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Matzner M, Launhardt L, Barth O, Humbeck K, Goss R, Heilmann I. Inter-Organellar Effects of Defective ER-Localized Linolenic Acid Formation on Thylakoid Lipid Composition, Non-Photochemical Quenching of Chlorophyll Fluorescence and Xanthophyll Cycle Activity in the Arabidopsis fad3 Mutant. PLANT & CELL PHYSIOLOGY 2024; 65:958-974. [PMID: 37991227 DOI: 10.1093/pcp/pcad141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 10/27/2023] [Accepted: 11/07/2023] [Indexed: 11/23/2023]
Abstract
Monogalactosyldiacylglycerol (MGDG) is the main lipid constituent of thylakoids and a structural component of photosystems and photosynthesis-related proteo-lipid complexes in green tissues. Previously reported changes in MGDG abundance upon stress treatments are hypothesized to reflect mobilization of MGDG-based polyunsaturated lipid intermediates to maintain extraplastidial membrane integrity. While exchange of lipid intermediates between compartmental membranes is well documented, physiological consequences of mobilizing an essential thylakoid lipid, such as MGDG, for an alternative purpose are not well understood. Arabidopsis seedlings exposed to mild (50 mM) salt treatment displayed significantly increased abundance of both MGDG and the extraplastidial lipid, phosphatidylcholine (PC). Interestingly, similar increases in MGDG and PC were observed in Arabidopsis fad3 mutant seedlings defective in endoplasmic reticulum (ER)-localized linolenic acid formation, in which compensatory plastid-to-ER-directed mobilization of linolenic acid-containing intermediates takes place. The postulated (salt) or evident (fad3) plastid-ER exchange of intermediates concurred with altered thylakoid function according to parameters of photosynthetic performance. While salt treatment of wild-type seedlings inhibited photosynthetic parameters in a dose-dependent manner, interestingly, untreated fad3 mutants did not show overall reduced photosynthetic quantum yield. By contrast, we observed a reduction specifically of non-photochemical quenching (NPQ) under high light, representing only part of observed salt effects. The decreased NPQ in the fad3 mutant was accompanied by reduced activity of the xanthophyll cycle, leading to a reduced concentration of the NPQ-effective pigment zeaxanthin. The findings suggest that altered ER-located fatty acid unsaturation and ensuing inter-organellar compensation impacts on the function of specific thylakoid enzymes, rather than globally affecting thylakoid function.
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Affiliation(s)
- Monique Matzner
- Department of Plant Biochemistry, Institute of Biochemistry and Biotechnology, Charles Tanford Protein Science Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3a, Halle (Saale) 06120, Germany
| | - Larissa Launhardt
- Department of Plant Biochemistry, Institute of Biochemistry and Biotechnology, Charles Tanford Protein Science Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3a, Halle (Saale) 06120, Germany
| | - Olaf Barth
- Department of Plant Physiology, Institute of Biology, Martin Luther University Halle-Wittenberg, Weinbergweg 10, Halle (Saale) 06120, Germany
| | - Klaus Humbeck
- Department of Plant Physiology, Institute of Biology, Martin Luther University Halle-Wittenberg, Weinbergweg 10, Halle (Saale) 06120, Germany
| | - Reimund Goss
- Department of Plant Physiology, Institute of Biology, University of Leipzig, Johannisallee 23, Leipzig 04103, Germany
| | - Ingo Heilmann
- Department of Plant Biochemistry, Institute of Biochemistry and Biotechnology, Charles Tanford Protein Science Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3a, Halle (Saale) 06120, Germany
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Lipid Polymorphism of the Subchloroplast-Granum and Stroma Thylakoid Membrane-Particles. I. 31P-NMR Spectroscopy. Cells 2021; 10:cells10092354. [PMID: 34572003 PMCID: PMC8470346 DOI: 10.3390/cells10092354] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 08/29/2021] [Accepted: 09/05/2021] [Indexed: 11/23/2022] Open
Abstract
Build-up of the energized state of thylakoid membranes and the synthesis of ATP are warranted by organizing their bulk lipids into a bilayer. However, the major lipid species of these membranes, monogalactosyldiacylglycerol, is a non-bilayer lipid. It has also been documented that fully functional thylakoid membranes, in addition to the bilayer, contain an inverted hexagonal (HII) phase and two isotropic phases. To shed light on the origin of these non-lamellar phases, we performed 31P-NMR spectroscopy experiments on sub-chloroplast particles of spinach: stacked, granum and unstacked, stroma thylakoid membranes. These membranes exhibited similar lipid polymorphism as the whole thylakoids. Saturation transfer experiments, applying saturating pulses at characteristic frequencies at 5 °C, provided evidence for distinct lipid phases—with component spectra very similar to those derived from mathematical deconvolution of the 31P-NMR spectra. Wheat-germ lipase treatment of samples selectively eliminated the phases exhibiting sharp isotropic peaks, suggesting easier accessibility of these lipids compared to the bilayer and the HII phases. Gradually increasing lipid exchanges were observed between the bilayer and the two isotropic phases upon gradually elevating the temperature from 5 to 35 °C, suggesting close connections between these lipid phases. Data concerning the identity and structural and functional roles of different lipid phases will be presented in the accompanying paper.
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Dlouhý O, Kurasová I, Karlický V, Javornik U, Šket P, Petrova NZ, Krumova SB, Plavec J, Ughy B, Špunda V, Garab G. Modulation of non-bilayer lipid phases and the structure and functions of thylakoid membranes: effects on the water-soluble enzyme violaxanthin de-epoxidase. Sci Rep 2020; 10:11959. [PMID: 32686730 PMCID: PMC7371714 DOI: 10.1038/s41598-020-68854-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 06/26/2020] [Indexed: 12/19/2022] Open
Abstract
The role of non-bilayer lipids and non-lamellar lipid phases in biological membranes is an enigmatic problem of membrane biology. Non-bilayer lipids are present in large amounts in all membranes; in energy-converting membranes they constitute about half of their total lipid content—yet their functional state is a bilayer. In vitro experiments revealed that the functioning of the water-soluble violaxanthin de-epoxidase (VDE) enzyme of plant thylakoids requires the presence of a non-bilayer lipid phase. 31P-NMR spectroscopy has provided evidence on lipid polymorphism in functional thylakoid membranes. Here we reveal reversible pH- and temperature-dependent changes of the lipid-phase behaviour, particularly the flexibility of isotropic non-lamellar phases, of isolated spinach thylakoids. These reorganizations are accompanied by changes in the permeability and thermodynamic parameters of the membranes and appear to control the activity of VDE and the photoprotective mechanism of non-photochemical quenching of chlorophyll-a fluorescence. The data demonstrate, for the first time in native membranes, the modulation of the activity of a water-soluble enzyme by a non-bilayer lipid phase.
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Affiliation(s)
- Ondřej Dlouhý
- Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Irena Kurasová
- Faculty of Science, University of Ostrava, Ostrava, Czech Republic.,Global Change Research Institute, Czech Academy of Sciences, Brno, Czech Republic
| | - Václav Karlický
- Faculty of Science, University of Ostrava, Ostrava, Czech Republic.,Global Change Research Institute, Czech Academy of Sciences, Brno, Czech Republic
| | - Uroš Javornik
- Slovenian NMR Center, National Institute of Chemistry, Ljubljana, Slovenia
| | - Primož Šket
- Slovenian NMR Center, National Institute of Chemistry, Ljubljana, Slovenia.,EN-FIST Center of Excellence, Ljubljana, Slovenia
| | - Nia Z Petrova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Sashka B Krumova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Janez Plavec
- Slovenian NMR Center, National Institute of Chemistry, Ljubljana, Slovenia.,EN-FIST Center of Excellence, Ljubljana, Slovenia.,Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Bettina Ughy
- Faculty of Science, University of Ostrava, Ostrava, Czech Republic. .,Institute of Plant Biology, Biological Research Centre, Szeged, Hungary.
| | - Vladimír Špunda
- Faculty of Science, University of Ostrava, Ostrava, Czech Republic. .,Global Change Research Institute, Czech Academy of Sciences, Brno, Czech Republic.
| | - Győző Garab
- Faculty of Science, University of Ostrava, Ostrava, Czech Republic. .,Institute of Plant Biology, Biological Research Centre, Szeged, Hungary.
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Goss R, Latowski D. Lipid Dependence of Xanthophyll Cycling in Higher Plants and Algae. FRONTIERS IN PLANT SCIENCE 2020; 11:455. [PMID: 32425962 PMCID: PMC7212465 DOI: 10.3389/fpls.2020.00455] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 03/27/2020] [Indexed: 05/11/2023]
Abstract
The xanthophyll cycles of higher plants and algae represent an important photoprotection mechanism. Two main xanthophyll cycles are known, the violaxanthin cycle of higher plants, green and brown algae and the diadinoxanthin cycle of Bacillariophyceae, Xanthophyceae, Haptophyceae, and Dinophyceae. The forward reaction of the xanthophyll cycles consists of the enzymatic de-epoxidation of violaxanthin to antheraxanthin and zeaxanthin or diadinoxanthin to diatoxanthin during periods of high light illumination. It is catalyzed by the enzymes violaxanthin or diadinoxanthin de-epoxidase. During low light or darkness the back reaction of the cycle, which is catalyzed by the enzymes zeaxanthin or diatoxanthin epoxidase, restores the epoxidized xanthophylls by a re-introduction of the epoxy groups. The de-epoxidation reaction takes place in the lipid phase of the thylakoid membrane and thus, depends on the nature, three dimensional structure and function of the thylakoid lipids. As the xanthophyll cycle pigments are usually associated with the photosynthetic light-harvesting proteins, structural re-arrangements of the proteins and changes in the protein-lipid interactions play an additional role for the operation of the xanthophyll cycles. In the present review we give an introduction to the lipid and fatty acid composition of thylakoid membranes of higher plants and algae. We introduce the readers to the reaction sequences, enzymes and function of the different xanthophyll cycles. The main focus of the review lies on the lipid dependence of xanthophyll cycling. We summarize the current knowledge about the role of lipids in the solubilization of xanthophyll cycle pigments. We address the importance of the three-dimensional lipid structures for the enzymatic xanthophyll conversion, with a special focus on non-bilayer lipid phases which are formed by the main thylakoid membrane lipid monogalactosyldiacylglycerol. We additionally describe how lipids and light-harvesting complexes interact in the thylakoid membrane and how these interactions can affect the structure of the thylakoids. In a dedicated chapter we offer a short overview of current membrane models, including the concept of membrane domains. We then use these concepts to present a model of the operative xanthophyll cycle as a transient thylakoid membrane domain which is formed during high light illumination of plants or algal cells.
