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Garty Y, Bussi Y, Levin-Zaidman S, Shimoni E, Kirchhoff H, Charuvi D, Nevo R, Reich Z. Thylakoid membrane stacking controls electron transport mode during the dark-to-light transition by adjusting the distances between PSI and PSII. NATURE PLANTS 2024; 10:512-524. [PMID: 38396112 DOI: 10.1038/s41477-024-01628-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 01/23/2024] [Indexed: 02/25/2024]
Abstract
The balance between linear electron transport (LET) and cyclic electron transport (CET) plays an essential role in plant adaptation and protection against photo-induced damage. This balance is largely maintained by phosphorylation-driven alterations in the PSII-LHCII assembly and thylakoid membrane stacking. During the dark-to-light transition, plants shift this balance from CET, which prevails to prevent overreduction of the electron transport chain and consequent photo-induced damage, towards LET, which enables efficient CO2 assimilation and biomass production. Using freeze-fracture cryo-scanning electron microscopy and transmission electron microscopy of Arabidopsis leaves, we reveal unique membrane regions possessing characteristics of both stacked and unstacked regions of the thylakoid network that form during this transition. A notable consequence of the morphological attributes of these regions, which we refer to as 'stacked thylakoid doublets', is an overall increase in the proximity and connectivity of the two photosystems (PSI and PSII) that drive LET. This, in turn, reduces diffusion distances and barriers for the mobile carriers that transfer electrons between the two PSs, thereby maximizing LET and optimizing the plant's ability to utilize light energy. The mechanics described here for the shift between CET and LET during the dark-to-light transition are probably also used during chromatic adaptation mediated by state transitions.
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Affiliation(s)
- Yuval Garty
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Yuval Bussi
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Smadar Levin-Zaidman
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, Israel
| | - Eyal Shimoni
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, Israel
| | - Helmut Kirchhoff
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Dana Charuvi
- Institute of Plant Sciences, Agricultural Research Organization, Volcani Institute, Rishon LeZion, Israel
| | - Reinat Nevo
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel.
| | - Ziv Reich
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel.
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2
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Caspy I, Fadeeva M, Mazor Y, Nelson N. Structure of Dunaliella photosystem II reveals conformational flexibility of stacked and unstacked supercomplexes. eLife 2023; 12:e81150. [PMID: 36799903 PMCID: PMC9949808 DOI: 10.7554/elife.81150] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 02/16/2023] [Indexed: 02/18/2023] Open
Abstract
Photosystem II (PSII) generates an oxidant whose redox potential is high enough to enable water oxidation , a substrate so abundant that it assures a practically unlimited electron source for life on earth . Our knowledge on the mechanism of water photooxidation was greatly advanced by high-resolution structures of prokaryotic PSII . Here, we show high-resolution cryogenic electron microscopy (cryo-EM) structures of eukaryotic PSII from the green alga Dunaliella salina at two distinct conformations. The conformers are also present in stacked PSII, exhibiting flexibility that may be relevant to the grana formation in chloroplasts of the green lineage. CP29, one of PSII associated light-harvesting antennae, plays a major role in distinguishing the two conformations of the supercomplex. We also show that the stacked PSII dimer, a form suggested to support the organisation of thylakoid membranes , can appear in many different orientations providing a flexible stacking mechanism for the arrangement of grana stacks in thylakoids. Our findings provide a structural basis for the heterogenous nature of the eukaryotic PSII on multiple levels.
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Affiliation(s)
- Ido Caspy
- Department of Biochemistry and Molecular Biology, The George S. Wise Faculty of Life Sciences, Tel Aviv UniversityTel AvivIsrael
| | - Maria Fadeeva
- Department of Biochemistry and Molecular Biology, The George S. Wise Faculty of Life Sciences, Tel Aviv UniversityTel AvivIsrael
| | - Yuval Mazor
- School of Molecular Sciences, Arizona State UniversityTempeUnited States
- Biodesign Center for Applied Structural Discovery, Arizona State UniversityTempeUnited States
| | - Nathan Nelson
- Department of Biochemistry and Molecular Biology, The George S. Wise Faculty of Life Sciences, Tel Aviv UniversityTel AvivIsrael
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3
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Staehelin LA, Paolillo DJ. A brief history of how microscopic studies led to the elucidation of the 3D architecture and macromolecular organization of higher plant thylakoids. PHOTOSYNTHESIS RESEARCH 2020; 145:237-258. [PMID: 33017036 PMCID: PMC7541383 DOI: 10.1007/s11120-020-00782-3] [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: 06/11/2020] [Accepted: 08/28/2020] [Indexed: 05/30/2023]
Abstract
Microscopic studies of chloroplasts can be traced back to the year 1678 when Antonie van Leeuwenhoek reported to the Royal Society in London that he saw green globules in grass leaf cells with his single-lens microscope. Since then, microscopic studies have continued to contribute critical insights into the complex architecture of chloroplast membranes and how their structure relates to function. This review is organized into three chronological sections: During the classic light microscope period (1678-1940), the development of improved microscopes led to the identification of green grana, a colorless stroma, and a membrane envelope. More recent (1990-2020) chloroplast dynamic studies have benefited from laser confocal and 3D-structured illumination microscopy. The development of the transmission electron microscope (1940-2000) and thin sectioning techniques demonstrated that grana consist of stacks of closely appressed grana thylakoids interconnected by non-appressed stroma thylakoids. When the stroma thylakoids were shown to spiral around the grana stacks as multiple right-handed helices, it was confirmed that the membranes of a chloroplast are all interconnected. Freeze-fracture and freeze-etch methods verified the helical nature of the stroma thylakoids, while also providing precise information on how the electron transport chain and ATP synthase complexes are non-randomly distributed between grana and stroma membrane regions. The last section (2000-2020) focuses on the most recent discoveries made possible by atomic force microscopy of hydrated membranes, and electron tomography and cryo-electron tomography of cryofixed thylakoids. These investigations have provided novel insights into thylakoid architecture and plastoglobules (summarized in a new thylakoid model), while also producing molecular-scale views of grana and stroma thylakoids in which individual functional complexes can be identified.
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Affiliation(s)
- L Andrew Staehelin
- Department of Molecular, Cellular and Developmental Biology, UCB 347, University of Colorado, Boulder, CO, 80309-0347, USA.
| | - Dominick J Paolillo
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA
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4
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Wood WHJ, Johnson MP. Modeling the Role of LHCII-LHCII, PSII-LHCII, and PSI-LHCII Interactions in State Transitions. Biophys J 2020; 119:287-299. [PMID: 32621865 DOI: 10.1016/j.bpj.2020.05.034] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 03/28/2020] [Accepted: 05/04/2020] [Indexed: 02/08/2023] Open
Abstract
The light-dependent reactions of photosynthesis take place in the plant chloroplast thylakoid membrane, a complex three-dimensional structure divided into the stacked grana and unstacked stromal lamellae domains. Plants regulate the macro-organization of photosynthetic complexes within the thylakoid membrane to adapt to changing environmental conditions and avoid oxidative stress. One such mechanism is the state transition that regulates photosynthetic light harvesting and electron transfer. State transitions are driven by changes in the phosphorylation of light harvesting complex II (LHCII), which cause a decrease in grana diameter and stacking, a decrease in energetic connectivity between photosystem II (PSII) reaction centers, and an increase in the relative LHCII antenna size of photosystem I (PSI) compared to PSII. Phosphorylation is believed to drive these changes by weakening the intramembrane lateral PSII-LHCII and LHCII-LHCII interactions and the intermembrane stacking interactions between these complexes, while simultaneously increasing the affinity of LHCII for PSI. We investigated the relative roles and contributions of these three types of interaction to state transitions using a lattice-based model of the thylakoid membrane based on existing structural data, developing a novel algorithm to simulate protein complex dynamics. Monte Carlo simulations revealed that state transitions are unlikely to lead to a large-scale migration of LHCII from the grana to the stromal lamellae. Instead, the increased light harvesting capacity of PSI is largely due to the more efficient recruitment of LHCII already residing in the stromal lamellae into PSI-LHCII supercomplexes upon its phosphorylation. Likewise, the increased light harvesting capacity of PSII upon dephosphorylation was found to be driven by a more efficient recruitment of LHCII already residing in the grana into functional PSII-LHCII clusters, primarily driven by lateral interactions.
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Affiliation(s)
- William H J Wood
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | - Matthew P Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom.
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5
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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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6
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Macroorganisation and flexibility of thylakoid membranes. Biochem J 2019; 476:2981-3018. [DOI: 10.1042/bcj20190080] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 09/19/2019] [Accepted: 10/03/2019] [Indexed: 02/07/2023]
Abstract
Abstract
The light reactions of photosynthesis are hosted and regulated by the chloroplast thylakoid membrane (TM) — the central structural component of the photosynthetic apparatus of plants and algae. The two-dimensional and three-dimensional arrangement of the lipid–protein assemblies, aka macroorganisation, and its dynamic responses to the fluctuating physiological environment, aka flexibility, are the subject of this review. An emphasis is given on the information obtainable by spectroscopic approaches, especially circular dichroism (CD). We briefly summarise the current knowledge of the composition and three-dimensional architecture of the granal TMs in plants and the supramolecular organisation of Photosystem II and light-harvesting complex II therein. We next acquaint the non-specialist reader with the fundamentals of CD spectroscopy, recent advances such as anisotropic CD, and applications for studying the structure and macroorganisation of photosynthetic complexes and membranes. Special attention is given to the structural and functional flexibility of light-harvesting complex II in vitro as revealed by CD and fluorescence spectroscopy. We give an account of the dynamic changes in membrane macroorganisation associated with the light-adaptation of the photosynthetic apparatus and the regulation of the excitation energy flow by state transitions and non-photochemical quenching.
