1
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Tikhonov AN. The cytochrome b 6f complex: plastoquinol oxidation and regulation of electron transport in chloroplasts. PHOTOSYNTHESIS RESEARCH 2024; 159:203-227. [PMID: 37369875 DOI: 10.1007/s11120-023-01034-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 06/12/2023] [Indexed: 06/29/2023]
Abstract
In oxygenic photosynthetic systems, the cytochrome b6f (Cytb6f) complex (plastoquinol:plastocyanin oxidoreductase) is a heart of the hub that provides connectivity between photosystems (PS) II and I. In this review, the structure and function of the Cytb6f complex are briefly outlined, being focused on the mechanisms of a bifurcated (two-electron) oxidation of plastoquinol (PQH2). In plant chloroplasts, under a wide range of experimental conditions (pH and temperature), a diffusion of PQH2 from PSII to the Cytb6f does not limit the intersystem electron transport. The overall rate of PQH2 turnover is determined mainly by the first step of the bifurcated oxidation of PQH2 at the catalytic site Qo, i.e., the reaction of electron transfer from PQH2 to the Fe2S2 cluster of the high-potential Rieske iron-sulfur protein (ISP). This point has been supported by the quantum chemical analysis of PQH2 oxidation within the framework of a model system including the Fe2S2 cluster of the ISP and surrounding amino acids, the low-potential heme b6L, Glu78 and 2,3,5-trimethylbenzoquinol (the tail-less analog of PQH2). Other structure-function relationships and mechanisms of electron transport regulation of oxygenic photosynthesis associated with the Cytb6f complex are briefly outlined: pH-dependent control of the intersystem electron transport and the regulatory balance between the operation of linear and cyclic electron transfer chains.
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Affiliation(s)
- Alexander N Tikhonov
- Department of Biophysics, Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow, Russian Federation, 119991.
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2
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Zamora RA, López-Ortiz M, Sales-Mateo M, Hu C, Croce R, Maniyara RA, Pruneri V, Giannotti MI, Gorostiza P. Light- and Redox-Dependent Force Spectroscopy Reveals that the Interaction between Plastocyanin and Plant Photosystem I Is Favored when One Partner Is Ready for Electron Transfer. ACS NANO 2022; 16:15155-15164. [PMID: 36067071 DOI: 10.1021/acsnano.2c06454] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Photosynthesis is a fundamental process that converts photons into chemical energy, driven by large protein complexes at the thylakoid membranes of plants, cyanobacteria, and algae. In plants, water-soluble plastocyanin (Pc) is responsible for shuttling electrons between cytochrome b6f complex and the photosystem I (PSI) complex in the photosynthetic electron transport chain (PETC). For an efficient turnover, a transient complex must form between PSI and Pc in the PETC, which implies a balance between specificity and binding strength. Here, we studied the binding frequency and the unbinding force between suitably oriented plant PSI and Pc under redox control using single molecule force spectroscopy (SMFS). The binding frequency (observation of binding-unbinding events) between PSI and Pc depends on their respective redox states. The interaction between PSI and Pc is independent of the redox state of PSI when Pc is reduced, and it is disfavored in the dark (reduced P700) when Pc is oxidized. The frequency of interaction between PSI and Pc is higher when at least one of the partners is in a redox state ready for electron transfer (ET), and the post-ET situation (PSIRed-PcOx) leads to lower binding. In addition, we show that the binding of ET-ready PcRed to PSI can be regulated externally by Mg2+ ions in solution.
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Affiliation(s)
- Ricardo A Zamora
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, Barcelona 08028, Spain
- CIBER-BBN, ISCIII, Barcelona 08028, Spain
| | - Manuel López-Ortiz
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, Barcelona 08028, Spain
- CIBER-BBN, ISCIII, Barcelona 08028, Spain
| | - Montserrat Sales-Mateo
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, Barcelona 08028, Spain
| | - Chen Hu
- Biophysics of Photosynthesis. Dep. Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Roberta Croce
- Biophysics of Photosynthesis. Dep. Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Rinu Abraham Maniyara
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels 08860, Spain
| | - Valerio Pruneri
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels 08860, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), Barcelona 08010, Spain
| | - Marina I Giannotti
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, Barcelona 08028, Spain
- CIBER-BBN, ISCIII, Barcelona 08028, Spain
- Department of Materials Science and Physical Chemistry, University of Barcelona, Martí i Franquès 10, Barcelona 08028, Spain
| | - Pau Gorostiza
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, Barcelona 08028, Spain
- CIBER-BBN, ISCIII, Barcelona 08028, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), Barcelona 08010, Spain
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3
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Teodor AH, Ooi EJ, Medina J, Alarcon M, Vaughn MD, Bruce BD, Bergkamp JJ. Aqueous-soluble bipyridine cobalt(ii/iii) complexes act as direct redox mediators in photosystem I-based biophotovoltaic devices. RSC Adv 2021; 11:10434-10450. [PMID: 35423559 PMCID: PMC8695705 DOI: 10.1039/d0ra10221k] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 02/28/2021] [Indexed: 01/13/2023] Open
Abstract
Sustainable energy production is critical for meeting growing worldwide energy demands. Due to its stability and reduction potential, photosystem I (PSI) is attractive as the photosensitizer in biophotovoltaic devices. Herein, we characterize aqueous and organic solvent soluble synthetic bipyridine-based cobalt complexes as redox mediators for PSI-based biophotovoltaics applications. Cobalt-based complexes are not destructive to protein and have appropriate midpoint potentials for electron donation to PSI. We report on PSI stability in organic solvents commonly used in biophotovoltaics. We also show the effects of a mixed organic solvent phase on PSI reduction kinetics, slowing reduction rates approximately 8–38 fold as compared to fully aqueous systems, with implications for dye regeneration rates in PSI-based biophotovoltaics. Further, we show evidence of direct electron transfer from cobalt complexes to PSI. Finally, we report on photocurrent generation from Co mediator-PSI biophotovoltaic devices. Taken together, we discuss the development of novel Co complexes and our ability to fine-tune their characteristics via functional groups and counteranion choice to drive interaction with a biological electron acceptor on multiple levels from redox midpoints, spectral overlap, and solvent requirements, among others. This work suggests that fine-tuning of redox active species for interaction with a biological partner is possible for the creation and improvement of low cost, carbon-neutral energy production in the future. Sustainable energy production is critical for meeting growing worldwide energy demands.![]()
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Affiliation(s)
- Alexandra H Teodor
- Graduate School of Genome Science and Technology, University of Tennessee at Knoxville and Oak Ridge National Laboratory USA
| | - Eu-Jee Ooi
- Department of Chemistry and Biochemistry, California State University Bakersfield USA
| | - Jackeline Medina
- Department of Chemistry and Biochemistry, California State University Bakersfield USA
| | - Miguel Alarcon
- Department of Chemistry and Biochemistry, California State University Bakersfield USA
| | | | - Barry D Bruce
- Graduate School of Genome Science and Technology, University of Tennessee at Knoxville and Oak Ridge National Laboratory USA .,Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee at Knoxville USA.,Department of Chemical and Biomolecular Engineering, University of Tennessee at Knoxville USA
| | - Jesse J Bergkamp
- Department of Chemistry and Biochemistry, California State University Bakersfield USA
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4
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Sarewicz M, Pintscher S, Pietras R, Borek A, Bujnowicz Ł, Hanke G, Cramer WA, Finazzi G, Osyczka A. Catalytic Reactions and Energy Conservation in the Cytochrome bc1 and b6f Complexes of Energy-Transducing Membranes. Chem Rev 2021; 121:2020-2108. [PMID: 33464892 PMCID: PMC7908018 DOI: 10.1021/acs.chemrev.0c00712] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Indexed: 12/16/2022]
Abstract
This review focuses on key components of respiratory and photosynthetic energy-transduction systems: the cytochrome bc1 and b6f (Cytbc1/b6f) membranous multisubunit homodimeric complexes. These remarkable molecular machines catalyze electron transfer from membranous quinones to water-soluble electron carriers (such as cytochromes c or plastocyanin), coupling electron flow to proton translocation across the energy-transducing membrane and contributing to the generation of a transmembrane electrochemical potential gradient, which powers cellular metabolism in the majority of living organisms. Cytsbc1/b6f share many similarities but also have significant differences. While decades of research have provided extensive knowledge on these enzymes, several important aspects of their molecular mechanisms remain to be elucidated. We summarize a broad range of structural, mechanistic, and physiological aspects required for function of Cytbc1/b6f, combining textbook fundamentals with new intriguing concepts that have emerged from more recent studies. The discussion covers but is not limited to (i) mechanisms of energy-conserving bifurcation of electron pathway and energy-wasting superoxide generation at the quinol oxidation site, (ii) the mechanism by which semiquinone is stabilized at the quinone reduction site, (iii) interactions with substrates and specific inhibitors, (iv) intermonomer electron transfer and the role of a dimeric complex, and (v) higher levels of organization and regulation that involve Cytsbc1/b6f. In addressing these topics, we point out existing uncertainties and controversies, which, as suggested, will drive further research in this field.