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Affiliation(s)
- Reimund Goss
- Department of Plant Physiology, Institute of Biology, Leipzig University, Leipzig, Germany
| | - Dariusz Latowski
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
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de Lange N, Leermakers FAM, Kleijn JM. Self-limiting aggregation of phospholipid vesicles. SOFT MATTER 2020; 16:2379-2389. [PMID: 32064491 DOI: 10.1039/c9sm01692a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Lipid vesicles are widely used as model systems to study biological membranes. The self-assembly of such vesicles into vesicle pairs provides further opportunity to study interactions between membranes. However, formation of vesicle pairs, while subsequently keeping their colloidal stability intact, is challenging. Here, we report on three strategies that lead to stable finite-sized aggregates of phospholipid vesicles: (i) vesicles containing biotinylated lipids are coupled together with streptavidin, (ii) bridging attraction is exploited by adding cationic polymers (polylysine) to negatively charged vesicles, and (iii) temperature as a control parameter is used for the aggregation of vesicles mixed with a thermo-sensitive surfactant. While each strategy has its own advantages and disadvantages for vesicle pair formation, the latter strategy additionally shows reversible limited aggregation: above the LCST of pNIPAm, vesicle pairs are formed, while below the LCST, single vesicles prevail. Mixing protocols were assessed by dynamic and static light scattering as well as fluorescence correlation spectroscopy to determine under which conditions vesicle pairs dominate the aggregate size distribution. We have strong indications that without subsequent perturbation, the individual vesicles remain intact and no fusion or leakage between vesicles occurs after vesicle pairs have formed.
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Affiliation(s)
- N de Lange
- Physical Chemistry & Soft Matter, Wageningen University and Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.
| | - F A M Leermakers
- Physical Chemistry & Soft Matter, Wageningen University and Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.
| | - J M Kleijn
- Physical Chemistry & Soft Matter, Wageningen University and Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.
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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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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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Lipid polymorphism in chloroplast thylakoid membranes - as revealed by 31P-NMR and time-resolved merocyanine fluorescence spectroscopy. Sci Rep 2017; 7:13343. [PMID: 29042649 PMCID: PMC5645462 DOI: 10.1038/s41598-017-13574-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 09/25/2017] [Indexed: 01/22/2023] Open
Abstract
Chloroplast thylakoid membranes contain virtually all components of the energy-converting photosynthetic machinery. Their energized state, driving ATP synthesis, is enabled by the bilayer organization of the membrane. However, their most abundant lipid species is a non-bilayer-forming lipid, monogalactosyl-diacylglycerol; the role of lipid polymorphism in these membranes is poorly understood. Earlier 31P-NMR experiments revealed the coexistence of a bilayer and a non-bilayer, isotropic lipid phase in spinach thylakoids. Packing of lipid molecules, tested by fluorescence spectroscopy of the lipophilic dye, merocyanine-540 (MC540), also displayed heterogeneity. Now, our 31P-NMR experiments on spinach thylakoids uncover the presence of a bilayer and three non-bilayer lipid phases; time-resolved fluorescence spectroscopy of MC540 also reveals the presence of multiple lipidic environments. It is also shown by 31P-NMR that: (i) some lipid phases are sensitive to the osmolarity and ionic strength of the medium, (ii) a lipid phase can be modulated by catalytic hydrogenation of fatty acids and (iii) a marked increase of one of the non-bilayer phases upon lowering the pH of the medium is observed. These data provide additional experimental evidence for the polymorphism of lipid phases in thylakoids and suggest that non-bilayer phases play an active role in the structural dynamics of thylakoid membranes.
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Schaller-Laudel S, Latowski D, Jemioła-Rzemińska M, Strzałka K, Daum S, Bacia K, Wilhelm C, Goss R. Influence of thylakoid membrane lipids on the structure of aggregated light-harvesting complexes of the diatom Thalassiosira pseudonana and the green alga Mantoniella squamata. PHYSIOLOGIA PLANTARUM 2017; 160:339-358. [PMID: 28317130 DOI: 10.1111/ppl.12565] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 02/02/2017] [Accepted: 02/17/2017] [Indexed: 05/25/2023]
Abstract
The study investigated the effect of the thylakoid membrane lipids monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG), sulphoquinovosyldiacylglycerol (SQDG) and phosphatidylglycerol (PG) on the structure of two algal light-harvesting complexes (LHCs). In contrast to higher plants whose thylakoid membranes are characterized by an enrichment of the neutral galactolipids MGDG and DGDG, both the green alga Mantoniella squamata and the centric diatom Thalassiosira pseudonana contain membranes with a high content of the negatively charged lipids SQDG and PG. The algal thylakoids do not show the typical grana-stroma differentiation of higher plants but a regular arrangement. To analyze the effect of the membrane lipids, the fucoxanthin chlorophyll protein (FCP) complex of T. pseudonana and the LHC of M. squamata (MLHC) were prepared by successive cation precipitation using Triton X-100 as detergent. With this method, it is possible to isolate LHCs with a reduced amount of associated lipids in an aggregated state. The results from 77 K fluorescence and photon correlation spectroscopy show that neither the neutral galactolipids nor the negatively charged lipids are able to significantly alter the aggregation state of the FCP or the MLHC. This is in contrast to higher plants where SQDG and PG lead to a strong disaggregation of the LHCII whereas MGDG and DGDG induce the formation of large macroaggregates. The results indicate that LHCs which are integrated into thylakoid membranes with a high amount of negatively charged lipids and a regular arrangement are less sensitive to lipid-induced structural alterations than their counterparts in membranes enriched in neutral lipids with a grana-stroma differentiation.
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Affiliation(s)
| | - Dariusz Latowski
- Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, 30-387, Poland
| | | | - Kazimierz Strzałka
- Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, 30-387, Poland
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, 30-387, Poland
| | - Sebastian Daum
- Institute of Chemistry, Martin-Luther-University Halle-Wittenberg, Halle, D-06120, Germany
| | - Kirsten Bacia
- Institute of Chemistry, Martin-Luther-University Halle-Wittenberg, Halle, D-06120, Germany
| | - Christian Wilhelm
- Institute of Biology, University of Leipzig, Leipzig, D-04103, Germany
| | - Reimund Goss
- Institute of Biology, University of Leipzig, Leipzig, D-04103, Germany
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Garab G, Ughy B, Goss R. Role of MGDG and Non-bilayer Lipid Phases in the Structure and Dynamics of Chloroplast Thylakoid Membranes. Subcell Biochem 2016; 86:127-57. [PMID: 27023234 DOI: 10.1007/978-3-319-25979-6_6] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In this chapter we focus our attention on the enigmatic structural and functional roles of the major, non-bilayer lipid monogalactosyl-diacylglycerol (MGDG) in the thylakoid membrane. We give an overview on the state of the art on the role of MGDG and non-bilayer lipid phases in the xanthophyll cycles in different organisms. We also discuss data on the roles of MGDG and other lipid molecules found in crystal structures of different photosynthetic protein complexes and in lipid-protein assemblies, as well as in the self-assembly of the multilamellar membrane system. Comparison and critical evaluation of different membrane models--that take into account and capitalize on the special properties of non-bilayer lipids and/or non-bilayer lipid phases, and thus to smaller or larger extents deviate from the 'standard' Singer-Nicolson model--will conclude this review. With this chapter the authors hope to further stimulate the discussion about, what we think, is perhaps the most exciting question of membrane biophysics: the why and wherefore of non-bilayer lipids and lipid phases in, or in association with, bilayer biological membranes.
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Affiliation(s)
- Győző Garab
- Biological Research Center, Hungarian Academy of Sciences, Szeged, Hungary.
| | - Bettina Ughy
- Biological Research Center, Hungarian Academy of Sciences, Szeged, Hungary
| | - Reimund Goss
- Institute of Biology, Department of Plant Physiology, University of Leipzig, Leipzig, Germany
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Garab G. Self-assembly and structural-functional flexibility of oxygenic photosynthetic machineries: personal perspectives. PHOTOSYNTHESIS RESEARCH 2016; 127:131-50. [PMID: 26494196 DOI: 10.1007/s11120-015-0192-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 09/02/2015] [Indexed: 05/24/2023]
Abstract
This short review, with a bit of historical aspect and a strong personal bias and emphases on open questions, is focusing on the (macro-)organization and structural-functional flexibilities of the photosynthetic apparatus of oxygenic photosynthetic organisms at different levels of the structural complexity-selected problems that have attracted most my attention in the past years and decades. These include (i) the anisotropic organization of the pigment-protein complexes and photosynthetic membranes-a basic organizing principle of living matter, which can, and probably should be adopted to intelligent materials; (ii) the organization of protein complexes into chiral macrodomains, large self-assembling highly organized but structurally flexible entities with unique spectroscopic fingerprints-structures, where, important, high-level regulatory functions appear to 'reside'; (iii) a novel, dissipation-assisted mechanism of structural changes, based on a thermo-optic effect: ultrafast thermal transients in the close vicinity of dissipation of unused excitation energy, which is capable of inducing elementary structural changes; it makes plants capable of responding to excess excitation with reaction rates proportional to the overexcitation above the light-saturation of photosynthesis; (iv) the 3D ultrastructure of the granum-stroma thylakoid membrane assembly and other multilamellar membrane systems, and their remodelings-associated with regulatory mechanisms; (v) the molecular organization and structural-functional plasticity of the main light-harvesting complex of plants, in relation to their crystal structure and different in vivo and in vitro states; and (vi) the enigmatic role of non-bilayer lipids and lipid phases in the bilayer thylakoid membrane-warranting its high protein content and contributing to its structural flexibility.
