMID: 32551630 DOI: 10.1021/acs.jpcb.0c03892] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Photosystem II (PSII) is a multiprotein complex that has a function of light-driven water oxidation. The catalytic site of water oxidation is the Mn4CaO5 cluster, which is bound to the lumenal side of PSII through amino acid residues from the D1 and CP43 proteins and is further surrounded by the extrinsic proteins. In this study, we have for the first time visualized the structural dynamics of the lumenal region of a PSII core complex using high-speed atomic force microscopy (HS-AFM). The HS-AFM images of a PSII membrane fragment showed stepwise dissociation of the PsbP and PsbO extrinsic proteins. Upon subsequent destruction of the Mn4CaO5 cluster, the lumenal domain of CP43 was found to undergo a conformational fluctuation. The observed structural flexibility and conformational fluctuation of the CP43 lumenal domain are suggested to play important roles in the biogenesis of PSII and the photoassembly of the Mn4CaO5 cluster.
Collapse
Affiliation(s)
- Takaya Tokano
- Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Yuki Kato
- Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Shogo Sugiyama
- Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Takayuki Uchihashi
- Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Takumi Noguchi
- Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| |
Collapse
|
24
|
|
25
|
Abstract
The oxygen-evolving center (OEC) in photosystem II (PSII) of plants, algae and cyanobacteria is a unique natural catalyst that splits water into electrons, protons and dioxygen. The crystallographic studies of PSII have revealed that the OEC is an asymmetric Mn4CaO5-cluster. The understanding of the structure-function relationship of this natural Mn4CaO5-cluster is impeded mainly due to the complexity of the protein environment and lack of a rational chemical model as a reference. Although it has been a great challenge for chemists to synthesize the OEC in the laboratory, significant advances have been achieved recently. Different artificial complexes have been reported, especially a series of artificial Mn4CaO4-clusters that closely mimic both the geometric and electronic structures of the OEC in PSII, which provides a structurally well-defined chemical model to investigate the structure-function relationship of the natural Mn4CaO5-cluster. The deep investigations on this artificial Mn4CaO4-cluster could provide new insights into the mechanism of the water-splitting reaction in natural photosynthesis and may help the development of efficient catalysts for the water-splitting reaction in artificial photosynthesis.
Collapse
|
26
|
Assessment of the manganese cluster's oxidation state via photoactivation of photosystem II microcrystals. Proc Natl Acad Sci U S A 2019; 117:141-145. [PMID: 31848244 DOI: 10.1073/pnas.1915879117] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Knowledge of the manganese oxidation states of the oxygen-evolving Mn4CaO5 cluster in photosystem II (PSII) is crucial toward understanding the mechanism of biological water oxidation. There is a 4 decade long debate on this topic that historically originates from the observation of a multiline electron paramagnetic resonance (EPR) signal with effective total spin of S = 1/2 in the singly oxidized S2 state of this cluster. This signal implies an overall oxidation state of either Mn(III)3Mn(IV) or Mn(III)Mn(IV)3 for the S2 state. These 2 competing assignments are commonly known as "low oxidation (LO)" and "high oxidation (HO)" models of the Mn4CaO5 cluster. Recent advanced EPR and Mn K-edge X-ray spectroscopy studies converge upon the HO model. However, doubts about these assignments have been voiced, fueled especially by studies counting the number of flash-driven electron removals required for the assembly of an active Mn4CaO5 cluster starting from Mn(II) and Mn-free PSII. This process, known as photoactivation, appeared to support the LO model since the first oxygen is reported to evolve already after 7 flashes. In this study, we improved the quantum yield and sensitivity of the photoactivation experiment by employing PSII microcrystals that retained all protein subunits after complete manganese removal and by oxygen detection via a custom built thin-layer cell connected to a membrane inlet mass spectrometer. We demonstrate that 9 flashes by a nanosecond laser are required for the production of the first oxygen, which proves that the HO model provides the correct description of the Mn4CaO5 cluster's oxidation states.