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Affiliation(s)
- Marcin Sarewicz
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Sebastian Pintscher
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Rafał Pietras
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Arkadiusz Borek
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Łukasz Bujnowicz
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Guy Hanke
- School
of Biological and Chemical Sciences, Queen
Mary University of London, London E1 4NS, U.K.
| | - William A. Cramer
- Department
of Biological Sciences, Purdue University, West Lafayette, Indiana 47907 United States
| | - Giovanni Finazzi
- Laboratoire
de Physiologie Cellulaire et Végétale, Université Grenoble Alpes, Centre National Recherche Scientifique,
Commissariat Energie Atomique et Energies Alternatives, Institut National
Recherche l’agriculture, l’alimentation et l’environnement, 38054 Grenoble Cedex 9, France
| | - Artur Osyczka
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
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5
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Malone LA, Proctor MS, Hitchcock A, Hunter CN, Johnson MP. Cytochrome b 6f - Orchestrator of photosynthetic electron transfer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2021; 1862:148380. [PMID: 33460588 DOI: 10.1016/j.bbabio.2021.148380] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 01/06/2021] [Accepted: 01/09/2021] [Indexed: 11/18/2022]
Abstract
Cytochrome b6f (cytb6f) lies at the heart of the light-dependent reactions of oxygenic photosynthesis, where it serves as a link between photosystem II (PSII) and photosystem I (PSI) through the oxidation and reduction of the electron carriers plastoquinol (PQH2) and plastocyanin (Pc). A mechanism of electron bifurcation, known as the Q-cycle, couples electron transfer to the generation of a transmembrane proton gradient for ATP synthesis. Cytb6f catalyses the rate-limiting step in linear electron transfer (LET), is pivotal for cyclic electron transfer (CET) and plays a key role as a redox-sensing hub involved in the regulation of light-harvesting, electron transfer and photosynthetic gene expression. Together, these characteristics make cytb6f a judicious target for genetic manipulation to enhance photosynthetic yield, a strategy which already shows promise. In this review we will outline the structure and function of cytb6f with a particular focus on new insights provided by the recent high-resolution map of the complex from Spinach.
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Affiliation(s)
- Lorna A Malone
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Matthew S Proctor
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Andrew Hitchcock
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Matthew P Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK.
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6
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Single-molecule study of redox control involved in establishing the spinach plastocyanin-cytochrome bf electron transfer complex. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:591-599. [DOI: 10.1016/j.bbabio.2019.06.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 06/18/2019] [Accepted: 06/21/2019] [Indexed: 01/06/2023]
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7
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Antal TK, Maslakov A, Yakovleva OV, Krendeleva TE, Riznichenko GY, Rubin AB. Simulation of chlorophyll fluorescence rise and decay kinetics, and P 700-related absorbance changes by using a rule-based kinetic Monte-Carlo method. PHOTOSYNTHESIS RESEARCH 2018; 138:191-206. [PMID: 30062532 DOI: 10.1007/s11120-018-0564-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 07/23/2018] [Indexed: 06/08/2023]
Abstract
A model of primary photosynthetic reactions in the thylakoid membrane was developed and its validity was tested by simulating three types of experimental kinetic curves: (1) the light-induced chlorophyll a fluorescence rise (OJIP transients) reflecting the stepwise transition of the photosynthetic electron transport chain from the oxidized to the fully reduced state; (2) the dark relaxation of the flash-induced fluorescence yield attributed to the QA- oxidation kinetics in PSII; and (3) the light-induced absorbance changes near 820 or 705 nm assigned to the redox transitions of P700 in PSI. A model was implemented by using a rule-based kinetic Monte-Carlo method and verified by simulating experimental curves under different treatments including photosynthetic inhibitors, heat stress, anaerobic conditions, and very high light intensity.
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Affiliation(s)
- T K Antal
- Department of Biophysics, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russian Federation, 119991.
| | - A Maslakov
- Department of Biophysics, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russian Federation, 119991
| | - O V Yakovleva
- Department of Biophysics, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russian Federation, 119991
| | - T E Krendeleva
- Department of Biophysics, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russian Federation, 119991
| | - G Yu Riznichenko
- Department of Biophysics, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russian Federation, 119991
| | - A B Rubin
- Department of Biophysics, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russian Federation, 119991
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8
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Kovalenko IB, Knyazeva OS, Antal TK, Ponomarev VY, Riznichenko GY, Rubin AB. Multiparticle Brownian dynamics simulation of experimental kinetics of cytochrome bf oxidation and photosystem I reduction by plastocyanin. PHYSIOLOGIA PLANTARUM 2017; 161:88-96. [PMID: 28369912 DOI: 10.1111/ppl.12570] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 01/22/2017] [Accepted: 02/22/2017] [Indexed: 06/07/2023]
Abstract
A model of electron transport from cytochrome f to photosystem I mediated by plastocyanin was designed on the basis of the multiparticle Brownian dynamics method. The model combines events which occur over a wide time range, including protein diffusion along the thylakoid membrane, long-distance interactions between proteins, formation of a multiprotein complex, electron transfer within a complex and complex dissociation. Results of the modeling were compared with the experimental kinetics measured in chloroplast thylakoids. Computer simulation demonstrated that the complex interior of the photosynthetic membrane, electrostatic interactions and Brownian diffusion provide physical conditions for the directed electron flow along the photosynthetic electron transport chain.