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Andreeva TD, Krumova SB, Minkov IL, Busheva M, Lalchev Z, Taneva SG. Protonation-induced changes in the macroorganization of LHCII monolayers. Colloids Surf A Physicochem Eng Asp 2014. [DOI: 10.1016/j.colsurfa.2013.12.044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Hind G, Wall JS, Várkonyi Z, Istokovics A, Lambrev PH, Garab G. Membrane crystals of plant light-harvesting complex II disassemble reversibly in light. PLANT & CELL PHYSIOLOGY 2014; 55:1296-303. [PMID: 24793749 PMCID: PMC4184361 DOI: 10.1093/pcp/pcu064] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 04/28/2014] [Indexed: 05/08/2023]
Abstract
Using the mass-measuring capability of scanning transmission electron microscopy, we demonstrate that membrane crystals of the main light-harvesting complex of plants possess the ability to undergo light-induced dark-reversible disassociations, independently of the photochemical apparatus. This is the first direct visualization of light-driven reversible reorganizations in an isolated photosynthetic antenna. These reorganizations, identified earlier by circular dichroism (CD), can be accounted for by a biological thermo-optic transition: structural changes are induced by fast heat transients and thermal instabilities near the dissipation, and self-association of the complexes in the lipid matrix. A comparable process in native membranes is indicated by earlier findings of essentially identical kinetics, and intensity and temperature dependences of the ΔCD in granal thylakoids.
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Affiliation(s)
- Geoffrey Hind
- Biosciences Department, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Joseph S Wall
- Biosciences Department, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Zsuzsanna Várkonyi
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, PO Box 521, H-6701, Hungary
| | - Anita Istokovics
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, PO Box 521, H-6701, Hungary
| | - Petar H Lambrev
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, PO Box 521, H-6701, Hungary
| | - Győző Garab
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, PO Box 521, H-6701, Hungary
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Alterations in Structural Organization Affect the Functional Ability of Photosynthetic Apparatus. ACTA ACUST UNITED AC 2014. [DOI: 10.1201/b16675-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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15
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Garab G. Hierarchical organization and structural flexibility of thylakoid membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1837:481-94. [PMID: 24333385 DOI: 10.1016/j.bbabio.2013.12.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 11/26/2013] [Accepted: 12/02/2013] [Indexed: 10/25/2022]
Abstract
Chloroplast thylakoid membranes accommodate densely packed protein complexes in ordered, often semi-crystalline arrays and are assembled into highly organized multilamellar systems, an organization warranting a substantial degree of stability. At the same time, they exhibit remarkable structural flexibility, which appears to play important - yet not fully understood - roles in different short-term adaptation mechanisms in response to rapidly changing environmental conditions. In this review I will focus on dynamic features of the hierarchically organized photosynthetic machineries at different levels of structural complexity: (i) isolated light harvesting complexes, (ii) molecular macroassemblies and supercomplexes, (iii) thylakoid membranes and (iv) their multilamellar membrane systems. Special attention will be paid to the most abundant systems, the major light harvesting antenna complex, LHCII, and to grana. Two physical mechanisms, which are less frequently treated in the literature, will receive special attention: (i) thermo-optic mechanism -elementary structural changes elicited by ultrafast local heat transients due to the dissipation of photon energy, which operates both in isolated antenna assemblies and the native thylakoid membranes, regulates important enzymatic functions and appears to play role in light adaptation and photoprotection mechanisms; and (ii) the mechanism by which non-bilayer lipids and lipid phases play key role in the functioning of xanthophyll cycle de-epoxidases and are proposed to regulate the protein-to-lipid ratio in thylakoid membranes and contribute to membrane dynamics. This article is part of a Special Issue entitled: Dynamic and ultrastructure of bioenergetic membranes and their components.
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Affiliation(s)
- Győző Garab
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, P.O. Box 521, H-6701 Szeged, Hungary.
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16
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Verma D, Jin S, Kanagaraj A, Singh ND, Daniel J, Kolattukudy PE, Miller M, Daniell H. Expression of fungal cutinase and swollenin in tobacco chloroplasts reveals novel enzyme functions and/or substrates. PLoS One 2013; 8:e57187. [PMID: 23451186 PMCID: PMC3581449 DOI: 10.1371/journal.pone.0057187] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2012] [Accepted: 01/18/2013] [Indexed: 12/22/2022] Open
Abstract
In order to produce low-cost biomass hydrolyzing enzymes, transplastomic lines were generated that expressed cutinase or swollenin within chloroplasts. While swollenin expressing plants were homoplasmic, cutinase transplastomic lines remained heteroplasmic. Both transplastomic lines showed interesting modifications in their phenotype, chloroplast structure, and functions. Ultrastructural analysis of chloroplasts from cutinase- and swollenin-expressing plants did not show typical lens shape and granal stacks. But, their thylakoid membranes showed unique scroll like structures and chloroplast envelope displayed protrusions, stretching into the cytoplasm. Unusual honeycomb structures typically observed in etioplasts were observed in mature chloroplasts expressing swollenin. Treatment of cotton fiber with chloroplast-derived swollenin showed enlarged segments and the intertwined inner fibers were irreversibly unwound and fully opened up due to expansin activity of swollenin, causing disruption of hydrogen bonds in cellulose fibers. Cutinase transplastomic plants showed esterase and lipase activity, while swollenin transplastomic lines lacked such enzyme activities. Higher plants contain two major galactolipids, monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG), in their chloroplast thylakoid membranes that play distinct roles in their structural organization. Surprisingly, purified cutinase effectively hydrolyzed DGDG to MGDG, showing alpha galactosidase activity. Such hydrolysis resulted in unstacking of granal thylakoids in chloroplasts and other structural changes. These results demonstrate DGDG as novel substrate and function for cutinase. Both MGDG and DGDG were reduced up to 47.7% and 39.7% in cutinase and 68.5% and 67.5% in swollenin expressing plants. Novel properties and functions of both enzymes reported here for the first time should lead to better understanding and enhanced biomass hydrolysis.
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Affiliation(s)
- Dheeraj Verma
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, United States of America
| | - Shuangxia Jin
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, United States of America
| | - Anderson Kanagaraj
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, United States of America
| | - Nameirakpam D. Singh
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, United States of America
| | - Jaiyanth Daniel
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, United States of America
| | - Pappachan E. Kolattukudy
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, United States of America
| | - Michael Miller
- Research Instrumentation Facility, Auburn University, Auburn, Alabama, United States of America
| | - Henry Daniell
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, United States of America
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17
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Zubik M, Luchowski R, Puzio M, Janik E, Bednarska J, Grudzinski W, Gruszecki WI. The negative feedback molecular mechanism which regulates excitation level in the plant photosynthetic complex LHCII: towards identification of the energy dissipative state. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1827:355-64. [PMID: 23219754 DOI: 10.1016/j.bbabio.2012.11.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 11/19/2012] [Accepted: 11/26/2012] [Indexed: 11/24/2022]
Abstract
Overexcitation of the photosynthetic apparatus is potentially dangerous because it can cause oxidative damage. Photoprotection realized via the feedback de-excitation in the pigment-protein light-harvesting complex LHCII, embedded in the chloroplast lipid environment, was studied with use of the steady-state and time-resolved fluorescence spectroscopy techniques. Illumination of LHCII results in the pronounced singlet excitation quenching, demonstrated by decreased quantum yield of the chlorophyll a fluorescence and shortening of the fluorescence lifetimes. Analysis of the 77K chlorophyll a fluorescence emission spectra reveals that the light-driven excitation quenching in LHCII is associated with the intensity increase of the spectral band in the region of 700nm, relative to the principal band at 680nm. The average chlorophyll a fluorescence lifetime at 700nm changes drastically upon temperature decrease: from 1.04ns at 300K to 3.63ns at 77K. The results of the experiments lead us to conclude that: (i) the 700nm band is associated with the inter-trimer interactions which result in the formation of the chlorophyll low-energy states acting as energy traps and non-radiative dissipation centers; (ii) the Arrhenius analysis, supported by the results of the FTIR measurements, suggests that the photo-reaction can be associated with breaking of hydrogen bonds. Possible involvement of photo-isomerization of neoxanthin, reported previously (Biochim. Biophys. Acta 1807 (2011) 1237-1243) in generation of the low-energy traps in LHCII is discussed.
