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Akhtar P, Balog-Vig F, Han W, Li X, Han G, Shen JR, Lambrev PH. Quantifying the Energy Spillover between Photosystems II and I in Cyanobacterial Thylakoid Membranes and Cells. PLANT & CELL PHYSIOLOGY 2024; 65:95-106. [PMID: 37874689 DOI: 10.1093/pcp/pcad127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 10/09/2023] [Accepted: 10/14/2023] [Indexed: 10/26/2023]
Abstract
The spatial separation of photosystems I and II (PSI and PSII) is thought to be essential for efficient photosynthesis by maintaining a balanced flow of excitation energy between them. Unlike the thylakoid membranes of plant chloroplasts, cyanobacterial thylakoids do not form tightly appressed grana stacks that enforce strict lateral separation. The coexistence of the two photosystems provides a ground for spillover-excitation energy transfer from PSII to PSI. Spillover has been considered as a pathway of energy transfer from the phycobilisomes to PSI and may also play a role in state transitions as means to avoid overexcitation of PSII. Here, we demonstrate a significant degree of energy spillover from PSII to PSI in reconstituted membranes and isolated thylakoid membranes of Thermosynechococcus (Thermostichus) vulcanus and Synechocystis sp. PCC 6803 by steady-state and time-resolved fluorescence spectroscopy. The quantum yield of spillover in these systems was determined to be up to 40%. Spillover was also found in intact cells but to a considerably lower degree (20%) than in isolated thylakoid membranes. The findings support a model of coexistence of laterally separated microdomains of PSI and PSII in the cyanobacterial cells as well as domains where the two photosystems are energetically connected. The methodology presented here can be applied to probe spillover in other photosynthetic organisms.
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Affiliation(s)
- Parveen Akhtar
- Institute of Plant Biology, HUN-REN Biological Research Centre, Szeged, Temesvári krt. 62, Szeged 6726, Hungary
| | - Fanny Balog-Vig
- Institute of Plant Biology, HUN-REN Biological Research Centre, Szeged, Temesvári krt. 62, Szeged 6726, Hungary
| | - Wenhui Han
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Xingyue Li
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Guangye Han
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Jian-Ren Shen
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Research Institute for Interdisciplinary Science, Okayama University, Okayama, 700-8530 Japan
| | - Petar H Lambrev
- Institute of Plant Biology, HUN-REN Biological Research Centre, Szeged, Temesvári krt. 62, Szeged 6726, Hungary
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Lambreva MD, Akhtar P, Sipka G, Margonelli A, Lambrev PH. Fluorescence quenching in thylakoid membranes induced by single-walled carbon nanotubes. Photochem Photobiol Sci 2023:10.1007/s43630-023-00403-7. [PMID: 36935477 DOI: 10.1007/s43630-023-00403-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 02/28/2023] [Indexed: 03/21/2023]
Abstract
The distinct photochemical and electrochemical properties of single-walled carbon nanotubes (SWCNTs) boosted the research interest in nanomaterial utilization in different in vivo and in vitro photosynthetic biohybrid setups. Aiming to unravel the yet not fully understood energetic interactions between the nanotubes and photosynthetic pigment-protein assemblies in an aqueous milieu, we studied SWCNT effects on the photochemical reactions of isolated thylakoid membranes (TMs), Photosystem II (PSII)-enriched membrane fragments and light-harvesting complexes (LHCII). The SWCNTs induced quenching of the steady-state chlorophyll fluorescence in the TM-biohybrid systems with a corresponding shortening of the average fluorescence lifetimes. The effect was not related to changes in the integrity and macroorganization of the photosynthetic membranes. Moreover, we found no evidence for direct excitation energy exchange between the SWCNTs and pigment-protein complexes, since neither the steady-state nor time-resolved fluorescence of LHCII-biohybrid systems differed from the corresponding controls. The attenuation of the fluorescence signal in the TM-biohybrid systems indicates possible leakage of photosynthetic electrons toward the nanotubes that most probably occurs at the level of the PSII acceptor site. Although it is too early to speculate on the nature of the involved electron donors and intermediate states, the observed energetic interaction could be exploited to increase the photoelectron capture efficiency of natural biohybrid systems for solar energy conversion.
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Affiliation(s)
- Maya D Lambreva
- Institute for Biological Systems, National Research Council, Via Salaria Km 29.300, 00015, Monterotondo Stazione, Rome, Italy.
| | - Parveen Akhtar
- Institute of Plant Biology, Biological Research Centre, Temesvári Krt. 62, 6726, Szeged, Hungary
| | - Gábor Sipka
- Institute of Plant Biology, Biological Research Centre, Temesvári Krt. 62, 6726, Szeged, Hungary
| | - Andrea Margonelli
- Institute of Crystallography, National Research Council, Via Salaria Km 29.300, 00015, Monterotondo Stazione, Rome, Italy
| | - Petar H Lambrev
- Institute of Plant Biology, Biological Research Centre, Temesvári Krt. 62, 6726, Szeged, Hungary.
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Rantala M, Ivanauskaite A, Laihonen L, Kanna SD, Ughy B, Mulo P. Chloroplast Acetyltransferase GNAT2 is Involved in the Organization and Dynamics of Thylakoid Structure. PLANT & CELL PHYSIOLOGY 2022; 63:1205-1214. [PMID: 35792507 PMCID: PMC9474947 DOI: 10.1093/pcp/pcac096] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 06/29/2022] [Accepted: 07/05/2022] [Indexed: 05/28/2023]
Abstract
Higher plants acclimate to changes in light conditions by adjusting the thylakoid membrane ultrastructure. Additionally, excitation energy transfer between photosystem II (PSII) and photosystem I (PSI) is balanced in a process known as state transition. These modifications are mediated by reversible phosphorylation of Lhcb1 and Lhcb2 proteins in different pools of light-harvesting complex (LHCII) trimers. Our recent study demonstrated that chloroplast acetyltransferase NUCLEAR SHUTTLE INTERACTING (NSI)/GNAT2 (general control non-repressible 5 (GCN5)-related N-acetyltransferase 2) is also needed for the regulation of light harvesting, evidenced by the inability of the gnat2 mutant to perform state transitions although there are no defects in LHCII phosphorylation. Here, we show that despite contrasting phosphorylation states of LHCII, grana packing in the gnat2 and state transition 7 (stn7) mutants possesses similar features, as the thylakoid structure of the mutants does not respond to the shift from darkness to light, which is in striking contrast to wild type (Wt). Circular dichroism and native polyacrylamide gel electrophoresis analyses further revealed that the thylakoid protein complex organization of gnat2 and stn7 resembles each other, but differ from that of Wt. Also, the location of the phosphorylated Lhcb2 as well as the LHCII antenna within the thylakoid network in gnat2 mutant is different from that of Wt. In gnat2, the LHCII antenna remains largely in grana stacks, where the phosphorylated Lhcb2 is found in all LHCII trimer pools, including those associated with PSII. These results indicate that in addition to phosphorylation-mediated regulation through STN7, the GNAT2 enzyme is involved in the organization and dynamics of thylakoid structure, probably through the regulation of chloroplast protein acetylation.