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7
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Single-molecule study of redox control involved in establishing the spinach plastocyanin-cytochrome bf electron transfer complex. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:591-599. [DOI: 10.1016/j.bbabio.2019.06.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 06/18/2019] [Accepted: 06/21/2019] [Indexed: 01/06/2023]
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8
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Johnson MP, Wientjes E. The relevance of dynamic thylakoid organisation to photosynthetic regulation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1861:148039. [PMID: 31228404 DOI: 10.1016/j.bbabio.2019.06.011] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 06/14/2019] [Accepted: 06/15/2019] [Indexed: 12/11/2022]
Abstract
The higher plant chloroplast thylakoid membrane system performs the light-dependent reactions of photosynthesis. These provide the ATP and NADPH required for the fixation of CO2 into biomass by the Calvin-Benson cycle and a range of other metabolic reactions in the stroma. Land plants are frequently challenged by fluctuations in their environment, such as light, nutrient and water availability, which can create a mismatch between the amounts of ATP and NADPH produced and the amounts required by the downstream metabolism. Left unchecked, such imbalances can lead to the production of reactive oxygen species that damage the plant and harm productivity. Fortunately, plants have evolved a complex range of regulatory processes to avoid or minimize such deleterious effects by controlling the efficiency of light harvesting and electron transfer in the thylakoid membrane. Generally the regulation of the light reactions has been studied and conceptualised at the microscopic level of protein-protein and protein-ligand interactions, however in recent years dynamic changes in the thylakoid macrostructure itself have been recognised to play a significant role in regulating light harvesting and electron transfer. Here we review the evidence for the involvement of macrostructural changes in photosynthetic regulation and review the techniques that brought this evidence to light.
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Affiliation(s)
- Matthew P Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom.
| | - Emilie Wientjes
- Laboratory of Biophysics, Wageningen University, Stippeneng 4, 6708 WE Wageningen, the Netherlands
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9
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Petrova N, Todinova S, Paunov M, Kovács L, Taneva S, Krumova S. Thylakoid membrane unstacking increases LHCII thermal stability and lipid phase fluidity. J Bioenerg Biomembr 2018; 50:425-435. [PMID: 30607760 DOI: 10.1007/s10863-018-9783-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 12/20/2018] [Indexed: 11/26/2022]
Abstract
Thylakoids are highly protein-enriched membranes that harbor a number of multicomponent photosynthetic complexes. Similarly to other biological membranes the protein constituents are heterogeneously distributed laterally in the plane of the membrane, however the specific segregation into stacked (grana patches) and unstacked (stroma lamellae) membrane layers is a unique feature of the thylakoid. Both the lateral and the vertical arrangements of the integral membrane proteins within the three-dimensional thylakoid ultrastructure are thought to have important physiological function. In this work we explore the role of membrane stacking for the thermal stability of the photosynthetic complexes in thylakoid membranes. By means of circular dichroism and differential scanning calorimetry we demonstrate that the thermal stability of the monomeric and trimeric forms of the major light harvesting complex of photosystem II (LHCII) increases upon unstacking. This effect was suggested to be due to the detachment of LHCII from photosystem II and consequent attachment to photosystem I subunits and/or the fluidization of the lipid matrix upon unstacking. The changes in the physical properties of the protein and lipid membrane components upon unstacking result in strongly reduced photosystem II excitation energy utilization.
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Affiliation(s)
- Nia Petrova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Svetla Todinova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Momchil Paunov
- Department of Biophysics and Radiobiology, Faculty of Biology, Sofia University "St. Kliment Ohridski", Sofia, Bulgaria
| | - Lászlo Kovács
- Biological Research Centre, Institute of Plant Biology, Szeged, Hungary
| | - Stefka Taneva
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Sashka Krumova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria.
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10
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Jäger S, Büchel C. Cation-dependent changes in the thylakoid membrane appression of the diatom Thalassiosira pseudonana. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1860:41-51. [PMID: 30447184 DOI: 10.1016/j.bbabio.2018.11.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 09/21/2018] [Accepted: 11/04/2018] [Indexed: 11/16/2022]
Abstract
Diatoms show a special organisation of their plastid membranes, such that their thylakoids span the entire plastid in bands of three. While in higher plants the interaction of the light harvesting complex II and photosystem II with divalent cations (especially Mg2+) was found to take part in the interplay of electrostatic attraction and repulsion in grana membrane appression, for diatoms the key players in maintaining proper membrane distances were not identified so far. In this work, we investigated the changes in the thylakoid architecture of Thalassiosira pseudonana in reaction to different salts by using circular dichroism and fluorescence spectroscopy in combination with other techniques. We show that divalent cations have an important influence on optimal pigment organisation and thus also on maintaining membrane appression. Thereby, monovalent cations are far less effective. The concentration needed is in a physiological range and fits well with the values obtained for higher plant grana stacking, despite the fact that strict protein segregation as seen in higher plant grana is missing.
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Affiliation(s)
- Stefanie Jäger
- Institute of Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438 Frankfurt, Germany
| | - Claudia Büchel
- Institute of Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438 Frankfurt, Germany.
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11
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Seiwert D, Witt H, Ritz S, Janshoff A, Paulsen H. The Nonbilayer Lipid MGDG and the Major Light-Harvesting Complex (LHCII) Promote Membrane Stacking in Supported Lipid Bilayers. Biochemistry 2018; 57:2278-2288. [PMID: 29577715 DOI: 10.1021/acs.biochem.8b00118] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The thylakoid membrane of algae and land plants is characterized by its intricate architecture, comprising tightly appressed membrane stacks termed grana. The contributions of individual components to grana stack formation are not yet fully elucidated. As an in vitro model, we use supported lipid bilayers made of thylakoid lipid mixtures to study the effect of major light-harvesting complex (LHCII), different lipids, and ions on membrane stacking, seen as elevated structures forming on top of the planar membrane surface in the presence of LHCII protein. These structures were examined by confocal laser scanning microscopy, atomic force microscopy, and fluorescence recovery after photobleaching, revealing multilamellar LHCII-membrane stacks composed of connected lipid bilayers. Both native-like and non-native interactions between the LHCII complexes may contribute to membrane appression in the supported bilayers. However, applying in vivo-like salt conditions to uncharged glycolipid membranes drastically increased the level of stack formation due to enforced LHCII-LHCII interactions, which is in line with recent crystallographic and cryo-electron microscopic data [Wan, T., et al. (2014) Mol. Plant 7, 916-919; Albanese, P., et al. (2017) Sci. Rep. 7, 10067-10083]. Furthermore, we observed the nonbilayer lipid MGDG to strongly promote membrane stacking, pointing to the long-term proposed function of MGDG in stabilizing the inner membrane leaflet of highly curved margins in the periphery of each grana disc because of its negative intrinsic curvature [Murphy, D. J. (1982) FEBS Lett. 150, 19-26].
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Affiliation(s)
- Dennis Seiwert
- Institute of Molecular Physiology , Johannes Gutenberg University Mainz , Johannes-von-Müller-Weg 6 , 55128 Mainz , Germany
| | - Hannes Witt
- Institute of Physical Chemistry , University of Goettingen , Tammannstrasse 6 , 37077 Goettingen , Germany
| | - Sandra Ritz
- Microscopy Core Facility , Institute of Molecular Biology , Ackermannweg 4 , 55128 Mainz , Germany
| | - Andreas Janshoff
- Institute of Physical Chemistry , University of Goettingen , Tammannstrasse 6 , 37077 Goettingen , Germany
| | - Harald Paulsen
- Institute of Molecular Physiology , Johannes Gutenberg University Mainz , Johannes-von-Müller-Weg 6 , 55128 Mainz , Germany
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12
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Ivanov AG, Velitchkova MY, Allakhverdiev SI, Huner NPA. Heat stress-induced effects of photosystem I: an overview of structural and functional responses. PHOTOSYNTHESIS RESEARCH 2017; 133:17-30. [PMID: 28391379 DOI: 10.1007/s11120-017-0383-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 04/03/2017] [Indexed: 05/24/2023]
Abstract
Temperature is one of the main factors controlling the formation, development, and functional performance of the photosynthetic apparatus in all photoautotrophs (green plants, algae, and cyanobacteria) on Earth. The projected climate change scenarios predict increases in air temperature across Earth's biomes ranging from moderate (3-4 °C) to extreme (6-8 °C) by the year 2100 (IPCC in Climate change 2007: The physical science basis: summery for policymakers, IPCC WG1 Fourth Assessment Report 2007; Climate change 2014: Mitigation of Climate Change, IPCC WG3 Fifth Assessment Report 2014). In some areas, especially of the Northern hemisphere, even more extreme warm seasonal temperatures may occur, which possibly will cause significant negative effects on the development, growth, and yield of important agricultural crops. It is well documented that high temperatures can cause direct damages of the photosynthetic apparatus and photosystem II (PSII) is generally considered to be the primary target of heat-induced inactivation of photosynthesis. However, since photosystem I (PSI) is considered to determine the global amount of enthalpy in living systems (Nelson in Biochim Biophys Acta 1807:856-863, 2011; Photosynth Res 116:145-151, 2013), the effects of elevated temperatures on PSI might be of vital importance for regulating the photosynthetic response of all photoautotrophs in the changing environment. In this review, we summarize the experimental data that demonstrate the critical impact of heat-induced alterations on the structure, composition, and functional performance of PSI and their significant implications on photosynthesis under future climate change scenarios.
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Affiliation(s)
- Alexander G Ivanov
- Department of Biology, University of Western Ontario, 1151 Richmond Street N., London, ON, N6A 5B7, Canada.