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Affiliation(s)
- Monika Zubik
- Department of Biophysics, Institute of Physics, Maria Curie-Sklodowska University, Lublin, Poland
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18
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Zhang Y, Liu C, Yang C. Analysis of heat-induced disassembly process of three different monomeric forms of the major light-harvesting chlorophyll a/b complex of photosystem II. PHOTOSYNTHESIS RESEARCH 2012; 111:103-11. [PMID: 21892736 DOI: 10.1007/s11120-011-9677-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2011] [Accepted: 07/26/2011] [Indexed: 05/20/2023]
Abstract
The temperature-dependent disassembly process of three monomeric isoforms, namely Lhcb1, Lhcb2, and Lhcb3, of the major light-harvesting chlorophyll (Chl) a/b complexes of photosystem II (LHCIIb) were characterized by observing the changes of absorption spectra, circular dichroism (CD), and dissociation processes of the bound pigments to the in vitro reconstituted complexes subjected to high temperatures. Our results suggest that the three isoforms of LHCIIb undergo conformational rearrangements, structural changes, and dissociations of the bound pigments when the ambient temperature increases from 20 to 90°C. The conformation of the complexes changed sensitively to the changing temperatures because the absorption peaks in the Soret region (436 and 471 nm) and the Qy region (650-660 and 680 nm) decreased immediately upon elevating the ambient temperatures. Analyzing temperature-dependent denaturing and pigment dissociation process, we can divide the disassembly process into three stages: The first stage, appeared from 20°C to around 50-60°C, was characterized by the diminishment of the absorption around 650-660 and 680 nm, accompanied by the blue-shift of the peak at 471 nm and disappearance of the absorbance at 436 nm, which is related to changes in the transition energy of the Chl b cluster, and the red-most Chl a cluster in the LHCIIb. The second stage, beginning at about 50-60°C, was signified by the diminishment of the CD signal between (+)483 nm and (-)490 nm, which implied the disturbance of dipole-dipole interaction of pigments, and the onset of the pigment dissociation. The last stage, beginning at about 70-80°C, indicates the complete dissociation of the pigments from the complex. The physiological aspects of the three stages in the denaturing process are also discussed.
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Affiliation(s)
- Yajie Zhang
- Key Laboratory of Photobiology; Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Beijing, 100093, China
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19
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Velikova V, Várkonyi Z, Szabó M, Maslenkova L, Nogues I, Kovács L, Peeva V, Busheva M, Garab G, Sharkey TD, Loreto F. Increased thermostability of thylakoid membranes in isoprene-emitting leaves probed with three biophysical techniques. PLANT PHYSIOLOGY 2011; 157:905-16. [PMID: 21807886 PMCID: PMC3192565 DOI: 10.1104/pp.111.182519] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Accepted: 07/28/2011] [Indexed: 05/19/2023]
Abstract
Three biophysical approaches were used to get insight into increased thermostability of thylakoid membranes in isoprene-emittingplants.Arabidopsis (Arabidopsis thaliana) plants genetically modified to make isoprene and Platanus orientalis leaves, in which isoprene emission was chemically inhibited, were used. First, in the circular dichroism spectrum the transition temperature of the main band at 694 nm was higher in the presence of isoprene, indicating that the heat stability of chiral macrodomains of chloroplast membranes, and specifically the stability of ordered arrays of light-harvesting complex II-photosystem II in the stacked region of the thylakoid grana, was improved in the presence of isoprene. Second, the decay of electrochromic absorbance changes resulting from the electric field component of the proton motive force (ΔA₅₁₅) was evaluated following single-turnover saturating flashes. The decay of ΔA₅₁₅ was faster in the absence of isoprene when leaves of Arabidopsis and Platanus were exposed to high temperature, indicating that isoprene protects the thylakoid membranes against leakiness at elevated temperature. Finally, thermoluminescence measurements revealed that S₂Q(B)⁻ charge recombination was shifted to higher temperature in Arabidopsis and Platanus plants in the presence of isoprene, indicating higher activation energy for S₂Q(B)⁻ redox pair, which enables isoprene-emitting plants to perform efficient primary photochemistry of photosystem II even at higher temperatures. The data provide biophysical evidence that isoprene improves the integrity and functionality of the thylakoid membranes at high temperature. These results contribute to our understanding of isoprene mechanism of action in plant protection against environmental stresses.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Francesco Loreto
- Institute of Plant Physiology and Genetics (V.V., L.M., V.P.) and Institute of Biophysics and Biomedical Engineering (M.B.), Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, 6726 Szeged, Hungary (Z.V., M.S., L.K., G.G.); Institute of Agroenvironmental and Forest Biology, National Research Council, 00015 Monterotondo, Rome, Italy (I.N.); Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824 (T.D.S.); Institute for Plant Protection, National Research Council, 50019 Sesto Fiorentino, Florence, Italy (F.L.)
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20
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Schaller S, Latowski D, Jemioła-Rzemińska M, Dawood A, Wilhelm C, Strzałka K, Goss R. Regulation of LHCII aggregation by different thylakoid membrane lipids. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1807:326-35. [PMID: 21215252 DOI: 10.1016/j.bbabio.2010.12.017] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Revised: 12/06/2010] [Accepted: 12/29/2010] [Indexed: 10/18/2022]
Abstract
In the present study the influence of the lipid environment on the organization of the main light-harvesting complex of photosystem II (LHCII) was investigated by 77K fluorescence spectroscopy. Measurements were carried out with a lipid-depleted and highly aggregated LHCII which was supplemented with the different thylakoid membrane lipids. The results show that the thylakoid lipids are able to modulate the spectroscopic properties of the LHCII aggregates and that the extent of the lipid effect depends on both the lipid species and the lipid concentration. Addition of the neutral galactolipids monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) seems to induce a modification of the disorganized structures of the lipid-depleted LHCII and to support the aggregated state of the complex. In contrast, we found that the anionic lipids sulfoquinovosyldiacylglycerol (SQDG) and phosphatidylglycerol (PG) exert a strong disaggregating effect on the isolated LHCII. LHCII disaggregation was partly suppressed under a high proton concentration and in the presence of cations. The strongest suppression was visible at the lowest pH value (pH 5) and the highest Mg(2+) concentration (40 mM) used in the present study. This suggests that the negative charge of the anionic lipids in conjunction with negatively charged domains of the LHCII proteins is responsible for the disaggregation. Additional measurements by photon correlation spectroscopy and sucrose gradient centrifugation, which were used to gain information about the size and molecular mass of the LHCII aggregates, confirmed the results of the fluorescence spectroscopy. LHCII treated with MGDG and DGDG formed an increased number of aggregates with large particle sizes in the micromm-range, whereas the incubation with anionic lipids led to much smaller LHCII particles (around 40 nm in the case of PG) with a homogeneous distribution.
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Affiliation(s)
- Susann Schaller
- Institute of Biology I, Plant Physiology, University of Leipzig, Johannisallee 21-23, 04103 Leipzig, Germany
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21
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Simidjiev I, Várkonyi Z, Lambrev PH, Garab G. Isolation and characterization of lamellar aggregates of LHCII and LHCII-lipid macro-assemblies with light-inducible structural transitions. Methods Mol Biol 2011; 684:127-38. [PMID: 20960127 DOI: 10.1007/978-1-60761-925-3_12] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We describe the method of isolation of loosely stacked lamellar aggregates of LHCII that are capable of undergoing light-induced reversible structural changes, similar to those in granal thylakoid membranes (LHCII, the main chlorophyll a/b light-harvesting antenna complex of photosystem II). This unexpected structural flexibility of the antenna complexes depends largely on the lipid content that is retained during the isolation. As revealed by circular dichroism, in lipid-LHCII aggregates, the pigment-pigment interactions are very similar to those in the thylakoid membranes, while they differ significantly from those in solubilized trimers. The essence of the procedure is to adjust--for the plant material used--the proper conditions of detergent solubilization and purification that are mild enough for the associated lipids but provide sufficient purity. Microcrystals and most other LHCII preparations, which are more delipidated, are not capable of similar changes. The light-induced structural reorganizations can be enhanced by the addition of different thylakoid lipids, which--depending on the lipid species--also lead to the transformation of the lamellar structure. The preparation of different LHCII-lipid macro-assemblies is also described. Both in structurally flexible LHCII preparations and in thylakoids, the changes originate from a thermo-optic effect: fast local thermal transients, T-jumps, due to the dissipation of the (excess) excitation energy, which lead to elementary structural transitions in the close vicinity of the dissipating centers. This can occur because thylakoids and structurally flexible LHCII assemblies, but, e.g., not the microcrystals, exhibit a thermal instability below the denaturation temperature, and thus (local) heating leads to reorganizations without the loss of the molecular architecture of the constituents. We also list the main biochemical and biophysical techniques that can be used for testing the structural flexibility of LHCII, and discuss the potential physiological significance of the structural changes in light adaptation and photoprotection of plants.
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Affiliation(s)
- Ilian Simidjiev
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, Szeged, Hungary
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22
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Zhang MP, Zhang CJ, Yu GH, Jiang YZ, Strasser RJ, Yuan ZY, Yang XS, Chen GX. Changes in chloroplast ultrastructure, fatty acid components of thylakoid membrane and chlorophyll a fluorescence transient in flag leaves of a super-high-yield hybrid rice and its parents during the reproductive stage. JOURNAL OF PLANT PHYSIOLOGY 2010; 167:277-85. [PMID: 20004497 DOI: 10.1016/j.jplph.2009.09.017] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2009] [Revised: 09/14/2009] [Accepted: 09/15/2009] [Indexed: 05/09/2023]
Abstract
In plants, it is well established that chloroplast is one of the early targgeted organelles to breakdown during leaves senescing. Here we applied a newly developed super-high-yield hybrid rice (Oryza sativa) LiangYouPeiJiu (LYPJ) and its parents lines to investigate changes in ultrastructure of chloroplasts, fatty acid composition of thylakoid membrane lipids and chlorophyll (Chl) a fluorescence transient in natural senescing leaves. We found that at full expansion of flag leaves in three lines, chloroplasts often showed oblong shapes with a typical membrane system of stroma and grana thylakoids, whereas their shapes had been changed from oblong to spherical during senescence. Our data showed that the initiation of senescence displayed accumulation of starch and an increase in the number and size of plastoglobuli with the damaged thylakoid membranes; subsequently, swollen thylakoid membranes in stroma and in grana with a significant increase in MDA content, and disorganization of thylakoid membrane system with significant changes in fatty acid composition of thylakoid membrane lipids were developed. Compared with its parents, the newly developed hybrid rice LYPJ had the highest capacity of carbohydrate transport from leaves (sources) to ears (sink), marked with the lowest accumulation of starch grains in the leaf chloroplasts, and the slowest senescing rate of chloroplast in overall leaf senescence process. Chl a fluorescence transients of three kinds of flag leaves were analyzed by so-called JIP-test. The results of analysis suggest that these findings inculding a high inherited activity of antioxidant enzymes and high photosynthetate transport to pretect chloroplast structure in the hybrid rice LYPJ have close relations to its super-high yield.
