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Pavlou A, Styring S, Mamedov F. The S 1 to S 2 and S 2 to S 3 state transitions in plant photosystem II: relevance to the functional and structural heterogeneity of the water oxidizing complex. PHOTOSYNTHESIS RESEARCH 2024:10.1007/s11120-024-01096-4. [PMID: 38662327 DOI: 10.1007/s11120-024-01096-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 03/18/2024] [Indexed: 04/26/2024]
Abstract
In Photosystem II, light-induced water splitting occurs via the S state cycle of the CaMn4O5-cluster. To understand the role of various possible conformations of the CaMn4O5-cluster in this process, the temperature dependence of the S1 → S2 and S2 → S3 state transitions, induced by saturating laser flashes, was studied in spinach photosystem II membrane preparations under different conditions. The S1 → S2 transition temperature dependence was shown to be much dependent on the type of the cryoprotectant and presence of 3.5% methanol, resulting in the variation of transition half-inhibition temperature by 50 K. No similar effect was observed for the S2 → S3 state transition, for which we also show that both the low spin g = 2.0 multiline and high spin g = 4.1 EPR configurations of the S2 state advance with similar efficiency to the S3 state, both showing a transition half-inhibition temperature of 240 K. This was further confirmed by following the appearance of the Split S3 EPR signal. The results are discussed in relevance to the functional and structural heterogeneity of the water oxidizing complex intermediates in photosystem II.
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Affiliation(s)
- Andrea Pavlou
- Molecular Biomimetics, Department of Chemistry-Ångström, Uppsala University, P.O. Box 523, 751 20, Uppsala, Sweden
| | - Stenbjörn Styring
- Molecular Biomimetics, Department of Chemistry-Ångström, Uppsala University, P.O. Box 523, 751 20, Uppsala, Sweden
| | - Fikret Mamedov
- Molecular Biomimetics, Department of Chemistry-Ångström, Uppsala University, P.O. Box 523, 751 20, Uppsala, Sweden.
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2
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Pavlou A, Mokvist F, Styring S, Mamedov F. Far-red photosynthesis: Two charge separation pathways exist in plant Photosystem II reaction center. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148994. [PMID: 37355002 DOI: 10.1016/j.bbabio.2023.148994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 06/09/2023] [Accepted: 06/15/2023] [Indexed: 06/26/2023]
Abstract
An alternative charge separation pathway in Photosystem II under the far-red light was proposed by us on the basis of electron transfer properties at 295 K and 5 K. Here we extend these studies to the temperature range of 77-295 K with help of electron paramagnetic resonance spectroscopy. Induction of the S2 state multiline signal, oxidation of Cytochrome b559 and ChlorophyllZ was studied in Photosystem II membrane preparations from spinach after application of a laser flashes in visible (532 nm) or far-red (730-750 nm) spectral regions. Temperature dependence of the S2 state signal induction after single flash at 730-750 nm (Tinhibition ~ 240 K) was found to be different than that at 532 nm (Tinhibition ~ 157 K). No contaminant oxidation of the secondary electron donors cytochrome b559 or chlorophyllZ was observed. Photoaccumulation experiments with extensive flashing at 77 K showed similar results, with no or very little induction of the secondary electron donors. Thus, the partition ratio defined as (yield of YZ/CaMn4O5-cluster oxidation):(yield of Cytb559/ChlZ/CarD2 oxidation) was found to be 0.4 at under visible light and 1.7 at under far-red light at 77 K. Our data indicate that different products of charge separation after far-red light exists in the wide temperature range which further support the model of the different primary photochemistry in Photosystem II with localization of hole on the ChlD1 molecule.
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Affiliation(s)
- Andrea Pavlou
- Molecular Biomimetics, Department of Chemistry-Ångström, Uppsala University, P.O. Box 523, 751 20 Uppsala, Sweden
| | - Fredrik Mokvist
- Molecular Biomimetics, Department of Chemistry-Ångström, Uppsala University, P.O. Box 523, 751 20 Uppsala, Sweden
| | - Stenbjörn Styring
- Molecular Biomimetics, Department of Chemistry-Ångström, Uppsala University, P.O. Box 523, 751 20 Uppsala, Sweden
| | - Fikret Mamedov
- Molecular Biomimetics, Department of Chemistry-Ångström, Uppsala University, P.O. Box 523, 751 20 Uppsala, Sweden.
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3
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Colpo A, Molinari A, Boldrini P, Živčak M, Brestič M, Demaria S, Baldisserotto C, Pancaldi S, Ferroni L. Thylakoid membrane appression in the giant chloroplast of Selaginella martensii Spring: A lycophyte challenges grana paradigms in shade-adapted species. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2023; 336:111833. [PMID: 37595894 DOI: 10.1016/j.plantsci.2023.111833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 07/17/2023] [Accepted: 08/15/2023] [Indexed: 08/20/2023]
Abstract
In vascular plants, the thylakoid architecture is dominated by the highly structured multiple membrane layers known as grana. The structural diversity of the thylakoid system among plant species is mainly determined by the adaptation to the growth light regime, according to a paradigm stating that shade-tolerant species are featured by a high membrane extension with an enhanced number of thylakoid layers per granum. In this study, the thylakoid system was analysed in Selaginella martensii Spring, a shade-adapted rainforest species belonging to lycophytes, a diminutive plant lineage, sister clade of all other vascular plants (euphyllophytes, including ferns and seed plants). The species is characterized by giant cup-shaped chloroplasts in the upper epidermis and, quantitatively less important, disk-shaped chloroplasts in the mesophyll and lower epidermis. The study aimed at the quantitative assessment of the thylakoid appression exploiting a combination of complementary methods, including electron microscopy, selective thylakoid solubilisation, electron paramagnetic resonance, and simultaneous analysis of fast chlorophyll a fluorescence and P700 redox state. With a chlorophyll a/b ratio of 2.6 and PSI/PSII ratio of 0.31, the plant confirmed two typical hallmarks of shade-adaptation. The morphometric analysis of electron micrographs revealed a 33% fraction of non-appressed thylakoid domains. However, contrasting with the structural paradigm of thylakoid shade-adaptation in angiosperms, S. martensii privileges the increase in the granum diameter in place of the increase in the number of layers building the granum. The very wide grana diameter, 727 nm on average, largely overcame the threshold of 500 nm currently hypothesized to allow an effective diffusion of long-range electron carriers. The fraction of non-appressed membranes based on the selective solubilisation of thylakoids with digitonin was 26%, lower than the morphometric determination, indicating the presence of non-appressed domains inaccessible to the detergent, most probably because of the high three-dimensional complexity of the thylakoid system in S. martensii. Particularly, strong irregularity of grana stacks is determined by assembling thylakoid layers of variable width that tend to slide apart from each other as the number of stacked layers increases.
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Affiliation(s)
- Andrea Colpo
- Department of Environmental and Prevention Sciences, University of Ferrara, Corso Ercole I d'Este 32, 44121 Ferrara, Italy
| | - Alessandra Molinari
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, Via Luigi Borsari 46, 44121 Ferrara, Italy
| | - Paola Boldrini
- Center of Electron Microscopy, University of Ferrara, Via Luigi Borsari 46, 44121 Ferrara, Italy
| | - Marek Živčak
- Department of Plant Physiology, Faculty of Agrobiology and Food Resources, Slovak University of Agriculture, A. Hlinku 2, Nitra, 949 76, Slovak Republic
| | - Marian Brestič
- Department of Plant Physiology, Faculty of Agrobiology and Food Resources, Slovak University of Agriculture, A. Hlinku 2, Nitra, 949 76, Slovak Republic
| | - Sara Demaria
- Department of Environmental and Prevention Sciences, University of Ferrara, Corso Ercole I d'Este 32, 44121 Ferrara, Italy
| | - Costanza Baldisserotto
- Department of Environmental and Prevention Sciences, University of Ferrara, Corso Ercole I d'Este 32, 44121 Ferrara, Italy
| | - Simonetta Pancaldi
- Department of Environmental and Prevention Sciences, University of Ferrara, Corso Ercole I d'Este 32, 44121 Ferrara, Italy
| | - Lorenzo Ferroni
- Department of Environmental and Prevention Sciences, University of Ferrara, Corso Ercole I d'Este 32, 44121 Ferrara, Italy.
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Paweł R, Aleksandra U, Elżbieta R. Enzymatic kinetics of photosystem II with DCBQ as a substrate in extended Michaelis-Menten model. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2023; 247:112780. [PMID: 37678075 DOI: 10.1016/j.jphotobiol.2023.112780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 08/17/2023] [Accepted: 08/24/2023] [Indexed: 09/09/2023]
Abstract
This study aimed to examine enzymatic kinetics of photosystem II (PSII) of maize mesophyll chloroplasts using the artificial electron acceptor 2,6-dichloro-1,4-benzoquinone (DCBQ) as a substrate. We extended Michealis-Menten kinetics model assuming that DCBQ can accept electrons from PSII in two ways: from a QB directly or from QA by docking in the QB site. We used a Clark oxygen electrode for measuring the PSII activity, depending on the concentration of DCBQ. We found that: [1] DCBQ acts as an electron acceptor or [2] as an inhibitor for PSII. At a concentration < 0.2 mM, DCBQ accepted electrons from the QB at a rate of 889 electrons/s, while at >> 0.2 mM it replaced QB following which the activity decreased to zero. DCBQ located in the QB also increased the affinity of the substrate to PSII. We determined the kinetic parameters for the chloroplasts of plants growing under high and low light intensity, to change thylakoid stacking and thus the rate of electron transport. The parameter KmB, which is a measure of the affinity of DCBQ to PSII, showed quantitative changes based on light intensity, while K was proportional to the size of the plastoquinone pool. We believe that our model can be applied as a tool to study "State transitions" and induced changes in grana stacking in plants exposed to various stresses, which will facilitate the regulation of electron transfer pathways through an appropriate balance between linear and cyclic electron transport.
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Affiliation(s)
- Rogowski Paweł
- Department of Molecular Plant Physiology, Institute of Environmental Biology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland.
| | - Urban Aleksandra
- Department of Molecular Plant Physiology, Institute of Environmental Biology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland.
| | - Romanowska Elżbieta
- Department of Molecular Plant Physiology, Institute of Environmental Biology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland.
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Shevela D, Kern JF, Govindjee G, Messinger J. Solar energy conversion by photosystem II: principles and structures. PHOTOSYNTHESIS RESEARCH 2023; 156:279-307. [PMID: 36826741 PMCID: PMC10203033 DOI: 10.1007/s11120-022-00991-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 12/01/2022] [Indexed: 05/23/2023]
Abstract
Photosynthetic water oxidation by Photosystem II (PSII) is a fascinating process because it sustains life on Earth and serves as a blue print for scalable synthetic catalysts required for renewable energy applications. The biophysical, computational, and structural description of this process, which started more than 50 years ago, has made tremendous progress over the past two decades, with its high-resolution crystal structures being available not only of the dark-stable state of PSII, but of all the semi-stable reaction intermediates and even some transient states. Here, we summarize the current knowledge on PSII with emphasis on the basic principles that govern the conversion of light energy to chemical energy in PSII, as well as on the illustration of the molecular structures that enable these reactions. The important remaining questions regarding the mechanism of biological water oxidation are highlighted, and one possible pathway for this fundamental reaction is described at a molecular level.
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Affiliation(s)
- Dmitry Shevela
- Department of Chemistry, Chemical Biological Centre, Umeå University, 90187, Umeå, Sweden.
| | - Jan F Kern
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Govindjee Govindjee
- Department of Plant Biology, Department of Biochemistry and Center of Biophysics & Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Johannes Messinger
- Department of Chemistry, Chemical Biological Centre, Umeå University, 90187, Umeå, Sweden.
- Molecular Biomimetics, Department of Chemistry - Ångström, Uppsala University, 75120, Uppsala, Sweden.