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Street, Bl. 21, 1113, Sofia, Bulgaria.
| | - Maya Y Velitchkova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Street, Bl. 21, 1113, Sofia, Bulgaria
| | - Suleyman I Allakhverdiev
- Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow, 127276, Russia
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow, 142290, Russia
- Department of Plant Physiology, Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, 119991, Russia
- Institute of Molecular Biology and Biotechnology, Azerbaijan National Academy of Sciences, Matbuat Avenue 2a, 1073, Baku, Azerbaijan
| | - Norman P A Huner
- Department of Biology, University of Western Ontario, 1151 Richmond Street N., London, ON, N6A 5B7, Canada
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13
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Live-cell visualization of excitation energy dynamics in chloroplast thylakoid structures. Sci Rep 2016; 6:29940. [PMID: 27416900 PMCID: PMC4945916 DOI: 10.1038/srep29940] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 06/27/2016] [Indexed: 11/09/2022] Open
Abstract
The intricate molecular processes underlying photosynthesis have long been studied using various analytic approaches. However, the three-dimensional (3D) dynamics of such photosynthetic processes remain unexplored due to technological limitations related to investigating intraorganellar mechanisms in vivo. By developing a system for high-speed 3D laser scanning confocal microscopy combined with high-sensitivity multiple-channel detection, we visualized excitation energy dynamics in thylakoid structures within chloroplasts of live Physcomitrella patens cells. Two distinct thylakoid structures in the chloroplast, namely the grana and stroma lamellae, were visualized three-dimensionally in live cells. The simultaneous detection of the shorter (than ~670 nm) and longer (than ~680 nm) wavelength regions of chlorophyll (Chl) fluorescence reveals different spatial characteristics-irregular and vertical structures, respectively. Spectroscopic analyses showed that the shorter and longer wavelength regions of Chl fluorescence are affected more by free light-harvesting antenna proteins and photosystem II supercomplexes, respectively. The high-speed 3D time-lapse imaging of the shorter and longer wavelength regions also reveals different structural dynamics-rapid and slow movements within 1.5 seconds, respectively. Such structural dynamics of the two wavelength regions of Chl fluorescence would indicate excitation energy dynamics between light-harvesting antenna proteins and photosystems, reflecting the energetically active nature of photosynthetic proteins in thylakoid membranes.
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14
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Charuvi D, Nevo R, Kaplan-Ashiri I, Shimoni E, Reich Z. Studying the Supramolecular Organization of Photosynthetic Membranes within Freeze-fractured Leaf Tissues by Cryo-scanning Electron Microscopy. J Vis Exp 2016:54066. [PMID: 27403565 PMCID: PMC4993236 DOI: 10.3791/54066] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Cryo-scanning electron microscopy (SEM) of freeze-fractured samples allows investigation of biological structures at near native conditions. Here, we describe a technique for studying the supramolecular organization of photosynthetic (thylakoid) membranes within leaf samples. This is achieved by high-pressure freezing of leaf tissues, freeze-fracturing, double-layer coating and finally cryo-SEM imaging. Use of the double-layer coating method allows acquiring high magnification (>100,000X) images with minimal beam damage to the frozen-hydrated samples as well as minimal charging effects. Using the described procedures we investigated the alterations in supramolecular distribution of photosystem and light-harvesting antenna protein complexes that take place during dehydration of the resurrection plant Craterostigma pumilum, in situ.
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Affiliation(s)
- Dana Charuvi
- Department of Biological Chemistry, Weizmann Institute of Science; Institute of Plant Sciences, Agricultural Research Organization, Volcani Center;
| | - Reinat Nevo
- Department of Biological Chemistry, Weizmann Institute of Science
| | | | - Eyal Shimoni
- Department of Chemical Research Support, Weizmann Institute of Science
| | - Ziv Reich
- Department of Biological Chemistry, Weizmann Institute of Science
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15
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Farooq S, Chmeliov J, Trinkunas G, Valkunas L, van Amerongen H. Is There Excitation Energy Transfer between Different Layers of Stacked Photosystem-II-Containing Thylakoid Membranes? J Phys Chem Lett 2016; 7:1406-1410. [PMID: 27014831 DOI: 10.1021/acs.jpclett.6b00474] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We have compared picosecond fluorescence decay kinetics for stacked and unstacked photosystem II membranes in order to evaluate the efficiency of excitation energy transfer between the neighboring layers. The measured kinetics were analyzed in terms of a recently developed fluctuating antenna model that provides information about the dimensionality of the studied system. Independently of the stacking state, all preparations exhibited virtually the same value of the apparent dimensionality, d = 1.6. Thus, we conclude that membrane stacking does not affect the efficiency of the delivery of excitation energy toward the reaction centers but ensures a more compact organization of the thylakoid membranes within the chloroplast and separation of photosystems I and II.
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Affiliation(s)
- Shazia Farooq
- Laboratory of Biophysics, Wageningen University , P.O. Box 8128, 6700 ET Wageningen, The Netherlands
| | - Jevgenij Chmeliov
- Department of Theoretical Physics, Faculty of Physics, Vilnius University , Saulėtekio Avenue 9, 10222 Vilnius, Lithuania
- Department of Molecular Compound Physics, Institute of Physics, Center for Physical Sciences and Technology , Goštauto 11, 01108 Vilnius, Lithuania
| | - Gediminas Trinkunas
- Department of Theoretical Physics, Faculty of Physics, Vilnius University , Saulėtekio Avenue 9, 10222 Vilnius, Lithuania
- Department of Molecular Compound Physics, Institute of Physics, Center for Physical Sciences and Technology , Goštauto 11, 01108 Vilnius, Lithuania
| | - Leonas Valkunas
- Department of Theoretical Physics, Faculty of Physics, Vilnius University , Saulėtekio Avenue 9, 10222 Vilnius, Lithuania
- Department of Molecular Compound Physics, Institute of Physics, Center for Physical Sciences and Technology , Goštauto 11, 01108 Vilnius, Lithuania
| | - Herbert van Amerongen
- Laboratory of Biophysics, Wageningen University , P.O. Box 8128, 6700 ET Wageningen, The Netherlands
- MicroSpectroscopy Centre, Wageningen University , P.O. Box 8128, 6700 ET Wageningen, The Netherlands
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16
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Abstract
The first step of photosynthesis in plants is the absorption of sunlight by pigments in the antenna complexes of photosystem II (PSII), followed by transfer of the nascent excitation energy to the reaction centers, where long-term storage as chemical energy is initiated. Quantum mechanical mechanisms must be invoked to explain the transport of excitation within individual antenna. However, it is unclear how these mechanisms influence transfer across assemblies of antenna and thus the photochemical yield at reaction centers in the functional thylakoid membrane. Here, we model light harvesting at the several-hundred-nanometer scale of the PSII membrane, while preserving the dominant quantum effects previously observed in individual complexes. We show that excitation moves diffusively through the antenna with a diffusion length of 50 nm until it reaches a reaction center, where charge separation serves as an energetic trap. The diffusion length is a single parameter that incorporates the enhancing effect of excited state delocalization on individual rates of energy transfer as well as the complex kinetics that arise due to energy transfer and loss by decay to the ground state. The diffusion length determines PSII's high quantum efficiency in ideal conditions, as well as how it is altered by the membrane morphology and the closure of reaction centers. We anticipate that the model will be useful in resolving the nonphotochemical quenching mechanisms that PSII employs in conditions of high light stress.
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17
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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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18
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Belgio E, Ungerer P, Ruban AV. Light-harvesting superstructures of green plant chloroplasts lacking photosystems. PLANT, CELL & ENVIRONMENT 2015; 38:2035-47. [PMID: 25737144 DOI: 10.1111/pce.12528] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 02/23/2015] [Indexed: 05/26/2023]
Abstract
The light-harvesting antenna of higher plant photosystem II (LHCII) is the major photosynthetic membrane component encoded by an entire family of homologous nuclear genes. On the contrary, the great majority of proteins of photosystems and electron transport components are encoded by the chloroplast genome. In this work, we succeeded in gradually inhibiting the expression of the chloroplast genes that led to the disappearance of the photosystem complexes, mimicking almost total photoinhibition. The treated plants, despite displaying only some early signs of senescence, sustained their metabolism and growth for several weeks. The only major remaining membrane component was LHCII antenna that formed superstructures - stacks of dozens of thylakoids or supergrana. Freeze-fracture electron microscopy revealed specific organization, directly displaying frequently bifurcated membranes with reduced or totally absent photosystem II (PSII) reaction centre complexes. Our findings show that it is possible to accumulate large amounts of light-harvesting membranes, organized into three-dimensional structures, in the absence of reaction centre complexes. This points to the reciprocal role of LHCII and PSII in self-assembly of the three-dimensional matrix of the photosynthetic membrane, dictating its size and flexible adaptation to the light environment.
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Affiliation(s)
- Erica Belgio
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - Petra Ungerer
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - Alexander V Ruban
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
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19
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Voitsekhovskaja OV, Tyutereva EV. Chlorophyll b in angiosperms: Functions in photosynthesis, signaling and ontogenetic regulation. JOURNAL OF PLANT PHYSIOLOGY 2015; 189:51-64. [PMID: 26513460 DOI: 10.1016/j.jplph.2015.09.013] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 09/10/2015] [Accepted: 09/11/2015] [Indexed: 05/22/2023]
Abstract
Chlorophyll b (Chlb) is an antenna chlorophyll. The binding of Chlb by antenna proteins is crucial for the correct assembly of the antenna complexes in thylakoid membranes. Since the levels of the proteins of major and minor antenna are affected to different extents by Chlb binding, the availability of Chlb influences the composition and the size of antenna complexes which in turn determine the supramolecular organization of the thylakoid membranes in grana. Therefore, Chlb synthesis levels have a major impact on lateral mobility and diffusion of membrane molecules, and thus affect not only light harvesting and thermal energy dissipation processes, but also linear electron transport and repair processes in grana. Furthermore, in angiosperms Chlb synthesis affects plant functions beyond chloroplasts. First, the stability of pigment-protein complexes in the antennae, which depends on Chlb, is an important factor in the regulation of plant ontogenesis, and Chlb levels were recently shown to influence plant ontogenetic signaling. Second, the amounts of minor antenna proteins in chloroplasts, which depend on the availability of Chlb, were recently shown to affect ABA levels and signaling in plants. These mechanisms can be examined in mutants where Chlb synthesis is reduced or abolished. The dramatic effects caused by the lack of Chlb on plant productivity are interpreted in this review in light of the pleiotropic effects on photosynthesis and signaling, and the potential to manipulate Chlb biosynthesis for the improvement of crop production is discussed.