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Affiliation(s)
- Mei-Ping Zhang
- Key Lab of Biodiversity and Biotechnology of Jiangsu Province, College of Life Sciences, Nanjing Normal University, Nanjing 210097, PR China
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23
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Schaller S, Latowski D, Jemioła-Rzemińska M, Wilhelm C, Strzałka K, Goss R. The main thylakoid membrane lipid monogalactosyldiacylglycerol (MGDG) promotes the de-epoxidation of violaxanthin associated with the light-harvesting complex of photosystem II (LHCII). BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1797:414-24. [PMID: 20035710 DOI: 10.1016/j.bbabio.2009.12.011] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Revised: 11/12/2009] [Accepted: 12/16/2009] [Indexed: 10/20/2022]
Abstract
In higher plants, the major part of the xanthophyll cycle pigment violaxanthin (Vx) is non-covalently bound to the main light-harvesting complex of PSII (LHCII). Under saturating light conditions Vx has to be released from its binding site into the surrounding lipid phase, where it is converted to zeaxanthin (Zx) by the enzyme Vx de-epoxidase (VDE). In the present study we investigated the influence of thylakoid lipids on the de-epoxidation of Vx, which was still associated with the LHCII. We isolated LHCII with different concentrations of native, endogenous lipids and Vx by sucrose gradient centrifugation or successive cation precipitation. Analysis of the different LHCII preparations showed that the concentration of LHCII-associated Vx was correlated with the concentration of the main thylakoid lipid monogalactosyldiacylglycerol (MGDG) associated with the complexes. Decreases in the MGDG content of the LHCII led to a diminished Vx concentration, indicating that a part of the total Vx pool was located in an MGDG phase surrounding the LHCII, whereas another part was bound to the LHCII apoproteins. We further studied the convertibility of LHCII-associated Vx in in-vitro enzyme assays by addition of isolated VDE. We observed an efficient and almost complete Vx conversion in the LHCII fractions containing high amounts of endogenous MGDG. LHCII preparations with low concentrations of MGDG exhibited a strongly reduced Vx de-epoxidation, which could be increased by addition of exogenous, pure MGDG. The de-epoxidation of LHCII-associated Vx was saturated at a much lower concentration of native, endogenous MGDG compared with the concentration of isolated, exogenous MGDG, which is needed for optimal VDE activity in in-vitro assays employing pure isolated Vx.
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Affiliation(s)
- Susann Schaller
- Institute of Biology I, Plant Physiology, University of Leipzig, Johannisallee 21-23, 04103 Leipzig, Germany
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24
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Jahns P, Latowski D, Strzalka K. Mechanism and regulation of the violaxanthin cycle: the role of antenna proteins and membrane lipids. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2008; 1787:3-14. [PMID: 18976630 DOI: 10.1016/j.bbabio.2008.09.013] [Citation(s) in RCA: 302] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Revised: 09/23/2008] [Accepted: 09/23/2008] [Indexed: 11/28/2022]
Abstract
The violaxanthin cycle describes the reversible conversion of violaxanthin to zeaxanthin via the intermediate antheraxanthin. This light-dependent xanthophyll conversion is essential for the adaptation of plants and algae to different light conditions and allows a reversible switch of photosynthetic light-harvesting complexes between a light-harvesting state under low light and a dissipative state under high light. The photoprotective functions of zeaxanthin have been intensively studied during the last decade, but much less attention has been directed to the mechanism and regulation of xanthophyll conversion. In this review, an overview is given on recent progress in the understanding of the role of (i) xanthophyll binding by antenna proteins and of (ii) the lipid properties of the thylakoid membrane in the regulation of xanthophyll conversion. The consequences of these findings for the mechanism and regulation of xanthophyll conversion in the thylakoid membrane will be discussed.
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Affiliation(s)
- Peter Jahns
- Plant Biochemistry, Heinrich-Heine-University Düsseldorf, Universitätsstr.1, D-40225 Düsseldorf, Germany.
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25
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Kwon KC, Cho MH. Deletion of the chloroplast-localized AtTerC gene product in Arabidopsis thaliana leads to loss of the thylakoid membrane and to seedling lethality. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2008; 55:428-42. [PMID: 18429937 DOI: 10.1111/j.1365-313x.2008.03523.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Early seedling development in plants depends on the biogenesis of chloroplasts from proplastids, accompanied by the formation of thylakoid membranes. An Arabidopsis thaliana gene, AtTerC, whose gene product shares sequence similarity with bacterial tellurite resistance C (TerC), is shown to be involved in a critical step required for the normal organization of prothylakoids and transition into mature thylakoid stacks. The AtTerC gene encodes an integral membrane protein, which contains eight putative transmembrane helices, localized in the thylakoid of the chloroplast, as shown by localization of an AtTerC-GFP fusion product in protoplasts and by immunoblot analysis of subfractions of chloroplasts. T-DNA insertional mutation of AtTerC resulted in a pigment-deficient and seedling-lethal phenotype under normal light conditions. Transmission electron microscopic analysis revealed that mutant etioplasts had normal prolamellar bodies (PLBs), although the prothylakoids had ring-like shapes surrounding the PLBs. In addition, the ultrastructures of mutant chloroplasts lacked thylakoids, did not have grana stacks, and showed numerous globular structures of varying sizes. Also, the accumulation of thylakoid membrane proteins was severely defective in this mutant. These results suggest that the AtTerC protein plays a crucial role in prothylakoid membrane biogenesis and thylakoid formation in early chloroplast development.
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Affiliation(s)
- Kwang-Chul Kwon
- Department of Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
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26
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Krumova SB, Dijkema C, de Waard P, Van As H, Garab G, van Amerongen H. Phase behavior of phosphatidylglycerol in spinach thylakoid membranes as revealed by 31P-NMR. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:997-1003. [PMID: 18230332 DOI: 10.1016/j.bbamem.2008.01.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2007] [Revised: 12/07/2007] [Accepted: 01/04/2008] [Indexed: 10/22/2022]
Abstract
Non-bilayer lipids account for about half of the total lipid content in chloroplast thylakoid membranes. This lends high propensity of the thylakoid lipid mixture to participate in different phases which might be functionally required. It is for instance known that the chloroplast enzyme violaxanthin de-epoxidase (VDE) requires a non-bilayer phase for proper functioning in vitro but direct evidence for the presence of non-bilayer lipid structures in thylakoid membranes under physiological conditions is still missing. In this work, we used phosphatidylglycerol (PG) as an intrinsic bulk lipid label for 31P-NMR studies to monitor lipid phases of thylakoid membranes. We show that in intact thylakoid membranes the characteristic lamellar signal is observed only below 20 degrees C. But at the same time an isotropic phase is present, which becomes even dominant between 14 and 28 degrees C despite the presence of fully functional large membrane sheets that are capable of generating and maintaining a transmembrane electric field. Tris-washed membranes show a similar behavior but the lamellar phase is present up to higher temperatures. Thus, our data show that the location of the phospholipids is not restricted to the bilayer phase and that the lamellar phase co-exists with a non-bilayer isotropic phase.
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Affiliation(s)
- Sashka B Krumova
- Wageningen University, Laboratory of Biophysics, PO Box 8128, 6700 ET Wageningen, The Netherlands
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27
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Kwa LG, Wegmann D, Brügger B, Wieland FT, Wanner G, Braun P. Mutation of a single residue, beta-glutamate-20, alters protein-lipid interactions of light harvesting complex II. Mol Microbiol 2007; 67:63-77. [PMID: 18034796 PMCID: PMC2229836 DOI: 10.1111/j.1365-2958.2007.06017.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
It is well established that assembly of the peripheral antenna complex, LH2, is required for proper photosynthetic membrane biogenesis in the purple bacterium Rhodobacter sphaeroides. The underlying interactions are, as yet, not understood. Here we examined the relationship between the morphology of the photosynthetic membrane and the lipid–protein interactions at the LH2–lipid interface. The non-bilayer lipid, phosphatidylethanolamine, is shown to be highly enriched in the boundary lipid phase of LH2. Sequence alignments indicate a putative lipid binding site, which includes β-glutamate-20 and the adjacent carotenoid end group. Replacement of β-glutamate-20 with alanine results in significant reduction of phosphatidylethanolamine and concomitant raise in phosphatidylcholine in the boundary lipid phase of LH2 without altering the lipid composition of the bulk phase. The morphology of the LH2 housing membrane is, however, unaffected by the amino acid replacement. In contrast, simultaneous modification of glutamate-20 and exchange of the carotenoid sphaeroidenone with neurosporene results in significant enlargement of the vesicular membrane invaginations. These findings suggest that the LH2 complex, specifically β-glutamate-20 and the carotenoids' polar head group, contribute to the shaping of the photosynthetic membrane by specific interactions with surrounding lipid molecules.