Collapse
|
27
|
The Biochemical Properties of Manganese in Plants. PLANTS 2019; 8:plants8100381. [PMID: 31569811 PMCID: PMC6843630 DOI: 10.3390/plants8100381] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 09/23/2019] [Accepted: 09/24/2019] [Indexed: 01/12/2023]
Abstract
Manganese (Mn) is an essential micronutrient with many functional roles in plant metabolism. Manganese acts as an activator and co-factor of hundreds of metalloenzymes in plants. Because of its ability to readily change oxidation state in biological systems, Mn plays and important role in a broad range of enzyme-catalyzed reactions, including redox reactions, phosphorylation, decarboxylation, and hydrolysis. Manganese(II) is the prevalent oxidation state of Mn in plants and exhibits fast ligand exchange kinetics, which means that Mn can often be substituted by other metal ions, such as Mg(II), which has similar ion characteristics and requirements to the ligand environment of the metal binding sites. Knowledge of the molecular mechanisms catalyzed by Mn and regulation of Mn insertion into the active site of Mn-dependent enzymes, in the presence of other metals, is gradually evolving. This review presents an overview of the chemistry and biochemistry of Mn in plants, including an updated list of known Mn-dependent enzymes, together with enzymes where Mn has been shown to exchange with other metal ions. Furthermore, the current knowledge of the structure and functional role of the three most well characterized Mn-containing metalloenzymes in plants; the oxygen evolving complex of photosystem II, Mn superoxide dismutase, and oxalate oxidase is summarized.
Collapse
|
28
|
Photosystem II oxygen-evolving complex photoassembly displays an inverse H/D solvent isotope effect under chloride-limiting conditions. Proc Natl Acad Sci U S A 2019; 116:18917-18922. [PMID: 31484762 PMCID: PMC6754581 DOI: 10.1073/pnas.1910231116] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Metal clusters play important roles in a wide variety of proteins. In cyanobacteria, algae, and plants, photosystem II uses light energy to oxidize water and release O2 at an active site that contains 1 calcium and 4 manganese atoms. This cluster must be built within the protein environment through a process known as photoassembly. Through experiments and simulations, we found that the efficiency of photoassembly was highly dependent on protons and chloride. Surprisingly, when the solvent was switched from H2O to deuterated water, D2O, the yield of photoassembly was higher. These results provide insights into the stepwise mechanism of photoassembly that can inform synthesis and repair strategies being developed for artificial photosynthesis technologies. Photosystem II (PSII) performs the solar-driven oxidation of water used to fuel oxygenic photosynthesis. The active site of water oxidation is the oxygen-evolving complex (OEC), a Mn4CaO5 cluster. PSII requires degradation of key subunits and reassembly of the OEC as frequently as every 20 to 40 min. The metals for the OEC are assembled within the PSII protein environment via a series of binding events and photochemically induced oxidation events, but the full mechanism is unknown. A role of proton release in this mechanism is suggested here by the observation that the yield of in vitro OEC photoassembly is higher in deuterated water, D2O, compared with H2O when chloride is limiting. In kinetic studies, OEC photoassembly shows a significant lag phase in H2O at limiting chloride concentrations with an apparent H/D solvent isotope effect of 0.14 ± 0.05. The growth phase of OEC photoassembly shows an H/D solvent isotope effect of 1.5 ± 0.2. We analyzed the protonation states of the OEC protein environment using classical Multiconformer Continuum Electrostatics. Combining experiments and simulations leads to a model in which protons are lost from amino acid that will serve as OEC ligands as metals are bound. Chloride and D2O increase the proton affinities of key amino acid residues. These residues tune the binding affinity of Mn2+/3+ and facilitate the deprotonation of water to form a proposed μ-hydroxo bridged Mn2+Mn3+ intermediate.
Collapse
|
29
|
Liang HZ, Zhu F, Wang RJ, Huang XH, Chu JJ. Photosystem II of Ligustrum lucidum in response to different levels of manganese exposure. Sci Rep 2019; 9:12568. [PMID: 31467311 PMCID: PMC6715691 DOI: 10.1038/s41598-019-48735-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 07/31/2019] [Indexed: 11/17/2022] Open
Abstract
The toxic effect of excessive manganese (Mn) on photosystem II (PSII) of woody species remains largely unexplored. In this study, five Mn concentrations (0, 12, 24, 36, and 48 mM) were used, and the toxicity of Mn on PSII behavior in leaves of Ligustrum lucidum was investigated using in vivo chlorophyll fluorescence transients. Results showed that excessive Mn levels induced positive L- and K- bands. Variable fluorescence at 2 ms (VJ) and 30 ms (VI), absorption flux (ABS/RC), trapped energy flux (TRo/RC), and dissipated energy flux (DIo/RC) increased in Mn-treated leaves, whereas the performance index (PIABS), electron transport flux (ETo/RC), maximum quantum yield (φPo), quantum yield of electron transport (φEo), and probability that an electron moves further than QA− (ψo) decreased. Also, excessive Mn significantly decreased the net photosynthesis rate and increased intercellular CO2 concentration. The results indicated that Mn blocked the electron transfer from the donor side to the acceptor side in PSII, which might be associated with the accumulation of QA−, hence limiting the net photosynthetic rate.
