101
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Quantum design of photosynthesis for bio-inspired solar-energy conversion. Nature 2017; 543:355-365. [PMID: 28300093 DOI: 10.1038/nature22012] [Citation(s) in RCA: 205] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 02/01/2017] [Indexed: 12/15/2022]
Abstract
Photosynthesis is the natural process that converts solar photons into energy-rich products that are needed to drive the biochemistry of life. Two ultrafast processes form the basis of photosynthesis: excitation energy transfer and charge separation. Under optimal conditions, every photon that is absorbed is used by the photosynthetic organism. Fundamental quantum mechanics phenomena, including delocalization, underlie the speed, efficiency and directionality of the charge-separation process. At least four design principles are active in natural photosynthesis, and these can be applied practically to stimulate the development of bio-inspired, human-made energy conversion systems.
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102
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Tietz S, Hall CC, Cruz JA, Kramer DM. NPQ (T) : a chlorophyll fluorescence parameter for rapid estimation and imaging of non-photochemical quenching of excitons in photosystem-II-associated antenna complexes. PLANT, CELL & ENVIRONMENT 2017; 40:1243-1255. [PMID: 28699261 DOI: 10.1111/pce.12924] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 01/10/2017] [Accepted: 01/11/2017] [Indexed: 05/05/2023]
Abstract
In photosynthesis, light energy is absorbed by light-harvesting complexes and used to drive photochemistry. However, a fraction of absorbed light is lost to non-photochemical quenching (NPQ) that reflects several important photosynthetic processes to dissipate excess energy. Currently, estimates of NPQ and its individual components (qE , qI , qZ and qT ) are measured from pulse-amplitude-modulation (PAM) measurements of chlorophyll fluorescence yield and require measurements of the maximal yield of fluorescence in fully dark-adapted material (Fm ), when NPQ is assumed to be negligible. Unfortunately, this approach requires extensive dark acclimation, often precluding widespread or high-throughput use, particularly under field conditions or in imaging applications, while introducing artefacts when Fm is measured in the presence of residual photodamaged centres. To address these limitations, we derived and characterized a new set of parameters, NPQ(T) , and its components that can be (1) measured in a few seconds, allowing for high-throughput and field applications; (2) does not require full relaxation of quenching processes and thus can be applied to photoinhibited materials; (3) can distinguish between NPQ and chloroplast movements; and (4) can be used to image NPQ in plants with large leaf movements. We discuss the applications benefits and caveats of both approaches.
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Affiliation(s)
- Stefanie Tietz
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, 48824-1312, USA
| | - Christopher C Hall
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, 48824-1312, USA
- Plant Biology, Michigan State University, East Lansing, MI, 48824-1312, USA
| | - Jeffrey A Cruz
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, 48824-1312, USA
- Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824-1312, USA
| | - David M Kramer
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, 48824-1312, USA
- Plant Biology, Michigan State University, East Lansing, MI, 48824-1312, USA
- Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824-1312, USA
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103
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Kawashima K, Ishikita H. Structural Factors That Alter the Redox Potential of Quinones in Cyanobacterial and Plant Photosystem I. Biochemistry 2017; 56:3019-3028. [PMID: 28530393 DOI: 10.1021/acs.biochem.7b00082] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Using the cyanobacterial and plant photosystem I (PSI) crystal structures and by considering the protonation states of all titratable residues, redox potentials (Em) of the two phylloquinones-A1A and A1B-were calculated. The calculated Em values were Em(A1A) = -773 mV and Em(A1B) = -818 mV for the plant PSI structure and Em(A1A) = -612 mV and Em(A1B) = -719 mV for the cyanobacterial PSI structure. Our analysis of the PSI crystal structures suggested that the side-chain orientations of Lys-B542 and Gln-B678 in the cyanobacterial crystal structure differ from these side-chain orientations in the plant crystal structure. Quantum mechanical/molecular mechanical calculations indicated that the geometry of the cyanobacterial PSI crystal structure was best described as the conformation where Asp-B575 is protonated and A1A is reduced to A1A•-, which might represent the high-potential A1A form ( Rutherford, A. W., Osyczka, A., Rappaport, F. ( 2012 ) FEBS Lett. 586 , 603 - 616 ). Reorienting the Lys-B542 and Gln-B678 side-chains and rearranging the H-bond pattern of the water cluster near Asp-B575 lowered the Em to Em(A1A) = -718 mV and Em(A1B) = -795 mV. It seems possible that PSI has two conformations: the high-potential A1A form and the low-potential A1A form.
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Affiliation(s)
- Keisuke Kawashima
- Department of Applied Chemistry, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
| | - Hiroshi Ishikita
- Department of Applied Chemistry, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
- Research Center for Advanced Science and Technology, The University of Tokyo , 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
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104
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The Complex Transcriptional Response of Acaryochloris marina to Different Oxygen Levels. G3-GENES GENOMES GENETICS 2017; 7:517-532. [PMID: 27974439 PMCID: PMC5295598 DOI: 10.1534/g3.116.036855] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Ancient oxygenic photosynthetic prokaryotes produced oxygen as a waste product, but existed for a long time under an oxygen-free (anoxic) atmosphere, before an oxic atmosphere emerged. The change in oxygen levels in the atmosphere influenced the chemistry and structure of many enzymes that contained prosthetic groups that were inactivated by oxygen. In the genome of Acaryochloris marina, multiple gene copies exist for proteins that are normally encoded by a single gene copy in other cyanobacteria. Using high throughput RNA sequencing to profile transcriptome responses from cells grown under microoxic and hyperoxic conditions, we detected 8446 transcripts out of the 8462 annotated genes in the Cyanobase database. Two-thirds of the 50 most abundant transcripts are key proteins in photosynthesis. Microoxic conditions negatively affected the levels of expression of genes encoding photosynthetic complexes, with the exception of some subunits. In addition to the known regulation of the multiple copies of psbA, we detected a similar transcriptional pattern for psbJ and psbU, which might play a key role in the altered components of photosystem II. Furthermore, regulation of genes encoding proteins important for reactive oxygen species-scavenging is discussed at genome level, including, for the first time, specific small RNAs having possible regulatory roles under varying oxygen levels.
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105
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Vinyard DJ, Khan S, Askerka M, Batista VS, Brudvig GW. Energetics of the S 2 State Spin Isomers of the Oxygen-Evolving Complex of Photosystem II. J Phys Chem B 2017; 121:1020-1025. [PMID: 28079373 DOI: 10.1021/acs.jpcb.7b00110] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The S2 redox intermediate of the oxygen-evolving complex in photosystem II is present as two spin isomers. The S = 1/2 isomer gives rise to a multiline electron paramagnetic resonance (EPR) signal at g = 2.0, whereas the S = 5/2 isomer exhibits a broad EPR signal at g = 4.1. The electronic structures of these isomers are known, but their role in the catalytic cycle of water oxidation remains unclear. We show that formation of the S = 1/2 state from the S = 5/2 state is exergonic at temperatures above 160 K. However, the S = 1/2 isomer decays to S1 more slowly than the S = 5/2 isomer. These differences support the hypotheses that the S3 state is formed via the S2 state S = 5/2 isomer and that the stabilized S2 state S = 1/2 isomer plays a role in minimizing S2QA- decay under light-limiting conditions.
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Affiliation(s)
- David J Vinyard
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Sahr Khan
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Mikhail Askerka
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Victor S Batista
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Gary W Brudvig
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
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106
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Metastable radical state, nonreactive with oxygen, is inherent to catalysis by respiratory and photosynthetic cytochromes bc1/b6f. Proc Natl Acad Sci U S A 2017; 114:1323-1328. [PMID: 28115711 DOI: 10.1073/pnas.1618840114] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Oxygenic respiration and photosynthesis based on quinone redox reactions face a danger of wasteful energy dissipation by diversion of the productive electron transfer pathway through the generation of reactive oxygen species (ROS). Nevertheless, the widespread quinone oxido-reductases from the cytochrome bc family limit the amounts of released ROS to a low, perhaps just signaling, level through an as-yet-unknown mechanism. Here, we propose that a metastable radical state, nonreactive with oxygen, safely holds electrons at a local energetic minimum during the oxidation of plastohydroquinone catalyzed by the chloroplast cytochrome b6f This intermediate state is formed by interaction of a radical with a metal cofactor of a catalytic site. Modulation of its energy level on the energy landscape in photosynthetic vs. respiratory enzymes provides a possible mechanism to adjust electron transfer rates for efficient catalysis under different oxygen tensions.
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107
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Kanazawa A, Ostendorf E, Kohzuma K, Hoh D, Strand DD, Sato-Cruz M, Savage L, Cruz JA, Fisher N, Froehlich JE, Kramer DM. Chloroplast ATP Synthase Modulation of the Thylakoid Proton Motive Force: Implications for Photosystem I and Photosystem II Photoprotection. FRONTIERS IN PLANT SCIENCE 2017; 8:719. [PMID: 28515738 PMCID: PMC5413553 DOI: 10.3389/fpls.2017.00719] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 04/19/2017] [Indexed: 05/18/2023]
Abstract
In wild type plants, decreasing CO2 lowers the activity of the chloroplast ATP synthase, slowing proton efflux from the thylakoid lumen resulting in buildup of thylakoid proton motive force (pmf). The resulting acidification of the lumen regulates both light harvesting, via the qE mechanism, and photosynthetic electron transfer through the cytochrome b6f complex. Here, we show that the cfq mutant of Arabidopsis, harboring single point mutation in its γ-subunit of the chloroplast ATP synthase, increases the specific activity of the ATP synthase and disables its down-regulation under low CO2. The increased thylakoid proton conductivity (gH+) in cfq results in decreased pmf and lumen acidification, preventing full activation of qE and more rapid electron transfer through the b6f complex, particularly under low CO2 and fluctuating light. These conditions favor the accumulation of electrons on the acceptor side of PSI, and result in severe loss of PSI activity. Comparing the current results with previous work on the pgr5 mutant suggests a general mechanism where increased PSI photodamage in both mutants is caused by loss of pmf, rather than inhibition of CEF per se. Overall, our results support a critical role for ATP synthase regulation in maintaining photosynthetic control of electron transfer to prevent photodamage.