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6
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Gu L, Grodzinski B, Han J, Marie T, Zhang YJ, Song YC, Sun Y. An exploratory steady-state redox model of photosynthetic linear electron transport for use in complete modelling of photosynthesis for broad applications. PLANT, CELL & ENVIRONMENT 2023; 46:1540-1561. [PMID: 36760139 DOI: 10.1111/pce.14563] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/24/2023] [Accepted: 02/05/2023] [Indexed: 06/18/2023]
Abstract
A photochemical model of photosynthetic electron transport (PET) is needed to integrate photophysics, photochemistry, and biochemistry to determine redox conditions of electron carriers and enzymes for plant stress assessment and mechanistically link sun-induced chlorophyll fluorescence to carbon assimilation for remotely sensing photosynthesis. Towards this goal, we derived photochemical equations governing the states and redox reactions of complexes and electron carriers along the PET chain. These equations allow the redox conditions of the mobile plastoquinone pool and the cytochrome b6 f complex (Cyt) to be inferred with typical fluorometry. The equations agreed well with fluorometry measurements from diverse C3 /C4 species across environments in the relationship between the PET rate and fraction of open photosystem II reaction centres. We found the oxidation of plastoquinol by Cyt is the bottleneck of PET, and genetically improving the oxidation of plastoquinol by Cyt may enhance the efficiency of PET and photosynthesis across species. Redox reactions and photochemical and biochemical interactions are highly redundant in their complex controls of PET. Although individual reaction rate constants cannot be resolved, they appear in parameter groups which can be collectively inferred with fluorometry measurements for broad applications. The new photochemical model developed enables advances in different fronts of photosynthesis research.
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Affiliation(s)
- Lianhong Gu
- Oak Ridge National Laboratory, Environmental Sciences Division and Climate Change Science Institute, Oak Ridge, Tennessee, USA
| | - Bernard Grodzinski
- Department of Plant Agriculture, University of Guelph, Guelph, Ontario, Canada
| | - Jimei Han
- School of Integrative Plant Science, Cornell University, Ithaca, New York, USA
| | - Telesphore Marie
- Department of Plant Agriculture, University of Guelph, Guelph, Ontario, Canada
| | - Yong-Jiang Zhang
- School of Biology and Ecology, University of Maine, Orono, Maine, USA
| | - Yang C Song
- Department of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, Arizona, USA
| | - Ying Sun
- School of Integrative Plant Science, Cornell University, Ithaca, New York, USA
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7
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Svoboda V, Oung HMO, Koochak H, Yarbrough R, Mckenzie SD, Puthiyaveetil S, Kirchhoff H. Quantification of energy-converting protein complexes in plant thylakoid membranes. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148945. [PMID: 36442511 DOI: 10.1016/j.bbabio.2022.148945] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 11/15/2022] [Accepted: 11/22/2022] [Indexed: 11/27/2022]
Abstract
Knowledge about the exact abundance and ratio of photosynthetic protein complexes in thylakoid membranes is central to understanding structure-function relationships in energy conversion. Recent modeling approaches for studying light harvesting and electron transport reactions rely on quantitative information on the constituent complexes in thylakoid membranes. Over the last decades several quantitative methods have been established and refined, enabling precise stoichiometric information on the five main energy-converting building blocks in the thylakoid membrane: Light-harvesting complex II (LHCII), Photosystem II (PSII), Photosystem I (PSI), cytochrome b6f complex (cyt b6f complex), and ATPase. This paper summarizes a few quantitative spectroscopic and biochemical methods that are currently available for quantification of plant thylakoid protein complexes. Two new methods are presented for quantification of LHCII and the cyt b6f complex, which agree well with established methods. In addition, recent improvements in mass spectrometry (MS) allow deeper compositional information on thylakoid membranes. The comparison between mass spectrometric and more classical protein quantification methods shows similar quantities of complexes, confirming the potential of thylakoid protein complex quantification by MS. The quantitative information on PSII, PSI, and LHCII reveal that about one third of LHCII must be associated with PSI for a balanced light energy absorption by the two photosystems.
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Affiliation(s)
- Vaclav Svoboda
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Hui Min Olivia Oung
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Haniyeh Koochak
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Robert Yarbrough
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Steven D Mckenzie
- Department of Biochemistry and Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
| | - Sujith Puthiyaveetil
- Department of Biochemistry and Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
| | - Helmut Kirchhoff
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA.
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8
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Verhoeven D, van Amerongen H, Wientjes E. Single chloroplast in folio imaging sheds light on photosystem energy redistribution during state transitions. PLANT PHYSIOLOGY 2023; 191:1186-1198. [PMID: 36478277 PMCID: PMC9922397 DOI: 10.1093/plphys/kiac561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 11/04/2022] [Indexed: 06/17/2023]
Abstract
Oxygenic photosynthesis is driven by light absorption in photosystem I (PSI) and photosystem II (PSII). A balanced excitation pressure between PSI and PSII is required for optimal photosynthetic efficiency. State transitions serve to keep this balance. If PSII is overexcited in plants and green algae, a mobile pool of light-harvesting complex II (LHCII) associates with PSI, increasing its absorption cross-section and restoring the excitation balance. This is called state 2. Upon PSI overexcitation, this LHCII pool moves to PSII, leading to state 1. Whether the association/dissociation of LHCII with the photosystems occurs between thylakoid grana and thylakoid stroma lamellae during state transitions or within the same thylakoid region remains unclear. Furthermore, although state transitions are thought to be accompanied by changes in thylakoid macro-organization, this has never been observed directly in functional leaves. In this work, we used confocal fluorescence lifetime imaging to quantify state transitions in single Arabidopsis (Arabidopsis thaliana) chloroplasts in folio with sub-micrometer spatial resolution. The change in excitation-energy distribution between PSI and PSII was investigated at a range of excitation wavelengths between 475 and 665 nm. For all excitation wavelengths, the PSI/(PSI + PSII) excitation ratio was higher in state 2 than in state 1. We next imaged the local PSI/(PSI + PSII) excitation ratio for single chloroplasts in both states. The data indicated that LHCII indeed migrates between the grana and stroma lamellae during state transitions. Finally, fluorescence intensity images revealed that thylakoid macro-organization is largely unaffected by state transitions. This single chloroplast in folio imaging method will help in understanding how plants adjust their photosynthetic machinery to ever-changing light conditions.
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Manoj KM, Bazhin NM, Jacob VD, Parashar A, Gideon DA, Manekkathodi A. Structure-function correlations and system dynamics in oxygenic photosynthesis: classical perspectives and murburn precepts. J Biomol Struct Dyn 2022; 40:10997-11023. [PMID: 34323659 DOI: 10.1080/07391102.2021.1953606] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
HIGHLIGHTS Contemporary beliefs on oxygenic photosynthesis are critiqued.Murburn model is suggested as an alternative explanation.In the new model, diffusible reactive species are the main protagonists.All pigments are deemed photo-redox active in the new stochastic mechanism.NADPH synthesis occurs via simple electron transfers, not via elaborate ETC.Oxygenesis is delocalized and not just centered at Mn-Complex.Energetics of murburn proposal for photophosphorylation is provided.The proposal ushers in a paradigm shift in photosynthesis research.
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Affiliation(s)
| | | | - Vivian David Jacob
- Satyamjayatu: The Science & Ethics Foundation, Kulappully, Kerala, India
| | - Abhinav Parashar
- Satyamjayatu: The Science & Ethics Foundation, Kulappully, Kerala, India
| | | | - Afsal Manekkathodi
- Satyamjayatu: The Science & Ethics Foundation, Kulappully, Kerala, India
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10
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Gu L, Grodzinski B, Han J, Marie T, Zhang Y, Song YC, Sun Y. Granal thylakoid structure and function: explaining an enduring mystery of higher plants. THE NEW PHYTOLOGIST 2022; 236:319-329. [PMID: 35832001 PMCID: PMC9805053 DOI: 10.1111/nph.18371] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 07/07/2022] [Indexed: 05/11/2023]
Abstract
In higher plants, photosystems II and I are found in grana stacks and unstacked stroma lamellae, respectively. To connect them, electron carriers negotiate tortuous multi-media paths and are subject to macromolecular blocking. Why does evolution select an apparently unnecessary, inefficient bipartition? Here we systematically explain this perplexing phenomenon. We propose that grana stacks, acting like bellows in accordions, increase the degree of ultrastructural control on photosynthesis through thylakoid swelling/shrinking induced by osmotic water fluxes. This control coordinates with variations in stomatal conductance and the turgor of guard cells, which act like an accordion's air button. Thylakoid ultrastructural dynamics regulate macromolecular blocking/collision probability, direct diffusional pathlengths, division of function of Cytochrome b6 f complex between linear and cyclic electron transport, luminal pH via osmotic water fluxes, and the separation of pH dynamics between granal and lamellar lumens in response to environmental variations. With the two functionally asymmetrical photosystems located distantly from each other, the ultrastructural control, nonphotochemical quenching, and carbon-reaction feedbacks maximally cooperate to balance electron transport with gas exchange, provide homeostasis in fluctuating light environments, and protect photosystems in drought. Grana stacks represent a dry/high irradiance adaptation of photosynthetic machinery to improve fitness in challenging land environments. Our theory unifies many well-known but seemingly unconnected phenomena of thylakoid structure and function in higher plants.
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Affiliation(s)
- Lianhong Gu
- Environmental Sciences Division and Climate Change Science InstituteOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Bernard Grodzinski
- Department of Plant AgricultureUniversity of GuelphGuelphONN1G 2W1Canada
| | - Jimei Han
- School of Integrative Plant ScienceCornell UniversityIthacaNY14853USA
| | - Telesphore Marie
- Department of Plant AgricultureUniversity of GuelphGuelphONN1G 2W1Canada
| | | | - Yang C. Song
- Department of Hydrology and Atmospheric SciencesUniversity of ArizonaTucsonAZ85721USA
| | - Ying Sun
- School of Integrative Plant ScienceCornell UniversityIthacaNY14853USA
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11
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Chang YS, Yang HC, Chao L. Formation of Supported Thylakoid Membrane Bioanodes for Effective Electron Transfer and Stable Photocurrent. ACS APPLIED MATERIALS & INTERFACES 2022; 14:22216-22224. [PMID: 35511069 DOI: 10.1021/acsami.2c04764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The light-dependent reactions of photosynthesis use light energy to generate photoelectrons traveling through the thylakoid membranes (TMs). Extracting the photoelectrons from the TMs to form bioanodes can have various applications. Most studies focus on modifying the electrode materials to increase the collected photocurrent. Seldom studies have investigated how the orientation of the TMs influences photocurrent collection. In addition, the formation of reactive oxygen species (ROS) during photosynthesis is a challenge for stable photocurrent generation. Here, we enhanced the photoelectron transfer from the TMs to electrodes by depositing expanded thylakoids as planar supported membranes onto an electrode. The high contact area between the external electrodes and TMs per unit mass of thylakoid allows the thylakoid to more effectively transfer electrons to the electrodes, thereby reducing the free electrons available for the ROS generation. We expanded the naturally stacked thylakoids into liposomes through osmotic pressure and dropcasted them onto an Au electrode. The electrochemical impedance measurement showed that the supported membrane bioanode formed by the expanded liposomes had a lower photoelectron transfer resistance. Additionally, we observed that the expanded TM bioanode provided a higher photocurrent and was more durable to air/water interfacial tension. These results suggest that the effective contact between the expanded TM and electrodes can lead to more efficient electron transfer and increase the system robustness. The photo fuel cell (PFC) made by the expanded TM bioanode had a higher open-circuit voltage than the one made by the stacked TM bioanode. Interestingly, we found that PFCs made of high-load TM bioanodes had fast photocurrent decay under continuous operation at high cell voltages. The poor contact of large numbers of TMs with the electrodes at the high-load TM bioanodes could cause more ROS accumulation and therefore decreased the operational stability, supporting the importance of effective contact between TMs and the electrodes.
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Affiliation(s)
- Yu-Shan Chang
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Hao-Cin Yang
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Ling Chao
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan
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12
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Joaquín-Ovalle FM, Guihurt G, Barcelo-Bovea V, Hani-Saba A, Fontanet-Gómez NC, Ramirez-Paz J, Kashino Y, Torres-Martinez Z, Doble-Cacho K, Delinois LJ, Delgado Y, Griebenow K. Oxidative Stress- and Autophagy-Inducing Effects of PSI-LHCI from Botryococcus braunii in Breast Cancer Cells. BIOTECH 2022; 11:9. [PMID: 35822782 PMCID: PMC9264392 DOI: 10.3390/biotech11020009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/19/2022] [Accepted: 03/28/2022] [Indexed: 11/24/2022] Open
Abstract
Botryococcus braunii (B. braunii) is a green microalga primarily found in freshwater, reservoirs, and ponds. Photosynthetic pigments from algae have shown many bioactive molecules with therapeutic potential. Herein, we report the purification, characterization, and anticancer properties of photosystem I light-harvesting complex I (PSI-LHCI) from the green microalga B. braunii UTEX2441. The pigment-protein complex was purified by sucrose density gradient and characterized by its distinctive peaks using absorption, low-temperature (77 K) fluorescence, and circular dichroism (CD) spectroscopic analyses. Protein complexes were resolved by blue native-PAGE and two-dimensional SDS-PAGE. Triple-negative breast cancer MDA-MB-231 cells were incubated with PSI-LHCI for all of our experiments. Cell viability was assessed, revealing a significant reduction in a time- and concentration-dependent manner. We confirmed the internalization of PSI-LHCI within the cytoplasm and nucleus after 12 h of incubation. Cell death mechanism by oxidative stress was confirmed by the production of reactive oxygen species (ROS) and specifically superoxide. Furthermore, we monitored autophagic flux, apoptotic and necrotic features after treatment with PSI-LHCI. Treated MDA-MB-231 cells showed positive autophagy signals in the cytoplasm and nucleus, and necrotic morphology by the permeabilization of the cell membrane. Our findings demonstrated for the first time the cytotoxic properties of B. braunii PSI-LHCI by the induction of ROS and autophagy in breast cancer cells.