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Affiliation(s)
- Marjaana Rantala
- Molecular Plant Biology, University of Turku, BioCity A, Tykistökatu 6, Turku, FI-20520, Finland
| | - Aiste Ivanauskaite
- Molecular Plant Biology, University of Turku, BioCity A, Tykistökatu 6, Turku, FI-20520, Finland
| | - Laura Laihonen
- Molecular Plant Biology, University of Turku, BioCity A, Tykistökatu 6, Turku, FI-20520, Finland
| | - Sai Divya Kanna
- Institute of Plant Biology, Biological Research Centre, Eötvös Loránd Research Network, Szeged H-6726, Hungary
- Doctoral School of Biology, University of Szeged, Szeged H-6726, Hungary
| | - Bettina Ughy
- Institute of Plant Biology, Biological Research Centre, Eötvös Loránd Research Network, Szeged H-6726, Hungary
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Patty CL, Pommerol A, Kühn JG, Demory BO, Thomas N. Directional Aspects of Vegetation Linear and Circular Polarization Biosignatures. ASTROBIOLOGY 2022; 22:1034-1046. [PMID: 35984943 PMCID: PMC9508456 DOI: 10.1089/ast.2021.0156] [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: 09/27/2021] [Accepted: 03/12/2022] [Indexed: 06/15/2023]
Abstract
Homochirality is a generic and unique property of all biochemical life and it is considered a universal and agnostic biosignature. Upon interaction with unpolarized light, homochirality induces fractional circular polarization in the light that is scattered from it, which can be sensed remotely. As such, it can be a prime candidate biosignature in the context of future life detection missions and observatories. The linear polarizance of vegetation is also sometimes envisaged as a biosignature, although it does not share the same molecular origin as circular polarization. It is known that linear polarization of surfaces is strongly dependent on the phase angle. The relationship between the phase angle and circular polarization stemming from macromolecular assemblies such as in vegetation, however, remained unclear. In this study, using the average of 27 different species, we demonstrate that the circular polarization-phase angle dependency of vegetation induces relatively small changes in spectral shape and mostly affects the signal magnitude. With these results, we underline the use of circular spectropolarimetry as a promising agnostic biosignature complementary to the use of linear spectropolarimetry and scalar reflectance.
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Affiliation(s)
- C.H. Lucas Patty
- Weltraumforschung und Planetologie (WP), Physikalisches Institut and Universität Bern, Bern, Switzerland
| | - Antoine Pommerol
- Weltraumforschung und Planetologie (WP), Physikalisches Institut and Universität Bern, Bern, Switzerland
| | - Jonas G. Kühn
- Center for Space and Habitability, Universität Bern, Bern, Switzerland
- Département d'Astronomie, Université de Genève, Versoix, Switzerland
| | | | - Nicolas Thomas
- Weltraumforschung und Planetologie (WP), Physikalisches Institut and Universität Bern, Bern, Switzerland
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Structural Entities Associated with Different Lipid Phases of Plant Thylakoid Membranes—Selective Susceptibilities to Different Lipases and Proteases. Cells 2022; 11:cells11172681. [PMID: 36078087 PMCID: PMC9454902 DOI: 10.3390/cells11172681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 08/21/2022] [Accepted: 08/25/2022] [Indexed: 11/21/2022] Open
Abstract
It is well established that plant thylakoid membranes (TMs), in addition to a bilayer, contain two isotropic lipid phases and an inverted hexagonal (HII) phase. To elucidate the origin of non-bilayer lipid phases, we recorded the 31P-NMR spectra of isolated spinach plastoglobuli and TMs and tested their susceptibilities to lipases and proteases; the structural and functional characteristics of TMs were monitored using biophysical techniques and CN-PAGE. Phospholipase-A1 gradually destroyed all 31P-NMR-detectable lipid phases of isolated TMs, but the weak signal of isolated plastoglobuli was not affected. Parallel with the destabilization of their lamellar phase, TMs lost their impermeability; other effects, mainly on Photosystem-II, lagged behind the destruction of the original phases. Wheat-germ lipase selectively eliminated the isotropic phases but exerted little or no effect on the structural and functional parameters of TMs—indicating that the isotropic phases are located outside the protein-rich regions and might be involved in membrane fusion. Trypsin and Proteinase K selectively suppressed the HII phase—suggesting that a large fraction of TM lipids encapsulate stroma-side proteins or polypeptides. We conclude that—in line with the Dynamic Exchange Model—the non-bilayer lipid phases of TMs are found in subdomains separated from but interconnected with the bilayer accommodating the main components of the photosynthetic machinery.
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Arshad R, Saccon F, Bag P, Biswas A, Calvaruso C, Bhatti AF, Grebe S, Mascoli V, Mahbub M, Muzzopappa F, Polyzois A, Schiphorst C, Sorrentino M, Streckaité S, van Amerongen H, Aro EM, Bassi R, Boekema EJ, Croce R, Dekker J, van Grondelle R, Jansson S, Kirilovsky D, Kouřil R, Michel S, Mullineaux CW, Panzarová K, Robert B, Ruban AV, van Stokkum I, Wientjes E, Büchel C. A kaleidoscope of photosynthetic antenna proteins and their emerging roles. PLANT PHYSIOLOGY 2022; 189:1204-1219. [PMID: 35512089 PMCID: PMC9237682 DOI: 10.1093/plphys/kiac175] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 03/17/2022] [Indexed: 05/17/2023]
Abstract
Photosynthetic light-harvesting antennae are pigment-binding proteins that perform one of the most fundamental tasks on Earth, capturing light and transferring energy that enables life in our biosphere. Adaptation to different light environments led to the evolution of an astonishing diversity of light-harvesting systems. At the same time, several strategies have been developed to optimize the light energy input into photosynthetic membranes in response to fluctuating conditions. The basic feature of these prompt responses is the dynamic nature of antenna complexes, whose function readily adapts to the light available. High-resolution microscopy and spectroscopic studies on membrane dynamics demonstrate the crosstalk between antennae and other thylakoid membrane components. With the increased understanding of light-harvesting mechanisms and their regulation, efforts are focusing on the development of sustainable processes for effective conversion of sunlight into functional bio-products. The major challenge in this approach lies in the application of fundamental discoveries in light-harvesting systems for the improvement of plant or algal photosynthesis. Here, we underline some of the latest fundamental discoveries on the molecular mechanisms and regulation of light harvesting that can potentially be exploited for the optimization of photosynthesis.