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Affiliation(s)
- Atsuko Kanazawa
- MSU-DOE Plant Research Lab, Michigan State University, East LansingMI, USA
- Chemistry, Michigan State University, East LansingMI, USA
| | | | - Kaori Kohzuma
- MSU-DOE Plant Research Lab, Michigan State University, East LansingMI, USA
| | - Donghee Hoh
- MSU-DOE Plant Research Lab, Michigan State University, East LansingMI, USA
- Cell and Molecular Biology, Michigan State University, East LansingMI, USA
| | - Deserah D. Strand
- MSU-DOE Plant Research Lab, Michigan State University, East LansingMI, USA
| | - Mio Sato-Cruz
- MSU-DOE Plant Research Lab, Michigan State University, East LansingMI, USA
| | - Linda Savage
- MSU-DOE Plant Research Lab, Michigan State University, East LansingMI, USA
| | - Jeffrey A. Cruz
- MSU-DOE Plant Research Lab, Michigan State University, East LansingMI, USA
- Biochemistry and Molecular Biology, Michigan State University, East LansingMI, USA
| | - Nicholas Fisher
- MSU-DOE Plant Research Lab, Michigan State University, East LansingMI, USA
| | - John E. Froehlich
- MSU-DOE Plant Research Lab, Michigan State University, East LansingMI, USA
- Biochemistry and Molecular Biology, Michigan State University, East LansingMI, USA
| | - David M. Kramer
- MSU-DOE Plant Research Lab, Michigan State University, East LansingMI, USA
- Biochemistry and Molecular Biology, Michigan State University, East LansingMI, USA
- *Correspondence: David M. Kramer,
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108
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Eaton-Rye JJ, Sobotka R. Editorial: Assembly of the Photosystem II Membrane-Protein Complex of Oxygenic Photosynthesis. FRONTIERS IN PLANT SCIENCE 2017; 8:884. [PMID: 28603539 PMCID: PMC5445156 DOI: 10.3389/fpls.2017.00884] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 05/11/2017] [Indexed: 05/08/2023]
Affiliation(s)
- Julian J. Eaton-Rye
- Department of Biochemistry, University of OtagoDunedin, New Zealand
- *Correspondence: Julian J. Eaton-Rye
| | - Roman Sobotka
- Laboratory of Photosynthesis, Center Algatech, Institute of Microbiology, Czech Academy of SciencesTřeboň, Czechia
- Faculty of Science, University of South BohemiaČeské Budějovice, Czechia
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109
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Bicarbonate-induced redox tuning in Photosystem II for regulation and protection. Proc Natl Acad Sci U S A 2016; 113:12144-12149. [PMID: 27791001 DOI: 10.1073/pnas.1608862113] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The midpoint potential (Em) of [Formula: see text], the one-electron acceptor quinone of Photosystem II (PSII), provides the thermodynamic reference for calibrating PSII bioenergetics. Uncertainty exists in the literature, with two values differing by ∼80 mV. Here, we have resolved this discrepancy by using spectroelectrochemistry on plant PSII-enriched membranes. Removal of bicarbonate (HCO3-) shifts the Em from ∼-145 mV to -70 mV. The higher values reported earlier are attributed to the loss of HCO3- during the titrations (pH 6.5, stirred under argon gassing). These findings mean that HCO3- binds less strongly when QA-• is present. Light-induced QA-• formation triggered HCO3- loss as manifest by the slowed electron transfer and the upshift in the Em of QA HCO3--depleted PSII also showed diminished light-induced 1O2 formation. This finding is consistent with a model in which the increase in the Em of [Formula: see text] promotes safe, direct [Formula: see text] charge recombination at the expense of the damaging back-reaction route that involves chlorophyll triplet-mediated 1O2 formation [Johnson GN, et al. (1995) Biochim Biophys Acta 1229:202-207]. These findings provide a redox tuning mechanism, in which the interdependence of the redox state of QA and the binding by HCO3- regulates and protects PSII. The potential for a sink (CO2) to source (PSII) feedback mechanism is discussed.
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110
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Davis GA, Kanazawa A, Schöttler MA, Kohzuma K, Froehlich JE, Rutherford AW, Satoh-Cruz M, Minhas D, Tietz S, Dhingra A, Kramer DM. Limitations to photosynthesis by proton motive force-induced photosystem II photodamage. eLife 2016. [PMID: 27697149 DOI: 10.7554/elife.16921.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023] Open
Abstract
The thylakoid proton motive force (pmf) generated during photosynthesis is the essential driving force for ATP production; it is also a central regulator of light capture and electron transfer. We investigated the effects of elevated pmf on photosynthesis in a library of Arabidopsis thaliana mutants with altered rates of thylakoid lumen proton efflux, leading to a range of steady-state pmf extents. We observed the expected pmf-dependent alterations in photosynthetic regulation, but also strong effects on the rate of photosystem II (PSII) photodamage. Detailed analyses indicate this effect is related to an elevated electric field (Δψ) component of the pmf, rather than lumen acidification, which in vivo increased PSII charge recombination rates, producing singlet oxygen and subsequent photodamage. The effects are seen even in wild type plants, especially under fluctuating illumination, suggesting that Δψ-induced photodamage represents a previously unrecognized limiting factor for plant productivity under dynamic environmental conditions seen in the field.
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Affiliation(s)
- Geoffry A Davis
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States
- Graduate Program of Cell and Molecular Biology, Michigan State University, East Lansing, United States
| | - Atsuko Kanazawa
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States
- Department of Chemistry, Michigan State University, East Lansing, United States
| | | | - Kaori Kohzuma
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States
| | - John E Froehlich
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States
| | | | - Mio Satoh-Cruz
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States
| | - Deepika Minhas
- Department of Horticulture, Washington State University, Pullman, United States
| | - Stefanie Tietz
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States
| | - Amit Dhingra
- Department of Horticulture, Washington State University, Pullman, United States
| | - David M Kramer
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, United States
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111
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Davis GA, Kanazawa A, Schöttler MA, Kohzuma K, Froehlich JE, Rutherford AW, Satoh-Cruz M, Minhas D, Tietz S, Dhingra A, Kramer DM. Limitations to photosynthesis by proton motive force-induced photosystem II photodamage. eLife 2016; 5. [PMID: 27697149 PMCID: PMC5050024 DOI: 10.7554/elife.16921] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 09/08/2016] [Indexed: 12/20/2022] Open
Abstract
The thylakoid proton motive force (pmf) generated during photosynthesis is the essential driving force for ATP production; it is also a central regulator of light capture and electron transfer. We investigated the effects of elevated pmf on photosynthesis in a library of Arabidopsis thaliana mutants with altered rates of thylakoid lumen proton efflux, leading to a range of steady-state pmf extents. We observed the expected pmf-dependent alterations in photosynthetic regulation, but also strong effects on the rate of photosystem II (PSII) photodamage. Detailed analyses indicate this effect is related to an elevated electric field (Δψ) component of the pmf, rather than lumen acidification, which in vivo increased PSII charge recombination rates, producing singlet oxygen and subsequent photodamage. The effects are seen even in wild type plants, especially under fluctuating illumination, suggesting that Δψ-induced photodamage represents a previously unrecognized limiting factor for plant productivity under dynamic environmental conditions seen in the field. DOI:http://dx.doi.org/10.7554/eLife.16921.001
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Affiliation(s)
- Geoffry A Davis
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States.,Graduate Program of Cell and Molecular Biology, Michigan State University, East Lansing, United States
| | - Atsuko Kanazawa
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States.,Department of Chemistry, Michigan State University, East Lansing, United States
| | | | - Kaori Kohzuma
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States
| | - John E Froehlich
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States
| | | | - Mio Satoh-Cruz
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States
| | - Deepika Minhas
- Department of Horticulture, Washington State University, Pullman, United States
| | - Stefanie Tietz
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States
| | - Amit Dhingra
- Department of Horticulture, Washington State University, Pullman, United States
| | - David M Kramer
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States.,Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, United States
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112
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From low- to high-potential bioenergetic chains: Thermodynamic constraints of Q-cycle function. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1569-1579. [DOI: 10.1016/j.bbabio.2016.06.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 06/14/2016] [Accepted: 06/16/2016] [Indexed: 11/27/2022]
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113
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Manbeck GF, Fujita E, Concepcion JJ. Proton-Coupled Electron Transfer in a Strongly Coupled Photosystem II-Inspired Chromophore–Imidazole–Phenol Complex: Stepwise Oxidation and Concerted Reduction. J Am Chem Soc 2016; 138:11536-49. [DOI: 10.1021/jacs.6b03506] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Gerald F. Manbeck
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - Etsuko Fujita
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - Javier J. Concepcion
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
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114
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Kozuleva MA, Ivanov BN. The Mechanisms of Oxygen Reduction in the Terminal Reducing Segment of the Chloroplast Photosynthetic Electron Transport Chain. PLANT & CELL PHYSIOLOGY 2016; 57:1397-1404. [PMID: 27016099 DOI: 10.1093/pcp/pcw035] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Accepted: 02/10/2016] [Indexed: 05/25/2023]
Abstract
The review is dedicated to ascertainment of the roles of the electron transfer cofactors of the pigment-protein complex of PSI, ferredoxin (Fd) and ferredoxin-NADP reductase in oxygen reduction in the photosynthetic electron transport chain (PETC) in the light. The data regarding oxygen reduction in other segments of the PETC are briefly analyzed, and it is concluded that their participation in the overall process in the PETC under unstressful conditions should be insignificant. Data concerning the contribution of Fd to the oxygen reduction in the PETC are examined. A set of collateral evidence as well as results of direct measurements of the involvement of Fd in this process in the presence of isolated thylakoids led to the inference that this contribution in vivo is negligible. The increase in oxygen reduction rate in the isolated thylakoids in the presence of either Fd or Fd plus NADP+ under increasing light intensity was attributed to the increase in oxygen reduction executed by the membrane-bound oxygen reductants. Data are presented which imply that a main reductant of the O2 molecule in the terminal reducing segment of the PETC is the electron transfer cofactor of PSI, phylloquinone. The physiological significance of characteristic properties of oxygen reductants in this segment of the PETC is discussed.