Collapse
Affiliation(s)
- Hui-Zi Liang
- College of Life Science and Technology, Central South University of Forestry and Technology, Changsha, 410004, P. R. China
| | - Fan Zhu
- College of Life Science and Technology, Central South University of Forestry and Technology, Changsha, 410004, P. R. China. .,Engineering Laboratory of Applied Technology for Forestry & Ecology in Southern China, Changsha, 410004, Hunan, China.
| | - Ren-Jie Wang
- Engineering Laboratory of Applied Technology for Forestry & Ecology in Southern China, Changsha, 410004, Hunan, China
| | - Xin-Hao Huang
- College of Life Science and Technology, Central South University of Forestry and Technology, Changsha, 410004, P. R. China
| | - Jing-Jing Chu
- College of Life Science and Technology, Central South University of Forestry and Technology, Changsha, 410004, P. R. China
| |
Collapse
|
30
|
Han R, Rempfer K, Zhang M, Dobbek H, Zouni A, Dau H, Luber S. Investigating the Structure and Dynamics of Apo‐Photosystem II. ChemCatChem 2019. [DOI: 10.1002/cctc.201900351] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Ruocheng Han
- Institut für ChemieUniversität Zürich Winterthurerstrasse 129 8057 Zürich Switzerland
| | - Katharina Rempfer
- Institut für ChemieUniversität Zürich Winterthurerstrasse 129 8057 Zürich Switzerland
| | - Miao Zhang
- Institut für BiologieHumboldt Universität zu Berlin Philippstrasse 13 10115 Berlin Germany
| | - Holger Dobbek
- Institut für BiologieHumboldt Universität zu Berlin Philippstrasse 13 10115 Berlin Germany
| | - Athina Zouni
- Institut für BiologieHumboldt Universität zu Berlin Philippstrasse 13 10115 Berlin Germany
| | - Holger Dau
- Institut für PhysikFreie Universität Berlin Arnimallee 14 14195 Berlin Germany
| | - Sandra Luber
- Institut für ChemieUniversität Zürich Winterthurerstrasse 129 8057 Zürich Switzerland
| |
Collapse
|
31
|
Shevela D, Ananyev G, Vatland AK, Arnold J, Mamedov F, Eichacker LA, Dismukes GC, Messinger J. 'Birth defects' of photosystem II make it highly susceptible to photodamage during chloroplast biogenesis. PHYSIOLOGIA PLANTARUM 2019; 166:165-180. [PMID: 30693529 DOI: 10.1111/ppl.12932] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 01/17/2019] [Accepted: 01/18/2019] [Indexed: 06/09/2023]
Abstract
High solar flux is known to diminish photosynthetic growth rates, reducing biomass productivity and lowering disease tolerance. Photosystem II (PSII) of plants is susceptible to photodamage (also known as photoinactivation) in strong light, resulting in severe loss of water oxidation capacity and destruction of the water-oxidizing complex (WOC). The repair of damaged PSIIs comes at a high energy cost and requires de novo biosynthesis of damaged PSII subunits, reassembly of the WOC inorganic cofactors and membrane remodeling. Employing membrane-inlet mass spectrometry and O2 -polarography under flashing light conditions, we demonstrate that newly synthesized PSII complexes are far more susceptible to photodamage than are mature PSII complexes. We examined these 'PSII birth defects' in barley seedlings and plastids (etiochloroplasts and chloroplasts) isolated at various times during de-etiolation as chloroplast development begins and matures in synchronization with thylakoid membrane biogenesis and grana membrane formation. We show that the degree of PSII photodamage decreases simultaneously with biogenesis of the PSII turnover efficiency measured by O2 -polarography, and with grana membrane stacking, as determined by electron microscopy. Our data from fluorescence, QB -inhibitor binding, and thermoluminescence studies indicate that the decline of the high-light susceptibility of PSII to photodamage is coincident with appearance of electron transfer capability QA - → QB during de-etiolation. This rate depends in turn on the downstream clearing of electrons upon buildup of the complete linear electron transfer chain and the formation of stacked grana membranes capable of longer-range energy transfer.