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Affiliation(s)
- Ilya B Kovalenko
- Biology Faculty, Lomonosov Moscow State University, Moscow, 119992, Russia
| | - Olga S Knyazeva
- Physical Faculty, Lomonosov Moscow State University, Moscow, 119992, Russia
| | - Taras K Antal
- Biology Faculty, Lomonosov Moscow State University, Moscow, 119992, Russia
| | | | | | - Andrei B Rubin
- Biology Faculty, Lomonosov Moscow State University, Moscow, 119992, Russia
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9
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Schreiber U, Klughammer C. Analysis of Photosystem I Donor and Acceptor Sides with a New Type of Online-Deconvoluting Kinetic LED-Array Spectrophotometer. PLANT & CELL PHYSIOLOGY 2016; 57:1454-1467. [PMID: 27053032 DOI: 10.1093/pcp/pcw044] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 02/16/2016] [Indexed: 05/13/2023]
Abstract
The newly developed Dual/KLAS-NIR spectrophotometer, technical details of which were reported very recently, is used in measuring redox changes of P700, plastocyanin (PC) and ferredoxin (Fd) in intact leaves of Hedera helix, Taxus baccata and Brassica napus An overview of various light-/dark-induced changes of deconvoluted P700+, PC+ and Fd- signals is presented demonstrating the wealth of novel information and the consistency of the obtained results. Fd- changes are particularly large after dark adaptation. PC oxidation precedes P700 oxidation during dark-light induction and in steady-state light response curves. Fd reoxidation during induction correlates with the secondary decline of simultaneously measured fluorescence yield, both of which are eliminated by removal of O2 By determination of 100% redox changes, relative contents of PC/P700 and Fd/P700 can be assessed, which show considerable variations between different leaves, with a trend to higher values in sun leaves. Based on deconvoluted P700+ signals, the complementary quantum yields of PSI, Y(I) (photochemical energy use), Y(ND) (non-photochemical loss due to oxidized primary donor) and Y(NA) (non-photochemical loss due to reduced acceptor) are determined as a function of light intensity and compared with the corresponding complementary quantum yields of PSII, Y(II) (photochemical energy use), Y(NPQ) (regulated non-photochemical loss) and Y(NO) (non-regulated non-photochemical loss). The ratio Y(I)/Y(II) increases with increasing intensities. In the low intensity range, a two-step increase of PC+ is indicative of heterogeneous PC pools.
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Affiliation(s)
- Ulrich Schreiber
- Julius-von Sachs Institut für Biowissenschaften, Universität Würzburg, D-97082 Würzburg, Germany
| | - Christof Klughammer
- Julius-von Sachs Institut für Biowissenschaften, Universität Würzburg, D-97082 Würzburg, Germany
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10
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Johnson MP, Vasilev C, Olsen JD, Hunter CN. Nanodomains of cytochrome b6f and photosystem II complexes in spinach grana thylakoid membranes. THE PLANT CELL 2014; 26:3051-61. [PMID: 25035407 PMCID: PMC4145131 DOI: 10.1105/tpc.114.127233] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 06/06/2014] [Accepted: 06/24/2014] [Indexed: 05/18/2023]
Abstract
The cytochrome b6f (cytb6f) complex plays a central role in photosynthesis, coupling electron transport between photosystem II (PSII) and photosystem I to the generation of a transmembrane proton gradient used for the biosynthesis of ATP. Photosynthesis relies on rapid shuttling of electrons by plastoquinone (PQ) molecules between PSII and cytb6f complexes in the lipid phase of the thylakoid membrane. Thus, the relative membrane location of these complexes is crucial, yet remains unknown. Here, we exploit the selective binding of the electron transfer protein plastocyanin (Pc) to the lumenal membrane surface of the cytb6f complex using a Pc-functionalized atomic force microscope (AFM) probe to identify the position of cytb6f complexes in grana thylakoid membranes from spinach (Spinacia oleracea). This affinity-mapping AFM method directly correlates membrane surface topography with Pc-cytb6f interactions, allowing us to construct a map of the grana thylakoid membrane that reveals nanodomains of colocalized PSII and cytb6f complexes. We suggest that the close proximity between PSII and cytb6f complexes integrates solar energy conversion and electron transfer by fostering short-range diffusion of PQ in the protein-crowded thylakoid membrane, thereby optimizing photosynthetic efficiency.
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Affiliation(s)
- Matthew P Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Cvetelin Vasilev
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - John D Olsen
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
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11
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Bernal-Bayard P, Molina-Heredia FP, Hervás M, Navarro JA. Photosystem I Reduction in Diatoms: As Complex as the Green Lineage Systems but Less Efficient. Biochemistry 2013; 52:8687-95. [DOI: 10.1021/bi401344f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Pilar Bernal-Bayard
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla & CSIC, Américo Vespucio 49, 41092 Sevilla, Spain
| | - Fernando P. Molina-Heredia
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla & CSIC, Américo Vespucio 49, 41092 Sevilla, Spain
| | - Manuel Hervás
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla & CSIC, Américo Vespucio 49, 41092 Sevilla, Spain
| | - José A. Navarro
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla & CSIC, Américo Vespucio 49, 41092 Sevilla, Spain
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12
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13
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Cloning, expression and purification of the luminal domain of spinach photosystem 1 subunit PsaF functional in binding to plastocyanin and with a disulfide bridge required for folding. Protein Expr Purif 2011; 78:156-66. [DOI: 10.1016/j.pep.2011.02.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 02/18/2011] [Accepted: 02/19/2011] [Indexed: 11/15/2022]
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14
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Busch A, Hippler M. The structure and function of eukaryotic photosystem I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1807:864-77. [PMID: 20920463 DOI: 10.1016/j.bbabio.2010.09.009] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 09/20/2010] [Accepted: 09/28/2010] [Indexed: 12/27/2022]
Abstract
Eukaryotic photosystem I consists of two functional moieties: the photosystem I core, harboring the components for the light-driven charge separation and the subsequent electron transfer, and the peripheral light-harvesting complex (LHCI). While the photosystem I-core remained highly conserved throughout the evolution, with the exception of the oxidizing side of photosystem I, the LHCI complex shows a high degree of variability in size, subunits composition and bound pigments, which is due to the large variety of different habitats photosynthetic organisms dwell in. Besides summarizing the most current knowledge on the photosystem I-core structure, we will discuss the composition and structure of the LHCI complex from different eukaryotic organisms, both from the red and the green clade. Furthermore, mechanistic insights into electron transfer between the donor and acceptor side of photosystem I and its soluble electron transfer carrier proteins will be given. This article is part of a Special Issue entitled: Regulation of Electron Transport in Chloroplasts.
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Affiliation(s)
- Andreas Busch
- Department of Plant Biology and Biotechnology, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark.
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15
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Knyazeva OS, Kovalenko IB, Abaturova AM, Riznichenko GY, Grachev EA, Rubin AB. Multiparticle computer simulation of plastocyanin diffusion and interaction with cytochrome f in the electrostatic field of the thylakoid membrane. Biophysics (Nagoya-shi) 2010. [DOI: 10.1134/s0006350910020090] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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16
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Lam E, Malkin R. Reconstruction of the chloroplast noncyclic electron transport pathway from water to NADP with three integral protein complexes. Proc Natl Acad Sci U S A 2010; 79:5494-8. [PMID: 16593225 PMCID: PMC346930 DOI: 10.1073/pnas.79.18.5494] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
RECONSTRUCTION OF PHOTOSYNTHETIC NONCYCLIC ELECTRON TRANSPORT FROM WATER TO NADP HAS BEEN ACCOMPLISHED BY USING THREE INTEGRAL PROTEIN COMPLEXES ISOLATED FROM CHLOROPLAST THYLAKOID MEMBRANES: photosystems I and II and the cytochrome b(6)-f complex. This system shows an absolute dependence on the presence of all three protein complexes for NADP reduction, in addition to plastocyanin, ferredoxin, and ferredoxin-NADP reductase. The reconstructed system was found to be sensitive to low concentrations of known inhibitors of noncyclic electron transport. Depletion of the Rieske iron-sulfur center and bound plastoquinone from the cytochrome b(6)-f complex resulted in an inhibition of the photoreduction of NADP.