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Affiliation(s)
- Freisa M. Joaquín-Ovalle
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, San Juan 00925, Puerto Rico; (F.M.J.-O.); (G.G.); (V.B.-B.); (A.H.-S.); (N.C.F.-G.); (J.R.-P.); (Z.T.-M.); (K.D.-C.); (L.J.D.)
| | - Grace Guihurt
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, San Juan 00925, Puerto Rico; (F.M.J.-O.); (G.G.); (V.B.-B.); (A.H.-S.); (N.C.F.-G.); (J.R.-P.); (Z.T.-M.); (K.D.-C.); (L.J.D.)
| | - Vanessa Barcelo-Bovea
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, San Juan 00925, Puerto Rico; (F.M.J.-O.); (G.G.); (V.B.-B.); (A.H.-S.); (N.C.F.-G.); (J.R.-P.); (Z.T.-M.); (K.D.-C.); (L.J.D.)
| | - Andraous Hani-Saba
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, San Juan 00925, Puerto Rico; (F.M.J.-O.); (G.G.); (V.B.-B.); (A.H.-S.); (N.C.F.-G.); (J.R.-P.); (Z.T.-M.); (K.D.-C.); (L.J.D.)
| | - Nicole C. Fontanet-Gómez
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, San Juan 00925, Puerto Rico; (F.M.J.-O.); (G.G.); (V.B.-B.); (A.H.-S.); (N.C.F.-G.); (J.R.-P.); (Z.T.-M.); (K.D.-C.); (L.J.D.)
| | - Josell Ramirez-Paz
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, San Juan 00925, Puerto Rico; (F.M.J.-O.); (G.G.); (V.B.-B.); (A.H.-S.); (N.C.F.-G.); (J.R.-P.); (Z.T.-M.); (K.D.-C.); (L.J.D.)
| | - Yasuhiro Kashino
- Graduate School of Science, University of Hyogo, Kobe 678-1297, Japan;
| | - Zally Torres-Martinez
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, San Juan 00925, Puerto Rico; (F.M.J.-O.); (G.G.); (V.B.-B.); (A.H.-S.); (N.C.F.-G.); (J.R.-P.); (Z.T.-M.); (K.D.-C.); (L.J.D.)
| | - Katerina Doble-Cacho
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, San Juan 00925, Puerto Rico; (F.M.J.-O.); (G.G.); (V.B.-B.); (A.H.-S.); (N.C.F.-G.); (J.R.-P.); (Z.T.-M.); (K.D.-C.); (L.J.D.)
| | - Louis J. Delinois
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, San Juan 00925, Puerto Rico; (F.M.J.-O.); (G.G.); (V.B.-B.); (A.H.-S.); (N.C.F.-G.); (J.R.-P.); (Z.T.-M.); (K.D.-C.); (L.J.D.)
| | - Yamixa Delgado
- Biochemistry & Pharmacology Department, San Juan Bautista School of Medicine, Caguas 00725, Puerto Rico
| | - Kai Griebenow
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, San Juan 00925, Puerto Rico; (F.M.J.-O.); (G.G.); (V.B.-B.); (A.H.-S.); (N.C.F.-G.); (J.R.-P.); (Z.T.-M.); (K.D.-C.); (L.J.D.)
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13
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Tokumitsu Y, Kozu T, Yamatani H, Ito T, Nakano H, Hase A, Sasada H, Takada Y, Kaga A, Ishimoto M, Kusaba M, Nakashima T, Abe J, Yamada T. Functional Divergence of G and Its Homologous Genes for Green Pigmentation in Soybean Seeds. FRONTIERS IN PLANT SCIENCE 2022; 12:796981. [PMID: 35069653 PMCID: PMC8766641 DOI: 10.3389/fpls.2021.796981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 12/13/2021] [Indexed: 06/14/2023]
Abstract
The degradation of chlorophyll in mature soybean seeds is closely related to the development of their yellow color. In this study, we examined G, its homologue G-like (GL), and their mutant alleles and investigated the relationship between these genes and chlorophyll accumulation in the seed coats of mature seeds. Transient expression of G and GL proteins fused with green fluorescent protein revealed that both were localized in plastids. Overexpression of G resulted in the accumulation of chlorophyll in the seed coats and cotyledons of mature seeds, indicating that high expression levels of G result in chlorophyll accumulation that exceeds its metabolism in the seeds of yellow soybean. Analysis of near isogenic lines at the G locus demonstrated a significant difference in the chlorophyll content of the seed coats and cotyledons of mature seeds when G and mutant g alleles were expressed in the d1d2 stay-green genetic background, indicating that the G protein might repress the SGR-independent degradation of chlorophyll. We examined the distribution of mutant alleles at the G and GL loci among cultivated and wild soybean germplasm. The g allele was widely distributed in cultivated soybean germplasm, except for green seed coat soybean lines, all of which contained the G allele. The gl alleles were much fewer in number than the g alleles and were mainly distributed in the genetic resources of cultivated soybean from Japan. None of the landraces and breeding lines investigated in this study were observed to contain both the g and gl alleles. Therefore, in conclusion, the mutation of the G locus alone is essential for establishing yellow soybeans, which are major current soybean breeding lines.
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Affiliation(s)
- Yusuke Tokumitsu
- Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
| | - Takuto Kozu
- Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
| | - Hiroshi Yamatani
- Institute of Crop Science, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Takeshi Ito
- Graduate School of Science, Hiroshima University, Higashihiroshima, Japan
| | - Haruna Nakano
- Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Ayaka Hase
- Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Hiroki Sasada
- Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Yoshitake Takada
- Western Region Agricultural Research Center, National Agriculture and Food Research Organization, Fukuyama, Japan
| | - Akito Kaga
- Institute of Crop Science, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Masao Ishimoto
- Institute of Crop Science, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Makoto Kusaba
- Graduate School of Science, Hiroshima University, Higashihiroshima, Japan
| | - Taiken Nakashima
- Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
| | - Jun Abe
- Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
| | - Tetsuya Yamada
- Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
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14
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Ermakova M, Bellasio C, Fitzpatrick D, Furbank RT, Mamedov F, von Caemmerer S. Upregulation of bundle sheath electron transport capacity under limiting light in C 4 Setaria viridis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 106:1443-1454. [PMID: 33772896 PMCID: PMC9291211 DOI: 10.1111/tpj.15247] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 02/15/2021] [Accepted: 03/22/2021] [Indexed: 05/22/2023]
Abstract
C4 photosynthesis is a biochemical pathway that operates across mesophyll and bundle sheath (BS) cells to increase CO2 concentration at the site of CO2 fixation. C4 plants benefit from high irradiance but their efficiency decreases under shade, causing a loss of productivity in crop canopies. We investigated shade acclimation responses of Setaria viridis, a model monocot of NADP-dependent malic enzyme subtype, focussing on cell-specific electron transport capacity. Plants grown under low light (LL) maintained CO2 assimilation rates similar to high light plants but had an increased chlorophyll and light-harvesting-protein content, predominantly in BS cells. Photosystem II (PSII) protein abundance, oxygen-evolving activity and the PSII/PSI ratio were enhanced in LL BS cells, indicating a higher capacity for linear electron flow. Abundances of PSI, ATP synthase, Cytochrome b6 f and the chloroplast NAD(P)H dehydrogenase complex, which constitute the BS cyclic electron flow machinery, were also increased in LL plants. A decline in PEP carboxylase activity in mesophyll cells and a consequent shortage of reducing power in BS chloroplasts were associated with a more oxidised plastoquinone pool in LL plants and the formation of PSII - light-harvesting complex II supercomplexes with an increased oxygen evolution rate. Our results suggest that the supramolecular composition of PSII in BS cells is adjusted according to the redox state of the plastoquinone pool. This discovery contributes to the understanding of the acclimation of PSII activity in C4 plants and will support the development of strategies for crop improvement, including the engineering of C4 photosynthesis into C3 plants.
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Affiliation(s)
- Maria Ermakova
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonAustralian Capital Territory2601Australia
| | - Chandra Bellasio
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonAustralian Capital Territory2601Australia
- University of the Balearic IslandsPalmaIlles Balears07122Spain
| | - Duncan Fitzpatrick
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonAustralian Capital Territory2601Australia
| | - Robert T. Furbank
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonAustralian Capital Territory2601Australia
| | - Fikret Mamedov
- Molecular BiomimeticsDepartment of Chemistry – Ångström LaboratoryUppsala UniversityUppsala75 120Sweden
| | - Susanne von Caemmerer
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonAustralian Capital Territory2601Australia
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15
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Lee J, Shin H, Kang C, Kim S. Solar Energy Conversion through Thylakoid Membranes Wired by Osmium Redox Polymer and Indium Tin Oxide Nanoparticles. CHEMSUSCHEM 2021; 14:2216-2225. [PMID: 33754497 DOI: 10.1002/cssc.202100288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/11/2021] [Indexed: 06/12/2023]
Abstract
For several decades, much attention has been paid to thylakoid membranes (TMs) as photocatalysts for converting solar light to electricity. Despite extensive research, current technology provides only limited photocurrents. Here, a novel method based on TM-composite material was developed for achieving high photocurrent. When a thin film composed of TMs, osmium redox polymer (Os-RP), and indium tin oxide nanoparticles (ITOnp) was formed on a porous graphite surface, appreciable photocurrent as high as 0.5 mA cm-2 was achieved at 0.4 V vs. Ag/AgCl. Each component plays its own role in transferring electrons from TMs to the anode, resulting in sharp drop in photocurrent with missing any component. Optimization between these three components showed 1 : 0.5 : 30 (TM/Os-RP/ITOnp) was the best ratio. Action spectra confirmed that TMs was the origin of photocurrent. It was inferred from blocking experiments using 3-(3,4-dichlorophenyl)-1,1-dimethylurea as an inhibitor that about 41 % of photocurrent was transferred from QA in photosystem II to the electrode via Os-RP and ITOnp. Quantum efficiencies at 430 and 660 nm were 12.2 and 18.5 %, respectively. Turnover frequency for water oxidation depended upon the amount of the composite. A complete cell with Pt/C cathode produced Pmax of 122 μW cm-2 at 758 μA cm-2 under one sun illumination, which is the highest power density to our knowledge. This study opened a possibility of using TMs as photocatalysts for solar energy conversion.
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Affiliation(s)
- Jinhwan Lee
- Department of Systems Biotechnology, Konkuk Institute of Technology, Konkuk University, 120 Neudong-ro, Gwangjin-gu, Seoul, 05029, Korea
| | - Hyosul Shin
- Department of Chemistry, Jeonbuk National University, 567 Baekje-daero, Jeonju, Jeonbuk, 54896, Korea
| | - Chan Kang
- Department of Chemistry, Jeonbuk National University, 567 Baekje-daero, Jeonju, Jeonbuk, 54896, Korea
| | - Sunghyun Kim
- Department of Systems Biotechnology, Konkuk Institute of Technology, Konkuk University, 120 Neudong-ro, Gwangjin-gu, Seoul, 05029, Korea
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16
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Rantala M, Rantala S, Aro EM. Composition, phosphorylation and dynamic organization of photosynthetic protein complexes in plant thylakoid membrane. Photochem Photobiol Sci 2021; 19:604-619. [PMID: 32297616 DOI: 10.1039/d0pp00025f] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The photosystems (PS), catalyzing the photosynthetic reactions of higher plants, are unevenly distributed in the thylakoid membrane: PSII, together with its light harvesting complex (LHC)II, is enriched in the appressed grana stacks, while PSI-LHCI resides in the non-appressed stroma thylakoids, which wind around the grana stacks. The two photosystems interact in a third membrane domain, the grana margins, which connect the grana and stroma thylakoids and allow the loosely bound LHCII to serve as an additional antenna for PSI. The light harvesting is balanced by reversible phosphorylation of LHCII proteins. Nevertheless, light energy also damages PSII and the repair process is regulated by reversible phosphorylation of PSII core proteins. Here, we discuss the detailed composition and organization of PSII-LHCII and PSI-LHCI (super)complexes in the thylakoid membrane of angiosperm chloroplasts and address the role of thylakoid protein phosphorylation in dynamics of the entire protein complex network of the photosynthetic membrane. Finally, we scrutinize the phosphorylation-dependent dynamics of the protein complexes in context of thylakoid ultrastructure and present a model on the reorganization of the entire thylakoid network in response to changes in thylakoid protein phosphorylation.