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Affiliation(s)
- Marina A Kozuleva
- Photosynthetic Electron Transport lab., Institute of Basic Biological Problems, Pushchino, 142290, Russia
| | - Boris N Ivanov
- Photosynthetic Electron Transport lab., Institute of Basic Biological Problems, Pushchino, 142290, Russia
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115
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Cazzaniga S, Bressan M, Carbonera D, Agostini A, Dall'Osto L. Differential Roles of Carotenes and Xanthophylls in Photosystem I Photoprotection. Biochemistry 2016; 55:3636-49. [PMID: 27290879 DOI: 10.1021/acs.biochem.6b00425] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Carotenes and their oxygenated derivatives, xanthophylls, are structural elements of the photosynthetic apparatus and contribute to increasing both the light-harvesting and photoprotective capacity of the photosystems. β-Carotene is present in both the core complexes and light-harvesting system (LHCI) of Photosystem (PS) I, while xanthophylls lutein and violaxanthin bind exclusively to its antenna moiety; another xanthophyll, zeaxanthin, which protects chloroplasts against photooxidative damage, binds to the LHCI complexes under conditions of excess light. We functionally dissected various components of the xanthophyll- and carotene-dependent photoprotection mechanism of PSI by analyzing two Arabidopsis mutants: szl1 plants, with a carotene content lower than that of the wild type, and npq1, with suppressed zeaxanthin formation. When exposed to excess light, the szl1 genotype displayed PSI photoinhibition stronger than that of wild-type plants, while removing zeaxanthin had no such effect. The PSI-LHCI complex purified from szl1 was more photosensitive than the corresponding wild-type and npq1 complexes, as is evident from its faster photobleaching and increased rate of singlet oxygen release, suggesting that β-carotene is crucial in controlling chlorophyll triplet formation. Accordingly, fluorescence-detected magnetic resonance analysis showed an increase in the amplitude of signals assigned to chlorophyll triplets in β-carotene-depleted complexes. When PSI was fractioned into its functional moieties, it was revealed that the boost in the rate of singlet oxygen release caused by β-carotene depletion was greater in LHCI than in the core complex. We conclude that PSI-LHCI complex-bound β-carotene elicits a protective response, consisting of a reduction in the yield of harmful triplet excited states, while accumulation of zeaxanthin plays a minor role in restoring phototolerance.
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Affiliation(s)
- Stefano Cazzaniga
- Dipartimento di Biotecnologie, Università di Verona , Strada Le Grazie 15, 37134 Verona, Italy
| | - Mauro Bressan
- Dipartimento di Biotecnologie, Università di Verona , Strada Le Grazie 15, 37134 Verona, Italy
| | - Donatella Carbonera
- Dipartimento di Scienze Chimiche, Università di Padova , via Marzolo 1, 35100 Padova, Italy
| | - Alessandro Agostini
- Dipartimento di Scienze Chimiche, Università di Padova , via Marzolo 1, 35100 Padova, Italy
| | - Luca Dall'Osto
- Dipartimento di Biotecnologie, Università di Verona , Strada Le Grazie 15, 37134 Verona, Italy
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116
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Impact of Antioxidants on Cardiolipin Oxidation in Liposomes: Why Mitochondrial Cardiolipin Serves as an Apoptotic Signal? OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:8679469. [PMID: 27313834 PMCID: PMC4899610 DOI: 10.1155/2016/8679469] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/25/2015] [Revised: 02/29/2016] [Accepted: 03/17/2016] [Indexed: 01/08/2023]
Abstract
Molecules of mitochondrial cardiolipin (CL) get selectively oxidized upon oxidative stress, which triggers the intrinsic apoptotic pathway. In a chemical model most closely resembling the mitochondrial membrane-liposomes of pure bovine heart CL-we compared ubiquinol-10, ubiquinol-6, and alpha-tocopherol, the most widespread naturally occurring antioxidants, with man-made, quinol-based amphiphilic antioxidants. Lipid peroxidation was induced by addition of an azo initiator in the absence and presence of diverse antioxidants, respectively. The kinetics of CL oxidation was monitored via formation of conjugated dienes at 234 nm. We found that natural ubiquinols and ubiquinol-based amphiphilic antioxidants were equally efficient in protecting CL liposomes from peroxidation; the chromanol-based antioxidants, including alpha-tocopherol, were 2-3 times less efficient. Amphiphilic antioxidants, but not natural ubiquinols and alpha-tocopherol, were able, additionally, to protect the CL bilayer from oxidation by acting from the water phase. We suggest that the previously reported therapeutic efficiency of mitochondrially targeted amphiphilic antioxidants is owing to their ability to protect those CL molecules that are inaccessible to natural hydrophobic antioxidants, being trapped within respiratory supercomplexes. The high susceptibility of such occluded CL molecules to oxidation may have prompted their recruitment as apoptotic signaling molecules by nature.
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Matsuoka T, Tanaka S, Ebina K. Reduced minimum model for the photosynthetic induction processes in photosystem I. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2016; 160:364-75. [PMID: 27183491 DOI: 10.1016/j.jphotobiol.2016.04.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Revised: 03/13/2016] [Accepted: 04/11/2016] [Indexed: 11/29/2022]
Abstract
Photosystem I (PS I) is one of the most important protein complexes for photosynthesis, which is present in plants, algae and cyanobacteria. A variety of mechanisms for environmental response in and around PS I have been elucidated experimentally and theoretically. During the photosynthetic induction time, the congestion of electron occurs in PS I and then the over-reduced PS I states are realized. This means that the degree of freedom of the redox states of PS I becomes large and thus the understanding of phenomena based on the model describing PS I in the state space becomes difficult. To understand the phenomena intuitively, we have reduced the complicated PS I model which has the multi-timescale property for electron and excitation-energy transfer processes into a simple one which has only the mono-timescale property through the use of hierarchical coarse-graining (HCG) method. The coarse-grained model describes the state of PS I by seven variable states, while the original model describes the PS I by 3×2(7)(=384) states. Based on the derived model, the I820 (820nm transmittance signal) curve in photosynthetic induction term, which indicates the accumulations of P700(+) and Pc(+), is simulated and analyzed in comparison with experiment. With respect to this signal curve, it is revealed that the initial increase up to the shoulder at 10(-3) s, the increase from that point to the peak at 2 ×10(-2) s, and the decay after that peak reflect the accumulations of P700(+), Pc(+) and P700FA(-)FB(-) (PS I state in which P700,FA(-) and FB(-) are observed.), respectively. Besides, the important role of the charge recombination processes from P700(+)A0A(-) and P700(+)A1A(-) states for the dissipation of the extra absorbed energy in photosynthetic induction period is confirmed.
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Affiliation(s)
- Takeshi Matsuoka
- Graduate School of System Informatics, Department of Computational Science, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe 657-8501, Japan.
| | - Shigenori Tanaka
- Graduate School of System Informatics, Department of Computational Science, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe 657-8501, Japan.
| | - Kuniyoshi Ebina
- Graduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Nada-ku, Kobe 657-8501, Japan.
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118
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Tiwari A, Mamedov F, Grieco M, Suorsa M, Jajoo A, Styring S, Tikkanen M, Aro EM. Photodamage of iron-sulphur clusters in photosystem I induces non-photochemical energy dissipation. NATURE PLANTS 2016; 2:16035. [PMID: 27249566 DOI: 10.1038/nplants.2016.35] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 02/22/2016] [Indexed: 05/19/2023]
Abstract
Photosystem I (PSI) uses light energy and electrons supplied by photosystem II (PSII) to reduce NADP(+) to NADPH. PSI is very tolerant of excess light but extremely sensitive to excess electrons from PSII. It has been assumed that PSI is protected from photoinhibition by strict control of the intersystem electron transfer chain (ETC). Here we demonstrate that the iron-sulphur (FeS) clusters of PSI are more sensitive to high light stress than previously anticipated, but PSI with damaged FeS clusters still functions as a non-photochemical photoprotective energy quencher (PSI-NPQ). Upon photoinhibition of PSI, the highly reduced ETC further triggers thylakoid phosphorylation-based mechanisms that increase energy flow towards PSI. It is concluded that the sensitivity of FeS clusters provides an additional photoprotective mechanism that is able to downregulate PSII, based on PSI quenching and protein phosphorylation.