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Affiliation(s)
- O V Voitsekhovskaja
- Komarov Botanical Institute, Russian Academy of Sciences, Plant Ecological Physiology, ul. Professora Popova, 2, 197376 St. Petersburg, Russia.
| | - E V Tyutereva
- Komarov Botanical Institute, Russian Academy of Sciences, Plant Ecological Physiology, ul. Professora Popova, 2, 197376 St. Petersburg, Russia
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20
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Charuvi D, Nevo R, Shimoni E, Naveh L, Zia A, Adam Z, Farrant JM, Kirchhoff H, Reich Z. Photoprotection conferred by changes in photosynthetic protein levels and organization during dehydration of a homoiochlorophyllous resurrection plant. PLANT PHYSIOLOGY 2015; 167:1554-65. [PMID: 25713340 PMCID: PMC4378169 DOI: 10.1104/pp.114.255794] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 02/20/2015] [Indexed: 05/18/2023]
Abstract
During desiccation, homoiochlorophyllous resurrection plants retain most of their photosynthetic apparatus, allowing them to resume photosynthetic activity quickly upon water availability. These plants rely on various mechanisms to prevent the formation of reactive oxygen species and/or protect their tissues from the damage they inflict. In this work, we addressed the issue of how homoiochlorophyllous resurrection plants deal with the problem of excessive excitation/electron pressures during dehydration using Craterostigma pumilum as a model plant. To investigate the alterations in the supramolecular organization of photosynthetic protein complexes, we examined cryoimmobilized, freeze-fractured leaf tissues using (cryo)scanning electron microscopy. These examinations revealed rearrangements of photosystem II (PSII) complexes, including a lowered density during moderate dehydration, consistent with a lower level of PSII proteins, as shown by biochemical analyses. The latter also showed a considerable decrease in the level of cytochrome f early during dehydration, suggesting that initial regulation of the inhibition of electron transport is achieved via the cytochrome b6f complex. Upon further dehydration, PSII complexes are observed to arrange into rows and semicrystalline arrays, which correlates with the significant accumulation of sucrose and the appearance of inverted hexagonal lipid phases within the membranes. As opposed to PSII and cytochrome f, the light-harvesting antenna complexes of PSII remain stable throughout the course of dehydration. Altogether, these results, along with photosynthetic activity measurements, suggest that the protection of retained photosynthetic components is achieved, at least in part, via the structural rearrangements of PSII and (likely) light-harvesting antenna complexes into a photochemically quenched state.
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Affiliation(s)
- Dana Charuvi
- Department of Biological Chemistry (D.C., R.N., Z.R.) and Electron Microscopy Unit (E.S.), Weizmann Institute of Science, Rehovot 76100, Israel;Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (L.N., Z.A.);Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340 (A.Z., H.K.); andDepartment of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa (J.M.F.)
| | - Reinat Nevo
- Department of Biological Chemistry (D.C., R.N., Z.R.) and Electron Microscopy Unit (E.S.), Weizmann Institute of Science, Rehovot 76100, Israel;Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (L.N., Z.A.);Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340 (A.Z., H.K.); andDepartment of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa (J.M.F.)
| | - Eyal Shimoni
- Department of Biological Chemistry (D.C., R.N., Z.R.) and Electron Microscopy Unit (E.S.), Weizmann Institute of Science, Rehovot 76100, Israel;Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (L.N., Z.A.);Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340 (A.Z., H.K.); andDepartment of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa (J.M.F.)
| | - Leah Naveh
- Department of Biological Chemistry (D.C., R.N., Z.R.) and Electron Microscopy Unit (E.S.), Weizmann Institute of Science, Rehovot 76100, Israel;Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (L.N., Z.A.);Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340 (A.Z., H.K.); andDepartment of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa (J.M.F.)
| | - Ahmad Zia
- Department of Biological Chemistry (D.C., R.N., Z.R.) and Electron Microscopy Unit (E.S.), Weizmann Institute of Science, Rehovot 76100, Israel;Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (L.N., Z.A.);Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340 (A.Z., H.K.); andDepartment of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa (J.M.F.)
| | - Zach Adam
- Department of Biological Chemistry (D.C., R.N., Z.R.) and Electron Microscopy Unit (E.S.), Weizmann Institute of Science, Rehovot 76100, Israel;Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (L.N., Z.A.);Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340 (A.Z., H.K.); andDepartment of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa (J.M.F.)
| | - Jill M Farrant
- Department of Biological Chemistry (D.C., R.N., Z.R.) and Electron Microscopy Unit (E.S.), Weizmann Institute of Science, Rehovot 76100, Israel;Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (L.N., Z.A.);Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340 (A.Z., H.K.); andDepartment of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa (J.M.F.)
| | - Helmut Kirchhoff
- Department of Biological Chemistry (D.C., R.N., Z.R.) and Electron Microscopy Unit (E.S.), Weizmann Institute of Science, Rehovot 76100, Israel;Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (L.N., Z.A.);Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340 (A.Z., H.K.); andDepartment of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa (J.M.F.)
| | - Ziv Reich
- Department of Biological Chemistry (D.C., R.N., Z.R.) and Electron Microscopy Unit (E.S.), Weizmann Institute of Science, Rehovot 76100, Israel;Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (L.N., Z.A.);Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340 (A.Z., H.K.); andDepartment of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa (J.M.F.)
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21
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Abstract
To truly understand bioenergetic processes such as ATP synthesis, membrane-bound substrate transport or flagellar rotation, systems need to be analysed in a cellular context. Cryo-ET (cryo-electron tomography) is an essential part of this process, as it is currently the only technique which can directly determine the spatial organization of proteins at the level of both the cell and the individual protein complexes. The need to assess bioenergetic processes at a cellular level is becoming more and more apparent with the increasing interest in mitochondrial diseases. In recent years, cryo-ET has contributed significantly to our understanding of the molecular organization of mitochondria and chloroplasts. The present mini-review first describes the technique of cryo-ET and then discusses its role in membrane bioenergetics specifically in chloroplasts and mitochondrial research.
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22
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Architectural switch in plant photosynthetic membranes induced by light stress. Proc Natl Acad Sci U S A 2012; 109:20130-5. [PMID: 23169624 DOI: 10.1073/pnas.1214265109] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Unavoidable side reactions of photosynthetic energy conversion can damage the water-splitting photosystem II (PSII) holocomplex embedded in the thylakoid membrane system inside chloroplasts. Plant survival is crucially dependent on an efficient molecular repair of damaged PSII realized by a multistep repair cycle. The PSII repair cycle requires a brisk lateral protein traffic between stacked grana thylakoids and unstacked stroma lamellae that is challenged by the tight stacking and low protein mobility in grana. We demonstrated that high light stress induced two main structural changes that work synergistically to improve the accessibility between damaged PSII in grana and its repair machinery in stroma lamellae: lateral shrinkage of grana diameter and increased protein mobility in grana thylakoids. It follows that high light stress triggers an architectural switch of the thylakoid network that is advantageous for swift protein repair. Studies of the thylakoid kinase mutant stn8 and the double mutant stn7/8 demonstrate the central role of protein phosphorylation for the structural alterations. These findings are based on the elaboration of mathematical tools for analyzing confocal laser-scanning microscopic images to study changes in the sophisticated thylakoid architecture in intact protoplasts.
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23
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Nevo R, Charuvi D, Tsabari O, Reich Z. Composition, architecture and dynamics of the photosynthetic apparatus in higher plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 70:157-76. [PMID: 22449050 DOI: 10.1111/j.1365-313x.2011.04876.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The process of oxygenic photosynthesis enabled and still sustains aerobic life on Earth. The most elaborate form of the apparatus that carries out the primary steps of this vital process is the one present in higher plants. Here, we review the overall composition and supramolecular organization of this apparatus, as well as the complex architecture of the lamellar system within which it is harbored. Along the way, we refer to the genetic, biochemical, spectroscopic and, in particular, microscopic studies that have been employed to elucidate the structure and working of this remarkable molecular energy conversion device. As an example of the highly dynamic nature of the apparatus, we discuss the molecular and structural events that enable it to maintain high photosynthetic yields under fluctuating light conditions. We conclude the review with a summary of the hypotheses made over the years about the driving forces that underlie the partition of the lamellar system of higher plants and certain green algae into appressed and non-appressed membrane domains and the segregation of the photosynthetic protein complexes within these domains.