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Affiliation(s)
- E Lam
- Department of Biophysics, University of California, Berkeley, California 94720
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Mitchell R, Spillmann A, Haehnel W. Plastoquinol diffusion in linear photosynthetic electron transport. Biophys J 2010; 58:1011-24. [PMID: 19431770 DOI: 10.1016/s0006-3495(90)82445-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
The diffusion of plastoquinol and its binding to the cytochrome bf complex, which occurs during linear photosynthetic electron transport and is analogous to reaction sequences found in most energy-converting membranes, has been studied in intact thylakoid membranes. The flash-induced electron transfer between the laterally separated photosystems II and photosystems I was measured by following the sigmoidal reduction kinetics of P-700(+) after previous oxidation of the intersystem electron carriers. The amount of flash-induced plastoquinol produced at photosystem II was (a) reduced by inhibition with dichlorophenyl-dimethylurea and (b) increased by giving a second saturating flash. These signals were simulated by a new model which combines a deterministic simulation of reaction kinetics with a Monte Carlo approach to the diffusion of plastoquinol, taking into account the known structural features of the thylakoid membrane. The plastoquinol molecules were assumed to be oxidized by either a diffusion-limited or a nondiffusion-limited step in a collisional mechanism or after binding to the cytochrome bf complex. The model was able to account for the experimental observations with a nondiffusion-limited collisional mechanism or with a binding mechanism, giving minimum values for the diffusion coefficient of plastoquinol of 2 x 10(-8) cm(2)s(-1) and 3 x 10(-7) cm(2)s(-1), respectively.
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Affiliation(s)
- R Mitchell
- Lehrstuhl für Biochemie der Pflanzen, Westfälische Wilhelms-Universität, Münster, Federal Republic of Germany
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18
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Rubin A, Riznichenko G. Modeling of the Primary Processes in a Photosynthetic Membrane. PHOTOSYNTHESIS IN SILICO 2009. [DOI: 10.1007/978-1-4020-9237-4_7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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19
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Kovalenko IB, Abaturova AM, Gromov PA, Ustinin DM, Riznichenko GY, Grachev EA, Rubin AB. Computer simulation of plastocyanin-cytochrome f complex formation in the thylakoid lumen. Biophysics (Nagoya-shi) 2008. [DOI: 10.1134/s0006350908020048] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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20
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Rodriguez RE, Lodeyro A, Poli HO, Zurbriggen M, Peisker M, Palatnik JF, Tognetti VB, Tschiersch H, Hajirezaei MR, Valle EM, Carrillo N. Transgenic tobacco plants overexpressing chloroplastic ferredoxin-NADP(H) reductase display normal rates of photosynthesis and increased tolerance to oxidative stress. PLANT PHYSIOLOGY 2007; 143:639-49. [PMID: 17189326 PMCID: PMC1803747 DOI: 10.1104/pp.106.090449] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2006] [Accepted: 12/13/2006] [Indexed: 05/13/2023]
Abstract
Ferredoxin-NADP(H) reductase (FNR) catalyzes the last step of photosynthetic electron transport in chloroplasts, driving electrons from reduced ferredoxin to NADP+. This reaction is rate limiting for photosynthesis under a wide range of illumination conditions, as revealed by analysis of plants transformed with an antisense version of the FNR gene. To investigate whether accumulation of this flavoprotein over wild-type levels could improve photosynthetic efficiency and growth, we generated transgenic tobacco (Nicotiana tabacum) plants expressing a pea (Pisum sativum) FNR targeted to chloroplasts. The alien product distributed between the thylakoid membranes and the chloroplast stroma. Transformants grown at 150 or 700 micromol quanta m(-2) s(-1) displayed wild-type phenotypes regardless of FNR content. Thylakoids isolated from plants with a 5-fold FNR increase over the wild type displayed only moderate stimulation (approximately 20%) in the rates of electron transport from water to NADP+. In contrast, when donors of photosystem I were used to drive NADP+ photoreduction, the activity was 3- to 4-fold higher than the wild-type controls. Plants expressing various levels of FNR (from 1- to 3.6-fold over the wild type) failed to show significant differences in CO2 assimilation rates when assayed over a range of light intensities and CO2 concentrations. Transgenic lines exhibited enhanced tolerance to photooxidative damage and redox-cycling herbicides that propagate reactive oxygen species. The results suggest that photosynthetic electron transport has several rate-limiting steps, with FNR catalyzing just one of them.
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Affiliation(s)
- Ramiro E Rodriguez
- Instituto de Biología Molecular y Celular de Rosario, División Biología Molecular, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, S2002LRK Rosario, Argentina
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21
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Kovalenko IB, Abaturova AM, Gromov PA, Ustinin DM, Grachev EA, Riznichenko GY, Rubin AB. Direct simulation of plastocyanin and cytochrome f interactions in solution. Phys Biol 2006; 3:121-9. [PMID: 16829698 DOI: 10.1088/1478-3975/3/2/004] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Most biological functions, including photosynthetic activity, are mediated by protein interactions. The proteins plastocyanin and cytochrome f are reaction partners in a photosynthetic electron transport chain. We designed a 3D computer simulation model of diffusion and interaction of spinach plastocyanin and turnip cytochrome f in solution. It is the first step in simulating the electron transfer from cytochrome f to photosystem 1 in the lumen of thylakoid. The model is multiparticle and it can describe the interaction of several hundreds of proteins. In our model the interacting proteins are represented as rigid bodies with spatial fixed charges. Translational and rotational motion of proteins is the result of the effect of stochastic Brownian force and electrostatic force. The Poisson-Boltzmann formalism is used to determine the electrostatic potential field generated around the proteins. Using this model we studied the kinetic characteristics of plastocyanin-cytochrome f complex formation for plastocyanin mutants at pH 7 and a variety of ionic strength values.
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Affiliation(s)
- I B Kovalenko
- Biological Faculty, Lomonosov Moscow State University, Leninskie Gory, Moscow 119992, Russia.
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22
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Sujak A, Drepper F, Haehnel W. Spectroscopic studies on electron transfer between plastocyanin and cytochrome b6f complex. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2004; 74:135-43. [PMID: 15157909 DOI: 10.1016/j.jphotobiol.2004.03.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2003] [Revised: 03/08/2004] [Accepted: 03/22/2004] [Indexed: 10/26/2022]
Abstract
This paper reports the results of the research on the interaction between the highly active cytochrome b(6)f complex and plastocyanin, both isolated from the same source - spinachia oleracea plants. An equilibrium constant K between the cytochrome f of the cytochrome b(6)f complex and plastocyanin has been estimated by two independent spectroscopic techniques: steady-state absorption spectroscopy and stopped-flow. The second-order rate constants k2 for forward and backward electron transfer between cytochrome f and plastocyanin have been found between 1.4-2 x 10(7) and 8-10 x 10(6) M(-1)s(-1), respectively, giving the value of an equilibrium constant of about 2+/-0.4 or a difference in redox potential between plastocyanin and cytochrome f of cytochrome b(6)f complex of ca. 17 mV. The value of K=1.7+/-0.3 has been estimated from steady-state experiments in which the initial and final concentrations of participating components after mixing have been estimated via differential spectra analysis or spectra deconvolution. We propose a method of evaluation of the final plastocyanin concentration after the electron transfer reaction between cytochrome bf complex and plastocyanin that overcomes the interference by the strong chlorophyll absorption in the spectral region where oxidised plastocyanin has its low extinction absorption band. The data from both experiments, in the system devoid of quinol being the electron donor to cytochrome b(6), suggest that in case of electron transfer from cytochrome f to plastocyanin electron transfer can either bypass cytochrome f or the Rieske iron-sulfur protein can be reduced prior to its movement to the quinol binding site of cytochrome b(6). The role of the Rieske protein in forward and backward electron transfer reactions is discussed.