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Affiliation(s)
- Marjaana Rantala
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520, Turku, Finland
| | - Sanna Rantala
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520, Turku, Finland
| | - Eva-Mari Aro
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520, Turku, Finland.
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17
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Theune ML, Hildebrandt S, Steffen-Heins A, Bilger W, Gutekunst K, Appel J. In-vivo quantification of electron flow through photosystem I - Cyclic electron transport makes up about 35% in a cyanobacterium. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1862:148353. [PMID: 33346012 DOI: 10.1016/j.bbabio.2020.148353] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 11/23/2020] [Accepted: 12/08/2020] [Indexed: 12/15/2022]
Abstract
Photosynthetic electron flow, driven by photosystem I and II, provides chemical energy for carbon fixation. In addition to a linear mode a second cyclic route exists, which only involves photosystem I. The exact contributions of linear and cyclic transport are still a matter of debate. Here, we describe the development of a method that allows quantification of electron flow in absolute terms through photosystem I in a photosynthetic organism for the first time. Specific in-vivo protocols allowed to discern the redox states of plastocyanin, P700 and the FeS-clusters including ferredoxin at the acceptor site of PSI in the cyanobacterium Synechocystis sp. PCC 6803 with the near-infrared spectrometer Dual-KLAS/NIR. P700 absorbance changes determined with the Dual-KLAS/NIR correlated linearly with direct determinations of PSI concentrations using EPR. Dark-interval relaxation kinetics measurements (DIRKPSI) were applied to determine electron flow through PSI. Counting electrons from hydrogen oxidation as electron donor to photosystem I in parallel to DIRKPSI measurements confirmed the validity of the method. Electron flow determination by classical PSI yield measurements overestimates electron flow at low light intensities and saturates earlier compared to DIRKPSI. Combination of DIRKPSI with oxygen evolution measurements yielded a proportion of 35% of surplus electrons passing PSI compared to PSII. We attribute these electrons to cyclic electron transport, which is twice as high as assumed for plants. Counting electrons flowing through the photosystems allowed determination of the number of quanta required for photosynthesis to 11 per oxygen produced, which is close to published values.
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Affiliation(s)
- Marius L Theune
- Department of Biology, Botanical Institute, Christian-Albrechts-University, 24118 Kiel, Germany
| | - Sarah Hildebrandt
- Department of Biology, Botanical Institute, Christian-Albrechts-University, 24118 Kiel, Germany
| | - Anja Steffen-Heins
- Division of Food Technology, Institute of Human Nutrition and Food Science, Christian-Albrechts-University, 24118 Kiel, Germany
| | - Wolfgang Bilger
- Department of Biology, Botanical Institute, Christian-Albrechts-University, 24118 Kiel, Germany
| | - Kirstin Gutekunst
- Department of Biology, Botanical Institute, Christian-Albrechts-University, 24118 Kiel, Germany
| | - Jens Appel
- Department of Biology, Botanical Institute, Christian-Albrechts-University, 24118 Kiel, Germany.
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18
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Gideon DA, Nirusimhan V, Manoj KM. Are plastocyanin and ferredoxin specific electron carriers or generic redox capacitors? Classical and murburn perspectives on two photosynthetic proteins. J Biomol Struct Dyn 2020; 40:1995-2009. [PMID: 33073701 DOI: 10.1080/07391102.2020.1835715] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
In the light reaction of oxygenic photosynthesis, plastocyanin (PC) and ferredoxins (Fd) are small/diffusible redox-active proteins playing key roles in electron transfer/transport phenomena. In the Z-scheme mechanistic purview, they are considered as specific affinity binding-based electron-relay agents, linking the functions of Cytochrome b6f (Cyt. b6f), Photosystem I (PS I) and Fd:NADPH oxidoreductase (FNR). The murburn explanation for photolytic photophosphorylation deems PC/Fd as generic 'redox capacitors', temporally accepting and releasing one-electron equivalents in reaction milieu. Herein, we explore the two theories with respect to structural, distributional and functional aspects of PC/Fd. Amino acid residues located on the surface loci of key patches of PC/Fd vary in electrostatic/contour (topography) signatures. Crystal structures of four different complexes each of Cyt.f-PC and Fd-FNR show little conservation in the contact-surfaces, thereby discrediting 'affinity binding-based electron transfers (ET)' as an evolutionary logic. Further, thermodynamic and kinetic data of wildtype and mutant proteins interactions do not align with Z-scheme. Furthermore, micromolar physiological concentrations of PC and the non-conducive architecture of chloroplasts render the classical model untenable. In the murburn model, as PC is optional, the observation that plants lacking PC survive and grow is justified. Further, the low physiological concentration/distribution of PC in chloroplast lumen/stroma is supported by murburn equilibriums, as higher concentrations would limit electron transfers. Thus, structural evidence, interactive dynamics with redox partners and physiological distribution/role of PC/Fd support the murburn perspective that these proteins serve as generic redox-capacitors in chloroplasts.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Daniel Andrew Gideon
- Department of Biochemistry, Satyamjayatu: The Science & Ethics Foundation, Palakkad, India.,Department of Biotechnology and Bioinformatics, Bishop Heber College (Autonomous), Tiruchirappalli, India
| | - Vijay Nirusimhan
- Department of Biotechnology and Bioinformatics, Bishop Heber College (Autonomous), Tiruchirappalli, India
| | - Kelath Murali Manoj
- Department of Biochemistry, Satyamjayatu: The Science & Ethics Foundation, Palakkad, India
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19
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Bhaduri S, Singh SK, Cohn W, Hasan SS, Whitelegge JP, Cramer WA. A novel chloroplast super-complex consisting of the ATP synthase and photosystem I reaction center. PLoS One 2020; 15:e0237569. [PMID: 32817667 PMCID: PMC7444523 DOI: 10.1371/journal.pone.0237569] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 07/29/2020] [Indexed: 11/18/2022] Open
Abstract
Several 'super-complexes' of individual hetero-oligomeric membrane protein complexes, whose function is to facilitate intra-membrane electron and proton transfer and harvesting of light energy, have been previously characterized in the mitochondrial cristae and chloroplast thylakoid membranes. We report the presence of an intra-membrane super-complex dominated by the ATP-synthase, photosystem I (PSI) reaction-center complex and the ferredoxin-NADP+ Reductase (FNR) in the thylakoid membrane. The presence of the super-complex has been documented by mass spectrometry, clear-native PAGE and Western Blot analyses. This is the first documented presence of ATP synthase in a super-complex with the PSI reaction-center located in the non-appressed stromal domain of the thylakoid membrane.
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Affiliation(s)
- Satarupa Bhaduri
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
| | - Sandeep K Singh
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
| | - Whitaker Cohn
- Pasarow Mass Spectrometry Laboratory, The Jane and Terry Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California/Los Angeles, Los Angeles, California, United States of America
| | - S. Saif Hasan
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
| | - Julian P. Whitelegge
- Pasarow Mass Spectrometry Laboratory, The Jane and Terry Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California/Los Angeles, Los Angeles, California, United States of America
| | - William A. Cramer
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
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20
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Miller TE, Beneyton T, Schwander T, Diehl C, Girault M, McLean R, Chotel T, Claus P, Cortina NS, Baret JC, Erb TJ. Light-powered CO 2 fixation in a chloroplast mimic with natural and synthetic parts. Science 2020; 368:649-654. [PMID: 32381722 DOI: 10.1126/science.aaz6802] [Citation(s) in RCA: 164] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 03/24/2020] [Indexed: 12/21/2022]
Abstract
Nature integrates complex biosynthetic and energy-converting tasks within compartments such as chloroplasts and mitochondria. Chloroplasts convert light into chemical energy, driving carbon dioxide fixation. We used microfluidics to develop a chloroplast mimic by encapsulating and operating photosynthetic membranes in cell-sized droplets. These droplets can be energized by light to power enzymes or enzyme cascades and analyzed for their catalytic properties in multiplex and real time. We demonstrate how these microdroplets can be programmed and controlled by adjusting internal compositions and by using light as an external trigger. We showcase the capability of our platform by integrating the crotonyl-coenzyme A (CoA)/ethylmalonyl-CoA/hydroxybutyryl-CoA (CETCH) cycle, a synthetic network for carbon dioxide conversion, to create an artificial photosynthetic system that interfaces the natural and the synthetic biological worlds.
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Affiliation(s)
- Tarryn E Miller
- Department of Biochemistry and Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg, Germany
| | - Thomas Beneyton
- University of Bordeaux, CNRS, Centre de Recherche Paul Pascal, UMR 5031, Pessac 33600, France
| | - Thomas Schwander
- Department of Biochemistry and Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg, Germany
| | - Christoph Diehl
- Department of Biochemistry and Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg, Germany
| | | | - Richard McLean
- Department of Biochemistry and Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg, Germany
| | - Tanguy Chotel
- University of Bordeaux, CNRS, Centre de Recherche Paul Pascal, UMR 5031, Pessac 33600, France
| | - Peter Claus
- Department of Biochemistry and Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg, Germany
| | - Niña Socorro Cortina
- Department of Biochemistry and Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg, Germany
| | - Jean-Christophe Baret
- University of Bordeaux, CNRS, Centre de Recherche Paul Pascal, UMR 5031, Pessac 33600, France. .,Institut Universitaire de France, Paris 75005, France
| | - Tobias J Erb
- Department of Biochemistry and Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg, Germany. .,Center for Synthetic Microbiology, Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg, Germany
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21
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Wei H, Liu C, Hu J, Jeong BR. Quality of Supplementary Morning Lighting (SML) During Propagation Period Affects Physiology, Stomatal Characteristics, and Growth of Strawberry Plants. PLANTS (BASEL, SWITZERLAND) 2020; 9:E638. [PMID: 32429476 PMCID: PMC7285151 DOI: 10.3390/plants9050638] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/12/2020] [Accepted: 05/14/2020] [Indexed: 11/16/2022]
Abstract
Artificial light supplementation is widely used in modern agriculture. Due to their numerous advantages, light emitting diodes (LEDs) are widely used to effectively increase the yield or control the development of crops. In the present study, the effects of supplementary morning lighting (SML) with LEDs on the physiology and stomatal characteristics of strawberry plants were studied, with the aim of awakening the plant guard cells before sunrise and enabling strawberry plants to efficiently photosynthesize immediately after sunrise. Young daughter plants of 'Maehyang' and 'Seolhyang' strawberry cultivars that have just rooted were grown under LEDs with different wavelengths-white (W), red (R), mixed blue and red (BR, 1:1), and blue (B)-to investigate the effects of the SML on the physiology, stomatal characteristics, and growth. The SML was provided for 2 h at an intensity of 100 μmol·m-2·s-1 PPFD before sunrise every morning. A group without supplementary lighting was set as the control. The results showed that the different SML qualities have significantly affected the stomatal characteristics. The B SML promoted the stomatal opening more effectively compared to the other SMLs. The stomatal conductance and quantum yield (Fv/Fm) of leaves treated with the SMLs were higher than those of the control group. The B and BR SMLs most significantly affected the stomatal conductance and quantum yield (Fv/Fm). After 30 days of the SML treatments, it was observed that the B SML effectively improved the plant quality, chlorophyll content, and carbohydrate accumulation in the two strawberry cultivars. In general, a short-term exposure to blue light before sunrise can effectively improve the quality and promote the production of strawberry plants.
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Affiliation(s)
- Hao Wei
- Department of Horticulture, Division of Applied Life Science (BK21 Plus Program), Graduate School of Gyeongsang National University, Jinju 52828, Korea; (H.W.); (C.L.); (J.H.)
| | - Chen Liu
- Department of Horticulture, Division of Applied Life Science (BK21 Plus Program), Graduate School of Gyeongsang National University, Jinju 52828, Korea; (H.W.); (C.L.); (J.H.)
| | - Jiangtao Hu
- Department of Horticulture, Division of Applied Life Science (BK21 Plus Program), Graduate School of Gyeongsang National University, Jinju 52828, Korea; (H.W.); (C.L.); (J.H.)
| | - Byoung Ryong Jeong
- Department of Horticulture, Division of Applied Life Science (BK21 Plus Program), Graduate School of Gyeongsang National University, Jinju 52828, Korea; (H.W.); (C.L.); (J.H.)