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Affiliation(s)
- Reinat Nevo
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
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24
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Goral TK, Johnson MP, Duffy CDP, Brain APR, Ruban AV, Mullineaux CW. Light-harvesting antenna composition controls the macrostructure and dynamics of thylakoid membranes in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 69:289-301. [PMID: 21919982 DOI: 10.1111/j.1365-313x.2011.04790.x] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We characterized a set of Arabidopsis mutants deficient in specific light-harvesting proteins, using freeze-fracture electron microscopy to probe the organization of complexes in the membrane and confocal fluorescence recovery after photobleaching to probe the dynamics of thylakoid membranes within intact chloroplasts. The same methods were used to characterize mutants lacking or over-expressing PsbS, a protein related to light-harvesting complexes that appears to play a role in regulation of photosynthetic light harvesting. We found that changes in the complement of light-harvesting complexes and PsbS have striking effects on the photosystem II macrostructure, and that these effects correlate with changes in the mobility of chlorophyll proteins within the thylakoid membrane. The mobility of chlorophyll proteins was found to correlate with the extent of photoprotective non-photochemical quenching, consistent with the idea that non-photochemical quenching involves extensive re-organization of complexes in the membrane. We suggest that a key feature of the physiological function of PsbS is to decrease the formation of ordered semi-crystalline arrays of photosystem II in the low-light state. Thus the presence of PsbS leads to an increase in the fluidity of the membrane, accelerating the re-organization of the photosystem II macrostructure that is necessary for induction of non-photochemical quenching.
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Affiliation(s)
- Tomasz K Goral
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E14NS, UK
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25
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Yao DCI, Brune DC, Vermaas WFJ. Lifetimes of photosystem I and II proteins in the cyanobacterium Synechocystis sp. PCC 6803. FEBS Lett 2011; 586:169-73. [PMID: 22197103 DOI: 10.1016/j.febslet.2011.12.010] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2011] [Revised: 12/07/2011] [Accepted: 12/07/2011] [Indexed: 11/26/2022]
Abstract
The half-life times of photosystem I and II proteins were determined using (15)N-labeling and mass spectrometry. The half-life times (30-75h for photosystem I components and <1-11h for the large photosystem II proteins) were similar when proteins were isolated from monomeric vs. oligomeric complexes on Blue-Native gels, suggesting that the two forms of both photosystems can interchange on a timescale of <1h or that only one form of each photosystem exists in thylakoids in vivo. The half-life times of proteins associated with either photosystem generally were unaffected by the absence of Small Cab-like proteins.
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Affiliation(s)
- Danny C I Yao
- School of Life Sciences and Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, AZ 85287-4501, USA
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26
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Austin JR, Staehelin LA. Three-dimensional architecture of grana and stroma thylakoids of higher plants as determined by electron tomography. PLANT PHYSIOLOGY 2011; 155:1601-11. [PMID: 21224341 PMCID: PMC3091084 DOI: 10.1104/pp.110.170647] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 12/24/2010] [Indexed: 05/17/2023]
Abstract
We have investigated the three-dimensional (3D) architecture of the thylakoid membranes of Arabidopsis (Arabidopsis thaliana), tobacco (Nicotiana tabacum), and spinach (Spinacia oleracea) with a resolution of approximately 7 nm by electron tomography of high-pressure-frozen/freeze-substituted intact chloroplasts. Higher-plant thylakoids are differentiated into two interconnected and functionally distinct domains, the photosystem II/light-harvesting complex II-enriched stacked grana thylakoids and the photosystem I/ATP synthase-enriched, nonstacked stroma thylakoids. The grana thylakoids are organized in the form of cylindrical stacks and are connected to the stroma thylakoids via tubular junctions. Our data confirm that the stroma thylakoids are wound around the grana stacks in the form of multiple, right-handed helices at an angle of 20° to 25° as postulated by a helical thylakoid model. The junctional connections between the grana and stroma thylakoids all have a slit-like architecture, but their size varies tremendously from approximately 15 × 30 nm to approximately 15 × 435 nm, which is approximately 5 times larger than seen in chemically fixed thylakoids. The variable slit length results in less periodicity in grana/stroma thylakoid organization than proposed in the original helical model. The stroma thylakoids also exhibit considerable architectural variability, which is dependent, in part, on the number and the orientation of adjacent grana stacks to which they are connected. Whereas some stroma thylakoids form solid, sheet-like bridges between adjacent grana, others exhibit a branching geometry with small, more tubular sheet domains also connecting adjacent, parallel stroma thylakoids. We postulate that the tremendous variability in size of the junctional slits may reflect a novel, active role of junctional slits in the regulation of photosynthetic function. In particular, by controlling the size of junctional slits, plants could regulate the flow of ions and membrane molecules between grana and stroma thylakoid membrane domains.
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Affiliation(s)
- Jotham R Austin
- Department of Molecular Genetics, and Cell Biology and Advance Electron Microscopy Facility, University of Chicago, Chicago, Illinois 60637, USA.
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27
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Johnson MP, Goral TK, Duffy CD, Brain AP, Mullineaux CW, Ruban AV. Photoprotective energy dissipation involves the reorganization of photosystem II light-harvesting complexes in the grana membranes of spinach chloroplasts. THE PLANT CELL 2011; 23:1468-79. [PMID: 21498680 PMCID: PMC3101555 DOI: 10.1105/tpc.110.081646] [Citation(s) in RCA: 253] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 03/08/2011] [Accepted: 03/28/2011] [Indexed: 05/18/2023]
Abstract
Plants must regulate their use of absorbed light energy on a minute-by-minute basis to maximize the efficiency of photosynthesis and to protect photosystem II (PSII) reaction centers from photooxidative damage. The regulation of light harvesting involves the photoprotective dissipation of excess absorbed light energy in the light-harvesting antenna complexes (LHCs) as heat. Here, we report an investigation into the structural basis of light-harvesting regulation in intact spinach (Spinacia oleracea) chloroplasts using freeze-fracture electron microscopy, combined with laser confocal microscopy employing the fluorescence recovery after photobleaching technique. The results demonstrate that formation of the photoprotective state requires a structural reorganization of the photosynthetic membrane involving dissociation of LHCII from PSII and its aggregation. The structural changes are manifested by a reduced mobility of LHC antenna chlorophyll proteins. It is demonstrated that these changes occur rapidly and reversibly within 5 min of illumination and dark relaxation, are dependent on ΔpH, and are enhanced by the deepoxidation of violaxanthin to zeaxanthin.
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Affiliation(s)
- Matthew P. Johnson
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Tomasz K. Goral
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Christopher D.P. Duffy
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Anthony P.R. Brain
- Centre for Ultrastructural Imaging, Kings College University of London, London SE1 1UL, United Kingdom
| | - Conrad W. Mullineaux
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Alexander V. Ruban
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom
- Address correspondence to
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28
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Giddings TH, Withers NW, Staehelin LA. Supramolecular structure of stacked and unstacked regions of the photosynthetic membranes of Prochloron sp., a prokaryote. Proc Natl Acad Sci U S A 2010; 77:352-6. [PMID: 16592754 PMCID: PMC348268 DOI: 10.1073/pnas.77.1.352] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Freeze-fracture replicas of the photosynthetic prokaryote Prochloron sp., collected at Coconut Island, Hawaii, show that the thylakoids are differentiated into stacked and unstacked regions much like the thylakoids of green algae and higher plants. On the exoplasmic (E) fracture face, the particle density is greater in stacked regions ( approximately 3100 particles/mum(2)) than in unstacked regions ( approximately 925 particles/mum(2)). On the complementary protoplasmic (P) fracture face, the particle density is lower in stacked regions ( approximately 2265 particles/mum(2) than in unstacked regions ( approximately 4980 particles/mum(2)). The histogram of the diameters of E face particles in unstacked regions shows a single broad peak centered at 80 A. In stacked regions, four distinct peaks, at 75, 105, 130, and 160 A, are observed. These size classes are virtually identical to those found on E faces of thylakoids of the green alga Chlamydomonas and of greening pea chloroplasts. In the latter systems, the different size classes of E face particles are believed to represent photosystem II units surrounded by variable amounts of chlorophyll a/b light-harvesting complex. We propose that the same interpretation applies to the thylakoids of Prochloron, which contain a similar chlorophyll a/b complex. Our results add to the evidence supporting the view of the chlorophyll a/b complex as both a light-harvesting complex and a membrane adhesion factor. The similarity of the architecture of the thylakoids of Prochloron to that of green algal and plant chloroplasts also provides additional evidence of an evolutionary relationship between Prochloron and the chloroplasts of green plants.
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Affiliation(s)
- T H Giddings
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado 80309
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Hohmann-Marriott MF, Roberson RW. Exploring photosynthesis by electron tomography. PHOTOSYNTHESIS RESEARCH 2009; 102:177-188. [PMID: 19548110 DOI: 10.1007/s11120-009-9452-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Accepted: 05/28/2009] [Indexed: 05/28/2023]
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Boekema EJ. Introduction to imaging methods in photosynthesis. PHOTOSYNTHESIS RESEARCH 2009; 102:107-9. [PMID: 19757143 PMCID: PMC2777216 DOI: 10.1007/s11120-009-9488-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Accepted: 08/10/2009] [Indexed: 05/28/2023]
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Nevo R, Chuartzman SG, Tsabari O, Reich Z, Charuvi D, Shimoni E. Architecture of Thylakoid Membrane Networks. LIPIDS IN PHOTOSYNTHESIS 2009. [DOI: 10.1007/978-90-481-2863-1_14] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Chuartzman SG, Nevo R, Shimoni E, Charuvi D, Kiss V, Ohad I, Brumfeld V, Reich Z. Thylakoid membrane remodeling during state transitions in Arabidopsis. THE PLANT CELL 2008; 20:1029-39. [PMID: 18398051 PMCID: PMC2390732 DOI: 10.1105/tpc.107.055830] [Citation(s) in RCA: 152] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2007] [Revised: 03/12/2008] [Accepted: 03/20/2008] [Indexed: 05/18/2023]
Abstract
Adaptability of oxygenic photosynthetic organisms to fluctuations in light spectral composition and intensity is conferred by state transitions, short-term regulatory processes that enable the photosynthetic apparatus to rapidly adjust to variations in light quality. In green algae and higher plants, these processes are accompanied by reversible structural rearrangements in the thylakoid membranes. We studied these structural changes in the thylakoid membranes of Arabidopsis thaliana chloroplasts using atomic force microscopy, scanning and transmission electron microscopy, and confocal imaging. Based on our results and on the recently determined three-dimensional structure of higher-plant thylakoids trapped in one of the two major light-adapted states, we propose a model for the transitions in membrane architecture. The model suggests that reorganization of the membranes involves fission and fusion events that occur at the interface between the appressed (granal) and nonappressed (stroma lamellar) domains of the thylakoid membranes. Vertical and lateral displacements of the grana layers presumably follow these localized events, eventually leading to macroscopic rearrangements of the entire membrane network.