Collapse
Affiliation(s)
- Dmitry Shevela
- Department of Chemistry, Chemical Biological Centre, Umeå University, S-90187, Umeå, Sweden
| | - Gennady Ananyev
- The Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ, 08854, USA
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, 08854, USA
| | - Ann K Vatland
- Centre for Organelle Research, Faculty of Science and Technology, University of Stavanger, N-4036, Stavanger, Norway
| | - Janine Arnold
- Centre for Organelle Research, Faculty of Science and Technology, University of Stavanger, N-4036, Stavanger, Norway
| | - Fikret Mamedov
- Molecular Biomimetics, Department of Chemistry - Ångström Laboratory, Uppsala University, S-75237, Uppsala, Sweden
| | - Lutz A Eichacker
- Centre for Organelle Research, Faculty of Science and Technology, University of Stavanger, N-4036, Stavanger, Norway
| | - G Charles Dismukes
- The Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ, 08854, USA
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, 08854, USA
| | - Johannes Messinger
- Department of Chemistry, Chemical Biological Centre, Umeå University, S-90187, Umeå, Sweden
- Molecular Biomimetics, Department of Chemistry - Ångström Laboratory, Uppsala University, S-75237, Uppsala, Sweden
| |
Collapse
|
32
|
The S3 State of the Oxygen-Evolving Complex: Overview of Spectroscopy and XFEL Crystallography with a Critical Evaluation of Early-Onset Models for O–O Bond Formation. INORGANICS 2019. [DOI: 10.3390/inorganics7040055] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The catalytic cycle of the oxygen-evolving complex (OEC) of photosystem II (PSII) comprises five intermediate states Si (i = 0–4), from the most reduced S0 state to the most oxidized S4, which spontaneously evolves dioxygen. The precise geometric and electronic structure of the Si states, and hence the mechanism of O–O bond formation in the OEC, remain under investigation, particularly for the final steps of the catalytic cycle. Recent advances in protein crystallography based on X-ray free-electron lasers (XFELs) have produced new structural models for the S3 state, which indicate that two of the oxygen atoms of the inorganic Mn4CaO6 core of the OEC are in very close proximity. This has been interpreted as possible evidence for “early-onset” O–O bond formation in the S3 state, as opposed to the more widely accepted view that the O–O bond is formed in the final state of the cycle, S4. Peroxo or superoxo formation in S3 has received partial support from computational studies. Here, a brief overview is provided of spectroscopic information, recent crystallographic results, and computational models for the S3 state. Emphasis is placed on computational S3 models that involve O–O formation, which are discussed with respect to their agreement with structural information, experimental evidence from various spectroscopic studies, and substrate exchange kinetics. Despite seemingly better agreement with some of the available crystallographic interpretations for the S3 state, models that implicate early-onset O–O bond formation are hard to reconcile with the complete line of experimental evidence, especially with X-ray absorption, X-ray emission, and magnetic resonance spectroscopic observations. Specifically with respect to quantum chemical studies, the inconclusive energetics for the possible isoforms of S3 is an acute problem that is probably beyond the capabilities of standard density functional theory.
Collapse
|
33
|
Xu HF, Dai GZ, Qiu BS. Weak red light plays an important role in awakening the photosynthetic machinery following desiccation in the subaerial cyanobacterium Nostoc flagelliforme. Environ Microbiol 2019; 21:2261-2272. [PMID: 30895692 DOI: 10.1111/1462-2920.14600] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 01/31/2019] [Accepted: 03/19/2019] [Indexed: 11/28/2022]
Abstract
The subaerial cyanobacterium Nostoc flagelliforme can survive for years in the desiccated state and light exposure may stimulate photosynthetic recovery during rehydration. However, the influence of light quality on photosynthetic recovery and the underlying mechanism remain unresolved. Exposure of field collected N. flagelliforme to light intensity ≥2 μmol photons m-2 s-1 showed that the speed of photosystem II (PSII) recovery was in the following order: red > green > blue ≈ violet light. Decreasing the light intensity showed that weak red light stimulated PSII recovery during rehydration. The chlorophyll fluorescence transient and oxygen evolution activity indicated that the oxygen evolution complex (OEC) was the activated site triggered by weak red light. The damaged D1 protein accumulated in the thylakoid membrane during dehydration and is degraded and resynthesized during dark rehydration. PsbO interaction with the thylakoid membrane was induced by weak red light. Thus, weak red light plays an important role in triggering OEC photoactivation and the formation of functional PSII during rehydration. In its arid habitats, weak red light could stimulate the awakening of dormant N. flagelliforme after absorbing water from nighttime dew or rain to maximize growth during the early daylight hours of the dry season.