- Institute of Agriculture & Life Science, Gyeongsang National University, Jinju 52828, Korea
- Research Institute of Life Science, Gyeongsang National University, Jinju 52828, Korea
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22
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Wietrzynski W, Schaffer M, Tegunov D, Albert S, Kanazawa A, Plitzko JM, Baumeister W, Engel BD. Charting the native architecture of Chlamydomonas thylakoid membranes with single-molecule precision. eLife 2020; 9:53740. [PMID: 32297859 PMCID: PMC7164959 DOI: 10.7554/elife.53740] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 04/03/2020] [Indexed: 12/18/2022] Open
Abstract
Thylakoid membranes scaffold an assortment of large protein complexes that work together to harness the energy of light. It has been a longstanding challenge to visualize how the intricate thylakoid network organizes these protein complexes to finely tune the photosynthetic reactions. Previously, we used in situ cryo-electron tomography to reveal the native architecture of thylakoid membranes (Engel et al., 2015). Here, we leverage technical advances to resolve the individual protein complexes within these membranes. Combined with a new method to visualize membrane surface topology, we map the molecular landscapes of thylakoid membranes inside green algae cells. Our tomograms provide insights into the molecular forces that drive thylakoid stacking and reveal that photosystems I and II are strictly segregated at the borders between appressed and non-appressed membrane domains. This new approach to charting thylakoid topology lays the foundation for dissecting photosynthetic regulation at the level of single protein complexes within the cell.
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Affiliation(s)
- Wojciech Wietrzynski
- Helmholtz Pioneer Campus, Helmholtz Zentrum München, Neuherberg, Germany.,Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Miroslava Schaffer
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Dimitry Tegunov
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Sahradha Albert
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Atsuko Kanazawa
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, United States
| | - Jürgen M Plitzko
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Wolfgang Baumeister
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Benjamin D Engel
- Helmholtz Pioneer Campus, Helmholtz Zentrum München, Neuherberg, Germany.,Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
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Mazur R, Gieczewska K, Kowalewska Ł, Kuta A, Proboszcz M, Gruszecki WI, Mostowska A, Garstka M. Specific Composition of Lipid Phases Allows Retaining an Optimal Thylakoid Membrane Fluidity in Plant Response to Low-Temperature Treatment. FRONTIERS IN PLANT SCIENCE 2020; 11:723. [PMID: 32582253 PMCID: PMC7291772 DOI: 10.3389/fpls.2020.00723] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 05/06/2020] [Indexed: 05/15/2023]
Abstract
Thylakoid membranes isolated from leaves of two plant species, the chilling tolerant (CT) pea and chilling sensitive (CS) runner bean, were assessed for the composition of lipids, carotenoids as well as for the arrangement of photosynthetic complexes. The response to stress conditions was investigated in dark-chilled and subsequently photo-activated detached leaves of pea and bean. Thylakoids of both species have a similar level of monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG), but different sulfoquinovosyldiacylglycerol to phosphatidylglycerol (PG) ratio. In pea thylakoid fraction, the MGDG, DGDG and PG, have a higher double bond index (DBI), whereas bean thylakoids contain higher levels of high melting point PG. Furthermore, the lutein to the β-carotene ratio is higher in bean thylakoids. Smaller protein/lipid ratio in pea than in bean thylakoids suggests different lipid-protein interactions in both species. The differences between species are also reflected by the course of temperature-dependent plots of chlorophyll fluorescence pointing various temperatures of the lipid phase transitions of pea and bean thylakoids. Our results showed higher fluidity of the thylakoid membrane network in pea than in bean in optimal temperature conditions. Dark-chilling decreases the photochemical activity and induces significant degradation of MGDG in bean but not in pea leaves. Similarly, substantial changes in the arrangement of photosynthetic complexes with increase in LHCII phosphorylation and disturbances of the thylakoid structure take place in bean thylakoids only. Changes in the physical properties of bean thylakoids are manifested by the conversion of a three-phase temperature-dependent plot to a one-phase plot. Subsequent photo-activation of chilled bean leaves caused a partial restoration of the photochemistry and of membrane physical properties, but not of the photosynthetic complexes arrangement nor the thylakoid network structure. Summarizing, the composition of the thylakoid lipid matrix of CT pea allows retaining the optimal fluidity of its chloroplast membranes under low temperatures. In contrast, the fluidity of CS bean thylakoids is drastically changed, leading to the reorganization of the supramolecular structure of the photosynthetic complexes and finally results in structural remodeling of the CS bean thylakoid network.
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Affiliation(s)
- Radosław Mazur
- Department of Metabolic Regulation, Faculty of Biology, Institute of Biochemistry, University of Warsaw, Warsaw, Poland
- *Correspondence: Radosław Mazur,
| | - Katarzyna Gieczewska
- Department of Plant Anatomy and Cytology, Faculty of Biology, Institute of Plant Experimental Biology and Biotechnology, University of Warsaw, Warsaw, Poland
| | - Łucja Kowalewska
- Department of Plant Anatomy and Cytology, Faculty of Biology, Institute of Plant Experimental Biology and Biotechnology, University of Warsaw, Warsaw, Poland
| | - Anna Kuta
- Department of Metabolic Regulation, Faculty of Biology, Institute of Biochemistry, University of Warsaw, Warsaw, Poland
| | - Małgorzata Proboszcz
- Department of Metabolic Regulation, Faculty of Biology, Institute of Biochemistry, University of Warsaw, Warsaw, Poland
| | - Wieslaw I. Gruszecki
- Department of Biophysics, Institute of Physics, Maria Curie-Skłodowska University, Lublin, Poland
| | - Agnieszka Mostowska
- Department of Plant Anatomy and Cytology, Faculty of Biology, Institute of Plant Experimental Biology and Biotechnology, University of Warsaw, Warsaw, Poland
| | - Maciej Garstka
- Department of Metabolic Regulation, Faculty of Biology, Institute of Biochemistry, University of Warsaw, Warsaw, Poland
- Maciej Garstka,
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24
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Bos P, Oosterwijk A, Koehorst R, Bader A, Philippi J, van Amerongen H, Wientjes E. Digitonin-sensitive LHCII enlarges the antenna of Photosystem I in stroma lamellae of Arabidopsis thaliana after far-red and blue-light treatment. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:651-658. [PMID: 31299182 DOI: 10.1016/j.bbabio.2019.07.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 06/14/2019] [Accepted: 07/07/2019] [Indexed: 11/16/2022]
Abstract
Light drives photosynthesis. In plants it is absorbed by light-harvesting antenna complexes associated with Photosystem I (PSI) and photosystem II (PSII). As PSI and PSII work in series, it is important that the excitation pressure on the two photosystems is balanced. When plants are exposed to illumination that overexcites PSII, a special pool of the major light-harvesting complex LHCII is phosphorylated and moves from PSII to PSI (state 2). If instead PSI is over-excited the LHCII complex is dephosphorylated and moves back to PSII (state 1). Recent findings have suggested that LHCII might also transfer energy to PSI in state 1. In this work we used a combination of biochemistry and (time-resolved) fluorescence spectroscopy to investigate the PSI antenna size in state 1 and state 2 for Arabidopsis thaliana. Our data shows that 0.7 ± 0.1 unphosphorylated LHCII trimers per PSI are present in the stroma lamellae of state-1 plants. Upon transition to state 2 the antenna size of PSI in the stroma membrane increases with phosphorylated LHCIIs to a total of 1.2 ± 0.1 LHCII trimers per PSI. Both phosphorylated and unphosphorylated LHCII function as highly efficient PSI antenna.
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Affiliation(s)
- Peter Bos
- Laboratory of Biophysics, Wageningen University, P.O. Box 8128, 6700 ET Wageningen, the Netherlands
| | - Anniek Oosterwijk
- Laboratory of Biophysics, Wageningen University, P.O. Box 8128, 6700 ET Wageningen, the Netherlands
| | - Rob Koehorst
- Laboratory of Biophysics, Wageningen University, P.O. Box 8128, 6700 ET Wageningen, the Netherlands; MicroSpectroscopy Research Facility, Wageningen University, P.O. Box 8128, 6700 ET Wageningen, the Netherlands
| | - Arjen Bader
- Laboratory of Biophysics, Wageningen University, P.O. Box 8128, 6700 ET Wageningen, the Netherlands; MicroSpectroscopy Research Facility, Wageningen University, P.O. Box 8128, 6700 ET Wageningen, the Netherlands
| | - John Philippi
- Laboratory of Biophysics, Wageningen University, P.O. Box 8128, 6700 ET Wageningen, the Netherlands
| | - Herbert van Amerongen
- Laboratory of Biophysics, Wageningen University, P.O. Box 8128, 6700 ET Wageningen, the Netherlands; MicroSpectroscopy Research Facility, Wageningen University, P.O. Box 8128, 6700 ET Wageningen, the Netherlands
| | - Emilie Wientjes
- Laboratory of Biophysics, Wageningen University, P.O. Box 8128, 6700 ET Wageningen, the Netherlands.
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25
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Kowalewska Ł, Bykowski M, Mostowska A. Spatial organization of thylakoid network in higher plants. BOTANY LETTERS 2019. [PMID: 0 DOI: 10.1080/23818107.2019.1619195] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Affiliation(s)
- Łucja Kowalewska
- Department of Plant Anatomy and Cytology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Michał Bykowski
- Department of Plant Anatomy and Cytology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Agnieszka Mostowska
- Department of Plant Anatomy and Cytology, Faculty of Biology, University of Warsaw, Warsaw, Poland
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26
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DeHaven BA, Goodlett DW, Sindt AJ, Noll N, De Vetta M, Smith MD, Martin CR, González L, Shimizu LS. Enhancing the Stability of Photogenerated Benzophenone Triplet Radical Pairs through Supramolecular Assembly. J Am Chem Soc 2018; 140:13064-13070. [PMID: 30212205 DOI: 10.1021/jacs.8b08501] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Supramolecular assembly of urea-tethered benzophenone molecules results in the formation of remarkably persistent triplet radical pairs upon UV irradiation at room temperature, whereas no radicals were observed in solution. The factors that lead to emergent organic radicals are correlated with the microenvironment around the benzophenone carbonyl, types of proximal hydrogens, and the rigid supramolecular network. The absorption spectra of the linear analogues were rationalized using time-dependent density functional theory calculations on the crystal structure and in dimethyl sulfoxide, employing an implicit solvation model to describe structural and electronic solvent effects. Inspection of the natural transition orbitals for the more important excitation bands of the absorption spectra indicates that crystallization of the benzophenone-containing molecules should present a stark contrast in photophysical properties versus that in solution, which was indeed reflected by their quantum efficiencies upon solid-state assembly. Persistent organic radicals have prospective applications ranging from organic light-emitting diode technology to NMR polarizing agents.
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Affiliation(s)
- Baillie A DeHaven
- Department of Chemistry and Biochemistry , University of South Carolina , Columbia , South Carolina 29208 , United States
| | - Dustin W Goodlett
- Department of Chemistry and Biochemistry , University of South Carolina , Columbia , South Carolina 29208 , United States
| | - Ammon J Sindt
- Department of Chemistry and Biochemistry , University of South Carolina , Columbia , South Carolina 29208 , United States
| | - Niklas Noll
- Department of Chemistry and Biochemistry , University of South Carolina , Columbia , South Carolina 29208 , United States
| | - Martina De Vetta
- Institute of Theoretical Chemistry, Faculty of Chemistry , University of Vienna , Währinger Strasse 17 , 1090 Vienna , Austria
| | - Mark D Smith
- Department of Chemistry and Biochemistry , University of South Carolina , Columbia , South Carolina 29208 , United States
| | - Corey R Martin
- Department of Chemistry and Biochemistry , University of South Carolina , Columbia , South Carolina 29208 , United States
| | - Leticia González
- Institute of Theoretical Chemistry, Faculty of Chemistry , University of Vienna , Währinger Strasse 17 , 1090 Vienna , Austria
| | - Linda S Shimizu
- Department of Chemistry and Biochemistry , University of South Carolina , Columbia , South Carolina 29208 , United States
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27
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The wavelength of the incident light determines the primary charge separation pathway in Photosystem II. Sci Rep 2018; 8:2837. [PMID: 29434283 PMCID: PMC5809461 DOI: 10.1038/s41598-018-21101-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 01/25/2018] [Indexed: 01/12/2023] Open
Abstract
Charge separation is a key component of the reactions cascade of photosynthesis, by which solar energy is converted to chemical energy. From this photochemical reaction, two radicals of opposite charge are formed, a highly reducing anion and a highly oxidising cation. We have previously proposed that the cation after far-red light excitation is located on a component different from PD1, which is the location of the primary electron hole after visible light excitation. Here, we attempt to provide further insight into the location of the primary charge separation upon far-red light excitation of PS II, using the EPR signal of the spin polarized 3P680 as a probe. We demonstrate that, under far-red light illumination, the spin polarized 3P680 is not formed, despite the primary charge separation still occurring at these conditions. We propose that this is because under far-red light excitation, the primary electron hole is localized on ChlD1, rather than on PD1. The fact that identical samples have demonstrated charge separation upon both far-red and visible light excitation supports our hypothesis that two pathways for primary charge separation exist in parallel in PS II reaction centres. These pathways are excited and activated dependent of the wavelength applied.