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Affiliation(s)
- Silvia G Chuartzman
- Department of Biological Chemistry, Weizman Institute of Science, Rehovot 76100, Israel
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Kirchhoff H, Haase W, Haferkamp S, Schott T, Borinski M, Kubitscheck U, Rögner M. Structural and functional self-organization of Photosystem II in grana thylakoids. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2007; 1767:1180-8. [PMID: 17617373 DOI: 10.1016/j.bbabio.2007.05.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2007] [Accepted: 05/31/2007] [Indexed: 11/17/2022]
Abstract
The biogenesis of the well-ordered macromolecular protein arrangement of photosystem (PS)II and light harvesting complex (LHC)II in grana thylakoid membranes is poorly understood and elusive. In this study we examine the capability of self organization of this arrangement by comparing the PSII distribution and antenna organization in isolated untreated stacked thylakoids with restacked membranes after unstacking. The PS II distribution was deduced from freeze-fracture electron microscopy. Furthermore, changes in the antenna organization and in the oligomerization state of photosystem II were monitored by chlorophyll a fluorescence parameters and size analysis of exoplasmatic fracture face particles. Low-salt induced unstacking leads to a randomization and intermixing of the protein complexes. In contrast, macromolecular PSII arrangement as well as antenna organization in thylakoids after restacking by restoring the original solvent composition is virtually identical to stacked control membranes. This indicates that the supramolecular protein arrangement in grana thylakoids is a self-organized process.
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Affiliation(s)
- Helmut Kirchhoff
- Institut für Botanik, Schlossgarten 3, D-48149 Münster, Germany.
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Stoitchkova K, Busheva M, Apostolova E, Andreeva A. Changes in the energy distribution in mutant thylakoid membranes of pea with modified pigment content. II. Changes due to magnesium ions concentration. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2006; 83:11-20. [PMID: 16406551 DOI: 10.1016/j.jphotobiol.2005.11.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2005] [Revised: 11/22/2005] [Accepted: 11/23/2005] [Indexed: 10/25/2022]
Abstract
Low-temperature (77K) steady-state chlorophyll fluorescence emission spectra, room temperature fluorescence and light scattering of thylakoid membranes isolated from pea mutants were studied as a function of Mg2+ concentration. The mutants have modified pigment content and altered structural organization of the pigment-protein complexes, distinct surface electric properties and functions. The analysis of the 77K emission spectra revealed that Mg2+-depletion of the medium caused not only an increased energy flow toward photosystem I in all investigated membranes but also changes in the quenching of the fluorescence, most probably by internal conversion. The results indicated that the macroorganization of the photosynthetic apparatus of mutants at supramolecular level (distribution and segregation of two photosystems in thylakoid membranes) and at supermolecular level (stacking of photosystem II supercomplexes) required different Mg ion concentrations. The data confirmed that the segregation of photosystems and the stacking of thylakoid membranes are two distinct phenomena and elucidated some features of their mechanisms. The segregation is initiated by changes in the lateral microorganization of light harvesting complexes II, their migration (repulsion from photosystem I) and subsequent separation of the two photosystems. Most likely 3D aggregation and formation of macrodomains, containing only photosystem II antenna complexes, play a certain precursory role for the increasing degree of the membrane stacking and the energy coupling between the light harvesting complexes II and the core complexes of photosystem II in the frame of photosystem II supercomplexes.
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Affiliation(s)
- Katerina Stoitchkova
- Sofia University, Faculty of Physics, Department of Condensed Matter Physics, 5, J. Bourchier Blvd., 1164 Sofia, Bulgaria
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Kruse O, Rupprecht J, Mussgnug JH, Dismukes GC, Hankamer B. Photosynthesis: a blueprint for solar energy capture and biohydrogen production technologies. Photochem Photobiol Sci 2005; 4:957-70. [PMID: 16307108 DOI: 10.1039/b506923h] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Solar energy capture, conversion into chemical energy and biopolymers by photoautotrophic organisms, is the basis for almost all life on Earth. A broad range of organisms have developed complex molecular machinery for the efficient conversion of sunlight to chemical energy over the past 3 billion years, which to the present day has not been matched by any man-made technologies. Chlorophyll photochemistry within photosystem II (PSII) drives the water-splitting reaction efficiently at room temperature, in contrast with the thermal dissociation reaction that requires a temperature of ca. 1550 K. The successful elucidation of the high-resolution structure of PSII, and in particular the structure of its Mn(4)Ca cluster provides an invaluable blueprint for designing solar powered biotechnologies for the future. This knowledge, combined with new molecular genetic tools, fully sequenced genomes, and an ever increasing knowledge base of physiological processes of oxygenic phototrophs has inspired scientists from many countries to develop new biotechnological strategies to produce renewable CO(2)-neutral energy from sunlight. This review focuses particularly on the potential of use of cyanobacteria and microalgae for biohydrogen production. Specifically this article reviews the predicted size of the global energy market and the constraints of global warming upon it, before detailing the complex set of biochemical pathways that underlie the photosynthetic process and how they could be modified for improved biohydrogen production.
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Affiliation(s)
- Olaf Kruse
- University of Bielefeld, Department of Biology, 33501 Bielefeld, Germany.
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Vacha F, Bumba L, Kaftan D, Vacha M. Microscopy and single molecule detection in photosynthesis. Micron 2005; 36:483-502. [PMID: 15951188 DOI: 10.1016/j.micron.2005.04.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2005] [Revised: 04/18/2005] [Accepted: 04/19/2005] [Indexed: 11/30/2022]
Abstract
Progress in various fields of microscopy techniques brought up enormous possibilities to study the photosynthesis down to the level of individual pigment-protein complexes. The aim of this review is to present recent developments in the photosynthesis research obtained using such highly advanced techniques. Three areas of microscopy techniques covering optical microscopy, electron microscopy and scanning probe microscopy are reviewed. Whereas the electron microscopy and scanning probe microscopy are used in photosynthesis mainly for structural studies of photosynthetic pigment-protein complexes, the optical microscopy is used also for functional studies.
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Affiliation(s)
- Frantisek Vacha
- Institute of Physical Biology, University of South Bohemia, Budejovice, Czech Republic.
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Raval MK, Biswal B, Biswal UC. The mystery of oxygen evolution: analysis of structure and function of photosystem II, the water-plastoquinone oxido-reductase. PHOTOSYNTHESIS RESEARCH 2005; 85:267-93. [PMID: 16170631 DOI: 10.1007/s11120-005-8163-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2004] [Accepted: 05/26/2005] [Indexed: 05/04/2023]
Abstract
Photosystem II (PS II) of thylakoid membrane of photosynthetic organisms has drawn attention of researchers over the years because it is the only system on Earth that provides us with oxygen that we breathe. In the recent past, structure of PS II has been the focus of research in plant science. The report of X-ray crystallographic structure of PS II complex by the research groups of James Barber and So Iwata in UK is a milestone in the area of research in photosynthesis. It follows the pioneering and elegant work from the laboratories of Horst Witt and W. Saenger in Germany, and J. Shen in Japan. It is time to analyze the historic events during the long journey made by the researchers to arrive at this point. This review makes an attempt to critically review the growth of the advancement of concepts and knowledge on the photosystem in the background of technological development. We conclude the review with perspectives on research and technology that should reveal the complete story of PS II of thylakoid in the future.
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Affiliation(s)
- M K Raval
- P.G. Department of Chemistry, Government College, Sundargarh, Orissa, India.
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Pfeiffer S, Krupinska K. New insights in thylakoid membrane organization. PLANT & CELL PHYSIOLOGY 2005; 46:1443-51. [PMID: 16208039 DOI: 10.1093/pcp/pci156] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
High-pressure freezing (HPF) in combination with freeze substitution (FS) was used to analyse changes in the structure of barley chloroplasts during the daily change of light and darkness. In contrast to conventional treatment of samples, HPF-FS revealed substantial differences in chloroplast shape, volume and ultrastructure in the light period and during darkness. While chloroplasts have an ellipsoidal shape in the light, they have an enlarged and round form during the dark period. Samples collected in the light show the typical differentiation of stroma and grana thylakoids as observed by conventional ultrastructural analyses. In chloroplasts of samples collected during the dark period, thylakoids were swollen and grana stacks to a large extent were disintegrated. Similar changes occurred when leaves in the light were treated with the uncoupler gramicidin. The results suggest that the light-dependent changes in thylakoid membrane organization are related to the light-dependent changes in the ionic milieu of the thylakoid lumen and the stroma.