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Affiliation(s)
- Arjun Tiwari
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland
| | - Fikret Mamedov
- Molecular Biomimetics, Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, SE-75120 Uppsala, Sweden
| | - Michele Grieco
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland
| | - Marjaana Suorsa
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland
| | - Anjana Jajoo
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland
| | - Stenbjörn Styring
- Molecular Biomimetics, Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, SE-75120 Uppsala, Sweden
| | - Mikko Tikkanen
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland
| | - Eva-Mari Aro
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland
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119
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Estimation of the driving force for dioxygen formation in photosynthesis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:23-33. [DOI: 10.1016/j.bbabio.2015.09.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 09/10/2015] [Accepted: 09/30/2015] [Indexed: 11/22/2022]
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120
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Electron Transfer Reactions at the Qo Site of the Cytochrome bc 1 Complex: The Good, the Bad, and the Ugly. ADVANCES IN PHOTOSYNTHESIS AND RESPIRATION 2016. [DOI: 10.1007/978-94-017-7481-9_21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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121
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Mechanisms of Superoxide Generation and Signaling in Cytochrome bc Complexes. ADVANCES IN PHOTOSYNTHESIS AND RESPIRATION 2016. [DOI: 10.1007/978-94-017-7481-9_20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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122
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Redox potential of the terminal quinone electron acceptor QB in photosystem II reveals the mechanism of electron transfer regulation. Proc Natl Acad Sci U S A 2015; 113:620-5. [PMID: 26715751 DOI: 10.1073/pnas.1520211113] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Photosystem II (PSII) extracts electrons from water at a Mn4CaO5 cluster using light energy and then transfers them to two plastoquinones, the primary quinone electron acceptor QA and the secondary quinone electron acceptor QB. This forward electron transfer is an essential process in light energy conversion. Meanwhile, backward electron transfer is also significant in photoprotection of PSII proteins. Modulation of the redox potential (Em) gap of QA and QB mainly regulates the forward and backward electron transfers in PSII. However, the full scheme of electron transfer regulation remains unresolved due to the unknown Em value of QB. Here, for the first time (to our knowledge), the Em value of QB reduction was measured directly using spectroelectrochemistry in combination with light-induced Fourier transform infrared difference spectroscopy. The Em(QB (-)/QB) was determined to be approximately +90 mV and was virtually unaffected by depletion of the Mn4CaO5 cluster. This insensitivity of Em(QB (-)/QB), in combination with the known large upshift of Em(QA (-)/QA), explains the mechanism of PSII photoprotection with an impaired Mn4CaO5 cluster, in which a large decrease in the Em gap between QA and QB promotes rapid charge recombination via QA (-).
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123
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Magnuson A, Cardona T. Thylakoid membrane function in heterocysts. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1857:309-19. [PMID: 26545609 DOI: 10.1016/j.bbabio.2015.10.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 09/30/2015] [Accepted: 10/29/2015] [Indexed: 01/19/2023]
Abstract
Multicellular cyanobacteria form different cell types in response to environmental stimuli. Under nitrogen limiting conditions a fraction of the vegetative cells in the filament differentiate into heterocysts. Heterocysts are specialized in atmospheric nitrogen fixation and differentiation involves drastic morphological changes on the cellular level, such as reorganization of the thylakoid membranes and differential expression of thylakoid membrane proteins. Heterocysts uphold a microoxic environment to avoid inactivation of nitrogenase by developing an extra polysaccharide layer that limits air diffusion into the heterocyst and by upregulating heterocyst-specific respiratory enzymes. In this review article, we summarize what is known about the thylakoid membrane in heterocysts and compare its function with that of the vegetative cells. We emphasize the role of photosynthetic electron transport in providing the required amounts of ATP and reductants to the nitrogenase enzyme. In the light of recent high-throughput proteomic and transcriptomic data, as well as recently discovered electron transfer pathways in cyanobacteria, our aim is to broaden current views of the bioenergetics of heterocysts. This article is part of a Special Issue entitled Organization and dynamics of bioenergetic systems in bacteria, edited by Conrad Mullineaux.
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Affiliation(s)
- Ann Magnuson
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, SE-75120, Uppsala, Sweden.
| | - Tanai Cardona
- Department of Life Sciences, Imperial College London, London SW7 2AZ, England, UK
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124
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Yin X, Struik PC. Constraints to the potential efficiency of converting solar radiation into phytoenergy in annual crops: from leaf biochemistry to canopy physiology and crop ecology. JOURNAL OF EXPERIMENTAL BOTANY 2015. [PMID: 26224881 DOI: 10.1093/jxb/erv371] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
A new simple framework was proposed to quantify the efficiency of converting incoming solar radiation into phytoenergy in annual crops. It emphasizes the need to account for (i) efficiency gain when scaling up from the leaf level to the canopy level, and (ii) efficiency loss due to incomplete canopy closure during early and late phases of the crop cycle. Equations are given to estimate losses due to the constraints in various biochemical or physiological steps. For a given amount of daily radiation, a longer daytime was shown to increase energy use efficiency, because of the convex shape of the photosynthetic light response. Due to the higher cyclic electron transport, C4 leaves were found to have a lower energy loss via non-photochemical quenching, compared with C3 leaves. This contributes to the more linear light response in C4 than in C3 photosynthesis. Because of this difference in the curvature of the light response, canopy-to-leaf photosynthesis ratio, benefit from the optimum acclimation of the leaf nitrogen profile in the canopy, and productivity gain from future improvements in leaf photosynthetic parameters and canopy architecture were all shown to be higher in C3 than in C4 species. The indicative efficiency of converting incoming solar radiation into phytoenergy is ~2.2 and 3.0% in present C3 and C4 crops, respectively, when grown under well-managed conditions. An achievable efficiency via future genetic improvement was estimated to be as high as 3.6 and 4.1% for C3 and C4 crops, respectively.
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Affiliation(s)
- Xinyou Yin
- Centre for Crop Systems Analysis, Department of Plant Sciences, Wageningen University, PO Box 430, 6700 AK Wageningen, The Netherlands
| | - Paul C Struik
- Centre for Crop Systems Analysis, Department of Plant Sciences, Wageningen University, PO Box 430, 6700 AK Wageningen, The Netherlands
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125
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Cardona T. A fresh look at the evolution and diversification of photochemical reaction centers. PHOTOSYNTHESIS RESEARCH 2015; 126:111-34. [PMID: 25512103 PMCID: PMC4582080 DOI: 10.1007/s11120-014-0065-x] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 12/05/2014] [Indexed: 05/18/2023]
Abstract
In this review, I reexamine the origin and diversification of photochemical reaction centers based on the known phylogenetic relations of the core subunits, and with the aid of sequence and structural alignments. I show, for example, that the protein folds at the C-terminus of the D1 and D2 subunits of Photosystem II, which are essential for the coordination of the water-oxidizing complex, were already in place in the most ancestral Type II reaction center subunit. I then evaluate the evolution of reaction centers in the context of the rise and expansion of the different groups of bacteria based on recent large-scale phylogenetic analyses. I find that the Heliobacteriaceae family of Firmicutes appears to be the earliest branching of the known groups of phototrophic bacteria; however, the origin of photochemical reaction centers and chlorophyll synthesis cannot be placed in this group. Moreover, it becomes evident that the Acidobacteria and the Proteobacteria shared a more recent common phototrophic ancestor, and this is also likely for the Chloroflexi and the Cyanobacteria. Finally, I argue that the discrepancies among the phylogenies of the reaction center proteins, chlorophyll synthesis enzymes, and the species tree of bacteria are best explained if both types of photochemical reaction centers evolved before the diversification of the known phyla of phototrophic bacteria. The primordial phototrophic ancestor must have had both Type I and Type II reaction centers.
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Affiliation(s)
- Tanai Cardona
- Department of Life Sciences, Imperial College London, Exhibition Road, London, SW7 2AZ, UK.
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126
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Longatte G, Fu HY, Buriez O, Labbé E, Wollman FA, Amatore C, Rappaport F, Guille-Collignon M, Lemaître F. Evaluation of photosynthetic electrons derivation by exogenous redox mediators. Biophys Chem 2015; 205:1-8. [PMID: 26051794 DOI: 10.1016/j.bpc.2015.05.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 05/07/2015] [Accepted: 05/11/2015] [Indexed: 11/18/2022]
Abstract
Oxygenic photosynthesis is the complex process that occurs in plants or algae by which the energy from the sun is converted into an electrochemical potential that drives the assimilation of carbon dioxide and the synthesis of carbohydrates. Quinones belong to a family of species commonly found in key processes of the Living, like photosynthesis or respiration, in which they act as electron transporters. This makes this class of molecules a popular candidate for biofuel cell and bioenergy applications insofar as they can be used as cargo to ship electrons to an electrode immersed in the cellular suspension. Nevertheless, such electron carriers are mostly selected empirically. This is why we report on a method involving fluorescence measurements to estimate the ability of seven different quinones to accept photosynthetic electrons downstream of photosystem II, the first protein complex in the light-dependent reactions of oxygenic photosynthesis. To this aim we use a mutant of Chlamydomonas reinhardtii, a unicellular green alga, impaired in electron downstream of photosystem II and assess the ability of quinones to restore electron flow by fluorescence. In this work, we defined and extracted a "derivation parameter" D that indicates the derivation efficiency of the exogenous quinones investigated. D then allows electing 2,6-dichlorobenzoquinone, 2,5-dichlorobenzoquinone and p-phenylbenzoquinone as good candidates. More particularly, our investigations suggested that other key parameters like the partition of quinones between different cellular compartments and their propensity to saturate these various compartments should also be taken into account in the process of selecting exogenous quinones for the purpose of deriving photoelectrons from intact algae.