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Affiliation(s)
- A Sujak
- Department of Plant Biochemistry, Freiburg University, Schänzlestrasse 1, Freiburg 79104, Germany.
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23
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Tsinoremas NF, Hubbard JA, Evans MC, Allen JF. P-700 photooxidation in state 1 and state 2 in cyanobacteria upon flash illumination with phycobilin- and chlorophyll-absorbed light. FEBS Lett 2002. [DOI: 10.1016/0014-5793(89)81727-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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24
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Armstrong FA, Driscoll PC, Allen H, Hill O. Catalysis of plastocyanin electron self-exchange by redox-inert multivalent cations. FEBS Lett 2001. [DOI: 10.1016/0014-5793(85)81292-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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25
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Lam E, Richard M. In vitro reconstitution of the electron pathway from water to cytochrome f
of spinach thylakoids. FEBS Lett 2001. [DOI: 10.1016/0014-5793(82)80635-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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26
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Finazzi G, Furia A, Barbagallo RP, Forti G. State transitions, cyclic and linear electron transport and photophosphorylation in Chlamydomonas reinhardtii. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1413:117-29. [PMID: 10556624 DOI: 10.1016/s0005-2728(99)00089-4] [Citation(s) in RCA: 146] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
The relationship between state transitions and the kinetic properties of the electron transfer chain has been studied in Chlamydomonas reinhardtii. The same turnover rate of cytochrome f was found in state 1 and 2. However, while DBMIB was inhibitory in both states, DCMU was effective only in state 1. These observations suggest that linear electron transport was active only in state 1, while a cyclic pathway around photosystem (PS) I operated in state 2. The reversible shift from linear to cyclic electron transport was modulated by changes of PSII antenna size, which inactivated the linear pathway, and by oxygen, which inhibited the cyclic one. Attainment of state 2, under anaerobiosis in the dark, was associated with the decline of the ATP/ADP ratio in the cells and the dark reduction of the intersystem carriers. Upon illumination of the cells, the ATP/ADP ratio increased in a few seconds to the aerobic level. Then, several minutes later, the F(m) returned to the state 1 level, and O(2) evolution was reactivated. This suggests that ATP, though required for photosynthesis, is not the rate-limiting factor in the reactivation of photosynthetic O(2) evolution, which is rather controlled by the redox state of the electron carriers.
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Affiliation(s)
- G Finazzi
- Centro CNR Biologia Cellulare e Molecolare delle Piante, Dipartimento di Biologia, Via Celoria 26, Milan, Italy
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28
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Sun J, Xu W, Hervás M, Navarro JA, Rosa MA, Chitnis PR. Oxidizing side of the cyanobacterial photosystem I. Evidence for interaction between the electron donor proteins and a luminal surface helix of the PsaB subunit. J Biol Chem 1999; 274:19048-54. [PMID: 10383406 DOI: 10.1074/jbc.274.27.19048] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Photosystem I (PSI) interacts with plastocyanin or cytochrome c6 on the luminal side. To identify sites of interaction between plastocyanin/cytochrome c6 and the PSI core, site-directed mutations were generated in the luminal J loop of the PsaB protein from Synechocystis sp. PCC 6803. The eight mutant strains differed in their photoautotrophic growth. Western blotting with subunit-specific antibodies indicated that the mutations affected the PSI level in the thylakoid membranes. PSI proteins could not be detected in the S600R/G601C/N602I, N609K/S610C/T611I, and M614I/G615C/W616A mutant membranes. The other mutant strains contained different levels of PSI proteins. Among the mutant strains that contained PSI proteins, the H595C/L596I, Q627H/L628C/I629S, and N638C/N639S mutants showed similar levels of PSI-mediated electron transfer activity when either cytochrome c6 or an artificial electron donor was used. In contrast, cytochrome c6 could not function as an electron donor to the W622C/A623R mutant, even though the PSI activity mediated by an artificial electron donor was detected in this mutant. Thus, the W622C/A623R mutation affected the interaction of the PSI complex with cytochrome c6. Biotin-maleimide modification of the mutant PSI complexes indicated that His-595, Trp-622, Leu-628, Tyr-632, and Asn-638 in wild-type PsaB may be exposed on the surface of the PSI complex. The results presented here demonstrate the role of an extramembrane loop of a PSI core protein in the interaction with soluble electron donor proteins.
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Affiliation(s)
- J Sun
- Department of Biochemistry and Biophysics, Iowa State University, Ames, Iowa 50011, USA
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29
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Reduction of photosystem I by cytochrome c6 and plastocyanin: molecular recognition and reaction mechanism. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s0302-4598(96)05116-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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30
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Klughammer C, Pace RJ. Photoreduction of the secondary Photosystem I electron acceptor vitamin K1 in intact spinach chloroplasts and Cyanobacteria in vivo. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1997. [DOI: 10.1016/s0005-2728(96)00129-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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31
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van Voorthuysen T, Dassen HH, Snel JF, Vredenberg WJ. Patch-clamp study on flash-induced secondary electrogenic transport in the thylakoid membrane. Interpretation in terms of a Q-cycle. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1996. [DOI: 10.1016/s0005-2728(96)00100-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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32
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Tiwari S, McHanty P. Cobalt induced changes in photosystem activity in Synechocystis PCC 6803: Alterations in energy distribution and stoichiometry. PHOTOSYNTHESIS RESEARCH 1996; 50:243-256. [PMID: 24271963 DOI: 10.1007/bf00033123] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/1996] [Accepted: 11/14/1996] [Indexed: 06/02/2023]
Abstract
Adaptive responses to excess (supraoptimal) level of cobalt supplied to the growth medium were studied in the cyanobacterium Synechocystis PCC 6803. Growth of cells in the medium containing 10 μM CoCl2 led to a large stimulation (50%) in O2-evolution and an overall increase (∼30%) in the photosynthetic electron transport rates. Analysis of variable Chl a fluorescence yield of PS II and immuno-detection of Photosystem II (PS II) reaction-center protein D1, showed a small increase (15-20%) in the number of PS II units in cobalt-grown cells. Cobalt-grown cells, therefore, had a slightly elevated PS II/PS I ratio compared to control.We observed alteration in the extent of energy distribution between the two photosystems in the eobalt grown cells. Energy was preferentially distributed in favour of PS II accompanied by a reduction in the extent of energy transfer from PS II to PS I in cobalt-grown cells. These cells also showed a smaller PS I absorption cross-section and a smaller size of intersystem electron pool than the control cells. Thus, our results suggest that supplementation of 10 μM CoCl2, to the normal growth medium causes multiple changes involving small increase in PS II to PS I ratio, enhanced funneling of energy to PS II and an increase in PS I electron transport, decrease PS I cross section and reduction in intersystem pool size. The cumulative effects of these alterations cause stimulation in electron transport and O2 evolution.