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Affiliation(s)
- Stephan Pfeiffer
- Central Microscopy, Center of Biology, University of Kiel, Am Botanischen Garten 5, D-24098 Kiel, Germany
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39
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Chow WS, Kim EH, Horton P, Anderson JM. Granal stacking of thylakoid membranes in higher plant chloroplasts: the physicochemical forces at work and the functional consequences that ensue. Photochem Photobiol Sci 2005; 4:1081-90. [PMID: 16307126 DOI: 10.1039/b507310n] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The formation of grana in chloroplasts of higher plants is examined in terms of the subtle interplay of physicochemical forces of attraction and repulsion. The attractive forces between two adjacent membranes comprise (1) van der Waals attraction that depends on the abundance and type of atoms in each membrane, on the distance between the membranes and on the dielectric constant, (2) depletion attraction that generates local order by granal stacking at the expense of greater disorder (i.e. entropy) in the stroma, and (3) an electrostatic attraction of opposite charges located on adjacent membranes. The repulsive forces comprise (1) electrostatic repulsion due to the net negative charge on the outer surface of thylakoid membranes, (2) hydration repulsion that operates at small separations between thylakoid membranes due to layers of bound water molecules, and (3) steric hindrance due to bulky protrusions of Photosystem I (PSI) and ATP synthase into the stroma. In addition, specific interactions may occur, but they await experimental demonstration. Although grana are not essential for photosynthesis, they are ubiquitous in higher plants. Grana may have been selected during evolution for the functional advantages that they confer on higher plants. The functional consequences of grana stacking include (1) enhancement of light capture through a vastly increased area-to-volume ratio and connectivity of several PSIIs with large functional antenna size, (2) the ability to control the lateral separation of PSI from PSII and, therefore, the balanced distribution of excitation energy between two photosystems working in series, (3) the reversible fine-tuning of energy distribution between the photosystems by State 1-State 2 transitions, (4) the ability to regulate light-harvesting via controlled thermal dissipation of excess excitation energy, detected as non-photochemical quenching, (5) dynamic flexibility in the light reactions mediated by a granal structure in response to regulation by a trans-thylakoid pH gradient, (6) delaying the premature degradation of D1 and D2 reaction-centre protein(s) in PSII by harbouring photoinactived PSIIs in appressed granal domains, (7) enhancement of the rate of non-cyclic synthesis of adenosine triphosphate (ATP) as well as the regulation of non-cyclic vs. cyclic ATP synthesis, and (8) the potential increase of photosynthetic capacity for a given composition of chloroplast constituents in full sunlight, concomitantly with enhancement of photochemical efficiency in canopy shade. Hence chloroplast ultrastructure and function are intimately intertwined.
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Affiliation(s)
- Wah Soon Chow
- Photobioenergetics Group, Research School of Biological Sciences, GPO Box 475, Canberra, ACT 2601, Australia.
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Kim EH, Chow WS, Horton P, Anderson JM. Entropy-assisted stacking of thylakoid membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2005; 1708:187-95. [PMID: 15953475 DOI: 10.1016/j.bbabio.2005.03.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2004] [Revised: 03/23/2005] [Accepted: 03/24/2005] [Indexed: 11/18/2022]
Abstract
Chloroplasts in plants and some green algae contain a continuous thylakoid membrane system that is structurally differentiated into stacked granal membranes interconnected by unstacked thylakoids, the stromal lamellae. Experiments were conducted to test the hypothesis that the thermodynamic tendency to increase entropy in chloroplasts contributes to thylakoid stacking to form grana. We show that the addition of bovine serum albumin or dextran, two very different water-soluble macromolecules, to a suspension of envelope-free chloroplasts with initially unstacked thylakoids induced thylakoid stacking. This novel restacking of thylakoids occurred spontaneously, accompanied by lateral segregation of PSII from PSI, thereby mimicking the natural situation. We suggest that such granal formation, induced by the macromolecules, is partly explained as a means of generating more volume for the diffusion of macromolecules in a crowded stromal environment, i.e., greater entropy overall. This mechanism may be relevant in vivo where the stroma has a very high concentration of enzymes of carbon metabolism, and where high metabolic fluxes are required.
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Affiliation(s)
- Eun-Ha Kim
- Photobioenergetics Group, Research School of Biological Sciences, Australian National University, GPO Box 475, Canberra, ACT 2601, Australia
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Dekker JP, Boekema EJ. Supramolecular organization of thylakoid membrane proteins in green plants. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2005; 1706:12-39. [PMID: 15620363 DOI: 10.1016/j.bbabio.2004.09.009] [Citation(s) in RCA: 591] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2004] [Revised: 09/10/2004] [Accepted: 09/15/2004] [Indexed: 11/26/2022]
Abstract
The light reactions of photosynthesis in green plants are mediated by four large protein complexes, embedded in the thylakoid membrane of the chloroplast. Photosystem I (PSI) and Photosystem II (PSII) are both organized into large supercomplexes with variable amounts of membrane-bound peripheral antenna complexes. PSI consists of a monomeric core complex with single copies of four different LHCI proteins and has binding sites for additional LHCI and/or LHCII complexes. PSII supercomplexes are dimeric and contain usually two to four copies of trimeric LHCII complexes. These supercomplexes have a further tendency to associate into megacomplexes or into crystalline domains, of which several types have been characterized. Together with the specific lipid composition, the structural features of the main protein complexes of the thylakoid membranes form the main trigger for the segregation of PSII and LHCII from PSI and ATPase into stacked grana membranes. We suggest that the margins, the strongly folded regions of the membranes that connect the grana, are essentially protein-free, and that protein-protein interactions in the lumen also determine the shape of the grana. We also discuss which mechanisms determine the stacking of the thylakoid membranes and how the supramolecular organization of the pigment-protein complexes in the thylakoid membrane and their flexibility may play roles in various regulatory mechanisms of green plant photosynthesis.
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Affiliation(s)
- Jan P Dekker
- Faculty of Sciences, Division of Physics and Astronomy, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, Netherlands.
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42
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Fagerberg WR, Bornman JF. Modification of leaf cytology and anatomy in Brassica napus grown under above ambient levels of supplemental UV-B radiation. Photochem Photobiol Sci 2005; 4:275-9. [PMID: 15738995 DOI: 10.1039/b400806e] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Plants exposed to natural solar radiation usually show acclimation responses on a daily and seasonal basis. Many of these responses are complex and modified by interactions with acclimation responses to other climatic factors. While changes in photosynthetically active radiation (PAR, 400-700 nm) are the driving force for many acclimation responses in plants, radiation outside the PAR range is also important. Recently, interest has increased in the potential role of UV-A (320-400 nm) and UV-B (280-320 nm) components of sunlight in plant developmental, physiological and daily acclimation processes. In order to explore the role of UV-B further, Brassica napus L. cv Paroll plants were grown to maturity under 13 kJ d(-1) of biologically effective ultraviolet-B radiation (UV-B(BE), 280-320 nm) plus 800 micromol photons m(-2) s(-1) photosynthetically active radiation (PAR, 400-700 nm) or PAR alone. Leaf anatomy and palisade cell structure were quantified using stereological techniques. The leaves of plants grown under UV-B radiation exhibited an increase in overall leaf width, although no change in leaf anatomy was discerned. Palisade cells in UV-B exposed leaves showed a significant decrease in chloroplast, mitochondrial, starch, and microbody volume density (Vv), while the vacuolar Vv increased compared to cells exposed to PAR only. In UV-B exposed leaves, there was an increase in the appressed and non-appressed thylakoid surface area density (Sv) within the chloroplasts. Since the relative proportion of appressed to non-appressed thylakoid surface area did not change, both thylakoid systems changed in concert with each other. Thylakoid stacks were broader and shorter in leaves subjected to UV-B. In general these responses were similar to those which occurred in plants moved from a high to low PAR environment and similar to mature plants exposed to 13 kJ d(-1) UV-B(BE) for only a short period of time. Although UV absorbing pigments increased by 21% in UV-B exposed leaves, there was no significant difference in chlorophyll a,b or carotenoid content compared to plants exposed to only PAR.
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Affiliation(s)
- W R Fagerberg
- Department of Plant Biology, University of New Hampshire, Durham, New Hampshire 03824, USA.
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Kirchhoff H, Borinski M, Lenhert S, Chi L, Büchel C. Transversal and Lateral Exciton Energy Transfer in Grana Thylakoids of Spinach. Biochemistry 2004; 43:14508-16. [PMID: 15533055 DOI: 10.1021/bi048473w] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The excitation energy transfer between photosystem (PS) II complexes was studied in isolated grana disks and thylakoids using chlorophyll a fluorescence induction measurements in the presence of DCMU under stacked and destacked conditions. Destacking of grana was achieved using a sonication protocol in a buffer without MgCl(2). The degree of stacking was controlled and quantified by atomic force microscopy and by the concomitant absorption changes. As expected from the literature, intact thylakoids showed a strong dependency of the connectivity of PSII centers, the F(m)/F(o) ratio as well as the fraction of PSIIbeta centers on the MgCl(2) concentration. In contrast, these parameters did not change in isolated grana disks. In particular, the connectivity remained constantly high irrespective of the degree of destacking. These differences were explained by the high protein density in grana disks, which hinders separation and mixing of proteins sufficiently to change energy transfer properties. Due to the occurrence of stroma lamella in intact thylakoids, intermixing of PSII and PSI is possible and allows for changes in F(m)/F(o) ratio as is the separation of LHCII from PSII, thus leading to an increase in the fraction of PSIIbeta. Even if mixing and separation of proteins are impaired in isolated grana disks, destacking should lead to a decrease in connectivity if transversal excitation energy transfer between two opposite membranes is significant. Because the connectivity is constant over all degrees of destacking employed, we conclude that the energy transfer in granas is mainly lateral.
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Affiliation(s)
- Helmut Kirchhoff
- Institut für Botanik, Schlossgarten 3, Wilhelm-Klemm-Strasse 10, D-48149 Münster, Germany.