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Affiliation(s)
- Guillaume Longatte
- Ecole Normale Supérieure-PSL Research University, Département de Chimie, Sorbonne Universités-UPMC Univ Paris 06, CNRS UMR 8640 PASTEUR, 24, rue Lhomond, 75005 Paris, France
| | - Han-Yi Fu
- Laboratoire de physiologie membranaire et moléculaire du chloroplaste, CNRS, UPMC UMR 7141, I.B.P.C., 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Olivier Buriez
- Ecole Normale Supérieure-PSL Research University, Département de Chimie, Sorbonne Universités-UPMC Univ Paris 06, CNRS UMR 8640 PASTEUR, 24, rue Lhomond, 75005 Paris, France
| | - Eric Labbé
- Ecole Normale Supérieure-PSL Research University, Département de Chimie, Sorbonne Universités-UPMC Univ Paris 06, CNRS UMR 8640 PASTEUR, 24, rue Lhomond, 75005 Paris, France
| | - Francis-André Wollman
- Laboratoire de physiologie membranaire et moléculaire du chloroplaste, CNRS, UPMC UMR 7141, I.B.P.C., 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Christian Amatore
- Ecole Normale Supérieure-PSL Research University, Département de Chimie, Sorbonne Universités-UPMC Univ Paris 06, CNRS UMR 8640 PASTEUR, 24, rue Lhomond, 75005 Paris, France
| | - Fabrice Rappaport
- Laboratoire de physiologie membranaire et moléculaire du chloroplaste, CNRS, UPMC UMR 7141, I.B.P.C., 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Manon Guille-Collignon
- Ecole Normale Supérieure-PSL Research University, Département de Chimie, Sorbonne Universités-UPMC Univ Paris 06, CNRS UMR 8640 PASTEUR, 24, rue Lhomond, 75005 Paris, France.
| | - Frédéric Lemaître
- Ecole Normale Supérieure-PSL Research University, Département de Chimie, Sorbonne Universités-UPMC Univ Paris 06, CNRS UMR 8640 PASTEUR, 24, rue Lhomond, 75005 Paris, France.
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127
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Fisher N, Kramer DM. Non-photochemical reduction of thylakoid photosynthetic redox carriers in vitro: relevance to cyclic electron flow around photosystem I? BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1837:1944-1954. [PMID: 25251244 DOI: 10.1016/j.bbabio.2014.09.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 09/07/2014] [Accepted: 09/14/2014] [Indexed: 01/17/2023]
Abstract
UNLABELLED Non-photochemical (dark) increases in chlorophyll a fluorescence yield associated with non-photochemical reduction of redox carriers (Fnpr) have been attributed to the reduction of plastoquinone (PQ) related to cyclic electron flow (CEF) around photosystem I. In vivo, this rise in fluorescence is associated with activity of the chloroplast plastoquinone reductase (plastid NAD(P)H plastoquinone oxidoreductase) complex. In contrast, this signal measured in isolated thylakoids has been attributed to the activity of the protein gradient regulation-5 (PGR5)/PGR5-like (PGRL1)-associated CEF pathway. Here, we report a systematic experimentation on the origin of Fnpr in isolated thylakoids. Addition of NADPH and ferredoxin to isolated spinach thylakoids resulted in the reduction of the PQ pool, but neither its kinetics nor its inhibitor sensitivities matched those of Fnpr. Notably, Fnpr was more rapid than PQ reduction, and completely insensitive to inhibitors of the PSII QB site and oxygen evolving complex as well as inhibitors of the cytochrome b6f complex. We thus conclude that Fnpr in isolated thylakoids is not a result of redox equilibrium with bulk PQ. Redox titrations and fluorescence emission spectra imply that Fnpr is dependent on the reduction of a low potential redox component (Em about − 340 mV) within photosystem II (PSII), and is likely related to earlier observations of low potential variants of QA within a subpopulation of PSII that is directly reducible by ferredoxin. The implications of these results for our understanding of CEF and other photosynthetic processes are discussed.
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Affiliation(s)
- Nicholas Fisher
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
| | - David M Kramer
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA; Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA.
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128
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Abstract
Technical progress in laser-sources and detectors has allowed the temporal and spatial resolution of chemical reactions down to femtoseconds and Å-units. In photon-excitable systems the key to chemical kinetics, trajectories across the vibrational saddle landscape, are experimentally accessible. Simple and thus well-defined chemical compounds are preferred objects for calibrating new methodologies and carving out paradigms of chemical dynamics, as shown in several contributions to this Faraday Discussion. Aerobic life on earth is powered by solar energy, which is captured by microorganisms and plants. Oxygenic photosynthesis relies on a three billion year old molecular machinery which is as well defined as simpler chemical constructs. It has been analysed to a very high precision. The transfer of excitation between pigments in antennae proteins, of electrons between redox-cofactors in reaction centres, and the oxidation of water by a Mn4Ca-cluster are solid state reactions. ATP, the general energy currency of the cell, is synthesized by a most agile, rotary molecular machine. While the efficiency of photosynthesis competes well with photovoltaics at the time scale of nanoseconds, it is lower by an order of magnitude for crops and again lower for bio-fuels. The enormous energy demand of mankind calls for engineered (bio-mimetic or bio-inspired) solar-electric and solar-fuel devices.
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Affiliation(s)
- Wolfgang Junge
- Dept. Biology & Chemistry, University of Osnabrück, R. 35/E42 Barbarastrasse 11, 49076 Osnabrück, Germany.
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129
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Cotton CAR, Douglass JS, De Causmaecker S, Brinkert K, Cardona T, Fantuzzi A, Rutherford AW, Murray JW. Photosynthetic constraints on fuel from microbes. Front Bioeng Biotechnol 2015; 3:36. [PMID: 25853129 PMCID: PMC4364286 DOI: 10.3389/fbioe.2015.00036] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 03/04/2015] [Indexed: 01/12/2023] Open
Affiliation(s)
| | | | | | | | - Tanai Cardona
- Department of Life Sciences, Imperial College London , London , UK
| | - Andrea Fantuzzi
- Department of Life Sciences, Imperial College London , London , UK
| | | | - James W Murray
- Department of Life Sciences, Imperial College London , London , UK
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130
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Marais A, Sinayskiy I, Petruccione F, van Grondelle R. A quantum protective mechanism in photosynthesis. Sci Rep 2015; 5:8720. [PMID: 25732807 PMCID: PMC4346811 DOI: 10.1038/srep08720] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 01/29/2015] [Indexed: 11/28/2022] Open
Abstract
Since the emergence of oxygenic photosynthesis, living systems have developed protective mechanisms against reactive oxygen species. During charge separation in photosynthetic reaction centres, triplet states can react with molecular oxygen generating destructive singlet oxygen. The triplet product yield in bacteria is observed to be reduced by weak magnetic fields. Reaction centres from plants' photosystem II share many features with bacterial reaction centres, including a high-spin iron whose function has remained obscure. To explain observations that the magnetic field effect is reduced by the iron, we propose that its fast-relaxing spin plays a protective role in photosynthesis by generating an effective magnetic field. We consider a simple model of the system, derive an analytical expression for the effective magnetic field and analyse the resulting triplet yield reduction. The protective mechanism is robust for realistic parameter ranges, constituting a clear example of a quantum effect playing a macroscopic role vital for life.
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Affiliation(s)
- Adriana Marais
- Quantum Research Group, School of Chemistry and Physics, University of KwaZulu-Natal, Durban, 4001, South Africa and National Institute for Theoretical Physics, KwaZulu-Natal, South Africa
| | - Ilya Sinayskiy
- Quantum Research Group, School of Chemistry and Physics, University of KwaZulu-Natal, Durban, 4001, South Africa and National Institute for Theoretical Physics, KwaZulu-Natal, South Africa
| | - Francesco Petruccione
- Quantum Research Group, School of Chemistry and Physics, University of KwaZulu-Natal, Durban, 4001, South Africa and National Institute for Theoretical Physics, KwaZulu-Natal, South Africa
| | - Rienk van Grondelle
- Institute for Lasers, Life and Biophotonics, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
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131
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de Vries S, Dörner K, Strampraad MJF, Friedrich T. Die Elektronentunnelraten im Atmungskettenkomplex I sind auf eine effiziente Energiewandlung abgestimmt. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201410967] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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132
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de Vries S, Dörner K, Strampraad MJF, Friedrich T. Electron tunneling rates in respiratory complex I are tuned for efficient energy conversion. Angew Chem Int Ed Engl 2015; 54:2844-8. [PMID: 25600069 PMCID: PMC4506566 DOI: 10.1002/anie.201410967] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Indexed: 12/13/2022]
Abstract
Respiratory complex I converts the free energy of ubiquinone reduction by NADH into a proton motive force, a redox reaction catalyzed by flavin mononucleotide(FMN) and a chain of seven iron–sulfur centers. Electron transfer rates between the centers were determined by ultrafast freeze-quenching and analysis by EPR and UV/Vis spectroscopy. The complex rapidly oxidizes three NADH molecules. The electron-tunneling rate between the most distant centers in the middle of the chain depends on the redox state of center N2 at the end of the chain, and is sixfold slower when N2 is reduced. The conformational changes that accompany reduction of N2 decrease the electronic coupling of the longest electron-tunneling step. The chain of iron–sulfur centers is not just a simple electron-conducting wire; it regulates the electron-tunneling rate synchronizing it with conformation-mediated proton pumping, enabling efficient energy conversion. Synchronization of rates is a principle means of enhancing the specificity of enzymatic reactions.
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Affiliation(s)
- Simon de Vries
- Department of Biotechnology, Institution Delft University of Technology, Julianalaan 67, 2628 BC, Delft (The Netherlands).