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Affiliation(s)
- Rameez Arshad
- Department of Biophysics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Olomouc 783 71, Czech Republic
- Electron Microscopy Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen 9747 AG, The Netherlands
| | - Francesco Saccon
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Pushan Bag
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå 901 87, Sweden
| | - Avratanu Biswas
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - Claudio Calvaruso
- Institute for Molecular Biosciences, Goethe University of Frankfurt, Frankfurt 60438, Germany
| | - Ahmad Farhan Bhatti
- Laboratory of Biophysics, Wageningen University, Wageningen, the Netherlands
| | - Steffen Grebe
- Department of Life Technologies, MolecularPlant Biology, University of Turku, Turku FI–20520, Finland
| | - Vincenzo Mascoli
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - Moontaha Mahbub
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
- Department of Botany, Jagannath University, Dhaka 1100, Bangladesh
| | - Fernando Muzzopappa
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif sur Yvette 1198, France
| | - Alexandros Polyzois
- Université de Paris, Faculté de Pharmacie de Paris, CiTCoM UMR 8038 CNRS, Paris 75006, France
| | | | - Mirella Sorrentino
- Photon Systems Instruments, spol. s.r.o., Drásov, Czech Republic
- Department of Agricultural Sciences, University of Naples Federico II, Naples 80138, Italy
| | - Simona Streckaité
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif sur Yvette 1198, France
| | | | - Eva-Mari Aro
- Department of Life Technologies, MolecularPlant Biology, University of Turku, Turku FI–20520, Finland
| | - Roberto Bassi
- Dipartimento di Biotecnologie, Università di Verona, Verona, Italy
| | - Egbert J Boekema
- Electron Microscopy Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen 9747 AG, The Netherlands
| | - Roberta Croce
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - Jan Dekker
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - Rienk van Grondelle
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - Stefan Jansson
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå 901 87, Sweden
| | - Diana Kirilovsky
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif sur Yvette 1198, France
| | - Roman Kouřil
- Department of Biophysics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Olomouc 783 71, Czech Republic
| | - Sylvie Michel
- Université de Paris, Faculté de Pharmacie de Paris, CiTCoM UMR 8038 CNRS, Paris 75006, France
| | - Conrad W Mullineaux
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Klára Panzarová
- Photon Systems Instruments, spol. s.r.o., Drásov, Czech Republic
| | - Bruno Robert
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif sur Yvette 1198, France
| | - Alexander V Ruban
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Ivo van Stokkum
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - Emilie Wientjes
- Laboratory of Biophysics, Wageningen University, Wageningen, the Netherlands
| | - Claudia Büchel
- Institute for Molecular Biosciences, Goethe University of Frankfurt, Frankfurt 60438, Germany
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Structural and functional roles of non-bilayer lipid phases of chloroplast thylakoid membranes and mitochondrial inner membranes. Prog Lipid Res 2022; 86:101163. [DOI: 10.1016/j.plipres.2022.101163] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 03/23/2022] [Accepted: 03/23/2022] [Indexed: 12/11/2022]
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Golub M, Lokstein H, Soloviov D, Kuklin A, Wieland DCF, Pieper J. Light-Harvesting Complex II Adopts Different Quaternary Structures in Solution as Observed Using Small-Angle Scattering. J Phys Chem Lett 2022; 13:1258-1265. [PMID: 35089716 DOI: 10.1021/acs.jpclett.1c03614] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The high-resolution crystal structure of the trimeric major light-harvesting complex of photosystem II (LHCII) is often perceived as the basis for understanding its light-harvesting and photoprotective functions. However, the LHCII solution structure and its oligomerization or aggregation state may generally differ from the crystal structure and, moreover, also depend on its functional state. In this regard, small-angle scattering experiments provide the missing link by offering structural information in aqueous solution at physiological temperatures. Herein, we use small-angle scattering to investigate the solution structures of two different preparations of solubilized LHCII employing the nonionic detergents n-octyl-β-d-glucoside (OG) and n-dodecyl-β-D-maltoside (β-DM). The data reveal that the LHCII-OG complex is equivalent to the trimeric crystal structure. Remarkably, however, we observe─for the first time─a stable oligomer composed of three LHCII trimers in the case of the LHCII-β-DM preparation, implying additional pigment-pigment interactions. The latter complex is assumed to mimic trimer-trimer interactions which play an important role in the context of photoprotective nonphotochemical quenching.
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Affiliation(s)
- Maksym Golub
- Institute of Physics, University of Tartu, Wilhelm Ostwald str. 1, 50411 Tartu, Estonia
| | - Heiko Lokstein
- Department of Chemical Physics and Optics, Charles University, Ke Karlovu 3, 121 16 Prague, Czech Republic
| | - Dmytro Soloviov
- Joint Institute for Nuclear Research, Joliot-Curie str. 6, 141980 Dubna, Russia
- Moscow Institute of Physics and Technology, Institutskiy per. 9, 141701 Dolgoprudny, Russia
- Institute for Safety Problems of Nuclear Power Plants NAS of Ukraine, Lysogirska str. 12, 03028 Kyiv, Ukraine
| | - Alexander Kuklin
- Joint Institute for Nuclear Research, Joliot-Curie str. 6, 141980 Dubna, Russia
- Moscow Institute of Physics and Technology, Institutskiy per. 9, 141701 Dolgoprudny, Russia
| | - D C Florian Wieland
- Helmholtz Zentrum Geesthacht, Institute for Materials Research, Department for Metallic Biomaterials, 21502 Geesthacht, Germany
| | - Jörg Pieper
- Institute of Physics, University of Tartu, Wilhelm Ostwald str. 1, 50411 Tartu, Estonia
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Kanna SD, Domonkos I, Kóbori TO, Dergez Á, Böde K, Nagyapáti S, Zsiros O, Ünnep R, Nagy G, Garab G, Szilák L, Solymosi K, Kovács L, Ughy B. Salt Stress Induces Paramylon Accumulation and Fine-Tuning of the Macro-Organization of Thylakoid Membranes in Euglena gracilis Cells. FRONTIERS IN PLANT SCIENCE 2021; 12:725699. [PMID: 34868111 PMCID: PMC8636990 DOI: 10.3389/fpls.2021.725699] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 09/28/2021] [Indexed: 05/13/2023]
Abstract
The effects of salt stress condition on the growth, morphology, photosynthetic performance, and paramylon content were examined in the mixotrophic, unicellular, flagellate Euglena gracilis. We found that salt stress negatively influenced cell growth, accompanied by a decrease in chlorophyll (Chl) content. Circular dichroism (CD) spectroscopy revealed the changes in the macro-organization of pigment-protein complexes due to salt treatment, while the small-angle neutron scattering (SANS) investigations suggested a reduction in the thylakoid stacking, an effect confirmed by the transmission electron microscopy (TEM). At the same time, the analysis of the thylakoid membrane complexes using native-polyacrylamide gel electrophoresis (PAGE) revealed no significant change in the composition of supercomplexes of the photosynthetic apparatus. Salt stress did not substantially affect the photosynthetic activity, as reflected by the fact that Chl fluorescence yield, electron transport rate (ETR), and energy transfer between the photosystems did not change considerably in the salt-grown cells. We have observed notable increases in the carotenoid-to-Chl ratio and the accumulation of paramylon in the salt-treated cells. We propose that the accumulation of storage polysaccharides and changes in the pigment composition and thylakoid membrane organization help the adaptation of E. gracilis cells to salt stress and contribute to the maintenance of cellular processes under stress conditions.