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Barber J. Engine of life and big bang of evolution: a personal perspective. PHOTOSYNTHESIS RESEARCH 2004; 80:137-55. [PMID: 16328816 DOI: 10.1023/b:pres.0000030662.04618.27] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Photosystem II (PS II) is the engine for essentially all life on our planet and its beginning 2.5 billion years ago was the 'big bang of evolution.' It produces reducing equivalents for making organic compounds on an enormous scale and at the same time provides us with an oxygenic atmosphere and protection against UV radiation (in the form of the ozone layer). In 1967, when I began my career in photosynthesis research, little was known about PS II. The Z-scheme had been formulated [Hill and Bendall (1960) Nature 186: 136-137] and Boardman and Anderson [(1964) Nature 203: 166-167] had isolated PS II as a discrete biochemical entity. PS II was known not only to be the source of oxygen but of variable chlorophyll fluorescence [Duysens and Sweers (1963) In: Studies on Microalgae and Photosynthetic Bacteria, pp. 353-372. University of Tokyo Press, Tokyo] and delayed chlorophyll fluorescence [Arnold and Davidson (1954) J Gen Physiol 37: 677-684]. P680 had just been discovered [Döring et al. (1967) Z Naturforsch 22b: 639-644]. No wonder the 'black box of PS II' was described at that time by Bessel Kok and George Cheniae [Current Topics in Bioenergetics 1: 1-47 (1966)] as the 'inner sanctum of photosynthesis.' What a change in our level of understanding of PS II since then! The contributions of many talented scientists have unraveled the mechanisms and structural basis of PS II function and we are now very close to revealing the molecular details of the remarkable and thermodynamically demanding reaction which it catalyzes, namely the splitting of water into its elemental constituents. It has been a privilege to be involved in this journey.
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Affiliation(s)
- James Barber
- Wolfson Laboratories, Department of Biological Sciences, South Kensington Campus, Imperial College, London, SW7 2AZ, UK,
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Kirchhoff H, Hinz HJ, Rösgen J. Aggregation and fluorescence quenching of chlorophyll a of the light-harvesting complex II from spinach in vitro. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2003; 1606:105-16. [PMID: 14507431 DOI: 10.1016/s0005-2728(03)00105-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The salt-induced aggregation of the light-harvesting complex (LHC) II isolated from spinach and its correlation with fluorescence quenching of chlorophyll a is reported. Two transitions with distinctly different properties were observed. One transition related to salt-induced fluorescence quenching takes place at low salt concentration and is dependent both on temperature and detergent concentration. This transition seems to be related to a change in the lateral microorganization of LHCII. The second transition occurs at higher salt concentration and involves aggregation. It is independent of temperature and of detergent at sub-cmc concentrations. During the latter transition the small LHCII sheets (approximately 100 nm in diameter) are stacked to form larger aggregates of approximately 3 microm diameter. Based on the comparison between the physical properties of the transition and theoretical models, direct and specific binding of cations can practically be ruled out as driving force for the aggregation. It seems that in vitro aggregation of LHCII is caused by a complex mixture of different effects such as dielectric and electrostatic properties of the solution and surface charges.
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Affiliation(s)
- Helmut Kirchhoff
- Institut für Botanik, Schlossgarten 3, D-48149 Münster, Germany.
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Bumba L, Vácha FE. Electron microscopy in structural studies of Photosystem II. PHOTOSYNTHESIS RESEARCH 2003; 77:1-19. [PMID: 16228380 DOI: 10.1023/a:1024927631196] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Various techniques of electron microscopy (EM) such as ultrathin sectioning, freeze-fracturing, freeze-etching, negative staining and (cryo-)electron crystallography of two-dimensional crystals have been employed, since now, to obtain much of the structural information of the Photosystem II (PS II) pigment-protein complex at both low and high resolution. This review summarizes information about the structure of this membrane complex as well as its arrangement and interactions with the antenna proteins in thylakoid membranes of higher plants and cyanobacteria obtained by means of EM. Results on subunit organization, with the emphasis on the proteins of the oxygen-evolving complex (OEC), are compared with the data obtained by X-ray crystallography of cyanobacterial PS II.
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Affiliation(s)
- Ladislav Bumba
- Faculty of Biological Sciences, University of South Bohemia, Branisovká 31, 370 05, Ceské Budejovice, Czech Republic,
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Staehelin LA. Chloroplast structure: from chlorophyll granules to supra-molecular architecture of thylakoid membranes. PHOTOSYNTHESIS RESEARCH 2003; 76:185-96. [PMID: 16228577 DOI: 10.1023/a:1024994525586] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
This review provides a brief historical account of how microscopical studies of chloroplasts have contributed to our current knowledge of the structural and functional organization of thylakoid membranes. It starts by tracing the origins of the terms plastid, grana, stroma and chloroplasts to light microscopic studies of 19th century German botanists, and then describes how different types of electron microscopical techniques have added to this field. The most notable contributions of thin section electron microscopy include the elucidation of the 3-D organization of thylakoid membranes, the discovery of prolamellar bodies in etioplasts, and the structural changes in thylakoid architecture that accompany the light-dependent transformation of etioplasts into chloroplasts. Attention is then focused on the roles that freeze-fracture and freeze-etch electron microscopy and immuno electron microscopy have played in defining the extent to which the functional complexes of thylakoids are non-randomly distributed between appressed, grana and non-appressed stroma thylakoids. Studies reporting on how this lateral differentiation can be altered experimentally, and how the spatial organization of functional complexes is affected by alterations in the light environment of plants are also included in this discussion. Finally, the review points to the possible uses of electron microscope tomography techniques in future structural studies of thylakoid membranes.
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Affiliation(s)
- L Andrew Staehelin
- Department of Molecular, Cellular and Developmental Biology, UCB 347, University of Colorado, Boulder, CO, 80309-0347, USA,
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Kaftan D, Brumfeld V, Nevo R, Scherz A, Reich Z. From chloroplasts to photosystems: in situ scanning force microscopy on intact thylakoid membranes. EMBO J 2002; 21:6146-53. [PMID: 12426386 PMCID: PMC137213 DOI: 10.1093/emboj/cdf624] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2002] [Revised: 09/17/2002] [Accepted: 09/30/2002] [Indexed: 11/14/2022] Open
Abstract
Envelope-free chloroplasts were imaged in situ by contact and tapping mode scanning force microscopy at a lateral resolution of 3-5 nm and vertical resolution of approximately 0.3 nm. The images of the intact thylakoids revealed detailed structural features of their surface, including individual protein complexes over stroma, grana margin and grana-end membrane domains. Structural and immunogold-assisted assignment of two of these complexes, photosystem I (PS I) and ATP synthase, allowed direct determination of their surface density, which, for both, was found to be highest in grana margins. Surface rearrangements and pigment- protein complex redistribution associated with salt-induced membrane unstacking were followed on native, hydrated specimens. Unstacking was accompanied by a substantial increase in grana diameter and, eventually, led to their merging with the stroma lamellae. Concomitantly, PS IIalpha effective antenna size decreased by 21% and the mean size of membrane particles increased substantially, consistent with attachment of mobile light-harvesting complex II to PS I. The ability to image intact photosynthetic membranes at molecular resolution, as demonstrated here, opens up new vistas to investigate thylakoid structure and function.
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Affiliation(s)
- David Kaftan
- Department of Plant Sciences and Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel and Centre for Photosynthesis, Laboratory of Applied Photobiology and Bio-Imaging, Institute of Landscape Ecology, Zámek 136, 37333 Nové Hrady, Czech Republic Corresponding author e-mail:
| | - Vlad Brumfeld
- Department of Plant Sciences and Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel and Centre for Photosynthesis, Laboratory of Applied Photobiology and Bio-Imaging, Institute of Landscape Ecology, Zámek 136, 37333 Nové Hrady, Czech Republic Corresponding author e-mail:
| | - Reinat Nevo
- Department of Plant Sciences and Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel and Centre for Photosynthesis, Laboratory of Applied Photobiology and Bio-Imaging, Institute of Landscape Ecology, Zámek 136, 37333 Nové Hrady, Czech Republic Corresponding author e-mail:
| | - Avigdor Scherz
- Department of Plant Sciences and Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel and Centre for Photosynthesis, Laboratory of Applied Photobiology and Bio-Imaging, Institute of Landscape Ecology, Zámek 136, 37333 Nové Hrady, Czech Republic Corresponding author e-mail:
| | - Ziv Reich
- Department of Plant Sciences and Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel and Centre for Photosynthesis, Laboratory of Applied Photobiology and Bio-Imaging, Institute of Landscape Ecology, Zámek 136, 37333 Nové Hrady, Czech Republic Corresponding author e-mail:
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Dekker JP, Germano M, van Roon H, Boekema EJ. Photosystem II solubilizes as a monomer by mild detergent treatment of unstacked thylakoid membranes. PHOTOSYNTHESIS RESEARCH 2002; 72:203-10. [PMID: 16228518 DOI: 10.1023/a:1016188818591] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We studied the aggregation state of Photosystem II in stacked and unstacked thylakoid membranes from spinach after a quick and mild solubilization with the non-ionic detergent n-dodecyl-alpha,D-maltoside, followed by analysis by diode-array-assisted gel filtration chromatography and electron microscopy. The results suggest that Photosystem II (PS II) isolates either as a paired, appressed membrane fragment or as a dimeric PS II-LHC II supercomplex upon mild solubilization of stacked thylakoid membranes or PS II grana membranes, but predominantly as a core monomer upon mild solubilization of unstacked thylakoid membranes. Analysis of paired grana membrane fragments reveals that the number of PS II dimers is strongly reduced in single membranes at the margins of the grana membrane fragments. We suggest that unstacking of thylakoid membranes results in a spontaneous disintegration of the PS II-LHC II supercomplexes into separated PS II core monomers and peripheral light-harvesting complexes.
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Affiliation(s)
- Jan P Dekker
- Faculty of Sciences, Division of Physics and Astronomy, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands,
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Anderson JM. Consequences of spatial separation of photosystem 1 and 2 in thylakoid membranes of higher plant chloroplasts. FEBS Lett 2001. [DOI: 10.1016/0014-5793(81)80041-5] [Citation(s) in RCA: 194] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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