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133
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Nawrocki WJ, Tourasse NJ, Taly A, Rappaport F, Wollman FA. The plastid terminal oxidase: its elusive function points to multiple contributions to plastid physiology. ANNUAL REVIEW OF PLANT BIOLOGY 2015; 66:49-74. [PMID: 25580838 DOI: 10.1146/annurev-arplant-043014-114744] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Plastids have retained from their cyanobacterial ancestor a fragment of the respiratory electron chain comprising an NADPH dehydrogenase and a diiron oxidase, which sustain the so-called chlororespiration pathway. Despite its very low turnover rates compared with photosynthetic electron flow, knocking out the plastid terminal oxidase (PTOX) in plants or microalgae leads to severe phenotypes that encompass developmental and growth defects together with increased photosensitivity. On the basis of a phylogenetic and structural analysis of the enzyme, we discuss its physiological contribution to chloroplast metabolism, with an emphasis on its critical function in setting the redox poise of the chloroplast stroma in darkness. The emerging picture of PTOX is that of an enzyme at the crossroads of a variety of metabolic processes, such as, among others, the regulation of cyclic electron transfer and carotenoid biosynthesis, which have in common their dependence on the redox state of the plastoquinone pool, set largely by the activity of PTOX in darkness.
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Affiliation(s)
- Wojciech J Nawrocki
- Laboratoire de Physiologie Membranaire et Moléculaire du Chloroplaste, UMR 7141, Centre National de la Recherche Scientifique-Université Pierre et Marie Curie
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134
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Sarewicz M, Osyczka A. Electronic connection between the quinone and cytochrome C redox pools and its role in regulation of mitochondrial electron transport and redox signaling. Physiol Rev 2015; 95:219-43. [PMID: 25540143 PMCID: PMC4281590 DOI: 10.1152/physrev.00006.2014] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Mitochondrial respiration, an important bioenergetic process, relies on operation of four membranous enzymatic complexes linked functionally by mobile, freely diffusible elements: quinone molecules in the membrane and water-soluble cytochromes c in the intermembrane space. One of the mitochondrial complexes, complex III (cytochrome bc1 or ubiquinol:cytochrome c oxidoreductase), provides an electronic connection between these two diffusible redox pools linking in a fully reversible manner two-electron quinone oxidation/reduction with one-electron cytochrome c reduction/oxidation. Several features of this homodimeric enzyme implicate that in addition to its well-defined function of contributing to generation of proton-motive force, cytochrome bc1 may be a physiologically important point of regulation of electron flow acting as a sensor of the redox state of mitochondria that actively responds to changes in bioenergetic conditions. These features include the following: the opposing redox reactions at quinone catalytic sites located on the opposite sides of the membrane, the inter-monomer electronic connection that functionally links four quinone binding sites of a dimer into an H-shaped electron transfer system, as well as the potential to generate superoxide and release it to the intermembrane space where it can be engaged in redox signaling pathways. Here we highlight recent advances in understanding how cytochrome bc1 may accomplish this regulatory physiological function, what is known and remains unknown about catalytic and side reactions within the quinone binding sites and electron transfers through the cofactor chains connecting those sites with the substrate redox pools. We also discuss the developed molecular mechanisms in the context of physiology of mitochondria.
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Affiliation(s)
- Marcin Sarewicz
- Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Artur Osyczka
- Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian University, Kraków, Poland
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135
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Sugiura M, Boussac A. Variants of photosystem II D1 protein in Thermosynechococcus elongatus. RESEARCH ON CHEMICAL INTERMEDIATES 2014. [DOI: 10.1007/s11164-014-1828-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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136
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Kozuleva MA, Petrova AA, Mamedov MD, Semenov AY, Ivanov BN. O2 reduction by photosystem I involves phylloquinone under steady-state illumination. FEBS Lett 2014; 588:4364-8. [PMID: 25311539 DOI: 10.1016/j.febslet.2014.10.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 09/13/2014] [Accepted: 10/01/2014] [Indexed: 11/29/2022]
Abstract
O2 reduction was investigated in photosystem I (PSI) complexes isolated from cyanobacteria Synechocystis sp. PCC 6803 wild type (WT) and menB mutant strain, which is unable to synthesize phylloquinone and contains plastoquinone at the quinone-binding site A1. PSI complexes from WT and menB mutant exhibited different dependencies of O2 reduction on light intensity, namely, the values of O2 reduction rate in WT did not reach saturation at high intensities, in contrast to the values in menB mutant. The obtained results suggest the immediate phylloquinone involvement in the light-induced O2 reduction by PSI.
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Affiliation(s)
- Marina A Kozuleva
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Russia.
| | - Anastasia A Petrova
- A.N. Belozersky Institute of Physical-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Mahir D Mamedov
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Russia; A.N. Belozersky Institute of Physical-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Alexey Yu Semenov
- A.N. Belozersky Institute of Physical-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Boris N Ivanov
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Russia
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137
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Pospíšil P, Prasad A. Formation of singlet oxygen and protection against its oxidative damage in Photosystem II under abiotic stress. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2014; 137:39-48. [DOI: 10.1016/j.jphotobiol.2014.04.025] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Revised: 04/25/2014] [Accepted: 04/27/2014] [Indexed: 01/10/2023]
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138
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Dang KV, Plet J, Tolleter D, Jokel M, Cuiné S, Carrier P, Auroy P, Richaud P, Johnson X, Alric J, Allahverdiyeva Y, Peltier G. Combined increases in mitochondrial cooperation and oxygen photoreduction compensate for deficiency in cyclic electron flow in Chlamydomonas reinhardtii. THE PLANT CELL 2014; 26:3036-50. [PMID: 24989042 PMCID: PMC4145130 DOI: 10.1105/tpc.114.126375] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
During oxygenic photosynthesis, metabolic reactions of CO2 fixation require more ATP than is supplied by the linear electron flow operating from photosystem II to photosystem I (PSI). Different mechanisms, such as cyclic electron flow (CEF) around PSI, have been proposed to participate in reequilibrating the ATP/NADPH balance. To determine the contribution of CEF to microalgal biomass productivity, here, we studied photosynthesis and growth performances of a knockout Chlamydomonas reinhardtii mutant (pgrl1) deficient in PROTON GRADIENT REGULATION LIKE1 (PGRL1)-mediated CEF. Steady state biomass productivity of the pgrl1 mutant, measured in photobioreactors operated as turbidostats, was similar to its wild-type progenitor under a wide range of illumination and CO2 concentrations. Several changes were observed in pgrl1, including higher sensitivity of photosynthesis to mitochondrial inhibitors, increased light-dependent O2 uptake, and increased amounts of flavodiiron (FLV) proteins. We conclude that a combination of mitochondrial cooperation and oxygen photoreduction downstream of PSI (Mehler reactions) supplies extra ATP for photosynthesis in the pgrl1 mutant, resulting in normal biomass productivity under steady state conditions. The lower biomass productivity observed in the pgrl1 mutant in fluctuating light is attributed to an inability of compensation mechanisms to respond to a rapid increase in ATP demand.