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28
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Wood WHJ, MacGregor-Chatwin C, Barnett SFH, Mayneord GE, Huang X, Hobbs JK, Hunter CN, Johnson MP. Dynamic thylakoid stacking regulates the balance between linear and cyclic photosynthetic electron transfer. NATURE PLANTS 2018; 4:116-127. [PMID: 29379151 DOI: 10.1038/s41477-017-0092-7] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 12/13/2017] [Indexed: 05/05/2023]
Abstract
Upon transition of plants from darkness to light the initiation of photosynthetic linear electron transfer (LET) from H2O to NADP+ precedes the activation of CO2 fixation, creating a lag period where cyclic electron transfer (CET) around photosystem I (PSI) has an important protective role. CET generates ΔpH without net reduced NADPH formation, preventing overreduction of PSI via regulation of the cytochrome b 6 f (cytb 6 f) complex and protecting PSII from overexcitation by inducing non-photochemical quenching. The dark-to-light transition also provokes increased phosphorylation of light-harvesting complex II (LHCII). However, the relationship between LHCII phosphorylation and regulation of the LET/CET balance is not understood. Here, we show that the dark-to-light changes in LHCII phosphorylation profoundly alter thylakoid membrane architecture and the macromolecular organization of the photosynthetic complexes, without significantly affecting the antenna size of either photosystem. The grana diameter and number of membrane layers per grana are decreased in the light while the number of grana per chloroplast is increased, creating a larger contact area between grana and stromal lamellae. We show that these changes in thylakoid stacking regulate the balance between LET and CET pathways. Smaller grana promote more efficient LET by reducing the diffusion distance for the mobile electron carriers plastoquinone and plastocyanin, whereas larger grana enhance the partition of the granal and stromal lamellae plastoquinone pools, enhancing the efficiency of CET and thus photoprotection by non-photochemical quenching.
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Affiliation(s)
- William H J Wood
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
| | | | - Samuel F H Barnett
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
| | - Guy E Mayneord
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
| | - Xia Huang
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
| | - Jamie K Hobbs
- Department of Physics and Astronomy, University of Sheffield, Sheffield, UK
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
| | - Matthew P Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK.
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29
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Murakami K, Matsuda R, Fujiwara K. Quantification of excitation energy distribution between photosystems based on a mechanistic model of photosynthetic electron transport. PLANT, CELL & ENVIRONMENT 2018; 41:148-159. [PMID: 28548208 DOI: 10.1111/pce.12986] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 04/16/2017] [Accepted: 04/25/2017] [Indexed: 06/07/2023]
Abstract
Absorbed light energy is converted into excitation energy. The excitation energy is distributed to photosystems depending on the wavelength and drives photochemical reactions. A non-destructive, mechanistic and quantitative method for estimating the fraction of the excitation energy distributed to photosystem II (f) was developed. For the f values for two simultaneously provided actinic lights (ALs) with different spectral distributions to be estimated, photochemical yields of the photosystems were measured under the ALs and were then fitted to an electron transport model assuming the balance between the electron transport rates through the photosystems. For the method to be tested using leaves with different properties in terms of the long-term and short-term acclimation (adjustment of photosystem stoichiometry and state transition, respectively), the f values for red and far-red light (R and FR) were estimated in leaves grown (~1 week) under white light without and with supplemental FR and adapted (~10 min) to R without and with supplemental FR. The f values for R were clearly greater than those for FR and those of leaves grown with and adapted to supplemental FR tended to be higher than the controls. These results are consistent with previous studies and therefore support the validity of the proposed method.
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Affiliation(s)
- Keach Murakami
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Bunkyo, Tokyo, 113-8657, Japan
| | - Ryo Matsuda
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Bunkyo, Tokyo, 113-8657, Japan
| | - Kazuhiro Fujiwara
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Bunkyo, Tokyo, 113-8657, Japan
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30
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Park S, Fischer AL, Li Z, Bassi R, Niyogi KK, Fleming GR. Snapshot Transient Absorption Spectroscopy of Carotenoid Radical Cations in High-Light-Acclimating Thylakoid Membranes. J Phys Chem Lett 2017; 8:5548-5554. [PMID: 29083901 DOI: 10.1021/acs.jpclett.7b02486] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Nonphotochemical quenching mechanisms regulate light harvesting in oxygenic photosynthesis. Measurement techniques for nonphotochemical quenching have typically focused on downstream effects of quenching, such as measuring reduced chlorophyll fluorescence. Here, to directly measure a species involved in quenching, we report snapshot transient absorption (TA) spectroscopy, which rapidly tracks carotenoid radical cation signals as samples acclimate to excess light. The formation of zeaxanthin radical cations, which is possible evidence of zeaxanthin-chlorophyll charge-transfer (CT) quenching, was investigated in spinach thylakoids. Together with fluorescence lifetime snapshot data and time-resolved high-performance liquid chromatography (HPLC) measurements, snapshot TA reveals that Zea•+ formation is closely related to energy-dependent quenching (qE) in nonphotochemical quenching. Quantitative and dynamic information on CT quenching discussed in this work give insight into the design principles of photoprotection in natural photosynthesis.
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Affiliation(s)
- Soomin Park
- Department of Chemistry, University of California , Berkeley, California 94720, United States
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Kavli Energy Nanoscience Institute , Berkeley, California 94720, United States
| | - Alexandra L Fischer
- Department of Chemistry, University of California , Berkeley, California 94720, United States
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Kavli Energy Nanoscience Institute , Berkeley, California 94720, United States
| | - Zhirong Li
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California , Berkeley, California 94720, United States
| | - Roberto Bassi
- Dipartimento di Biotecnologie, Universitá di Verona , Strada Le Grazie, I-37134 Verona, Italia
| | - Krishna K Niyogi
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California , Berkeley, California 94720, United States
| | - Graham R Fleming
- Department of Chemistry, University of California , Berkeley, California 94720, United States
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Kavli Energy Nanoscience Institute , Berkeley, California 94720, United States
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31
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Miranda H, Immerzeel P, Gerber L, Hörnaeus K, Lind SB, Pattanaik B, Lindberg P, Mamedov F, Lindblad P. Sll1783, a monooxygenase associated with polysaccharide processing in the unicellular cyanobacterium Synechocystis PCC 6803. PHYSIOLOGIA PLANTARUM 2017; 161:182-195. [PMID: 28429526 DOI: 10.1111/ppl.12582] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 03/25/2017] [Accepted: 03/31/2017] [Indexed: 06/07/2023]
Abstract
Cyanobacteria play a pivotal role as the primary producer in many aquatic ecosystems. The knowledge on the interacting processes of cyanobacteria with its environment - abiotic and biotic factors - is still very limited. Many potential exocytoplasmic proteins in the model unicellular cyanobacterium Synechocystis PCC 6803 have unknown functions and their study is essential to improve our understanding of this photosynthetic organism and its potential for biotechnology use. Here we characterize a deletion mutant of Synechocystis PCC 6803, Δsll1783, a strain that showed a remarkably high light resistance which is related with its lower thylakoid membrane formation. Our results suggests Sll1783 to be involved in a mechanism of polysaccharide degradation and uptake and we hypothesize it might function as a sensor for cell density in cyanobacterial cultures.
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Affiliation(s)
- Hélder Miranda
- Department of Chemistry - Ångström Laboratory, Molecular Biomimetics and Science for Life Laboratory, Uppsala University, Uppsala, SE-75120, Sweden
| | - Peter Immerzeel
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, Umeå, SE-901 83, Sweden
| | - Lorenz Gerber
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, Umeå, SE-901 83, Sweden
| | - Katarina Hörnaeus
- Department of Chemistry - BMC, Analytical Chemistry and Science for Life Laboratory, Uppsala University, Uppsala, SE-751 24, Sweden
| | - Sara Bergström Lind
- Department of Chemistry - BMC, Analytical Chemistry and Science for Life Laboratory, Uppsala University, Uppsala, SE-751 24, Sweden
| | - Bagmi Pattanaik
- Department of Chemistry - Ångström Laboratory, Molecular Biomimetics and Science for Life Laboratory, Uppsala University, Uppsala, SE-75120, Sweden
| | - Pia Lindberg
- Department of Chemistry - Ångström Laboratory, Molecular Biomimetics and Science for Life Laboratory, Uppsala University, Uppsala, SE-75120, Sweden
| | - Fikret Mamedov
- Department of Chemistry - Ångström Laboratory, Molecular Biomimetics and Science for Life Laboratory, Uppsala University, Uppsala, SE-75120, Sweden
| | - Peter Lindblad
- Department of Chemistry - Ångström Laboratory, Molecular Biomimetics and Science for Life Laboratory, Uppsala University, Uppsala, SE-75120, Sweden
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32
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Wientjes E, Philippi J, Borst JW, van Amerongen H. Imaging the Photosystem I/Photosystem II chlorophyll ratio inside the leaf. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:259-265. [DOI: 10.1016/j.bbabio.2017.01.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 01/10/2017] [Accepted: 01/13/2017] [Indexed: 02/03/2023]
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33
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Albanese P, Manfredi M, Meneghesso A, Marengo E, Saracco G, Barber J, Morosinotto T, Pagliano C. Dynamic reorganization of photosystem II supercomplexes in response to variations in light intensities. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1651-60. [PMID: 27378191 DOI: 10.1016/j.bbabio.2016.06.011] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 06/28/2016] [Accepted: 06/30/2016] [Indexed: 10/21/2022]
Abstract
Plants are sessile organisms and need to acclimate to ever-changing light conditions in order to survive. These changes trigger a dynamic reorganization of the membrane protein complexes in the thylakoid membranes. Photosystem II (PSII) and its light harvesting system (LHCII) are the major target of this acclimation response, and accumulating evidences indicate that the amount and composition of PSII-LHCII supercomplexes in thylakoids are dynamically adjusted in response to changes in light intensity and quality. In this study, we characterized the PSII-LHCII supercomplexes in thylakoid membranes of pea plants in response to long-term acclimation to different light intensities. We provide evidence of a reorganization of the PSII-LHCII supercomplexes showing distinct changes in their antenna moiety. Mass spectrometry analysis revealed a specific reduction of Lhcb3, Lhcb6 and M-LHCII trimers bound to the PSII cores, while the Lhcb4.3 isoform increased in response to high light intensities. The modulation of Lhcb protein content correlates with the reduction of the functional PSII antenna size. These results suggest that the Lhcb3, Lhcb4.3 and Lhcb6 antenna subunits are major players in modulation of the PSII antenna size upon long-term acclimation to increased light levels. PsbS was not detected in the isolated PSII-LHCII supercomplexes at any light condition, despite an increased accumulation in thylakoids of high light acclimated plants, suggesting that PsbS is not a constitutive component of PSII-LHCII supercomplexes.
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Affiliation(s)
- Pascal Albanese
- Applied Science and Technology Department-BioSolar Lab, Politecnico di Torino, Viale T. Michel 5, 15121, Alessandria, Italy; Department of Biology, University of Padova, Via Ugo Bassi 58 B, 35121 Padova, Italy
| | - Marcello Manfredi
- ISALIT-Department of Science and Technological Innovation, University of Eastern Piedmont, Viale T. Michel 11, 15121 Alessandria, Italy; Department of Science and Technological Innovation, University of Eastern Piedmont, Viale T. Michel 11, 15121 Alessandria, Italy
| | - Andrea Meneghesso
- Department of Biology, University of Padova, Via Ugo Bassi 58 B, 35121 Padova, Italy
| | - Emilio Marengo
- Department of Science and Technological Innovation, University of Eastern Piedmont, Viale T. Michel 11, 15121 Alessandria, Italy
| | - Guido Saracco
- Center for Space Human Robotics IIT@POLITO, Istituto Italiano di Tecnologia, Corso Trento 21, 10129, Turin, Italy
| | - James Barber
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | - Tomas Morosinotto
- Department of Biology, University of Padova, Via Ugo Bassi 58 B, 35121 Padova, Italy
| | - Cristina Pagliano
- Applied Science and Technology Department-BioSolar Lab, Politecnico di Torino, Viale T. Michel 5, 15121, Alessandria, Italy.