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Affiliation(s)
- Sai Divya Kanna
- Institute of Plant Biology, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
- Doctoral School of Biology, University of Szeged, Szeged, Hungary
| | - Ildikó Domonkos
- Institute of Plant Biology, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
| | - Tímea Ottília Kóbori
- Doctoral School of Biology, University of Szeged, Szeged, Hungary
- Division for Biotechnology, Bay Zoltán Nonprofit Ltd. for Applied Research, Szeged, Hungary
| | - Ágnes Dergez
- Division for Biotechnology, Bay Zoltán Nonprofit Ltd. for Applied Research, Szeged, Hungary
| | - Kinga Böde
- Institute of Plant Biology, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
- Doctoral School of Biology, University of Szeged, Szeged, Hungary
| | - Sarolta Nagyapáti
- Institute of Plant Biology, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
- Doctoral School of Biology, University of Szeged, Szeged, Hungary
| | - Ottó Zsiros
- Institute of Plant Biology, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
| | - Renáta Ünnep
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Eötvös Loránd Research Network, Budapest, Hungary
| | - Gergely Nagy
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Eötvös Loránd Research Network, Budapest, Hungary
- European Spallation Source ESS ERIC, Lund, Sweden
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen PSI, Villigen, Switzerland
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Gyözö Garab
- Institute of Plant Biology, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
- Faculty of Science, University of Ostrava, Ostrava, Czechia
| | | | - Katalin Solymosi
- Department of Plant Anatomy, ELTE Eötvös Loránd University, Budapest, Hungary
| | - László Kovács
- Institute of Plant Biology, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
| | - Bettina Ughy
- Institute of Plant Biology, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
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10
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Mazur R, Mostowska A, Kowalewska Ł. How to Measure Grana - Ultrastructural Features of Thylakoid Membranes of Plant Chloroplasts. FRONTIERS IN PLANT SCIENCE 2021; 12:756009. [PMID: 34691132 PMCID: PMC8527009 DOI: 10.3389/fpls.2021.756009] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 09/09/2021] [Indexed: 06/11/2023]
Abstract
Granum is a basic structural unit of the thylakoid membrane network of plant chloroplasts. It is composed of multiple flattened membranes forming a stacked arrangement of a cylindrical shape. Grana membranes are composed of lipids and tightly packed pigment-protein complexes whose primary role is the catalysis of photosynthetic light reactions. These membranes are highly dynamic structures capable of adapting to changing environmental conditions by fine-tuning photochemical efficiency, manifested by the structural reorganization of grana stacks. Due to a nanometer length scale of the structural granum features, the application of high-resolution electron microscopic techniques is essential for a detailed analysis of the granum architecture. This mini-review overviews recent approaches to quantitative grana structure analyses from electron microscopy data, highlighting the basic manual measurements and semi-automated workflows. We outline and define structural parameters used by different authors, for instance, granum height and diameter, thylakoid thickness, end-membrane length, Stacking Repeat Distance, and Granum Lateral Irregularity. This article also presents insights into efficient and effective measurements of grana stacks visualized on 2D micrographs. The information on how to correctly interpret obtained data, taking into account the 3D nature of grana stacks projected onto 2D space of electron micrograph, is also given. Grana ultrastructural observations reveal key features of this intriguing membrane arrangement, broadening our knowledge of the thylakoid network's remarkable plasticity.
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Affiliation(s)
- Radosław Mazur
- Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Agnieszka Mostowska
- Department of Plant Anatomy and Cytology, Institute of Plant Experimental Biology and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Łucja Kowalewska
- Department of Plant Anatomy and Cytology, Institute of Plant Experimental Biology and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
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11
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Karlický V, Kmecová Materová Z, Kurasová I, Nezval J, Štroch M, Garab G, Špunda V. Accumulation of geranylgeranylated chlorophylls in the pigment-protein complexes of Arabidopsis thaliana acclimated to green light: effects on the organization of light-harvesting complex II and photosystem II functions. PHOTOSYNTHESIS RESEARCH 2021; 149:233-252. [PMID: 33948813 PMCID: PMC8382614 DOI: 10.1007/s11120-021-00827-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 02/19/2021] [Indexed: 06/12/2023]
Abstract
Light quality significantly influences plant metabolism, growth and development. Recently, we have demonstrated that leaves of barley and other plant species grown under monochromatic green light (500-590 nm) accumulated a large pool of chlorophyll a (Chl a) intermediates with incomplete hydrogenation of their phytyl chains. In this work, we studied accumulation of these geranylgeranylated Chls a and b in pigment-protein complexes (PPCs) of Arabidopsis plants acclimated to green light and their structural-functional consequences on the photosynthetic apparatus. We found that geranylgeranylated Chls are present in all major PPCs, although their presence was more pronounced in light-harvesting complex II (LHCII) and less prominent in supercomplexes of photosystem II (PSII). Accumulation of geranylgeranylated Chls hampered the formation of PSII and PSI super- and megacomplexes in the thylakoid membranes as well as their assembly into chiral macrodomains; it also lowered the temperature stability of the PPCs, especially that of LHCII trimers, which led to their monomerization and an anomaly in the photoprotective mechanism of non-photochemical quenching. Role of geranylgeranylated Chls in adverse effects on photosynthetic apparatus of plants acclimated to green light is discussed.
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Affiliation(s)
- Václav Karlický
- Department of Physics, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00, Ostrava, Czech Republic.
- Global Change Research Institute, Czech Academy of Sciences, Bělidla 986/4a, 603 00, Brno, Czech Republic.
| | - Zuzana Kmecová Materová
- Department of Physics, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00, Ostrava, Czech Republic
| | - Irena Kurasová
- Department of Physics, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00, Ostrava, Czech Republic
- Global Change Research Institute, Czech Academy of Sciences, Bělidla 986/4a, 603 00, Brno, Czech Republic
| | - Jakub Nezval
- Department of Physics, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00, Ostrava, Czech Republic
| | - Michal Štroch
- Department of Physics, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00, Ostrava, Czech Republic
- Global Change Research Institute, Czech Academy of Sciences, Bělidla 986/4a, 603 00, Brno, Czech Republic
| | - Győző Garab
- Department of Physics, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00, Ostrava, Czech Republic.