Collapse
Affiliation(s)
- Hai-Feng Xu
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, Hubei, 430079, P. R. China
| | - Guo-Zheng Dai
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, Hubei, 430079, P. R. China
| | - Bao-Sheng Qiu
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, Hubei, 430079, P. R. China
| |
Collapse
|
34
|
Nakamura S, Noguchi T. Initial Mn2+ binding site in photoassembly of the water-oxidizing Mn4CaO5 cluster in photosystem II as studied by quantum mechanics/molecular mechanics calculations. Chem Phys Lett 2019. [DOI: 10.1016/j.cplett.2019.02.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|
35
|
Das S, Khatua K, Rakshit A, Carmona A, Sarkar A, Bakthavatsalam S, Ortega R, Datta A. Emerging chemical tools and techniques for tracking biological manganese. Dalton Trans 2019; 48:7047-7061. [DOI: 10.1039/c9dt00508k] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This frontier article discusses chemical tools and techniques for tracking and imaging Mn ions in biology.
Collapse
Affiliation(s)
- Sayani Das
- Department of Chemical Sciences
- Tata Institute of Fundamental Research
- Colaba
- India
| | - Kaustav Khatua
- Department of Chemical Sciences
- Tata Institute of Fundamental Research
- Colaba
- India
| | - Ananya Rakshit
- Department of Chemical Sciences
- Tata Institute of Fundamental Research
- Colaba
- India
| | - Asuncion Carmona
- Chemical Imaging and Speciation
- CENBG
- University of Bordeaux
- UMR 5797
- 33175 Gradignan
| | - Anindita Sarkar
- Department of Biological Chemistry
- University of Michigan
- Ann Arbor
- USA
| | | | - Richard Ortega
- Chemical Imaging and Speciation
- CENBG
- University of Bordeaux
- UMR 5797
- 33175 Gradignan
| | - Ankona Datta
- Department of Chemical Sciences
- Tata Institute of Fundamental Research
- Colaba
- India
| |
Collapse
|
36
|
Straka L, Rittmann BE. Light-dependent kinetic model for microalgae experiencing photoacclimation, photodamage, and photodamage repair. ALGAL RES 2018. [DOI: 10.1016/j.algal.2018.02.022] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
|
37
|
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.
Collapse
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
| |
Collapse
|
38
|
Petrie S, Stranger R, Pace RJ. What Mn K β spectroscopy reveals concerning the oxidation states of the Mn cluster in photosystem II. Phys Chem Chem Phys 2018; 19:27682-27693. [PMID: 28983541 DOI: 10.1039/c7cp04797e] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The oxygen evolving complex, (OEC) in Photosystem II contains a Mn4Ca cluster and catalyses oxidation of water to molecular oxygen and protons, the most energetically demanding reaction in nature. The catalytic mechanism remains unresolved and the precise Mn oxidation levels through which the cluster cycles during functional turnover are controversial. Two proposals for these redox levels exist; the 'high' and 'low' oxidation state paradigms, which differ systematically by two oxidation equivalents throughout the redox accumulating catalytic S state cycle (states S0…S3). Presently the 'high' paradigm is more favored. For S1 the assumed mean redox levels of Mn are 3.5 (high) and 3.0 (low) respectively. Mn K region X-ray spectroscopy has been extensively used to examine the OEC Mn oxidation levels, with Kβ emission spectroscopy increasingly the method of choice. Here we review the results from application of this and closely related techniques to PS II, building on our earlier examination of these and other data on the OEC oxidation states (Pace et al., Dalton Trans., 2012, 41, 11145). We compare the most recent results with a range of earlier Mn Kβ experiments on the photosystem and related model Mn systems. New analyses of these data are given, highlighting certain key spectral considerations which appear not to have been sufficiently appreciated earlier. These show that the recent and earlier PS II Kβ results have a natural internal consistency, leading to the strong conclusion that the low paradigm oxidation state assignment for the functional OEC is favoured.