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Affiliation(s)
- S Tiwari
- School of Life Sciences, Jawaharlal Nehru University, 110 067, New Delhi, India
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33
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Burkey KO, Wells R. Effects of natural shade on soybean thylakoid membrane composition. PHOTOSYNTHESIS RESEARCH 1996; 50:149-58. [PMID: 24271932 DOI: 10.1007/bf00014885] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/1996] [Accepted: 09/24/1996] [Indexed: 05/06/2023]
Abstract
The effect of natural shade on chloroplast thylakoid membrane activity and composition was examined for soybean (Glycine Max. cv. Young) grown under field conditions. Plots with high (10 plants m(-1) row) or low (1 plant m(-1) row) plant density were established. Expanding leaves were tagged at 50, 58 and 65 days after planting (DAP). At 92 DAP, tagged leaves were used as reference points to characterize canopy light environments and isolate thylakoid membranes. Light environments ranged from a photosynthetic photon flux density (PPFD) of 87% of full sun to a PPFD of 10% of full sun. The decline in PPFD was accompanied by an increase in the far-red/red (735 nm/645 nm) ratio from 0.9 to approximately six. The major effects of shade on chloroplast thylakoid membranes were a reduction in chloroplast coupling factor and a shift in light-harvesting capacity from Photosystem I to Photosystem II. Photosynthetic electron transport capacity was not affected by differences in PPFD, but was 20 to 30% higher in the 1 plant m(-1) row treatment. The plant density effect on electron transport was associated with differences in plastocyanin concentration, suggesting that plastocyanin is a limiting factor in soybean. Shade did not have a significant effect on the concentration of Photosystem II, Cyt b6f, or Photosystem I complexes.
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Affiliation(s)
- K O Burkey
- United States Department of Agriculture-Agricultural Research Service, North Carolina State University, Box 7631, 27695-7631, Raleigh, NC, USA
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34
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Burkey KO, Gizlice Z, Carter TE. Genetic variation in soybean photosynthetic electron transport capacity is related to plastocyanin concentration in the chloroplast. PHOTOSYNTHESIS RESEARCH 1996; 49:141-9. [PMID: 24271611 DOI: 10.1007/bf00117664] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/1996] [Accepted: 07/08/1996] [Indexed: 05/06/2023]
Abstract
Fifteen ancestral genotypes of United States soybean cultivars were screened for differences in photosynthetic electron transport capacity using isolated thylakoid membranes. Plants were grown in controlled environment chambers under high or low irradiance conditions. Thylakoid membranes were isolated from mature leaves. Photosynthetic electron transport was assayed as uncoupled Hill activity using 2,6-dichlorophenolindophenol (DCIP). Soybean electron transport activity was dependent on genotype and growth irradiance and ranged from 6 to 91 mmol DCIP reduced [mol chlorophyll](-1) s(-1). Soybean plastocyanin pool size ranged from 0.1 to 1.3 mol plastocyanin [mol Photosystem I](-1). In contrast, barley and spinach electron transport activities were 140 and 170 mmol DCIP reduced [mol chlorophyll](-1) s(-1), respectively, with plastocyanin pool sizes of 3 to 4 mol plastocyanin [mol Photosystem I](-1). No significant differences in the concentrations of Photosystem II, plastoquinone, cytochrome b6f complexes, or Photosystem I were observed. Thus, genetic differences in electron transport activity were correlated with plastocyanin pool size. The results suggested that plastocyanin pool size can vary significantly and may limit photosynthetic electron transport capacity in certain species such as soybean. Soybean plastocyanin consisted of two isoforms with apparent molecular masses of 14 and 11 kDa, whereas barley and spinach plastocyanins each consisted of single polypeptides of 8 and 12 kDa, respectively.
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Affiliation(s)
- K O Burkey
- United States Department of Agriculture-Agricultural Research Service, 27695-7631, Raleigh, USA
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35
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Chitnis PR, Xu Q, Chitnis VP, Nechushtai R. Function and organization of Photosystem I polypeptides. PHOTOSYNTHESIS RESEARCH 1995; 44:23-40. [PMID: 24307023 DOI: 10.1007/bf00018294] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/1994] [Accepted: 12/27/1994] [Indexed: 06/02/2023]
Abstract
Photosystem I functions as a plastocyanin:ferredoxin oxidoreductase in the thylakoid membranes of chloroplasts and cyanobacteria. The PS I complex contains the photosynthetic pigments, the reaction center P700, and five electron transfer centers (A0, A1, FX, FA, and FB) that are bound to the PsaA, PsaB, and PsaC proteins. In addition, PS I complex contains at least eight other polypeptides that are accessory in their functions. Recent use of cyanobacterial molecular genetics has revealed functions of the accessory subunits of PS I. Site-directed mutagenesis is now being used to explore structure-function relations in PS I. The overall architecture of PSI complex has been revealed by X-ray crystallography, electron microscopy, and biochemical methods. The information obtained by different techniques can be used to propose a model for the organization of PS I. Spectroscopic and molecular genetic techniques have deciphered interaction of PS I proteins with the soluble electron transfer partners. This review focuses on the recent structural, biochemical and molecular genetic studies that decipher topology and functions of PS I proteins, and their interactions with soluble electron carriers.
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Affiliation(s)
- P R Chitnis
- Division of Biology, Kansas State University, Manhattan, Kansas, USA
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36
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Expression of Anabaena PCC 7937 plastocyanin in Synechococcus PCC 7942 enhances photosynthetic electron transfer and alters the electron distribution between photosystem I and cytochrome-c oxidase. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(18)46896-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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37
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Hope AB, Matthews DB, Valente P. The kinetics of reactions around the cytochrome bf complex studied in an isolated system. PHOTOSYNTHESIS RESEARCH 1994; 40:199-206. [PMID: 24311289 DOI: 10.1007/bf00019337] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/1993] [Accepted: 02/22/1994] [Indexed: 06/02/2023]
Abstract
The kinetics of oxidation and reduction of P700, plastocyanin, cytochrome f and cytochrome b-563 were studied in a reconstituted system consisting of Photosystem I particles, cytochrome bf complex and plastocyanin, all derived from pea leaf chloroplasts. Decyl plastoquinol was the reductant of the bf complex. Turnovers of the system were initiated by laser flashes. The reaction between oxidised P700 and plastocyanin was non-homogeneous in that a second-order rate coefficient of c. 5×10(-7) M(-1) s(-1) applied to 80% of the P700(+) and c. 0.7×10(7) M(-1) s(-1) to the remainder. In the presence of bf complex, but without quinol, the electron transfer between cytochrome f and oxidised plastocyanin could be described by a second-order rate coefficient of c. 4×10(7) M(-1) s(-1) (forward), and c. 1.6×10(7) M(-1) s(-1) (reverse). The equilibrium coefficient was thus 2.5. Unexpectedly, there was little reduction of cytochrome f (+) or plastocyanin(+) by electrons from the Rieske centre. With added quinol, reduction of cytochrome b-563 occurred. Concomitantly, electrons appeared in the oxidised species. It was inferred that either the Rieske centre was not involved in the high-potential chain of electron transfer events, or that, only in the presence of quinol, electrons were quickly passed from the Rieske centre to cytochrome f (+). Additionally, the presence of quinol altered the equilibrium coefficient for the cyt f/PC interaction from 2.5 to c. 5. The reaction between quinol and the bf complex was describable by a second-order rate coefficient of about 3×10(6) M(-1) s(-1). The pattern of the redox reactions around the bf complex could be simulated in detail with a Q-cycle model as previously found for chloroplasts.