- Biological Research Center, Institute of Plant Biology, Temesvári körút 62, 6726, Szeged, Hungary.
| | - Vladimír Špunda
- Department of Physics, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00, Ostrava, Czech Republic.
- Global Change Research Institute, Czech Academy of Sciences, Bělidla 986/4a, 603 00, Brno, Czech Republic.
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12
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Korotych OI, Nguyen TT, Reagan BC, Burch-Smith TM, Bruce BD. Poly(styrene-co-maleic acid)-mediated isolation of supramolecular membrane protein complexes from plant thylakoids. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2021; 1862:148347. [PMID: 33253667 DOI: 10.1016/j.bbabio.2020.148347] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 11/09/2020] [Accepted: 11/21/2020] [Indexed: 12/25/2022]
Abstract
Derivatives of poly(styrene-co-maleic acid) (pSMA), have recently emerged as effective reagents for extracting membrane protein complexes from biological membranes. Despite recent progress in using SMAs to study artificial and bacterial membranes, very few reports have addressed their use in studying the highly abundant and well characterized thylakoid membranes. Recently, we tested the ability of twelve commercially available SMA copolymers with different physicochemical properties to extract membrane protein complexes (MPCs) from spinach thylakoid membrane. Based on the efficacy of both protein and chlorophyll extraction, we have found five highly efficient SMA copolymers: SMA® 1440, XIRAN® 25010, XIRAN® 30010, SMA® 17352, and SMA® PRO 10235, that show promise in extracting MPCs from chloroplast thylakoids. To further advance the application of these polymers for studying biomembrane organization, we have examined the composition of thylakoid supramolecular protein complexes extracted by the five SMA polymers mentioned above. Two commonly studied plants, spinach (Spinacia oleracea) and pea (Pisum sativum), were used for extraction as model biomembranes. We found that the pSMAs differentially extract protein complexes from spinach and pea thylakoids. Based on their differential activity, which correlates with the polymer chemical structure, pSMAs can be divided into two groups: unfunctionalized polymers and ester derivatives.
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Affiliation(s)
- Olena I Korotych
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee at Knoxville, TN 37996, United States of America
| | - Thao T Nguyen
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee at Knoxville, TN 37996, United States of America
| | - Brandon C Reagan
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee at Knoxville, TN 37996, United States of America
| | - Tessa M Burch-Smith
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee at Knoxville, TN 37996, United States of America
| | - Barry D Bruce
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee at Knoxville, TN 37996, United States of America; Department of Chemical and Biomolecular Engineering, University of Tennessee at Knoxville, TN 37996, United States of America.
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13
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Yu L, Fan J, Zhou C, Xu C. Chloroplast lipid biosynthesis is fine-tuned to thylakoid membrane remodeling during light acclimation. PLANT PHYSIOLOGY 2021; 185:94-107. [PMID: 33631801 PMCID: PMC8133659 DOI: 10.1093/plphys/kiaa013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 10/21/2020] [Indexed: 05/29/2023]
Abstract
Reprogramming metabolism, in addition to modifying the structure and function of the photosynthetic machinery, is crucial for plant acclimation to changing light conditions. One of the key acclimatory responses involves reorganization of the photosynthetic membrane system including changes in thylakoid stacking. Glycerolipids are the main structural component of thylakoids and their synthesis involves two main pathways localized in the plastid and the endoplasmic reticulum (ER); however, the role of lipid metabolism in light acclimation remains poorly understood. We found that fatty acid synthesis, membrane lipid content, the plastid lipid biosynthetic pathway activity, and the degree of thylakoid stacking were significantly higher in plants grown under low light compared with plants grown under normal light. Plants grown under high light, on the other hand, showed a lower rate of fatty acid synthesis, a higher fatty acid flux through the ER pathway, higher triacylglycerol content, and thylakoid membrane unstacking. We additionally demonstrated that changes in rates of fatty acid synthesis under different growth light conditions are due to post-translational regulation of the plastidic acetyl-CoA carboxylase activity. Furthermore, Arabidopsis mutants defective in one of the two glycerolipid biosynthetic pathways displayed altered growth patterns and a severely reduced ability to remodel thylakoid architecture, particularly under high light. Overall, this study reveals how plants fine-tune fatty acid and glycerolipid biosynthesis to cellular metabolic needs in response to long-term changes in light conditions, highlighting the importance of lipid metabolism in light acclimation.
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Affiliation(s)
- Linhui Yu
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Jilian Fan
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Chao Zhou
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Changcheng Xu
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973, USA
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14
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Nami F, Tian L, Huber M, Croce R, Pandit A. Lipid and protein dynamics of stacked and cation-depletion induced unstacked thylakoid membranes. BBA ADVANCES 2021; 1:100015. [PMID: 37082020 PMCID: PMC10074959 DOI: 10.1016/j.bbadva.2021.100015] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Chloroplast thylakoid membranes in plants and green algae form 3D architectures of stacked granal membranes interconnected by unstacked stroma lamellae. They undergo dynamic structural changes as a response to changing light conditions that involve grana unstacking and lateral supramolecular reorganization of the integral membrane protein complexes. We assessed the dynamics of thylakoid membrane components and addressed how they are affected by thylakoid unstacking, which has consequences for protein mobility and the diffusion of small electron carriers. By a combined nuclear and electron paramagnetic-resonance approach the dynamics of thylakoid lipids was assessed in stacked and cation-depletion induced unstacked thylakoids of Chlamydomonas (C.) reinhardtii. We could distinguish between structural, bulk and annular lipids and determine membrane fluidity at two membrane depths: close to the lipid headgroups and in the lipid bilayer center. Thylakoid unstacking significantly increased the dynamics of bulk and annular lipids in both areas and increased the dynamics of protein helices. The unstacking process was associated with membrane reorganization and loss of long-range ordered Photosystem II- Light-Harvesting Complex II (PSII-LHCII) complexes. The fluorescence lifetime characteristics associated with membrane unstacking are similar to those associated with state transitions in intact C. reinhardtii cells. Our findings could be relevant for understanding the structural and functional implications of thylakoid unstacking that is suggested to take place during several light-induced processes, such as state transitions, photoacclimation, photoinhibition and PSII repair.