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Fingerprinting the macro-organisation of pigment-protein complexes in plant thylakoid membranes in vivo by circular-dichroism spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1479-1489. [PMID: 27154055 DOI: 10.1016/j.bbabio.2016.04.287] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 04/30/2016] [Indexed: 11/24/2022]
Abstract
Macro-organisation of the protein complexes in plant thylakoid membranes plays important roles in the regulation and fine-tuning of photosynthetic activity. These delicate structures might, however, undergo substantial changes during isolating the thylakoid membranes or during sample preparations, e.g., for electron microscopy. Circular-dichroism (CD) spectroscopy is a non-invasive technique which can thus be used on intact samples. Via excitonic and psi-type CD bands, respectively, it carries information on short-range excitonic pigment-pigment interactions and the macro-organisation (chiral macrodomains) of pigment-protein complexes (psi, polymer or salt-induced). In order to obtain more specific information on the origin of the major psi-type CD bands, at around (+)506, (-)674 and (+)690nm, we fingerprinted detached leaves and isolated thylakoid membranes of wild-type and mutant plants and also tested the effects of different environmental conditions in vivo. We show that (i) the chiral macrodomains disassemble upon mild detergent treatments, but not after crosslinking the protein complexes; (ii) in different wild-type leaves of dicotyledonous and monocotyledonous angiosperms the CD features are quite robust, displaying very similar excitonic and psi-type bands, suggesting similar protein composition and (macro-) organisation of photosystem II (PSII) supercomplexes in the grana; (iii) the main positive psi-type bands depend on light-harvesting protein II contents of the membranes; (iv) the (+)506nm band appears only in the presence of PSII-LHCII supercomplexes and does not depend on the xanthophyll composition of the membranes. Hence, CD spectroscopy can be used to detect different macro-domains in the thylakoid membranes with different outer antenna compositions in vivo.
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Järvi S, Isojärvi J, Kangasjärvi S, Salojärvi J, Mamedov F, Suorsa M, Aro EM. Photosystem II Repair and Plant Immunity: Lessons Learned from Arabidopsis Mutant Lacking the THYLAKOID LUMEN PROTEIN 18.3. FRONTIERS IN PLANT SCIENCE 2016; 7:405. [PMID: 27064270 PMCID: PMC4814454 DOI: 10.3389/fpls.2016.00405] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 03/16/2016] [Indexed: 05/29/2023]
Abstract
Chloroplasts play an important role in the cellular sensing of abiotic and biotic stress. Signals originating from photosynthetic light reactions, in the form of redox and pH changes, accumulation of reactive oxygen and electrophile species or stromal metabolites are of key importance in chloroplast retrograde signaling. These signals initiate plant acclimation responses to both abiotic and biotic stresses. To reveal the molecular responses activated by rapid fluctuations in growth light intensity, gene expression analysis was performed with Arabidopsis thaliana wild type and the tlp18.3 mutant plants, the latter showing a stunted growth phenotype under fluctuating light conditions (Biochem. J, 406, 415-425). Expression pattern of genes encoding components of the photosynthetic electron transfer chain did not differ between fluctuating and constant light conditions, neither in wild type nor in tlp18.3 plants, and the composition of the thylakoid membrane protein complexes likewise remained unchanged. Nevertheless, the fluctuating light conditions repressed in wild-type plants a broad spectrum of genes involved in immune responses, which likely resulted from shade-avoidance responses and their intermixing with hormonal signaling. On the contrary, in the tlp18.3 mutant plants there was an imperfect repression of defense-related transcripts upon growth under fluctuating light, possibly by signals originating from minor malfunction of the photosystem II (PSII) repair cycle, which directly or indirectly modulated the transcript abundances of genes related to light perception via phytochromes. Consequently, a strong allocation of resources to defense reactions in the tlp18.3 mutant plants presumably results in the stunted growth phenotype under fluctuating light.
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Affiliation(s)
- Sari Järvi
- Molecular Plant Biology, Department of Biochemistry, University of TurkuTurku, Finland
| | - Janne Isojärvi
- Molecular Plant Biology, Department of Biochemistry, University of TurkuTurku, Finland
| | | | - Jarkko Salojärvi
- Plant Biology, Department of Biosciences, University of HelsinkiHelsinki, Finland
| | - Fikret Mamedov
- Molecular Biomimetics, Department of Chemistry—Ångström Laboratory, Uppsala UniversityUppsala, Sweden
| | - Marjaana Suorsa
- Molecular Plant Biology, Department of Biochemistry, University of TurkuTurku, Finland
| | - Eva-Mari Aro
- Molecular Plant Biology, Department of Biochemistry, University of TurkuTurku, Finland
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36
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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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37
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Chen YE, Yuan S, Schröder WP. Comparison of methods for extracting thylakoid membranes of Arabidopsis plants. PHYSIOLOGIA PLANTARUM 2016; 156:3-12. [PMID: 26337850 DOI: 10.1111/ppl.12384] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 06/18/2015] [Accepted: 07/15/2015] [Indexed: 05/27/2023]
Abstract
Robust and reproducible methods for extracting thylakoid membranes are required for the analysis of photosynthetic processes in higher plants such as Arabidopsis. Here, we compare three methods for thylakoid extraction using two different buffers. Method I involves homogenizing the plant material with a metal/glass blender; method II involves manually grinding the plant material in ice-cold grinding buffer with a mortar and method III entails snap-freezing followed by manual grinding with a mortar, after which the frozen powder is thawed in isolation buffer. Thylakoid membrane samples extracted using each method were analyzed with respect to protein and chlorophyll content, yields relative to starting material, oxygen-evolving activity, protein complex content and phosphorylation. We also examined how the use of fresh and frozen thylakoid material affected the extracts' contents of protein complexes. The use of different extraction buffers did not significantly alter the protein content of the extracts in any case. Method I yielded thylakoid membranes with the highest purity and oxygen-evolving activity. Method III used low amounts of starting material and was capable of capturing rapid phosphorylation changes in the sample at the cost of higher levels of contamination. Method II yielded thylakoid membrane extracts with properties intermediate between those obtained with the other two methods. Finally, frozen and freshly isolated thylakoid membranes performed identically in blue native-polyacrylamide gel electrophoresis experiments conducted in order to separate multimeric protein supracomplexes.
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Affiliation(s)
- Yang-Er Chen
- Department of Chemistry, University of Umeå, Umeå, SE-901 87, Sweden
- College of Life Sciences, Sichuan Agricultural University, Ya'an, 625014, China
| | - Shu Yuan
- College of Resources and Environmental Sciences, Sichuan Agricultural University, Chengdu, 611130, China
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38
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Lee J, Im J, Kim S. Mediatorless solar energy conversion by covalently bonded thylakoid monolayer on the glassy carbon electrode. Bioelectrochemistry 2015; 108:21-7. [PMID: 26625272 DOI: 10.1016/j.bioelechem.2015.11.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 11/17/2015] [Accepted: 11/18/2015] [Indexed: 10/22/2022]
Abstract
Light reactions of photosynthesis that take place in thylakoid membranes found in plants or cyanobacteria are among the most effective ways of utilizing light. Unlike most researches that use photosystem I or photosystem II as conversion units for converting light to electricity, we have developed a simple method in which the thylakoid monolayer was covalently immobilized on the glassy carbon electrode surface. The activity of isolated thylakoid membrane was confirmed by measuring evolving oxygen under illumination. Glassy carbon surfaces were first modified with partial or full monolayers of carboxyphenyl groups by reductive C-C coupling using 4-aminobenzoic acid and aniline and then thylakoid membrane was bioconjugated through the peptide bond between amine residues of thylakoid and carboxyl groups on the surface. Surface properties of modified surfaces were characterized by cyclic voltammetry, contact angle measurements, and electrochemical impedance spectroscopy. Photocurrent of 230 nA cm(-2) was observed when the thylakoid monolayer was formed on the mixed monolayer of 4-carboxylpheny and benzene at applied potential of 0.4V vs. Ag/AgCl. A small photocurrent resulted when the 4-carboxyphenyl full monolayer was used. This work shows the possibility of solar energy conversion by directly employing the whole thylakoid membrane through simple surface modification.
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Affiliation(s)
- Jinhwan Lee
- Department of Bioscience and Biotechnology, Konkuk University, Seoul 143-701, South Korea
| | - Jaekyun Im
- Department of Bioscience and Biotechnology, Konkuk University, Seoul 143-701, South Korea
| | - Sunghyun Kim
- Department of Bioscience and Biotechnology, Konkuk University, Seoul 143-701, South Korea.
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39
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Ruban AV, Johnson MP. Visualizing the dynamic structure of the plant photosynthetic membrane. NATURE PLANTS 2015; 1:15161. [PMID: 27251532 DOI: 10.1038/nplants.2015.161] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 09/29/2015] [Indexed: 05/28/2023]
Abstract
The chloroplast thylakoid membrane is the site for the initial steps of photosynthesis that convert solar energy into chemical energy, ultimately powering almost all life on earth. The heterogeneous distribution of protein complexes within the membrane gives rise to an intricate three-dimensional structure that is nonetheless extremely dynamic on a timescale of seconds to minutes. These dynamics form the basis for the regulation of photosynthesis, and therefore the adaptability of plants to different environments. High-resolution microscopy has in recent years begun to provide new insights into the structural dynamics underlying a number of regulatory processes such as membrane stacking, photosystem II repair, photoprotective energy dissipation, state transitions and alternative electron transfer. Here we provide an overview of the essentials of thylakoid membrane structure in plants, and consider how recent advances, using a range of microscopies, have substantially increased our knowledge of the thylakoid dynamic structure. We discuss both the successes and limitations of the currently available techniques and highlight newly emerging microscopic methods that promise to move the field beyond the current 'static' view of membrane organization based on frozen snapshots to a 'live' view of functional membranes imaged under native aqueous conditions at ambient temperature and responding dynamically to external stimuli.
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Affiliation(s)
- Alexander V Ruban
- School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
| | - Matthew P Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
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40
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Suorsa M, Rantala M, Mamedov F, Lespinasse M, Trotta A, Grieco M, Vuorio E, Tikkanen M, Järvi S, Aro EM. Light acclimation involves dynamic re-organization of the pigment-protein megacomplexes in non-appressed thylakoid domains. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 84:360-73. [PMID: 26332430 DOI: 10.1111/tpj.13004] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Revised: 08/20/2015] [Accepted: 08/24/2015] [Indexed: 05/24/2023]
Abstract
Thylakoid energy metabolism is crucial for plant growth, development and acclimation. Non-appressed thylakoids harbor several high molecular mass pigment-protein megacomplexes that have flexible compositions depending upon the environmental cues. This composition is important for dynamic energy balancing in photosystems (PS) I and II. We analysed the megacomplexes of Arabidopsis wild type (WT) plants and of several thylakoid regulatory mutants. The stn7 mutant, which is defective in phosphorylation of the light-harvesting complex (LHC) II, possessed a megacomplex composition that was strikingly different from that of the WT. Of the nine megacomplexes in total for the non-appressed thylakoids, the largest megacomplex in particular was less abundant in the stn7 mutant under standard growth conditions. This megacomplex contains both PSI and PSII and was recently shown to allow energy spillover between PSII and PSI (Nat. Commun., 6, 2015, 6675). The dynamics of the megacomplex composition was addressed by exposing plants to different light conditions prior to thylakoid isolation. The megacomplex pattern in the WT was highly dynamic. Under darkness or far red light it showed low levels of LHCII phosphorylation and resembled the stn7 pattern; under low light, which triggers LHCII phosphorylation, it resembled that of the tap38/pph1 phosphatase mutant. In contrast, solubilization of the entire thylakoid network with dodecyl maltoside, which efficiently solubilizes pigment-protein complexes from all thylakoid compartments, revealed that the pigment-protein composition remained stable despite the changing light conditions or mutations that affected LHCII (de)phosphorylation. We conclude that the composition of pigment-protein megacomplexes specifically in non-appressed thylakoids undergoes redox-dependent changes, thus facilitating maintenance of the excitation balance between the two photosystems upon changes in light conditions.