Collapse
Affiliation(s)
- Simon Petrie
- Research School of Chemistry, College of Physical & Mathematical Sciences, College of Science, Australian National University, Canberra, ACT 0200, Australia.
| | | | | |
Collapse
|
39
|
Yatabe T, Tokunaga T, Matsumoto T, Kikkawa M, Yoon KS, Ogo S. A Mn I Model for the Photoinhibited Species of Oxygen-evolving Complex. CHEM LETT 2018. [DOI: 10.1246/cl.170869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Takeshi Yatabe
- Center for Small Molecule Energy, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Taisuke Tokunaga
- Center for Small Molecule Energy, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Takahiro Matsumoto
- Center for Small Molecule Energy, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Mitsuhiro Kikkawa
- Center for Small Molecule Energy, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Ki-Seok Yoon
- Center for Small Molecule Energy, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Seiji Ogo
- Center for Small Molecule Energy, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| |
Collapse
|
40
|
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
Collapse
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
| |
Collapse
|
41
|
Rodionova MV, Zharmukhamedov SK, Karacan MS, Venedik KB, Shitov AV, Tunç T, Mamaş S, Kreslavski VD, Karacan N, Klimov VV, Allakhverdiev SI. Evaluation of new Cu(II) complexes as a novel class of inhibitors against plant carbonic anhydrase, glutathione reductase, and photosynthetic activity in photosystem II. PHOTOSYNTHESIS RESEARCH 2017; 133:139-153. [PMID: 28497193 DOI: 10.1007/s11120-017-0392-9] [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: 04/13/2017] [Accepted: 04/28/2017] [Indexed: 06/07/2023]
Abstract
Increasing inefficiency of production of important agricultural plants raises one of the biggest problems in the modern world. Herbicide application is still the best method of weed management. Traditional herbicides blocking only one of the plant metabolic pathways is ineffective due to the rapid growth of herbicide-resistant weeds. The synthesis of novel compounds effectively suppressing several metabolic processes, and therefore achieving the synergism effect would serve as the alternative approach to weed problem. For this reason, recently, we synthesized a series of nine novel Cu(II) complexes and four ligands, characterized them with different analyses techniques, and carried out their primary evaluation as inhibitors of photosynthetic electron transfer in spinach thylakoids (design, synthesis, and evaluation of a series of Cu(II) based metal-organic complexes as possible inhibitors of photosynthesis, J Photochem Photobiol B, submitted). Here, we evaluated in vitro inhibitory potency of these agents against: photochemistry and carbonic anhydrase activity of photosystem II (PSII); α-carbonic anhydrase from bovine erythrocytes; as well as glutathione reductase from chloroplast and baker's yeast. Our results show that all Cu(II) complexes excellently inhibit glutathione reductase and PSII carbonic anhydrase activity. Some of them also decently inhibit PSII photosynthetic activity.
Collapse
Affiliation(s)
- Margarita V Rodionova
- Controlled Photobiosynthesis Laboratory, Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow, Russia, 127276
| | - Sergei K Zharmukhamedov
- Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya Street 2, Pushchino, Moscow Region, Russia, 142290
| | - Mehmet Sayım Karacan
- Department of Chemistry, Science Faculty, Gazi University, Teknikokullar, Ankara, Turkey
| | - Kubra Begum Venedik
- Department of Chemistry, Science Faculty, Gazi University, Teknikokullar, Ankara, Turkey
| | - Alexandr V Shitov
- Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya Street 2, Pushchino, Moscow Region, Russia, 142290
| | - Turgay Tunç
- Department of Chemistry and Process Engineering, Faculty of Engineering-Architecture, Ahi Evran University, Kirsehir, Turkey
| | - Serhat Mamaş
- Department of Chemistry, Science Faculty, Gazi University, Teknikokullar, Ankara, Turkey
| | - Vladimir D Kreslavski
- Controlled Photobiosynthesis Laboratory, Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow, Russia, 127276
- Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya Street 2, Pushchino, Moscow Region, Russia, 142290
| | - Nurcan Karacan
- Department of Chemistry, Science Faculty, Gazi University, Teknikokullar, Ankara, Turkey.
| | - Vyacheslav V Klimov
- Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya Street 2, Pushchino, Moscow Region, Russia, 142290
| | - Suleyman I Allakhverdiev
- Controlled Photobiosynthesis Laboratory, Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow, Russia, 127276.
- Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya Street 2, Pushchino, Moscow Region, Russia, 142290.
- Department of Plant Physiology, Faculty of Biology, M.V. Lomonosov Moscow State University, Leninskie Gory 1-12, Moscow, Russia, 119991.
- Bionanotechnology Laboratory, Institute of Molecular Biology and Biotechnology, Azerbaijan National Academy of Sciences, Baku, Azerbaijan.
| |
Collapse
|
42
|
Alaimo AA, Koumousi ES, Cunha-Silva L, McCormick LJ, Teat SJ, Psycharis V, Raptopoulou CP, Mukherjee S, Li C, Gupta SD, Escuer A, Christou G, Stamatatos TC. Structural Diversities in Heterometallic Mn–Ca Cluster Chemistry from the Use of Salicylhydroxamic Acid: {MnIII4Ca2}, {MnII/III6Ca2}, {MnIII/IV8Ca}, and {MnIII8Ca2} Complexes with Relevance to Both High- and Low-Valent States of the Oxygen-Evolving Complex. Inorg Chem 2017; 56:10760-10774. [DOI: 10.1021/acs.inorgchem.7b01740] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Alysha A. Alaimo
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, L2S 3A1 St. Catharines, Ontario, Canada
| | | | - Luís Cunha-Silva
- REQUIMTE-LAQV & Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, 4169-007 Porto, Portugal
| | - Laura J. McCormick
- Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Simon J. Teat
- Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Vassilis Psycharis
- Institute of Nanoscience and Nanotechnology, NCSR “Demokritos”, 15310 Agia Paraskevi, Attikis, Greece
| | - Catherine P. Raptopoulou
- Institute of Nanoscience and Nanotechnology, NCSR “Demokritos”, 15310 Agia Paraskevi, Attikis, Greece
| | - Shreya Mukherjee
- Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, United States
| | - Chaoran Li
- Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, United States
| | - Sayak Das Gupta
- Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, United States
| | - Albert Escuer
- Departament
de Quimica Inorganica and Institut de Nanociencia i Nanotecnologia
(IN2UB), Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain
| | - George Christou
- Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, United States
| | - Theocharis C. Stamatatos
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, L2S 3A1 St. Catharines, Ontario, Canada
| |
Collapse
|
43
|
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
| |
Collapse
|
44
|
Zhang M, Bommer M, Chatterjee R, Hussein R, Yano J, Dau H, Kern J, Dobbek H, Zouni A. Structural insights into the light-driven auto-assembly process of the water-oxidizing Mn 4CaO 5-cluster in photosystem II. eLife 2017; 6. [PMID: 28718766 PMCID: PMC5542773 DOI: 10.7554/elife.26933] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 07/17/2017] [Indexed: 01/11/2023] Open
Abstract
In plants, algae and cyanobacteria, Photosystem II (PSII) catalyzes the light-driven splitting of water at a protein-bound Mn4CaO5-cluster, the water-oxidizing complex (WOC). In the photosynthetic organisms, the light-driven formation of the WOC from dissolved metal ions is a key process because it is essential in both initial activation and continuous repair of PSII. Structural information is required for understanding of this chaperone-free metal-cluster assembly. For the first time, we obtained a structure of PSII from Thermosynechococcus elongatus without the Mn4CaO5-cluster. Surprisingly, cluster-removal leaves the positions of all coordinating amino acid residues and most nearby water molecules largely unaffected, resulting in a pre-organized ligand shell for kinetically competent and error-free photo-assembly of the Mn4CaO5-cluster. First experiments initiating (i) partial disassembly and (ii) partial re-assembly after complete depletion of the Mn4CaO5-cluster agree with a specific bi-manganese cluster, likely a di-µ-oxo bridged pair of Mn(III) ions, as an assembly intermediate. DOI:http://dx.doi.org/10.7554/eLife.26933.001
Collapse
Affiliation(s)
- Miao Zhang
- Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Martin Bommer
- Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Ruchira Chatterjee
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Rana Hussein
- Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Junko Yano
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Holger Dau
- Freie Universität Berlin, Berlin, Germany
| | - Jan Kern
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Holger Dobbek
- Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Athina Zouni
- Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
| |
Collapse
|
45
|