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Affiliation(s)
- Faezeh Nami
- Institute of Chemistry, Leiden University, 2333 CC, Leiden, The Netherlands
| | - Lijin Tian
- Institute of Chemistry, Leiden University, 2333 CC, Leiden, The Netherlands
| | - Martina Huber
- Department of Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, 2300 RA, Leiden, The Netherlands
| | - Roberta Croce
- Department of Physics and Astronomy, VU University Amsterdam, 1081 HV, Amsterdam, The Netherlands
| | - Anjali Pandit
- Institute of Chemistry, Leiden University, 2333 CC, Leiden, The Netherlands
- Corresponding author:
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15
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Ünnep R, Paul S, Zsiros O, Kovács L, Székely NK, Steinbach G, Appavou MS, Porcar L, Holzwarth AR, Garab G, Nagy G. Thylakoid membrane reorganizations revealed by small-angle neutron scattering of Monstera deliciosa leaves associated with non-photochemical quenching. Open Biol 2020; 10:200144. [PMID: 32931722 PMCID: PMC7536078 DOI: 10.1098/rsob.200144] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 08/14/2020] [Indexed: 12/14/2022] Open
Abstract
Non-photochemical quenching (NPQ) is an important photoprotective mechanism in plants and algae. Although the process is extensively studied, little is known about its relationship with ultrastructural changes of the thylakoid membranes. In order to better understand this relationship, we studied the effects of illumination on the organization of thylakoid membranes in Monstera deliciosa leaves. This evergreen species is known to exhibit very large NPQ and to possess giant grana with dozens of stacked thylakoids. It is thus ideally suited for small-angle neutron scattering measurements (SANS)-a non-invasive technique, which is capable of providing spatially and statistically averaged information on the periodicity of the thylakoid membranes and their rapid reorganizations in vivo. We show that NPQ-inducing illumination causes a strong decrease in the periodic order of granum thylakoid membranes. Development of NPQ and light-induced ultrastructural changes, as well as the relaxation processes, follow similar kinetic patterns. Surprisingly, whereas NPQ is suppressed by diuron, it impedes only the relaxation of the structural changes and not its formation, suggesting that structural changes do not cause but enable NPQ. We also demonstrate that the diminishment of SANS peak does not originate from light-induced redistribution and reorientation of chloroplasts inside the cells.
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Affiliation(s)
- Renáta Ünnep
- Neutron Spectroscopy Department, Centre for Energy Research, H-1121 Budapest, Konkoly-Thege Miklós út 29-33, Hungary
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Suman Paul
- Max-Planck-Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim a.d. Ruhr, Germany
| | - Ottó Zsiros
- Biological Research Centre, Institute of Plant Biology, 6726 Szeged, Hungary
| | - László Kovács
- Biological Research Centre, Institute of Plant Biology, 6726 Szeged, Hungary
| | - Noémi K. Székely
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at MLZ, 85748 Garching, Germany
| | - Gábor Steinbach
- Biological Research Centre, Institute of Biophysics, Temesvári körút 62, 6726 Szeged, Hungary
| | - Marie-Sousai Appavou
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at MLZ, 85748 Garching, Germany
| | - Lionel Porcar
- Institut Laue-Langevin, BP 156, 38042 Grenoble Cedex 9, France
| | - Alfred R. Holzwarth
- Max-Planck-Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim a.d. Ruhr, Germany
| | - Győző Garab
- Biological Research Centre, Institute of Plant Biology, 6726 Szeged, Hungary
- Department of Physics, Faculty of Science, Ostrava University, Chittussiho 10, 710 00 Ostrava, Czech Republic
| | - Gergely Nagy
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- European Spallation Source ESS ERIC, PO Box 176, 221 00 Lund, Sweden
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, 1121 Budapest, Hungary
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16
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Wilhelm C, Goss R, Garab G. The fluid-mosaic membrane theory in the context of photosynthetic membranes: Is the thylakoid membrane more like a mixed crystal or like a fluid? JOURNAL OF PLANT PHYSIOLOGY 2020; 252:153246. [PMID: 32777580 DOI: 10.1016/j.jplph.2020.153246] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/14/2020] [Accepted: 07/17/2020] [Indexed: 06/11/2023]
Abstract
Since the publication of the fluid-mosaic membrane theory by Singer and Nicolson in 1972 generations of scientists have adopted this fascinating concept for all biological membranes. Assuming the membrane as a fluid implies that the components embedded in the lipid bilayer can freely diffuse like swimmers in a water body. During the detailed biochemical analysis of the thylakoid protein components of chloroplasts from higher plants and algae, in the '80 s and '90 s it became clear that photosynthetic membranes are not homogeneous either in the vertical or the lateral directions. The lateral heterogeneity became obvious by the differentiation of grana and stroma thylakoids, but also the margins have been identified with a highly specific protein pattern. Further refinement of the fluid mosaic model was needed to take into account the presence of non-bilayer lipids, which are the most abundant lipids in all energy-converting membranes, and the polymorphism of lipid phases, which has also been documented in thylakoid membranes. These observations lead to the question, how mobile the components are in the lipid phase and how this ordering is made and maintained and how these features might be correlated with the non-bilayer propensity of the membrane lipids. Assuming instead of free diffusion, a "controlled neighborhood" replaced the model of fluidity by the model of a "mixed crystal structure". In this review we describe why basic photosynthetic regulation mechanisms depend on arrays of crystal-like lipid-protein macro-assemblies. The mechanisms which define the ordering in macrodomains are still not completely clear, but some recent experiments give an idea how this fascinating order is produced, adopted and maintained. We use the operation of the xanthophyll cycle as a rather well understood model challenging and complementing the standard Singer-Nicolson model via assigning special roles to non-bilayer lipids and non-lamellar lipid phases in the structure and function of thylakoid membranes.
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Affiliation(s)
- Christian Wilhelm
- Leipzig University, Institute of Biology, SenProf Algal Biotechnology, Permoserstr. 15, 04315, Leipzig, Germany; German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, D-04103, Leipzig, Germany.
| | - Reimund Goss
- Leipzig University, Institute of Biology, Department of Plant Physiology, Johannisallee 21-23, D-04103, Leipzig, Germany
| | - Gyözö Garab
- Biological Research Centre, Institute of Plant Biology, Temesvári körút 62, H-6726, Szeged, Hungary; University of Ostrava, Department of Physics, Faculty of Science, Chittussiho 10, CZ-710 00, Ostrava, Slezská Ostrava, Czech Republic
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17
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Dlouhý O, Kurasová I, Karlický V, Javornik U, Šket P, Petrova NZ, Krumova SB, Plavec J, Ughy B, Špunda V, Garab G. Modulation of non-bilayer lipid phases and the structure and functions of thylakoid membranes: effects on the water-soluble enzyme violaxanthin de-epoxidase. Sci Rep 2020; 10:11959. [PMID: 32686730 PMCID: PMC7371714 DOI: 10.1038/s41598-020-68854-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 06/26/2020] [Indexed: 12/19/2022] Open
Abstract
The role of non-bilayer lipids and non-lamellar lipid phases in biological membranes is an enigmatic problem of membrane biology. Non-bilayer lipids are present in large amounts in all membranes; in energy-converting membranes they constitute about half of their total lipid content—yet their functional state is a bilayer. In vitro experiments revealed that the functioning of the water-soluble violaxanthin de-epoxidase (VDE) enzyme of plant thylakoids requires the presence of a non-bilayer lipid phase. 31P-NMR spectroscopy has provided evidence on lipid polymorphism in functional thylakoid membranes. Here we reveal reversible pH- and temperature-dependent changes of the lipid-phase behaviour, particularly the flexibility of isotropic non-lamellar phases, of isolated spinach thylakoids. These reorganizations are accompanied by changes in the permeability and thermodynamic parameters of the membranes and appear to control the activity of VDE and the photoprotective mechanism of non-photochemical quenching of chlorophyll-a fluorescence. The data demonstrate, for the first time in native membranes, the modulation of the activity of a water-soluble enzyme by a non-bilayer lipid phase.