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Affiliation(s)
- Kieu-Van Dang
- CEA, Institut de Biologie Environnementale et de Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, CEA Cadarache, F-13108 Saint-Paul-lez-Durance, France CNRS, UMR 7265 Biologie Végétale et Microbiologie Environnementale, F-13108 Saint-Paul-lez-Durance, France Aix Marseille Université, UMR 7265 Biologie Végétale et Microbiologie Environnementale, F-13284 Marseille, France
| | - Julie Plet
- CEA, Institut de Biologie Environnementale et de Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, CEA Cadarache, F-13108 Saint-Paul-lez-Durance, France CNRS, UMR 7265 Biologie Végétale et Microbiologie Environnementale, F-13108 Saint-Paul-lez-Durance, France Aix Marseille Université, UMR 7265 Biologie Végétale et Microbiologie Environnementale, F-13284 Marseille, France
| | - Dimitri Tolleter
- CEA, Institut de Biologie Environnementale et de Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, CEA Cadarache, F-13108 Saint-Paul-lez-Durance, France CNRS, UMR 7265 Biologie Végétale et Microbiologie Environnementale, F-13108 Saint-Paul-lez-Durance, France Aix Marseille Université, UMR 7265 Biologie Végétale et Microbiologie Environnementale, F-13284 Marseille, France
| | - Martina Jokel
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland
| | - Stéphan Cuiné
- CEA, Institut de Biologie Environnementale et de Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, CEA Cadarache, F-13108 Saint-Paul-lez-Durance, France CNRS, UMR 7265 Biologie Végétale et Microbiologie Environnementale, F-13108 Saint-Paul-lez-Durance, France Aix Marseille Université, UMR 7265 Biologie Végétale et Microbiologie Environnementale, F-13284 Marseille, France
| | - Patrick Carrier
- CEA, Institut de Biologie Environnementale et de Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, CEA Cadarache, F-13108 Saint-Paul-lez-Durance, France CNRS, UMR 7265 Biologie Végétale et Microbiologie Environnementale, F-13108 Saint-Paul-lez-Durance, France Aix Marseille Université, UMR 7265 Biologie Végétale et Microbiologie Environnementale, F-13284 Marseille, France
| | - Pascaline Auroy
- CEA, Institut de Biologie Environnementale et de Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, CEA Cadarache, F-13108 Saint-Paul-lez-Durance, France CNRS, UMR 7265 Biologie Végétale et Microbiologie Environnementale, F-13108 Saint-Paul-lez-Durance, France Aix Marseille Université, UMR 7265 Biologie Végétale et Microbiologie Environnementale, F-13284 Marseille, France
| | - Pierre Richaud
- CEA, Institut de Biologie Environnementale et de Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, CEA Cadarache, F-13108 Saint-Paul-lez-Durance, France CNRS, UMR 7265 Biologie Végétale et Microbiologie Environnementale, F-13108 Saint-Paul-lez-Durance, France Aix Marseille Université, UMR 7265 Biologie Végétale et Microbiologie Environnementale, F-13284 Marseille, France
| | - Xenie Johnson
- CEA, Institut de Biologie Environnementale et de Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, CEA Cadarache, F-13108 Saint-Paul-lez-Durance, France CNRS, UMR 7265 Biologie Végétale et Microbiologie Environnementale, F-13108 Saint-Paul-lez-Durance, France Aix Marseille Université, UMR 7265 Biologie Végétale et Microbiologie Environnementale, F-13284 Marseille, France
| | - Jean Alric
- CEA, Institut de Biologie Environnementale et de Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, CEA Cadarache, F-13108 Saint-Paul-lez-Durance, France CNRS, UMR 7265 Biologie Végétale et Microbiologie Environnementale, F-13108 Saint-Paul-lez-Durance, France Aix Marseille Université, UMR 7265 Biologie Végétale et Microbiologie Environnementale, F-13284 Marseille, France
| | - Yagut Allahverdiyeva
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland
| | - Gilles Peltier
- CEA, Institut de Biologie Environnementale et de Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, CEA Cadarache, F-13108 Saint-Paul-lez-Durance, France CNRS, UMR 7265 Biologie Végétale et Microbiologie Environnementale, F-13108 Saint-Paul-lez-Durance, France Aix Marseille Université, UMR 7265 Biologie Végétale et Microbiologie Environnementale, F-13284 Marseille, France
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139
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Telfer A. Singlet oxygen production by PSII under light stress: mechanism, detection and the protective role of β-carotene. PLANT & CELL PHYSIOLOGY 2014; 55:1216-23. [PMID: 24566536 PMCID: PMC4080269 DOI: 10.1093/pcp/pcu040] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 02/14/2014] [Indexed: 05/18/2023]
Abstract
In this review, I outline the indirect evidence for the formation of singlet oxygen ((1)O(2)) obtained from experiments with the isolated PSII reaction center complex. I also review the methods we used to measure singlet oxygen directly, including luminescence at 1,270 nm, both steady state and time resolved. Other methods we used were histidine-catalyzed molecular oxygen uptake (enabling (1)O(2) yield measurements), and dye bleaching and difference absorption spectroscopy to identify where quenchers of (1)O(2) can access this toxic species. We also demonstrated the protective behavior of carotenoids bound within Chl-protein complexes which bring about a substantial amount of (1)O(2) quenching within the reaction center complex. Finally, I describe how these techniques have been used and expanded in research on photoinhibition and on the role of (1)O(2) as a signaling molecule in instigating cellular responses to various stress factors. I also discuss the current views on the role of (1)O(2) as a signaling molecule and the distance it might be able to travel within cells.
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Affiliation(s)
- Alison Telfer
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College London, London SW7 2AZ, UK
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140
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Koroidov S, Shevela D, Shutova T, Samuelsson G, Messinger J. Mobile hydrogen carbonate acts as proton acceptor in photosynthetic water oxidation. Proc Natl Acad Sci U S A 2014; 111:6299-304. [PMID: 24711433 PMCID: PMC4035973 DOI: 10.1073/pnas.1323277111] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cyanobacteria, algae, and plants oxidize water to the O2 we breathe, and consume CO2 during the synthesis of biomass. Although these vital processes are functionally and structurally well separated in photosynthetic organisms, there is a long-debated role for CO2/ in water oxidation. Using membrane-inlet mass spectrometry we demonstrate that acts as a mobile proton acceptor that helps to transport the protons produced inside of photosystem II by water oxidation out into the chloroplast's lumen, resulting in a light-driven production of O2 and CO2. Depletion of from the media leads, in the absence of added buffers, to a reversible down-regulation of O2 production by about 20%. These findings add a previously unidentified component to the regulatory network of oxygenic photosynthesis and conclude the more than 50-y-long quest for the function of CO2/ in photosynthetic water oxidation.
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Affiliation(s)
| | | | - Tatiana Shutova
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, S-90187 Umeå, Sweden
| | - Göran Samuelsson
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, S-90187 Umeå, Sweden
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141
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Yano J, Yachandra V. Mn4Ca cluster in photosynthesis: where and how water is oxidized to dioxygen. Chem Rev 2014; 114:4175-205. [PMID: 24684576 PMCID: PMC4002066 DOI: 10.1021/cr4004874] [Citation(s) in RCA: 473] [Impact Index Per Article: 47.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Indexed: 12/25/2022]
Affiliation(s)
- Junko Yano
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Vittal Yachandra
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
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142
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Scholes GD, Sargent EH. Bioinspired materials: Boosting plant biology. NATURE MATERIALS 2014; 13:329-331. [PMID: 24651425 DOI: 10.1038/nmat3926] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Affiliation(s)
- Gregory D Scholes
- Department of Chemistry, University of Toronto, 80 St George Street, Toronto, Ontario M5S 3H6, Canada
| | - Edward H Sargent
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario M5S 3G4, Canada
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143
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Vinyard DJ, Gimpel J, Ananyev GM, Mayfield SP, Dismukes GC. Engineered Photosystem II reaction centers optimize photochemistry versus photoprotection at different solar intensities. J Am Chem Soc 2014; 136:4048-55. [PMID: 24548276 DOI: 10.1021/ja5002967] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The D1 protein of Photosystem II (PSII) provides most of the ligating amino acid residues for the Mn4CaO5 water-oxidizing complex (WOC) and half of the reaction center cofactors, and it is present as two isoforms in the cyanobacterium Synechococcus elongatus PCC 7942. These isoforms, D1:1 and D1:2, confer functional advantages for photosynthetic growth at low and high light intensities, respectively. D1:1, D1:2, and seven point mutations in the D1:2 background that are native to D1:1 were expressed in the green alga Chlamydomonas reinhardtii. We used these nine strains to show that those strains that confer a higher yield of PSII charge separation under light-limiting conditions (where charge recombination is significant) have less efficient photochemical turnover, measured in terms of both a lower WOC turnover probability and a longer WOC cycle period. Conversely, these same strains under light saturation (where charge recombination does not compete) confer a correspondingly faster O2 evolution rate and greater protection against photoinhibition. Taken together, the data clearly establish that PSII primary charge separation is a trade-off between photochemical productivity (water oxidation and plastoquinone reduction) and charge recombination (photoprotection). These trade-offs add up to a significant growth advantage for the two natural isoforms. These insights provide fundamental design principles for engineering of PSII reaction centers with optimal photochemical efficiencies for growth at low versus high light intensities.
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Affiliation(s)
- David J Vinyard
- Department of Chemistry and Chemical Biology and ‡Waksman Institute of Microbiology, Rutgers, The State University of New Jersey , Piscataway, New Jersey 08854, United States
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144
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Abstract
Electrons have so little mass that in less than a second they can tunnel through potential energy barriers that are several electron-volts high and several nanometers wide. Electron tunneling is a critical functional element in a broad spectrum of applications, ranging from semiconductor diodes to the photosynthetic and respiratory charge transport chains. Prior to the 1970s, chemists generally believed that reactants had to collide in order to effect a transformation. Experimental demonstrations that electrons can transfer between reactants separated by several nanometers led to a revision of the chemical reaction paradigm. Experimental investigations of electron exchange between redox partners separated by molecular bridges have elucidated many fundamental properties of these reactions, particularly the variation of rate constants with distance. Theoretical work has provided critical insights into the superexchange mechanism of electronic coupling between distant redox centers. Kinetics measurements have shown that electrons can tunnel about 2.5 nm through proteins on biologically relevant time scales. Longer-distance biological charge flow requires multiple electron tunneling steps through chains of redox cofactors. The range of phenomena that depends on long-range electron tunneling continues to expand, providing new challenges for both theory and experiment.
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Affiliation(s)
- Jay R. Winkler
- Beckman Institute, California
Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
| | - Harry B. Gray
- Beckman Institute, California
Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
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145
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The importance of the hydrophilic region of PsbL for the plastoquinone electron acceptor complex of Photosystem II. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:1435-46. [PMID: 24576450 DOI: 10.1016/j.bbabio.2014.02.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 02/12/2014] [Accepted: 02/15/2014] [Indexed: 11/23/2022]
Abstract
The PsbL protein is a 4.5kDa subunit at the monomer-monomer interface of Photosystem II (PS II) consisting of a single membrane-spanning domain and a hydrophilic stretch of ~15 residues facing the cytosolic (or stromal) side of the photosystem. Deletion of conserved residues in the N-terminal region has been used to investigate the importance of this hydrophilic extension. Using Synechocystis sp. PCC 6803, three deletion strains: ∆(N6-N8), ∆(P11-V12) and ∆(E13-N15), have been created. The ∆(N6-N8) and ∆(P11-V12) strains remained photoautotrophic but were more susceptible to photodamage than the wild type; however, the ∆(E13-N15) cells had the most severe phenotype. The Δ(E13-N15) mutant showed decreased photoautotrophic growth, a reduced number of PS II centers, impaired oxygen evolution in the presence of PS II-specific electron acceptors, and was highly susceptible to photodamage. The decay kinetics of chlorophyll a variable fluorescence after a single turnover saturating flash and the sensitivity to low concentrations of PS II-directed herbicides in the Δ(E13-N15) strain indicate that the binding of plastoquinone to the QB-binding site had been altered such that the affinity of QB is reduced. In addition, the PS II-specific electron acceptor 2,5-dimethyl-p-benzoquinone was found to inhibit electron transfer through the quinone-acceptor complex of the ∆(E13-N15) strain. The PsbL Y20A mutant was also investigated and it exhibited increased susceptibility to photodamage and increased herbicide sensitivity. Our data suggest that the N-terminal hydrophilic region of PsbL influences forward electron transfer from QA through indirect interactions with the D-E loop of the D1 reaction center protein. Our results further indicate that disruption of interactions between the N-terminal region of PsbL and other PS II subunits or lipids destabilizes PS II dimer formation. This article is part of a special issue entitled: photosynthesis research for sustainability: keys to produce clean energy.