Najafpour MM, Heidari S, Balaghi SE, Hołyńska M, Sadr MH, Soltani B, Khatamian M, Larkum AW, Allakhverdiev SI. Proposed mechanisms for water oxidation by Photosystem II and nanosized manganese oxides. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:156-174. [DOI: 10.1016/j.bbabio.2016.11.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 11/05/2016] [Accepted: 11/08/2016] [Indexed: 12/18/2022]
|
46
|
Patel J, Majee K, Ahmad E, Das B, Padhi SK. Effect of Pyridyl Substitution on Chemical and Photochemical Water Oxidation by [Ru(terpyridine)(bipyridine)(OH
2
)]
2+
Scaffolds. Eur J Inorg Chem 2016. [DOI: 10.1002/ejic.201601193] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Jully Patel
- Artificial Photosynthesis Lab Department of Applied Chemistry Indian Institute of Technology (ISM) 826004 Dhanbad India
| | - Karunamay Majee
- Artificial Photosynthesis Lab Department of Applied Chemistry Indian Institute of Technology (ISM) 826004 Dhanbad India
| | - Ejaz Ahmad
- Artificial Photosynthesis Lab Department of Applied Chemistry Indian Institute of Technology (ISM) 826004 Dhanbad India
| | - Babulal Das
- Department of Chemistry IIT Guwahati 781039 Assam India
| | - Sumanta Kumar Padhi
- Artificial Photosynthesis Lab Department of Applied Chemistry Indian Institute of Technology (ISM) 826004 Dhanbad India
| |
Collapse
|
47
|
Yamada Y, Tadokoro H, Fukuzumi S. An effective preparation method of composite photocatalysts for hydrogen evolution using an organic photosensitizer and metal particles assembled on alumina-silica. Catal Today 2016. [DOI: 10.1016/j.cattod.2016.01.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
48
|
Khorobrykh A, Yanykin D, Klimov V. Enhancement of photoassembly of the functionally active water-oxidizing complex in Mn-depleted photosystem II membranes upon transition to anaerobic conditions. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2016; 163:211-5. [DOI: 10.1016/j.jphotobiol.2016.08.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 08/19/2016] [Accepted: 08/22/2016] [Indexed: 10/21/2022]
|
49
|
Gates C, Ananyev G, Dismukes GC. The strontium inorganic mutant of the water oxidizing center (CaMn4O5) of PSII improves WOC efficiency but slows electron flux through the terminal acceptors. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1550-1560. [DOI: 10.1016/j.bbabio.2016.06.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 05/26/2016] [Accepted: 06/10/2016] [Indexed: 01/26/2023]
|
50
|
Morris JN, Eaton-Rye JJ, Summerfield TC. Environmental pH and the Requirement for the Extrinsic Proteins of Photosystem II in the Function of Cyanobacterial Photosynthesis. FRONTIERS IN PLANT SCIENCE 2016; 7:1135. [PMID: 27555848 PMCID: PMC4977308 DOI: 10.3389/fpls.2016.01135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Accepted: 07/18/2016] [Indexed: 06/06/2023]
Abstract
In one of the final stages of cyanobacterial Photosystem II (PS II) assembly, binding of up to four extrinsic proteins to PS II stabilizes the oxygen-evolving complex (OEC). Growth of cyanobacterial mutants deficient in certain combinations of these thylakoid-lumen-associated polypeptides is sensitive to changes in environmental pH, despite the physical separation of the membrane-embedded PS II complex from the external environment. In this perspective we discuss the effect of environmental pH on OEC function and photoautotrophic growth in cyanobacteria with reference to pH-sensitive PS II mutants lacking extrinsic proteins. We consider the possibilities that, compared to pH 10.0, pH 7.5 increases susceptibility to PS II-generated reactive oxygen species (ROS) causing photoinhibition and reducing PS II assembly in some mutants, and that perturbations to channels in the lumenal regions of PS II might alter the accessibility of water to the active site as well as egress of oxygen and protons to the thylakoid lumen. Reduced levels of PS II in these mutants, and reduced OEC activity arising from the disruption of substrate/product channels, could reduce the trans-thylakoid pH gradient (ΔpH), leading to the impairment of photosynthesis. Growth of some PS II mutants at pH 7.5 can be rescued by elevating CO2 levels, suggesting that the pH-sensitive phenotype might primarily be an indirect result of back-pressure in the electron transport chain that results in heightened production of ROS by the impaired photosystem.
Collapse
Affiliation(s)
- Jaz N. Morris
- Department of Botany, University of OtagoDunedin, New Zealand
| | | | | |
Collapse
|