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Affiliation(s)
- Ondřej Dlouhý
- Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Irena Kurasová
- Faculty of Science, University of Ostrava, Ostrava, Czech Republic.,Global Change Research Institute, Czech Academy of Sciences, Brno, Czech Republic
| | - Václav Karlický
- Faculty of Science, University of Ostrava, Ostrava, Czech Republic.,Global Change Research Institute, Czech Academy of Sciences, Brno, Czech Republic
| | - Uroš Javornik
- Slovenian NMR Center, National Institute of Chemistry, Ljubljana, Slovenia
| | - Primož Šket
- Slovenian NMR Center, National Institute of Chemistry, Ljubljana, Slovenia.,EN-FIST Center of Excellence, Ljubljana, Slovenia
| | - Nia Z Petrova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Sashka B Krumova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Janez Plavec
- Slovenian NMR Center, National Institute of Chemistry, Ljubljana, Slovenia.,EN-FIST Center of Excellence, Ljubljana, Slovenia.,Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Bettina Ughy
- Faculty of Science, University of Ostrava, Ostrava, Czech Republic. .,Institute of Plant Biology, Biological Research Centre, Szeged, Hungary.
| | - Vladimír Špunda
- Faculty of Science, University of Ostrava, Ostrava, Czech Republic. .,Global Change Research Institute, Czech Academy of Sciences, Brno, Czech Republic.
| | - Győző Garab
- Faculty of Science, University of Ostrava, Ostrava, Czech Republic. .,Institute of Plant Biology, Biological Research Centre, Szeged, Hungary.
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18
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Zsiros O, Nagy G, Patai R, Solymosi K, Gasser U, Polgár TF, Garab G, Kovács L, Hörcsik ZT. Similarities and Differences in the Effects of Toxic Concentrations of Cadmium and Chromium on the Structure and Functions of Thylakoid Membranes in Chlorella variabilis. FRONTIERS IN PLANT SCIENCE 2020; 11:1006. [PMID: 32733513 PMCID: PMC7358611 DOI: 10.3389/fpls.2020.01006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 06/19/2020] [Indexed: 05/26/2023]
Abstract
Trace metal contaminations in natural waters, wetlands, and wastewaters pose serious threats to aquatic ecosystems-mainly via targeting microalgae. In this work, we investigated the effects of toxic amounts of chromium and cadmium ions on the structure and function of the photosynthetic machinery of Chlorella variabilis cells. To halt the propagation of cells, we used high concentrations of Cd and Cr, 50-50 mg L-1, in the forms of CdCl2 x 2.5 H2O and K2Cr2O7, respectively. Both treatments led to similar, about 50% gradual diminishment of the chlorophyll contents of the cells in 48 h, which was, however, accompanied by a small (~10%) but statistically significant enrichment (Cd) and loss (Cr) of ß-carotene. Both Cd and Cr inhibited the activity of photosystem II (PSII)-but with more severe inhibitions with Cr. On the contrary, the PsbA (D1) protein of PSII and the PsbO protein of the oxygen-evolving complex were retained more in Cr-treated cells than in the presence of Cd. These data and the higher susceptibility of P700 redox transients in Cr-treated cells suggest that, unlike with Cd, PSII is not the main target in the photochemical apparatus. These differences at the level of photochemistry also brought about dissimilarities at higher levels of the structural complexity of the photosynthetic apparatus. Circular dichroism (CD) spectroscopy measurements revealed moderate perturbations in the macro-organization of the protein complexes-with more pronounced decline in Cd-treated cells than in the cells with Cr. Also, as reflected by transmission electron microscopy and small-angle neutron scattering, the thylakoid membranes suffered shrinking and were largely fragmented in Cd-treated cells, whereas no changes could be discerned with Cr. The preservation of integrity of membranes in Cr-treated cells was most probably aided by high proportion of the de-epoxidized xanthophylls, which were absent with Cd. It can thus be concluded that beside strong similarities of the toxic effects of Cr and Cd, the response of the photosynthetic machinery of C. variabilis to these two trace metal ions substantially differ from each other-strongly suggesting different inhibitory and protective mechanisms following the primary toxic events.
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Affiliation(s)
- Ottó Zsiros
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
| | - Gergely Nagy
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen PSI, Villigen, Switzerland
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Budapest, Hungary
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Roland Patai
- Institute of Biophysics, Biological Research Centre, Szeged, Hungary
| | - Katalin Solymosi
- Department of Plant Anatomy, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Urs Gasser
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen PSI, Villigen, Switzerland
| | - Tamás F. Polgár
- Institute of Biophysics, Biological Research Centre, Szeged, Hungary
| | - Győző Garab
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
- Department of Physics, Faculty of Science, University of Ostrava, Ostrava, Czechia
| | - László Kovács
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
| | - Zsolt Tibor Hörcsik
- Department of Biology Nyíregyháza, Institute of Environmental Sciences, University of Nyíregyháza, Nyíregyháza, Hungary
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19
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Lingvay M, Akhtar P, Sebők-Nagy K, Páli T, Lambrev PH. Photobleaching of Chlorophyll in Light-Harvesting Complex II Increases in Lipid Environment. FRONTIERS IN PLANT SCIENCE 2020; 11:849. [PMID: 32670321 PMCID: PMC7327537 DOI: 10.3389/fpls.2020.00849] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 05/26/2020] [Indexed: 05/18/2023]
Abstract
Excess light causes damage to the photosynthetic apparatus of plants and algae primarily via reactive oxygen species. Singlet oxygen can be formed by interaction of chlorophyll (Chl) triplet states, especially in the Photosystem II reaction center, with oxygen. Whether Chls in the light-harvesting antenna complexes play direct role in oxidative photodamage is less clear. In this work, light-induced photobleaching of Chls in the major trimeric light-harvesting complex II (LHCII) is investigated in different molecular environments - protein aggregates, embedded in detergent micelles or in reconstituted membranes (proteoliposomes). The effects of intense light treatment were analyzed by absorption and circular dichroism spectroscopy, steady-state and time-resolved fluorescence and EPR spectroscopy. The rate and quantum yield of photobleaching was estimated from the light-induced Chl absorption changes. Photobleaching occurred mainly in Chl a and was accompanied by strong fluorescence quenching of the remaining unbleached Chls. The rate of photobleaching increased by 140% when LHCII was embedded in lipid membranes, compared to detergent-solubilized LHCII. Removing oxygen from the medium or adding antioxidants largely suppressed the bleaching, confirming its oxidative mechanism. Singlet oxygen formation was monitored by EPR spectroscopy using spin traps and spin labels to detect singlet oxygen directly and indirectly, respectively. The quantum yield of Chl a photobleaching in membranes and detergent was found to be 3.4 × 10-5 and 1.4 × 10-5, respectively. These values compare well with the yields of ROS production estimated from spin-trap EPR spectroscopy (around 4 × 10-5 and 2 × 10-5). A kinetic model is proposed, quantifying the generation of Chl and carotenoid triplet states and singlet oxygen. The high quantum yield of photobleaching, especially in the lipid membrane, suggest that direct photodamage of the antenna occurs with rates relevant to photoinhibition in vivo. The results represent further evidence that the molecular environment of LHCII has profound impact on its functional characteristics, including, among others, the susceptibility to photodamage.