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Affiliation(s)
- Lee Gyan Kwa
- Department Biologie I der LM-Universität München, Botanik, 80638 München, Germany
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Filek M, Zembala M, Dudek A, Laggner P, Kriechbaum M. Electric and structural studies of hormone interaction with chloroplast envelope membranes isolated from vegetative and generative rape. JOURNAL OF PLANT PHYSIOLOGY 2007; 164:861-7. [PMID: 16884821 DOI: 10.1016/j.jplph.2006.05.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2005] [Accepted: 05/30/2006] [Indexed: 05/11/2023]
Abstract
The electric and structural properties of envelope membranes of chloroplasts obtained from vegetative and generative plants of rape and the effect of hormone (IAA, GA(3) and zearalenone) treatment were determined by zeta potential and small-angle X-ray scattering (SAXS) methods. Chloroplasts were isolated from leaves cut off from the vegetative (before cooling) and generative apical parts of plants. The lipid composition of chloroplast envelope membranes were analyzed by chromatographic techniques. Envelopes from generative plants contained higher levels of digalactosyldiacylglycerol (DGDG) and smaller amounts of phospholipids (PLs) in comparison to those obtained from vegetative ones. Moreover, envelopes of generative plants were characterized by higher fractions of unsaturated fatty acids. The zeta potential changes caused by hormone treatment were higher for chloroplasts isolated from vegetative plants in comparison to chloroplasts isolated from generative ones. An especially strong effect was observed for chloroplasts treated with IAA. The thickness of bilayers of untreated chloroplasts from vegetative plants were larger by 0.4 nm when comparing to the thickness of layers obtained from generative ones. The effect of hormones (GA(3) and zearalenone) was detected only for vegetative chloroplasts. Both applied methods indicated differences in the properties of untreated and hormone-treated chloroplasts obtained from vegetative and generative plants.
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Affiliation(s)
- Maria Filek
- Institute of Plant Physiology, Polish Academy of Sciences, Podłuzna 3, 30-239 Krakow, Poland.
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29
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Tokaji Z, Tandori J, Maróti P. Light- and Redox-dependent Thermal Stability of the Reaction Center of the Photosynthetic Bacterium Rhodobacter sphaeroides¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2002)0750605lardts2.0.co2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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30
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Gruszecki WI, Grudzinski W, Gospodarek M, Patyra M, Maksymiec W. Xanthophyll-induced aggregation of LHCII as a switch between light-harvesting and energy dissipation systems. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2006; 1757:1504-11. [PMID: 16978579 DOI: 10.1016/j.bbabio.2006.08.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2006] [Revised: 08/06/2006] [Accepted: 08/08/2006] [Indexed: 11/23/2022]
Abstract
The xanthophyll cycle pigments, violaxanthin and zeaxanthin, present outside the light-harvesting pigment-protein complexes of Photosystem II (LHCII) considerably enhance specific aggregation of proteins as revealed by analysis of the 77 K chlorophyll a fluorescence emission spectra. Analysis of the infrared absorption spectra in the Amide I region shows that the aggregation is associated with formation of intermolecular hydrogen bonding between the alpha helices of neighboring complexes. The aggregation gives rise to new electronic energy levels, in the Soret region (530 nm) and corresponding to the Q spectral region (691 nm), as revealed by analysis of the resonance light scattering spectra. New electronic energy levels are interpreted in terms of exciton coupling of protein-bound photosynthetic pigments. The energy of the Q excitonic level of chlorophyll is not high enough to drive the light reactions of Photosystem II but better suited to transfer excitation energy to Photosystem I, which creates favourable energetic conditions for the state I-state II transition. The lack of fluorescence emission from this energy level, at physiological temperatures, is indicative of either very high thermal energy conversion rate or efficient excitation quenching by carotenoids. Chlorophyll a fluorescence was quenched up to 61% and 34% in the zeaxanthin- and violaxanthin-containing samples, respectively, as compared to pure LHCII. Enhanced aggregation of LHCII, observed in the presence of the xanthophyll cycle pigments, is discussed in terms of the switch between light-harvesting and energy dissipation systems.
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Affiliation(s)
- Wieslaw I Gruszecki
- Department of Biophysics, Institute of Physics, Maria Curie-Sklodowska University, 20-601 Lublin, Poland.
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31
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Goss R, Latowski D, Grzyb J, Vieler A, Lohr M, Wilhelm C, Strzalka K. Lipid dependence of diadinoxanthin solubilization and de-epoxidation in artificial membrane systems resembling the lipid composition of the natural thylakoid membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2006; 1768:67-75. [PMID: 16843433 DOI: 10.1016/j.bbamem.2006.06.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2006] [Revised: 06/02/2006] [Accepted: 06/02/2006] [Indexed: 11/26/2022]
Abstract
In the present study, the solubility and enzymatic de-epoxidation of diadinoxanthin (Ddx) was investigated in three different artificial membrane systems: (1) Unilamellar liposomes composed of different concentrations of the bilayer forming lipid phosphatidylcholine (PC) and the inverted hexagonal phase (H(II) phase) forming lipid monogalactosyldiacylglycerol (MGDG), (2) liposomes composed of PC and the H(II) phase forming lipid phosphatidylethanolamine (PE), and (3) an artificial membrane system composed of digalactosyldiacylglycerol (DGDG) and MGDG, which resembles the lipid composition of the natural thylakoid membrane. Our results show that Ddx de-epoxidation strongly depends on the concentration of the inverted hexagonal phase forming lipids MGDG or PE in the liposomes composed of PC or DGDG, thus indicating that the presence of inverted hexagonal structures is essential for Ddx de-epoxidation. The difference observed for the solubilization of Ddx in H(II) phase forming lipids compared with bilayer forming lipids indicates that Ddx is not equally distributed in the liposomes composed of different concentrations of bilayer versus non-bilayer lipids. In artificial membranes with a high percentage of bilayer lipids, a large part of Ddx is located in the membrane bilayer. In membranes composed of equal proportions of bilayer and H(II) phase forming lipids, the majority of the Ddx molecules is located in the inverted hexagonal structures. The significance of the pigment distribution and the three-dimensional structure of the H(II) phase for the de-epoxidation reaction is discussed, and a possible scenario for the lipid dependence of Ddx (and violaxanthin) de-epoxidation in the native thylakoid membrane is proposed.
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Affiliation(s)
- Reimund Goss
- Institute of Biology I, Plant Physiology, University of Leipzig, Johannisallee 21-23, 04103 Leipzig, Germany.
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32
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Apostolova EL, Dobrikova AG, Ivanova PI, Petkanchin IB, Taneva SG. Relationship between the organization of the PS II super complex and the functions of the photosynthetic apparatus. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2006; 83:114-22. [PMID: 16464603 DOI: 10.1016/j.jphotobiol.2005.12.012] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2005] [Revised: 12/20/2005] [Accepted: 12/20/2005] [Indexed: 10/25/2022]
Abstract
The chlorophyll fluorescence and the photosynthetic oxygen evolution (flash-induced oxygen yield patterns and oxygen bursts under continuous irradiation) were investigated in the thylakoid membranes with different stoichiometry and organization of the chlorophyll-protein complexes. Data show that the alteration in the organization of the photosystem II (PS II) super complex, i.e. the amount and the organization of the light-harvesting chlorophyll a/b protein complex (LHCII), which strongly modifies the electric properties of the membranes, influences both the energy redistribution between the two photosystems and the oxygen production reaction. The decrease of surface electric parameters (charge density and dipole moments), associated with increased degree of LHCII oligomerization, correlates with the strong reduction of the energy transfer from PS II to PSI. In the studied pea thylakoid membranes (wild types Borec, Auralia and their mutants Coeruleovireus 2/16, Costata2/133, Chlorotica XV/1422) with enhanced degree of oligomerization of LHCII was observed: (i) an increase of the S(0) populations of PS II in darkness; (ii) an increase of the misses; (iii) an alteration of the decay kinetics of the oxygen bursts under continuous irradiation. There is a strict correlation between the degree of LHCII oligomerization in the investigated pea mutants and the ratio of functionally active PS II alpha to PS II beta centers, while in thylakoid membranes without oligomeric structure of LHCII (Chlorina f2 barley mutant) the PS II alpha centers are not registered.
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Affiliation(s)
- Emilia L Apostolova
- Institute of Biophysics, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl.21, Sofia 1113, Bulgaria.
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33
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Holm JK, Várkonyi Z, Kovács L, Posselt D, Garab G. Thermo-optically induced reorganizations in the main light harvesting antenna of plants. II. Indications for the role of LHCII-only macrodomains in thylakoids. PHOTOSYNTHESIS RESEARCH 2005; 86:275-82. [PMID: 16172945 DOI: 10.1007/s11120-005-5302-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2005] [Accepted: 04/11/2005] [Indexed: 05/04/2023]
Abstract
We have investigated the circular dichroism spectral transients associated with the light-induced reversible reorganizations in chirally organized macrodomains of pea thylakoid membranes and loosely stacked lamellar aggregates of the main chlorophyll a/b light harvesting complexes (LHCII) isolated from the same membranes. These reorganizations have earlier been assigned to originate from a thermo-optic effect. According to the thermo-optic mechanism, fast local thermal transients due to dissipation of the excess excitation energy induce elementary structural changes in the close vicinity of the dissipation [Cseh et al. (2000) Biochemistry 39: 15250-15257]. Here we show that despite the markedly different CD spectra in the dark, the transient (light-minus-dark) CD spectra associated with the structural changes induced by high light in thylakoids and LHCII are virtually indistinguishable. This, together with other close similarities between the two systems, strongly suggests that the gross short-term, thermo-optically induced structural reorganizations in the membranes occur mainly, albeit probably not exclusively, in the LHCII-only domains [Boekema et al. (2000) J Mol Biol 301: 1123-1133]. Hence, LHCII-only domains might play an important role in light adaptation and photoprotection of plants.