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Affiliation(s)
- Marjaana Suorsa
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Marjaana Rantala
- 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, 75120, Uppsala, Sweden
| | - Maija Lespinasse
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Andrea Trotta
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Michele Grieco
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Eerika Vuorio
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Mikko Tikkanen
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Sari Järvi
- 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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41
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Yin L, Vener AV, Spetea C. The membrane proteome of stroma thylakoids from Arabidopsis thaliana studied by successive in-solution and in-gel digestion. PHYSIOLOGIA PLANTARUM 2015; 154:433-446. [PMID: 25402197 DOI: 10.1111/ppl.12308] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 11/06/2014] [Accepted: 11/10/2014] [Indexed: 06/04/2023]
Abstract
From individual localization and large-scale proteomic studies, we know that stroma-exposed thylakoid membranes harbor part of the machinery performing the light-dependent photosynthetic reactions. The minor components of the stroma thylakoid proteome, regulating and maintaining the photosynthetic machinery, are in the process of being unraveled. In this study, we developed in-solution and in-gel proteolytic digestion methods, and used them to identify minor membrane proteins, e.g. transporters, in stroma thylakoids prepared from Arabidopsis thaliana (L.) Heynh Columbia-0 leaves. In-solution digestion with chymotrypsin yielded the largest number of peptides, but in combination with methanol extraction resulted in identification of the largest number of membrane proteins. Although less efficient in extracting peptides, in-gel digestion with trypsin and chymotrypsin led to identification of additional proteins. We identified a total of 58 proteins including 44 membrane proteins. Almost half are known thylakoid proteins with roles in photosynthetic light reactions, proteolysis and import. The other half, including many transporters, are not known as chloroplast proteins, because they have been either curated (manually assigned) to other cellular compartments or not curated at all at the plastid protein databases. Transporters include ATP-binding cassette (ABC) proteins, transporters for K(+) and other cations. Other proteins either have a role in processes probably linked to photosynthesis, namely translation, metabolism, stress and signaling or are contaminants. Our results indicate that all these proteins are present in stroma thylakoids; however, individual studies are required to validate their location and putative roles. This study also provides strategies complementary to traditional methods for identification of membrane proteins from other cellular compartments.
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Affiliation(s)
- Lan Yin
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, 405 30, Sweden
| | - Alexander V Vener
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, 581 85, Sweden
| | - Cornelia Spetea
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, 405 30, Sweden
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42
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Bell AJ, Frankel LK, Bricker TM. High Yield Non-detergent Isolation of Photosystem I-Light-harvesting Chlorophyll II Membranes from Spinach Thylakoids: IMPLICATIONS FOR THE ORGANIZATION OF THE PS I ANTENNAE IN HIGHER PLANTS. J Biol Chem 2015; 290:18429-37. [PMID: 26055710 DOI: 10.1074/jbc.m115.663872] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Indexed: 11/06/2022] Open
Abstract
Styrene-maleic acid copolymer was used to effect a non-detergent partial solubilization of thylakoids from spinach. A high density membrane fraction, which was not solubilized by the copolymer, was isolated and was highly enriched in the Photosystem (PS) I-light-harvesting chlorophyll (LHC) II supercomplex and depleted of PS II, the cytochrome b6/f complex, and ATP synthase. The LHC II associated with the supercomplex appeared to be energetically coupled to PS I based on 77 K fluorescence, P700 photooxidation, and PS I electron transport light saturation experiments. The chlorophyll (Chl) a/b ratio of the PS I-LHC II membranes was 3.2 ± 0.9, indicating that on average, three LHC II trimers may associate with each PS I. The implication of these findings within the context of higher plant PS I antenna organization is discussed.
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Affiliation(s)
- Adam J Bell
- From the Department of Biological Sciences, Biochemistry and Molecular Biology Section, Louisiana State University, Baton Rouge, Louisiana 70803
| | - Laurie K Frankel
- From the Department of Biological Sciences, Biochemistry and Molecular Biology Section, Louisiana State University, Baton Rouge, Louisiana 70803
| | - Terry M Bricker
- From the Department of Biological Sciences, Biochemistry and Molecular Biology Section, Louisiana State University, Baton Rouge, Louisiana 70803
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43
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Kim E, Ahn TK, Kumazaki S. Changes in Antenna Sizes of Photosystems during State Transitions in Granal and Stroma-Exposed Thylakoid Membrane of Intact Chloroplasts in Arabidopsis Mesophyll Protoplasts. ACTA ACUST UNITED AC 2015; 56:759-68. [DOI: 10.1093/pcp/pcv004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 01/13/2015] [Indexed: 11/13/2022]
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44
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Lee J, Kim S. Mediator-free solar energy conversion by the artificially installed thylakoid membrane on the functionalized electrode. Electrochem commun 2014. [DOI: 10.1016/j.elecom.2014.10.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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45
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Mokvist F, Mamedov F, Styring S. Defining the far-red limit of photosystem I: the primary charge separation is functional to 840 nm. J Biol Chem 2014; 289:24630-9. [PMID: 25023284 DOI: 10.1074/jbc.m114.555649] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The far-red limit of photosystem I (PS I) photochemistry was studied by EPR spectroscopy using laser flashes between 730 and 850 nm. In manganese-depleted spinach thylakoid membranes, the primary donor in PS I, P700, was oxidized simultaneously with tyrosine Z, the secondary donor in PS II. It was found that at 295 K PS I photochemistry, observed as P700 (+) formation, was functional up to 840 nm. This is 30 nm further to the red region than was reported for PS II photochemistry (Thapper, A., Mamedov, F., Mokvist, F., Hammarström, L., and Styring, S. (2009) Plant Cell 21, 2391-2401). The same far-red limit for the P700 (+) formation was observed in a PS I reaction center core preparation from Nostoc punctiforme. The reduction of the acceptor side of PS I, observed as reduction of the iron-sulfur centers FA and FB by low temperature EPR measurements, was also functional at 15 K with light up to >830 nm. Taken together, these results, obtained from both plants and cyanobacteria, most likely rule out involvement of the red-absorbing antenna chlorophylls in this reaction. Instead we propose the existence of weak charge transfer bands absorbing in the far-red region in the ensemble of excitonically coupled chlorophyll a molecules around P700 similar to what has been found in the reaction center of PS II. These charge transfer bands could be responsible for the far-red light absorption leading to PS I photochemistry at wavelengths up to 840 nm.
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Affiliation(s)
- Fredrik Mokvist
- From Molecular Biomimetics, Department of Chemistry-Ångström, Uppsala University, Ångström Laboratory, P. O. Box 523, S-751 20 Uppsala, Sweden
| | - Fikret Mamedov
- From Molecular Biomimetics, Department of Chemistry-Ångström, Uppsala University, Ångström Laboratory, P. O. Box 523, S-751 20 Uppsala, Sweden
| | - Stenbjörn Styring
- From Molecular Biomimetics, Department of Chemistry-Ångström, Uppsala University, Ångström Laboratory, P. O. Box 523, S-751 20 Uppsala, Sweden
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46
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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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47
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Mokvist F, Sjöholm J, Mamedov F, Styring S. The Photochemistry in Photosystem II at 5 K Is Different in Visible and Far-Red Light. Biochemistry 2014; 53:4228-38. [DOI: 10.1021/bi5006392] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Fredrik Mokvist
- Molecular Biomimetics, Department
of Chemistry-Ångström, Uppsala University, Ångström Laboratory, P.O. Box 523, S-751 20 Uppsala, Sweden
| | - Johannes Sjöholm
- Molecular Biomimetics, Department
of Chemistry-Ångström, Uppsala University, Ångström Laboratory, P.O. Box 523, S-751 20 Uppsala, Sweden
| | - Fikret Mamedov
- Molecular Biomimetics, Department
of Chemistry-Ångström, Uppsala University, Ångström Laboratory, P.O. Box 523, S-751 20 Uppsala, Sweden
| | - Stenbjörn Styring
- Molecular Biomimetics, Department
of Chemistry-Ångström, Uppsala University, Ångström Laboratory, P.O. Box 523, S-751 20 Uppsala, Sweden
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48
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Computer modeling of electron and proton transport in chloroplasts. Biosystems 2014; 121:1-21. [PMID: 24835748 DOI: 10.1016/j.biosystems.2014.04.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2014] [Revised: 04/27/2014] [Accepted: 04/28/2014] [Indexed: 11/21/2022]
Abstract
Photosynthesis is one of the most important biological processes in biosphere, which provides production of organic substances from atmospheric CO2 and water at expense of solar energy. In this review, we contemplate computer models of oxygenic photosynthesis in the context of feedback regulation of photosynthetic electron transport in chloroplasts, the energy-transducing organelles of the plant cell. We start with a brief overview of electron and proton transport processes in chloroplasts coupled to ATP synthesis and consider basic regulatory mechanisms of oxygenic photosynthesis. General approaches to computer simulation of photosynthetic processes are considered, including the random walk models of plastoquinone diffusion in thylakoid membranes and deterministic approach to modeling electron transport in chloroplasts based on the mass action law. Then we focus on a kinetic model of oxygenic photosynthesis that includes key stages of the linear electron transport, alternative pathways of electron transfer around photosystem I (PSI), transmembrane proton transport and ATP synthesis in chloroplasts. This model includes different regulatory processes: pH-dependent control of the intersystem electron transport, down-regulation of photosystem II (PSII) activity (non-photochemical quenching), the light-induced activation of the Bassham-Benson-Calvin (BBC) cycle. The model correctly describes pH-dependent feedback control of electron transport in chloroplasts and adequately reproduces a variety of experimental data on induction events observed under different experimental conditions in intact chloroplasts (variations of CO2 and O2 concentrations in atmosphere), including a complex kinetics of P700 (primary electron donor in PSI) photooxidation, CO2 consumption in the BBC cycle, and photorespiration. Finally, we describe diffusion-controlled photosynthetic processes in chloroplasts within the framework of the model that takes into account complex architecture of chloroplasts and lateral heterogeneity of lamellar system of thylakoids. The lateral profiles of pH in the thylakoid lumen and in the narrow gap between grana thylakoids have been calculated under different metabolic conditions. Analyzing topological aspects of diffusion-controlled stages of electron and proton transport in chloroplasts, we conclude that along with the NPQ mechanism of attenuation of PSII activity and deceleration of PQH2 oxidation by the cytochrome b6f complex caused by the lumen acidification, the intersystem electron transport may be down-regulated due to the light-induced alkalization of the narrow partition between adjacent thylakoids of grana. The computer models of electron and proton transport described in this article may be integrated as appropriate modules into a comprehensive model of oxygenic photosynthesis.
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Lazarova D, Popova A, Stanoeva D, Velitchkova M. Involvement of Reactive Oxygen Radicals in Photoinhibition of Primary Photosynthetic Reactions—Effect of Temperature and Oxygen Radical Scavengers. BIOTECHNOL BIOTEC EQ 2014. [DOI: 10.1080/13102818.2009.10818475] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Kauny J, Sétif P. NADPH fluorescence in the cyanobacterium Synechocystis sp. PCC 6803: a versatile probe for in vivo measurements of rates, yields and pools. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:792-801. [PMID: 24463053 DOI: 10.1016/j.bbabio.2014.01.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 01/10/2014] [Accepted: 01/13/2014] [Indexed: 10/25/2022]
Abstract
We measured the kinetics of light-induced NADPH formation and subsequent dark consumption by monitoring in vivo its fluorescence in the cyanobacterium Synechocystis PCC 6803. Spectral data allowed the signal changes to be attributed to NAD(P)H and signal linearity vs the chlorophyll concentration was shown to be recoverable after appropriate correction. Parameters associated to reduction of NADP(+) to NADPH by ferredoxin-NADP(+)-oxidoreductase were determined: After single excitation of photosystem I, half of the signal rise is observed in 8ms; Evidence for a kinetic limitation which is attributed to an enzyme bottleneck is provided; After two closely separated saturating flashes eliciting two photosystem I turnovers in less than 2ms, more than 50% of the cytoplasmic photoreductants (reduced ferredoxin and photosystem I acceptors) are diverted from NADPH formation by competing processes. Signal quantitation in absolute NADPH concentrations was performed by adding exogenous NADPH to the cell suspensions and by estimating the enhancement factor of in vivo fluorescence (between 2 and 4). The size of the visible (light-dependent) NADP (NADP(+)+NADPH) pool was measured to be between 1.4 and 4 times the photosystem I concentration. A quantitative discrepancy is found between net oxygen evolution and NADPH consumption by the light-activated Calvin-Benson cycle. The present study shows that NADPH fluorescence is an efficient probe for studying in vivo the energetic metabolism of cyanobacteria which can be used for assessing multiple phenomena occurring over different time scales.
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Affiliation(s)
- Jocelyn Kauny
- iBiTec-S, CNRS UMR 8221, CEA Saclay, 91191 Gif-sur-Yvette, France.
| | - Pierre Sétif
- iBiTec-S, CNRS UMR 8221, CEA Saclay, 91191 Gif-sur-Yvette, France.
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