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Affiliation(s)
- Mónika Lingvay
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
- Doctoral School of Physics, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Parveen Akhtar
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
| | | | - Tibor Páli
- Institute of Biophysics, Biological Research Centre, Szeged, Hungary
| | - Petar H. Lambrev
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
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20
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Müh F, Zouni A. Structural basis of light-harvesting in the photosystem II core complex. Protein Sci 2020; 29:1090-1119. [PMID: 32067287 PMCID: PMC7184784 DOI: 10.1002/pro.3841] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 02/06/2020] [Accepted: 02/06/2020] [Indexed: 12/20/2022]
Abstract
Photosystem II (PSII) is a membrane-spanning, multi-subunit pigment-protein complex responsible for the oxidation of water and the reduction of plastoquinone in oxygenic photosynthesis. In the present review, the recent explosive increase in available structural information about the PSII core complex based on X-ray crystallography and cryo-electron microscopy is described at a level of detail that is suitable for a future structure-based analysis of light-harvesting processes. This description includes a proposal for a consistent numbering scheme of protein-bound pigment cofactors across species. The structural survey is complemented by an overview of the state of affairs in structure-based modeling of excitation energy transfer in the PSII core complex with emphasis on electrostatic computations, optical properties of the reaction center, the assignment of long-wavelength chlorophylls, and energy trapping mechanisms.
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Affiliation(s)
- Frank Müh
- Department of Theoretical Biophysics, Institute for Theoretical Physics, Johannes Kepler University Linz, Linz, Austria
| | - Athina Zouni
- Humboldt-Universität zu Berlin, Institute for Biology, Biophysics of Photosynthesis, Berlin, Germany
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21
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Zsiros O, Ünnep R, Nagy G, Almásy L, Patai R, Székely NK, Kohlbrecher J, Garab G, Dér A, Kovács L. Role of Protein-Water Interface in the Stacking Interactions of Granum Thylakoid Membranes-As Revealed by the Effects of Hofmeister Salts. FRONTIERS IN PLANT SCIENCE 2020; 11:1257. [PMID: 32922427 PMCID: PMC7456932 DOI: 10.3389/fpls.2020.01257] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 07/30/2020] [Indexed: 05/08/2023]
Abstract
The thylakoid membranes of vascular plants are differentiated into stacked granum and unstacked stroma regions. The formation of grana is triggered by the macrodomain formation of photosystem II and light-harvesting complex II (PSII-LHCII) and thus their lateral segregation from the photosystem I-light-harvesting complex I (PSI-LHCI) super-complexes and the ATP-synthase; which is then stabilized by stacking interactions of the adjacent PSII-LHCII enriched regions of the thylakoid membranes. The self-assembly and dynamics of this highly organized membrane system and the nature of forces acting between the PSII-LHCII macrodomains are not well understood. By using circular dichroism (CD) spectroscopy, small-angle neutron scattering (SANS) and transmission electron microscopy (TEM), we investigated the effects of Hofmeister salts on the organization of pigment-protein complexes and on the ultrastructure of thylakoid membranes. We found that the kosmotropic agent (NH4)2SO4 and the Hofmeister-neutral NaCl, up to 2 M concentrations, hardly affected the macro-organization of the protein complexes and the membrane ultrastructure. In contrast, chaotropic salts, NaClO4, and NaSCN destroyed the mesoscopic structures, the multilamellar organization of the thylakoid membranes and the chiral macrodomains of the protein complexes but without noticeably affecting the short-range, pigment-pigment excitonic interactions. Comparison of the concentration- and time-dependences of SANS, TEM and CD parameters revealed the main steps of the disassembly of grana in the presence of chaotropes. It begins with a rapid diminishment of the long-range periodic order of the grana membranes, apparently due to an increased stacking disorder of the thylakoid membranes, as reflected by SANS experiments. SANS measurements also allowed discrimination between the cationic and anionic effects-in stacking and disorder, respectively. This step is followed by a somewhat slower disorganization of the TEM ultrastructure, due to the gradual loss of stacked membrane pairs. Occurring last is the stepwise decrease and disappearance of the long-range chiral order of the protein complexes, the rate of which was faster in LHCII-deficient membranes. These data are interpreted in terms of a theory, from our laboratory, according to which Hofmeister salts primarily affect the hydrophylic-hydrophobic interactions of proteins, and the stroma-exposed regions of the intrinsic membrane proteins, in particular-pointing to the role of protein-water interface in the stacking interactions of granum thylakoid membranes.
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Affiliation(s)
- Ottó Zsiros
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
| | - Renáta Ünnep
- Neutron Spectroscopy Department, Centre for Energy Research, Budapest, Hungary
| | - Gergely Nagy
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen PSI, Switzerland
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Budapest, Hungary
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - László Almásy
- Neutron Spectroscopy Department, Centre for Energy Research, Budapest, Hungary
| | - Roland Patai
- Institute of Biophysics, Biological Research Centre, Szeged, Hungary
| | - Noémi K. Székely
- Jülich Centre for Neutron Science at MLZ, Forschungszentrum Jülich GmbH, Garching, Germany
| | - Joachim Kohlbrecher
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Győző Garab
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
- Department of Physics, Faculty of Science, University of Ostrava, Ostrava, Czechia
- *Correspondence: Győző Garab, ; András Dér, ; László Kovács,
| | - András Dér
- Institute of Biophysics, Biological Research Centre, Szeged, Hungary
- *Correspondence: Győző Garab, ; András Dér, ; László Kovács,
| | - László Kovács
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
- *Correspondence: Győző Garab, ; András Dér, ; László Kovács,
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