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Affiliation(s)
- Jens Kai Holm
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, P.O. Box 521, 6701 Szeged, Hungary
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Cseh Z, Vianelli A, Rajagopal S, Krumova S, Kovács L, Papp E, Barzda V, Jennings R, Garab G. Thermo-optically induced reorganizations in the main light harvesting antenna of plants. I. Non-Arrhenius type of temperature dependence and linear light-intensity dependencies. PHOTOSYNTHESIS RESEARCH 2005; 86:263-73. [PMID: 16172944 DOI: 10.1007/s11120-005-5104-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2005] [Accepted: 04/05/2005] [Indexed: 05/04/2023]
Abstract
Thermo-optically induced structural reorganizations have earlier been identified in isolated LHCII, the main chlorophyll a/b light harvesting complexes of Photosystem II, and in granal thylakoid membranes [Cseh et al. (2000) Biochemistry 39: 15250-15257; Garab et al. (2002) Biochemistry 41: 15121-15129]. According to the thermo-optic mechanism, structural changes can be induced by fast, local thermal transients due to the dissipation of excess excitation energy. In this paper, we analyze the temperature and light-intensity dependencies of thermo-optically induced reversible and irreversible reorganizations in the chiral macrodomains of lamellar aggregates of isolated LHCII and of granal thylakoid membranes. We show that these structural changes exhibit non-Arrhenius type of temperature dependencies, which originate from the 'combination' of the ambient temperature and the local thermal transient. The experimental data can satisfactorily be simulated with the aid of a simple mathematical model based on the thermo-optic effect. The model also predicts, in good accordance with experimental data published earlier and presented in this paper, that the reorganizations depend linearly on the intensity of the excess light, a unique property that is probably important in light adaptation and photoprotection of plants.
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Affiliation(s)
- Zoltán Cseh
- Institute of Plant Biology, Hungarian Academy of Sciences, Szeged, P.O. Box 521, 6701 Hungary
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35
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Iwaszko E, Wardak A, Krupa Z, Gruszecki WI. Ion transport across model lipid membranes containing light-harvesting complex II: an effect of light. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2005; 74:13-21. [PMID: 15043842 DOI: 10.1016/j.jphotobiol.2004.01.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2003] [Revised: 01/22/2004] [Accepted: 01/23/2004] [Indexed: 11/23/2022]
Abstract
The effect of light on proton transport across lipid membranes of small unilamellar liposomes containing incorporated major light-harvesting pigment-protein complex of Photosystem II (LHCII) has been studied with the application of pH-sensitive dyes entrapped inside vesicles. Proton permeability coefficient for LHCII-modified membranes was found to be about twice as high as in the case of the control pure lipid vesicles. Illumination of the samples with light absorbed by the LHCII-bound photosynthetic pigments considerably affects the kinetics of proton transport: it increases the rate and decreases the steady-state level of proton gradient across the membranes. The effect was interpreted in terms of heat-induced conformational changes of LHCII molecular structures that affect proton buffering capacity of this protein. Both the control and the LHCII-modified lipid membranes have been found to be practically impermeable to Ca(++) ions, as demonstrated by fluorescence of liposome-entrapped calcium-sensitive probe calcium crimson. The slight differences in the proton transport across the LHCII-containing membranes under the presence of Ca(++) suggest calcium binding to this antenna protein.
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Affiliation(s)
- Ewa Iwaszko
- Department of Biophysics, Institute of Physics, Maria Curie-Skłodowska University, PL. M. Curie-Sklodowskiej 1, Lublin 20-031, Poland
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Tandori J, Tokaji Z, Misurda K, Maróti P. Thermodynamics of Light-induced and Thermal Degradation of Bacteriochlorins in Reaction Center Protein of Photosynthetic Bacteria. Photochem Photobiol 2005; 81:1518-25. [PMID: 16164369 DOI: 10.1562/2005-05-31-ra-556] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The rate constants of thermal (irreversible) damage of bacteriochlorin pigments (bacteriochlorophyll monomer [B], bacteriochlorophyll dimer [P] and bacteriopheophytine [H]) in reaction center [RC] protein from the photosynthetic bacterium Rhodobacter sphaeroides were studied in the dark and during intense (400 mW x cm(-2)) laser light excitation (wavelengths 488 and 515 nm) under deoxygenated conditions. While the kinetics of degradation of P and B were monoexponential, the decay kinetics of H were overlapped by an initial lag phase at elevated (>40 degrees C) temperature. This is explained by removal of the central metal ion from the bacteriochlorophylls as part of their degradation processes. At all temperatures, the rates of damage were very similar for all bacteriochlorin pigments and were larger in the light than in the dark. The logarithm of the rate constant of pigment degradation and loss of photochemistry as a function of reciprocal (absolute) temperature (Arrhenius/Eyring plot) showed single phase in the light and double phases in the dark. Below 20 degrees C, the rate of pigment degradation in the RC decreased so dramatically in the dark that it became limited by the natural degradation process of bacteriochlorophyll measured in solution. The function of loss of photochemistry in the dark was also biphasic and had a break point at 40 degrees C. The damage in the dark required high enthalpy change (DeltaH(++) = 64 kcal/mol for P and DeltaH(++) = 60 kcal/mol for B) and entropy increase (T x DeltaS(++) = 38 kcal/mol for P and T x DeltaS(++) = 34 kcal/mol for B at T = 300 K), whereas significantly smaller enthalpy change (DeltaH(++) = 21 kcal/mol for P and B and DeltaH(++) = 13 kcal/mol for H) and practically no (T x DeltaS(++) = -1 kcal/mol for P and B at T = 300 K) or small (T x DeltaS(++) = -9 kcal/mol for H at T = 300 K) entropy change was needed in the light. The thermodynamic parameters of activation reveal major steps common in the degradation of all bacteriochlorin pigments: ring opening reactions at C5 or C20 meso-bridges (or both) and breaking/removal of the phytyl chain. Their contribution in the degradation is probably reflected in the observed enthalpy/entropy compensation at an almost constant (DeltaG(++) = 22-26 kcal/mol at T = 300 K) free energy change of activation.
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Affiliation(s)
- Júlia Tandori
- Department of Biophysics, University of Szeged, Hungary
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Prakash JSS, Baig MA, Bhagwat AS, Mohanty P. Characterisation of senescence-induced changes in light harvesting complex II and photosystem I complex of thylakoids of Cucumis sativus cotyledons: age induced association of LHCII with photosystem I. JOURNAL OF PLANT PHYSIOLOGY 2003; 160:175-184. [PMID: 12685033 DOI: 10.1078/0176-1617-00529] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Structure and function of chloroplasts are known to after during senescence. The senescence-induced specific changes in light harvesting antenna of photosystem II (PSII) and photosystem I (PSI) were investigated in Cucumis cotyledons. Purified light harvesting complex II (LHCII) and photosystem I complex were isolated from 6-day non-senescing and 27-day senescing Cucumis cotyledons. The chlorophyll a/b ratio of LHCII obtained from 6-day-old control cotyledons and their absorption, chlorophyll a fluorescence emission and the circular dichroism (CD) spectral properties were comparable to the LHCII preparations from other plants such as pea and spinach. The purified LHCII obtained from 27-day senescing cotyledons had a Chl a/b ratio of 1.25 instead of 1.2 as with 6-day LHCII and also exhibited significant changes in the visible CD spectrum compared to that of 6-day LHCII, indicating some specific alterations in the organisation of chlorophylls of LHCII. The light harvesting antenna of photosystems are likely to be altered due to aging. The room temperature absorption spectrum of LHCII obtained from 27-day senescing cotyledons showed changes in the peak positions. Similarly, comparison of 77K chlorophyll a fluorescence emission characteristics of LHCII preparation from senescing cotyledons with that of control showed a small shift in the peak position and the alteration in the emission profile, which is suggestive of possible changes in energy transfer within LHCII chlorophylls. Further, the salt induced aggregation of LHCII samples was lower, resulting in lower yields of LHCII from 27-day cotyledons than from normal cotyledons. Moreover, the PSI preparations of 6-day cotyledons showed Chl a/b ratios of 5 to 5.5, where as the PSI sample of 27-day cotyledons had a Chl a/b ratio of 2.9 suggesting LHCII association with PSI. The absorption, fluorescence emission and visible CD spectral measurements as well as the polypeptide profiles of 27-day cotyledon-PSI complexes indicated age-induced association of LHCII of PSII with PSI obtained from 27-day cotyledons. We modified our isolation protocols by increasing the duration of detergent Triton X-100 treatment for preparing the PSI and LHCII complexes from 27-day cotyledons. However, the PSI complexes isolated from senescing samples invariably proved to have significantly low Chl a/b ratio suggesting an age induced lateral movement and possible association of LHCII with PSI complexes. The analyses of polypeptide compositions of LHCII and PSI holocomplexes isolated from 6-day control and 27-day senescing cotyledons showed distinctive differences in their profiles. The presence of 26-28 kDa polypeptide in PSI complexes from 27-day cotyledons, but not in 6-day control PSI complexes is in agreement with the notion that senescence induced migration of LHCII to stroma lamellae and its possible association with PSI. We suggest that the migration of LHCII to the stroma lamellae region and its possible association with PSI might cause the destacking and flattening of grana structure during senescence of the chloroplasts. Such structural changes in light harvesting antenna are likely to alter energy transfer between two photosystems. The nature of aging induced migration and association of LHCII with PSI and its existence in other senescing systems need to be estimated in the future.