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Affiliation(s)
- A B Hope
- School of Biological Sciences, Flinders University, G.P.O. Box 2100, 5001, Adelaide, S.A., Australia
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38
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Laser flash kinetic analysis of Synechocystis PCC 6803 cytochrome c6 and plastocyanin oxidation by Photosystem I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1994. [DOI: 10.1016/0005-2728(94)90228-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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39
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Laisk A, Oja V. Range of photosynthetic control of postillumination P700(+) reduction rate in sunflower leaves. PHOTOSYNTHESIS RESEARCH 1994; 39:39-50. [PMID: 24310999 DOI: 10.1007/bf00027141] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/1993] [Accepted: 09/29/1993] [Indexed: 05/16/2023]
Abstract
The kinetics of the postillumination reduction of P700(+) which reflects the rate constant for plastoquinol (PQH2) oxidation was recorded in sunflower leaves at different photon absorption densities (PAD), CO2 and O2 concentrations. The P700 oxidation state was calculated from the leaf transmittance at 830 nm logged at 50 μs intervals. The P700(+) dark reduction kinetics were fitted with two exponents with time constants of 6.5 and about 45 ms at atmospheric CO2 and O2 concentrations. The time constant of the fast component, which is the major contributor to the linear electron transport rate (ETR), did not change over the range of PADs of 14.5 to 134 nmol cm(-2) s(-1) in 21% O2, but it increased up to 40 ms under severe limitation of ETR at low O2 and CO2. The acceptor side of Photosystem I (PS I) became reduced in correlation with the downregulation of the PQH2 oxidation rate constant. It is concluded that thylakoid pH-related downregulation of the PQH2 oxidation rate constant (photosynthetic control) is not present under normal atmospheric conditions but appears under severe limitation of the availability of electron acceptors. The measured range of photosynthetic control fits with the maximum variation of ETR under natural stress in C3 plants. Increasing the carboxylase/oxygenase specificity would lead to higher reduction of the PS I acceptor side under stress.
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Affiliation(s)
- A Laisk
- Institute of Molecular and Cell Biology, Tartu University, Riia str. 181, EE2400, Tartu, Estonia
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40
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Supramolecular membrane protein assemblies in photosynthesis and respiration. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1993. [DOI: 10.1016/0005-2728(93)90039-i] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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41
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Hervás M, De la Rosa MA, Tollin G. A comparative laser-flash absorption spectroscopy study of algal plastocyanin and cytochrome c552 photooxidation by photosystem I particles from spinach. EUROPEAN JOURNAL OF BIOCHEMISTRY 1992; 203:115-20. [PMID: 1309695 DOI: 10.1111/j.1432-1033.1992.tb19835.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Laser-flash kinetic absorption spectroscopy has been used to compare the rate constants for electron transfer from reduced plastocyanin and cytochrome c552, obtained from the green alga Monoraphidium braunii, to photooxidized P700 (P700+) in photosystem I (PSI) particles from spinach Sigmoidal protein concentration dependence for the observed electron-transfer rate constants are obtained for both proteins. In the absence of added salts, the P700+ reduction rate increases as the pH decreases from approximately 8 to 5.5, then decreases to pH 3.5, this effect being more pronounced with cytochrome c552 than with plastocyanin. At neutral pH, plastocyanin is a more efficient electron donor to P700+ than cytochrome c552, whereas at pH 5.5, which is closer to physiological conditions, the two redox proteins react with approximately equal rate constants. In the presence of increasing concentrations of added salts, the P700+ reduction rate constants for both proteins increase at pH greater than 5.5, but decrease at pH less than 4. At neutral pH, the observed rate constants for both algal proteins have a biphasic dependence on sodium chloride concentration, increasing in a parallel manner with increasing salt concentration, reaching a maximum value at 50 mM NaCl, then decreasing. A similar biphasic dependence is obtained with magnesium chloride, but in this case the maximum value is reached at salt concentrations ten times smaller, suggesting a specific role for the divalent cations in the electron-transfer reaction.
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Affiliation(s)
- M Hervás
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla, Spain
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42
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Nordling M, Sigfridsson K, Young S, Lundberg LG, Hansson O. Flash-photolysis studies of the electron transfer from genetically modified spinach plastocyanin to photosystem I. FEBS Lett 1991; 291:327-30. [PMID: 1657646 DOI: 10.1016/0014-5793(91)81313-w] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Plastocyanin (Pc) has been modified by site-directed mutagenesis at two separate electron-transfer (ET) sites: Leu-12-Glu at a hydrophobic patch, and Tyr-83-His at an acidic patch. The reduction potential at pH 7.5 is decreased by 26 mV in Pc(Leu-12-Glu) and increased by 35 mV in Pc(Tyr-83-His). The latter mutant shows a 2-fold slower intracomplex ET to photosystem I (PSI) as expected from the decreased driving force. The affinity for PSI is unaffected for this mutant but is drastically decreased for Pc(Leu-12-Glu). It is concluded that the hydrophobic patch is more important for the ET to PSI.
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Affiliation(s)
- M Nordling
- Department of Biochemistry and Biophysics, Chalmers University of Technology, Göteborg, Sweden
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43
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Chitnis P, Purvis D, Nelson N. Molecular cloning and targeted mutagenesis of the gene psaF encoding subunit III of photosystem I from the cyanobacterium Synechocystis sp. PCC 6803. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)54902-4] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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44
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Almog O, Lotan O, Shoham G, Nechushtai R. The composition and organization of photosystem I. J Basic Clin Physiol Pharmacol 1991; 2:123-40. [PMID: 1797091 DOI: 10.1515/jbcpp.1991.2.3.123] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Photosystem I, extensively studied in the past decade, was shown to be homologous in all photosynthetic organisms of the higher plants type. Its core complex was found to be highly conserved through evolution from cyanobacteria to higher plants. The genes coding for the subunits of CCI were isolated and the resulting sequences provided information about secondary structural elements. These suggested secondary structures enabled the prediction of the topology of these subunits in the photosynthetic membrane. Structural studies using both electron microscopy and X-ray crystallography, on isolated particles as well as on the complexes in the photosynthetic membrane, led to a better understanding of the overall structure of CCI. Recently two forms of three dimensional crystals of CCI were obtained. These crystals contain all the original components of CCI (both protein and pigments); these components have not been altered by crystallization. It is expected that a detailed crystallographic analysis of these crystals, together with biochemical, spectroscopical and molecular biology studies, will eventually lead to the elucidation of the high resolution structure of the photosystem I core complex and to the understanding of the exact role and mode of action of this complex in the photosynthetic membrane.