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146
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Schmitt FJ, Renger G, Friedrich T, Kreslavski VD, Zharmukhamedov SK, Los DA, Kuznetsov VV, Allakhverdiev SI. Reactive oxygen species: re-evaluation of generation, monitoring and role in stress-signaling in phototrophic organisms. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:835-48. [PMID: 24530357 DOI: 10.1016/j.bbabio.2014.02.005] [Citation(s) in RCA: 154] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 02/06/2014] [Accepted: 02/07/2014] [Indexed: 12/11/2022]
Abstract
This review provides an overview about recent developments and current knowledge about monitoring, generation and the functional role of reactive oxygen species (ROS) - H2O2, HO2, HO, OH(-), (1)O2 and O2(-) - in both oxidative degradation and signal transduction in photosynthetic organisms including microscopic techniques for ROS detection and controlled generation. Reaction schemes elucidating formation, decay and signaling of ROS in cyanobacteria as well as from chloroplasts to the nuclear genome in eukaryotes during exposure of oxygen-evolving photosynthetic organisms to oxidative stress are discussed that target the rapidly growing field of regulatory effects of ROS on nuclear gene expression.
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Affiliation(s)
- Franz-Josef Schmitt
- Technical University Berlin, Institute of Chemistry, Sekr. PC 14, Max-Volmer-Laboratory of Biophysical Chemistry, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Gernot Renger
- Technical University Berlin, Institute of Chemistry, Sekr. PC 14, Max-Volmer-Laboratory of Biophysical Chemistry, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Thomas Friedrich
- Technical University Berlin, Institute of Chemistry, Sekr. PC 14, Max-Volmer-Laboratory of Biophysical Chemistry, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Vladimir D Kreslavski
- Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya Street 2, Pushchino, Moscow Region 142290, Russia; Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow 127276, Russia
| | - Sergei K Zharmukhamedov
- Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya Street 2, Pushchino, Moscow Region 142290, Russia
| | - Dmitry A Los
- Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow 127276, Russia
| | - Vladimir V Kuznetsov
- Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow 127276, Russia; Tomsk State University, Lenin Avenue 36, Tomsk 634050, Russia
| | - Suleyman I Allakhverdiev
- Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya Street 2, Pushchino, Moscow Region 142290, Russia; Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow 127276, Russia.
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147
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Sugiura M, Boussac A. Some Photosystem II properties depending on the D1 protein variants in Thermosynechococcus elongatus. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:1427-34. [PMID: 24388918 DOI: 10.1016/j.bbabio.2013.12.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 12/17/2013] [Accepted: 12/25/2013] [Indexed: 10/25/2022]
Abstract
Cyanobacteria have multiple psbA genes encoding PsbA, the D1 reaction center protein of the Photosystem II complex which bears together with PsbD, the D2 protein, most of the cofactors involved in electron transfer reactions. The thermophilic cyanobacterium Thermosynechococcus elongatus has three psbA genes differently expressed depending on the environmental conditions. Among the 344 residues constituting each of the 3 possible PsbA variants there are 21 substitutions between PsbA1 and PsbA3, 31 between PsbA1 and PsbA2 and 27 between PsbA2 and PsbA3. In this review, we summarize the changes already identified in the properties of the redox cofactors depending on the D1 variant constituting Photosystem II in T. elongatus. This article is part of a special issue entitled: photosynthesis research for sustainability: keys to produce clean energy.
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Affiliation(s)
- Miwa Sugiura
- Proteo-science Research Center, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan; PRESTO, Japan Science and Technology Agency (JST), 4-1-8, Honcho, Kawauchi, Saitama 332-0012, Japan.
| | - Alain Boussac
- iBiTec-S, CNRS UMR 8221, CEA Saclay, 91191 Gif-sur-Yvette, France.
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148
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Lai YH, Kato M, Mersch D, Reisner E. Comparison of photoelectrochemical water oxidation activity of a synthetic photocatalyst system with photosystem II. Faraday Discuss 2014; 176:199-211. [DOI: 10.1039/c4fd00059e] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
This discussion describes a direct comparison of photoelectrochemical (PEC) water oxidation activity between a photosystem II (PSII)-functionalised photoanode and a synthetic nanocomposite photoanode. The semi-biological photoanode is composed of PSII from the thermophilic cyanobacterium Thermosynechococcus elongatus on a mesoporous indium tin oxide electrode (mesoITO|PSII). PSII embeds all of the required functionalities for light absorption, charge separation and water oxidation and ITO serves solely as the electron collector. The synthetic photoanode consists of a TiO2 and NiOx coated nanosheet-structured WO3 electrode (nanoWO3|TiO2|NiOx). The composite structure of the synthetic electrode allows mimicry of the functional key features in PSII: visible light is absorbed by WO3, TiO2 serves as a protection and charge separation layer and NiOx serves as the water oxidation electrocatalyst. MesoITO|PSII uses low energy red light, whereas nanoWO3|TiO2|NiOx requires high energy photons of blue-end visible and UV regions to oxidise water. The electrodes have a comparable onset potential at approximately 0.6 V vs. reversible hydrogen electrode (RHE). MesoITO|PSII reaches its saturation photocurrent at 0.84 V vs. RHE, whereas nanoWO3|TiO2|NiOx requires more than 1.34 V vs. RHE. This suggests that mesoITO|PSII suffers from fewer limitations from charge recombination and slow water oxidation catalysis than the synthetic electrode. MesoITO|PSII displays a higher ‘per active’ site activity, but is less photostable and displays a much lower photocurrent per geometrical surface area and incident photon to current conversion efficiency (IPCE) than nanoWO3|TiO2|NiOx.
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Affiliation(s)
- Yi-Hsuan Lai
- Christian Doppler Laboratory for Sustainable SynGas Chemistry
- Department of Chemistry
- University of Cambridge
- Cambridge CB2 1EW, UK
| | - Masaru Kato
- Christian Doppler Laboratory for Sustainable SynGas Chemistry
- Department of Chemistry
- University of Cambridge
- Cambridge CB2 1EW, UK
| | - Dirk Mersch
- Christian Doppler Laboratory for Sustainable SynGas Chemistry
- Department of Chemistry
- University of Cambridge
- Cambridge CB2 1EW, UK
| | - Erwin Reisner
- Christian Doppler Laboratory for Sustainable SynGas Chemistry
- Department of Chemistry
- University of Cambridge
- Cambridge CB2 1EW, UK
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149
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Sugiura M, Azami C, Koyama K, Rutherford AW, Rappaport F, Boussac A. Modification of the pheophytin redox potential in Thermosynechococcus elongatus Photosystem II with PsbA3 as D1. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:139-48. [DOI: 10.1016/j.bbabio.2013.09.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 09/12/2013] [Accepted: 09/13/2013] [Indexed: 10/26/2022]
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150
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Crofts AR, Hong S, Wilson C, Burton R, Victoria D, Harrison C, Schulten K. The mechanism of ubihydroquinone oxidation at the Qo-site of the cytochrome bc1 complex. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1827:1362-77. [PMID: 23396004 PMCID: PMC3995752 DOI: 10.1016/j.bbabio.2013.01.009] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Revised: 12/12/2012] [Accepted: 01/18/2013] [Indexed: 01/04/2023]
Abstract
1. Recent results suggest that the major flux is carried by a monomeric function, not by an intermonomer electron flow. 2. The bifurcated reaction at the Qo-site involves sequential partial processes, - a rate limiting first electron transfer generating a semiquinone (SQ) intermediate, and a rapid second electron transfer in which the SQ is oxidized by the low potential chain. 3. The rate constant for the first step in a strongly endergonic, proton-first-then-electron mechanism, is given by a Marcus-Brønsted treatment in which a rapid electron transfer is convoluted with a weak occupancy of the proton configuration needed for electron transfer. 4. A rapid second electron transfer pulls the overall reaction over. Mutation of Glu-295 of cyt b shows it to be a key player. 5. In more crippled mutants, electron transfer is severely inhibited and the bell-shaped pH dependence of wildtype is replaced by a dependence on a single pK at ~8.5 favoring electron transfer. Loss of a pK ~6.5 is explained by a change in the rate limiting step from the first to the second electron transfer; the pK ~8.5 may reflect dissociation of QH. 6. A rate constant (<10(3)s(-1)) for oxidation of SQ in the distal domain by heme bL has been determined, which precludes mechanisms for normal flux in which SQ is constrained there. 7. Glu-295 catalyzes proton exit through H(+) transfer from QH, and rotational displacement to deliver the H(+) to exit channel(s). This opens a volume into which Q(-) can move closer to the heme to speed electron transfer. 8. A kinetic model accounts well for the observations, but leaves open the question of gating mechanisms. For the first step we suggest a molecular "escapement"; for the second a molecular ballet choreographed through coulombic interactions. This article is part of a Special Issue entitled: Respiratory complex III and related bc complexes.
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Affiliation(s)
- Antony R Crofts
- Center for Biophysics and Computational Biology, University of Illinois, Urbana, IL 61801, USA; Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA.
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