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Tokaji Z, Tandori J, Maróti P. Light- and redox-dependent thermal stability of the reaction center of the photosynthetic Bacterium rhodobacter sphaeroides. Photochem Photobiol 2002; 75:605-12. [PMID: 12081322 DOI: 10.1562/0031-8655(2002)075<0605:lardts>2.0.co;2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Irreversible loss of the photochemical activity and damage of the pigments (bacteriochlorophyll [Bchl] monomer, Bchl dimer [P] and bacteriopheophytin) by combined treatment with intense and continuous visible light and elevated temperature have been studied in a deoxygenated solution of reaction center (RC) protein from the nonsulfur purple photosynthetic bacterium Rhodobacter sphaeroides. Both the fraction of RC in the charge-separated redox state (P+Q-, where Q is a quinone electron acceptor) and the degradation of the pigments showed saturation as a function of increasing light intensity up to 400 mW cm(-2) (488/515 nm) or 1100 microE m(-2) s(-1) (white light). The thermal denaturation curves of the RC in the P+Q- redox state demonstrated broadening and 10-20 degrees C shift to lower temperature (after 30-90 min heat treatment) compared with those in the PQ redox state. Similar but less striking behavior was seen for RC of other redox states (P+Q and PQ-) generated either by light or by electrochemical treatment in the dark. These experiments suggest that it is not the intense light per se but the changes in the redox state of the protein that are responsible for the increased sensitivity to photo- and heat damage. The RC with a charge pair (P+Q-) is more vulnerable to elevated temperature than the RC with (P+Q or PQ-) or without (PQ) a single charge. To reveal both the thermodynamic and kinetic aspects of the denaturation, a simple three-state model of coupled reversible thermal and irreversible kinetic transitions is presented. These effects may have relevance to the heat stability of other redox proteins in bioenergetics.
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Affiliation(s)
- Zsolt Tokaji
- Institute of Biophysics, Biological Research Center of the Hungarian Academy of Sciences, Szeged
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39
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Garstka M, Jagielski A. Peroxidative reactions attenuate oxygen effect on spectroscopic properties of isolated chloroplasts. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2001; 64:82-92. [PMID: 11705734 DOI: 10.1016/s1011-1344(01)00223-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Steady-state absorption and fluorescence excitation spectra have been measured at 25 degrees C in order to elucidate the differences between isolated chloroplasts from pea (chilling-sensitive plant) and bean (chilling-tolerant plant) and their response to oxygen treatment. A weaker light harvesting in bean in comparison with pea chloroplasts is related to higher free fatty acids level and extended peroxidation activities of bean chloroplasts. Peroxidation of free fatty acids in bean chloroplasts results in an accumulation of oxygenated forms of fatty acids demonstrated by a large negative band around 400 nm in absorption difference spectra, while the excitation spectra are not significantly altered. Similar changes have been observed in the lipase-treated pea chloroplasts. In contrast, in both pea and bean chloroplasts exhibiting no peroxidation due to antimycin A treatment, oxygen induces a pronounced absorbance increase in the regions around 435, 470 and 674 nm indicating the chloroplast swelling. A decline of chlorophyll fluorescence excitation caused by oxygen, may result from a decrease in energy transfer from antennae complexes to chlorophyll species emitting at both 680 and 740 nm. The oxygen-induced changes are partially reversed upon restoration of anaerobic conditions. The presented data show for the first time, that in contrast to pea chloroplasts the peroxidation abolishes an oxygen-induced decrease in light harvesting in bean chloroplasts, i.e., a chilling-sensitive plant.
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Affiliation(s)
- M Garstka
- Department of Metabolism Regulation, Institute of Biochemistry, Faculty of Biology, Warsaw University, Miecznikowa 1, PL-02-096, Warsaw, Poland.
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40
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Metzler DE, Metzler CM, Sauke DJ. Light and Life. Biochemistry 2001. [DOI: 10.1016/b978-012492543-4/50026-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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41
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Garab G, Lohner K, Laggner P, Farkas T. Self-regulation of the lipid content of membranes by non-bilayer lipids: a hypothesis. TRENDS IN PLANT SCIENCE 2000; 5:489-494. [PMID: 11077258 DOI: 10.1016/s1360-1385(00)01767-2] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Many biological membranes contain lipids that do not form a lamellar phase but the roles of these lipids are not well understood. An artificial membrane assembled from the main non-bilayer lipid and the major integral protein of pea thylakoids revealed that the protein spatially inhibits the formation of non-bilayer structures in the lamellae. Without this inhibition, excess lipids are secreted, creating lipid reservoirs for metabolism and/or later uptake. This determines the protein:lipid ratio in the membrane and hence the balance between structural flexibility and the stability of the key constituents that participate in cooperative interactions.
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Affiliation(s)
- G Garab
- Institute of Plant Biology and Institute of Biochemistry, Biological Research Center, Hungarian Academy of Sciences, PO Box 521, H-6701 Szeged, Hungary.
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42
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Wardak A, Brodowski R, Krupa Z, Gruszecki WI. Effect of light-harvesting complex II on ion transport across model lipid membranes. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2000; 56:12-8. [PMID: 11073311 DOI: 10.1016/s1011-1344(00)00050-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The effect of the incorporation of the major light-harvesting complex of photosystem II (LHCII) to planar bilayer lipid membranes (BLMs) formed from soybean asolectin and unilamellar small liposomes formed from egg-yolk phosphatidylcholine on ion transport across the lipid bilayer has been studied. The specific conductivity of the BLM rises from 5.2 +/- 0.8 x 10(-9) up to 510 x 10(-9) O(-1) cm(-2) upon the incorporation of LHCII. The conductivity of the membrane with LHCII depends upon the ionic strength of the bathing solution and is higher by a factor of five when the KCl concentration increases from 0.02 to 0.22 M. Such a strong effect has not been observed in the same system without LHCII. The liposome model is also applied to analyse the effect of LHCII on the bilayer permeability to protons. Unilamellar liposomes with a diameter less than 50 nm have been prepared, containing (trapped inside) Neutral Red, a pigment sensitive to proton concentration. A gradient of protons on the membrane is generated by the acidification of the liposome suspension and spectral changes of Neutral Red are recorded in time, reflecting the penetration of protons into the internal space of liposomes. Two components of proton permeation across liposome membranes are observed: a fast one (proceeding within seconds) and a slow one (operating on the time scale of minutes). The rate of both components of proton transport across LHCII-containing membranes is higher than for liposomes alone. The enhancement effect of LHCII on the ion transport across the lipid membrane is discussed in terms of aggregation of the pigment-protein complexes. The possible physiological importance of such an effect in controlling ion permeability across the thylakoid membrane is discussed.
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Affiliation(s)
- A Wardak
- Department of General Physics, Institute of Physics, Technical University, Lublin, Poland
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43
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Abstract
All biological membranes contain lipids that prefer to adopt a non-bilayer phase. Recent results suggest that, in the thylakoid membrane, membrane proteins force all the lipids to adopt a bilayer structure, and that the non-bilayer-forming lipids in the thylakoid membrane serve to drive the formation of membrane stacks.
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Affiliation(s)
- A G Lee
- Division of Biochemistry and Molecular Biology, School of Biological Sciences, University of Southampton, Southampton, SO 16 7PX, UK
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Simidjiev I, Stoylova S, Amenitsch H, Javorfi T, Mustardy L, Laggner P, Holzenburg A, Garab G. Self-assembly of large, ordered lamellae from non-bilayer lipids and integral membrane proteins in vitro. Proc Natl Acad Sci U S A 2000; 97:1473-6. [PMID: 10677486 PMCID: PMC26458 DOI: 10.1073/pnas.97.4.1473] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/1999] [Accepted: 12/13/1999] [Indexed: 11/18/2022] Open
Abstract
In many biological membranes, the major lipids are "non-bilayer lipids," which in purified form cannot be arranged in a lamellar structure. The structural and functional roles of these lipids are poorly understood. This work demonstrates that the in vitro association of the two main components of a membrane, the non-bilayer lipid monogalactosyldiacylglycerol (MGDG) and the chlorophyll-a/b light-harvesting antenna protein of photosystem II (LHCII) of pea thylakoids, leads to the formation of large, ordered lamellar structures: (i) thin-section electron microscopy and circular dichroism spectroscopy reveal that the addition of MGDG induces the transformation of isolated, disordered macroaggregates of LHCII into stacked lamellar aggregates with a long-range chiral order of the complexes; (ii) small-angle x-ray scattering discloses that LHCII perturbs the structure of the pure lipid and destroys the inverted hexagonal phase; and (iii) an analysis of electron micrographs of negatively stained 2D crystals indicates that in MGDG-LHCII the complexes are found in an ordered macroarray. It is proposed that, by limiting the space available for MGDG in the macroaggregate, LHCII inhibits formation of the inverted hexagonal phase of lipids; in thylakoids, a spatial limitation is likely to be imposed by the high concentration of membrane-associated proteins.
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Affiliation(s)
- I Simidjiev
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, H-6701, Szeged, Hungary
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45
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Abstract
A new two step photobleaching process is observed under continuous illumination of bacteriorhodopsin. This photobleaching is considerable even at physiological temperatures and becomes large at 50-60 degrees C. The photobleaching also increases with increasing pH from 7 to 10. We suggest that the bleaching at its final stage could be due to the dissociation of the retinal and a local thermal denaturation-like process. These facts may question the generally held belief that BR is a stable protein in vivo for a long period of time. Our results may have relevance also to practical applications of bacteriorhodopsin where the stability of bacteriorhodopsin is a key issue. In certain instances, the use of bacteriorhodopsin may require cooled conditions. Here, we defined the conditions under which bacteriorhodopsin is stable. The permanent photobleaching offers a new way of picture imaging and information input for bacteriorhodopsin-based optical devices.
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Affiliation(s)
- Z Dancsházy
- Institute of Biophysics, Biological Research Centre of the Hungarian Academy of Sciences, Szeged
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