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Affiliation(s)
- O Almog
- Department of Inorganic Chemistry, Hebrew University, Jerusalem, Israel
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45
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Delosme R. Electron transfer from cytochrome f to photosystem I in green algae. PHOTOSYNTHESIS RESEARCH 1991; 29:45-54. [PMID: 24415039 DOI: 10.1007/bf00035205] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/1991] [Accepted: 06/06/1991] [Indexed: 06/03/2023]
Abstract
The time course of P700(+) reduction and cytochrome f oxidation following a single-turnover flash excitation of photosystem I was measured under various conditions in different strains of green algae. P700(+) was reduced with a half-time of 4 μs. The rate of cytochrome f oxidation was found to depend widely on physiological factors. Reversible transitions are described from a 'slow-oxidation' state (t 1/2=500 μs) to a 'fast-oxidation' state (t 1/2=80 μs). The addition of ionophore strongly favours and stabilizes the 'fast-oxidation' state. We suggest that these transitions reflect either reversible association between the cytochrome bf complex and the reaction center of photosystem I or changes in the mobility of oxidized plastocyanin. The transitions might be under the control of the membrane potential or the intracellular ATP content. The relation of these reversible transitions with the 'light state' transitions, and their possible involvement in a switch from linear to cyclic electron transfer, are discussed.
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Affiliation(s)
- R Delosme
- Institut de Biologie Physico-Chimique, Paris, France
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46
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Foyer C, Furbank R, Harbinson J, Horton P. The mechanisms contributing to photosynthetic control of electron transport by carbon assimilation in leaves. PHOTOSYNTHESIS RESEARCH 1990; 25:83-100. [PMID: 24420275 DOI: 10.1007/bf00035457] [Citation(s) in RCA: 87] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/1989] [Accepted: 03/07/1990] [Indexed: 05/22/2023]
Abstract
'Photosynthetic control' describes the processes that serve to modify chloroplast membrane reactions in order to co-ordinate the synthesis of ATP and NADPH with the rate at which these metabolites can be used in carbon metabolism. At low irradiance, optimisation of the use of excitation energy is required, while at high irradiance photosynthetic control serves to dissipate excess excitation energy when the potential rate of ATP and NADPH synthesis exceed demand. The balance between ΔpH, ATP synthesis and redox state adjusts supply to demand such that the [ATP]/[ADP] and [NADPH]/[NADP(+)] ratios are remarkably constant in steady-state conditions and modulation of electron transport occurs without extreme fluctuations in these pools.
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Affiliation(s)
- C Foyer
- Laboratoire du Métabolisme, I.N.R.A., Route de St-Cyr, 78000, Versailles, France
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47
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Chylla RA, Whitmarsh J. Light saturation response of inactive photosystem II reaction centers in spinach. PHOTOSYNTHESIS RESEARCH 1990; 25:39-48. [PMID: 24420169 DOI: 10.1007/bf00051734] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/1989] [Accepted: 02/09/1990] [Indexed: 05/09/2023]
Abstract
The effective absorption cross section of inactive photosystem II (PS II) centers, which is the product of the effective antenna size and the quantum yield for photochemistry, was investigated by comparing the light saturation curves of inactive PS II and active reaction centers in intact chloroplasts and thylakoid membranes of spinach (Spinacia oleracea). Inactive PS II centers are defined as the impaired PS II reaction centers that require greater than 50 ms for the reoxidation of QA (-) subsequent to a single turnover flash. Active reaction centers are defined as the rapidly turning over PS II centers (recovery time less than 50 ms) and all of the PS I centers. The electrochromic shift, measured by the flash-induced absorbance increase at 518 nm, was used to probe the activity of the reaction centers. Light saturation curves were generated for inactive PS II centers and active reaction centers by measuring the extent of the absorbance increase at 518 nm induced by red actinic flashes of variable energy. The light saturation curves show that inactive PS II centers required over twice as many photons as active reaction centers to achieve the same yield. The ratio of the flash energy required for 50% saturation for active reaction centers (PS II active + PS I) compared to inactive PS II centers was 0.45±0.04 in intact chloroplasts, and 0.54±0.11 in thylakoid membranes. Analysis of the light saturation curves using a Poisson statistical model in which the ratio of the antenna size of active PS II centers to that of PS I is considered to range from 1 to 1.5, indicates that the effective absorption cross section of inactive PS II centers was 0.54-0.37 times that of active PS II centers. If the quantum yield for photochemistry is assumed to be one, we estimate that the antenna system serving the inactive PS II centers contains approx. 110 chlorophyll molecules.
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Affiliation(s)
- R A Chylla
- Department of Physiology and Biophysics, University of Illinois, USA
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48
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Durell SR, Lee CH, Ross RT, Gross EL. Factor analysis of the near-ultraviolet absorption spectrum of plastocyanin using bilinear, trilinear, and quadrilinear models. Arch Biochem Biophys 1990; 278:148-60. [PMID: 2321955 DOI: 10.1016/0003-9861(90)90243-r] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Factor analysis was used to resolve the spectral components in the near-uv absorption spectrum of plastocyanin. The data set was absorption as a function of four variables: wavelength, species of plastocyanin, oxidation state of the copper center, and environmental pH. The data were fit with the traditional bilinear model, as well as with trilinear and quadrilinear models. Trilinear and quadrilinear models have the advantage that they uniquely define the components, avoiding the indeterminacy of bilinear models. Bilinear analysis using the absorption spectra of tyrosine and copper metallothionein as targets resulted in a two-component solution which was nearly identical to that obtained using trilinear and quadrilinear models, for which no targets are required. The two-component models separate the absorption into tyrosine and copper center components. The absorption of tyrosine is found to be pH dependent in reduced plastocyanin, and the absorption magnitude of the reduced copper center is the same in the four different plastocyanin species. Further resolution is provided by a three-component quadrilinear model. The results indicate that there are at least two different electronic transitions which cause the absorption of the reduced copper center and that one of them couples to a tyrosine residue. It is the absorption of this coupled tyrosine residue which is pH dependent. Correlation of the results with previous studies indicates that it is Tyr 83 which is the perturbed residue. The separation of the absorption of the copper center and Tyr 83 provides spectroscopic probes for the conformations of the north pole and east face reaction sites on the plastocyanin protein.
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Affiliation(s)
- S R Durell
- Biophysics Program, Ohio State University, Columbus, 43210
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49
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Durell SR, Labanowski JK, Gross EL. Modeling of the electrostatic potential field of plastocyanin. Arch Biochem Biophys 1990; 277:241-54. [PMID: 2310192 DOI: 10.1016/0003-9861(90)90575-j] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The DelPhi computer program is used to calculate the electrostatic potential field of the photosynthetic electron transport protein plastocyanin. Knowledge of the potential field is important for understanding the mechanisms by which plastocyanin interacts with other charged reagents. The program uses a macroscopic, continuum approach in which the protein and solvent are assigned different dielectric constants, the crystal structure of the protein defines the dielectric boundary, and the ionic strength of the solvent is taken into account. The potential field is determined by numerically solving the Poisson-Boltzmann equation. The field surrounding plastocyanin is characterized by a region of positive potential over the copper center active site, and a region of negative potential over the adjacent association site containing tyrosine 83. The shape and magnitude of the potential field shows a strong dependence on the ionic strength and pH of the solvent. The program is able to accurately predict the effect of the copper center oxidation state on the pKa of a tetranitromethane derivative of tyrosine 83 using an intrinsic protein dielectric constant of 2 to 4. Evidence is also presented that the glutamate 68 side chain is exposed to the solvent to a greater extent in the solution structure of plastocyanin than in the crystal structure.
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Affiliation(s)
- S R Durell
- Biophysics Program, Ohio State University, Columbus 43210
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50
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Chitnis PR, Reilly PA, Miedel MC, Nelson N. Structure and targeted mutagenesis of the gene encoding 8-kDa subunit of photosystem I from the cyanobacterium Synechocystis sp. PCC 6803. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)51474-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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