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Kondo K, Yoshimi R, Apdila ET, Wakabayashi KI, Awai K, Hisabori T. Changes in intracellular energetic and metabolite states due to increased galactolipid levels in Synechococcus elongatus PCC 7942. Sci Rep 2023; 13:259. [PMID: 36604524 PMCID: PMC9816115 DOI: 10.1038/s41598-022-26760-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 12/20/2022] [Indexed: 01/07/2023] Open
Abstract
The lipid composition of thylakoid membranes is conserved from cyanobacteria to green plants. However, the biosynthetic pathways of galactolipids, the major components of thylakoid membranes, are known to differ substantially between cyanobacteria and green plants. We previously reported on a transformant of the unicellular rod-shaped cyanobacterium Synechococcus elongatus PCC 7942, namely SeGPT, in which the synthesis pathways of the galactolipids monogalactosyldiacylglycerol and digalactosyldiacylglycerol are completely replaced by those of green plants. SeGPT exhibited increased galactolipid content and could grow photoautotrophically, but its growth rate was slower than that of wild-type S. elongatus PCC 7942. In the present study, we investigated pleiotropic effects that occur in SeGPT and determined how its increased lipid content affects cell proliferation. Microscopic observations revealed that cell division and thylakoid membrane development are impaired in SeGPT. Furthermore, physiological analyses indicated that the bioenergetic state of SeGPT is altered toward energy storage, as indicated by increased levels of intracellular ATP and glycogen. We hereby report that we have identified a new promising candidate as a platform for material production by modifying the lipid synthesis system in this way.
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Affiliation(s)
- Kumiko Kondo
- grid.32197.3e0000 0001 2179 2105Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-Ku, Yokohama, 226-8503 Japan
| | - Rina Yoshimi
- grid.32197.3e0000 0001 2179 2105Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-Ku, Yokohama, 226-8503 Japan ,grid.32197.3e0000 0001 2179 2105School of Life Science and Technology, Tokyo Institute of Technology, Nagatsuta 4259, Midori-Ku, Yokohama, 226-8503 Japan
| | - Egi Tritya Apdila
- grid.263536.70000 0001 0656 4913Department of Biological Science, Faculty of Science, Shizuoka University, Suruga-Ku, Shizuoka, 422-8529 Japan
| | - Ken-ichi Wakabayashi
- grid.32197.3e0000 0001 2179 2105Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-Ku, Yokohama, 226-8503 Japan ,grid.32197.3e0000 0001 2179 2105School of Life Science and Technology, Tokyo Institute of Technology, Nagatsuta 4259, Midori-Ku, Yokohama, 226-8503 Japan
| | - Koichiro Awai
- Department of Biological Science, Faculty of Science, Shizuoka University, Suruga-Ku, Shizuoka, 422-8529, Japan.
| | - Toru Hisabori
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-Ku, Yokohama, 226-8503, Japan. .,School of Life Science and Technology, Tokyo Institute of Technology, Nagatsuta 4259, Midori-Ku, Yokohama, 226-8503, Japan.
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2
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A Mathematical Modeling and Statistical Analysis of Phycobiliprotein Fluorescence Decay under Exposure to Excitation Light. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12157469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Photosynthetic phycobiliprotein complexes from Spirulina maxima were purified and fractioned by gel chromatography. A mathematical model was developed for the fractionated phycobiliprotein complexes to successfully represent the fluorescence decay rate under exposure to excitation light. Each fractionated complex had a different ratio of phycobiliproteins, such as allophycocyanin, phycocyanin, or phycoerythrin, but their fluorescence decay trends were determined to statistically have a high similarity. The mathematical model was derived based on mass balance in the sense that the fluorescence of phycobiliprotein complex was linearly dependent on its mass. The model considered both exponentially decreasing (early light-exposure period) and linearly decreasing (later period), and successfully fit the whole period of fluorescence decay trend.
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3
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Arshad R, Saccon F, Bag P, Biswas A, Calvaruso C, Bhatti AF, Grebe S, Mascoli V, Mahbub M, Muzzopappa F, Polyzois A, Schiphorst C, Sorrentino M, Streckaité S, van Amerongen H, Aro EM, Bassi R, Boekema EJ, Croce R, Dekker J, van Grondelle R, Jansson S, Kirilovsky D, Kouřil R, Michel S, Mullineaux CW, Panzarová K, Robert B, Ruban AV, van Stokkum I, Wientjes E, Büchel C. A kaleidoscope of photosynthetic antenna proteins and their emerging roles. PLANT PHYSIOLOGY 2022; 189:1204-1219. [PMID: 35512089 PMCID: PMC9237682 DOI: 10.1093/plphys/kiac175] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 03/17/2022] [Indexed: 05/17/2023]
Abstract
Photosynthetic light-harvesting antennae are pigment-binding proteins that perform one of the most fundamental tasks on Earth, capturing light and transferring energy that enables life in our biosphere. Adaptation to different light environments led to the evolution of an astonishing diversity of light-harvesting systems. At the same time, several strategies have been developed to optimize the light energy input into photosynthetic membranes in response to fluctuating conditions. The basic feature of these prompt responses is the dynamic nature of antenna complexes, whose function readily adapts to the light available. High-resolution microscopy and spectroscopic studies on membrane dynamics demonstrate the crosstalk between antennae and other thylakoid membrane components. With the increased understanding of light-harvesting mechanisms and their regulation, efforts are focusing on the development of sustainable processes for effective conversion of sunlight into functional bio-products. The major challenge in this approach lies in the application of fundamental discoveries in light-harvesting systems for the improvement of plant or algal photosynthesis. Here, we underline some of the latest fundamental discoveries on the molecular mechanisms and regulation of light harvesting that can potentially be exploited for the optimization of photosynthesis.
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Affiliation(s)
- Rameez Arshad
- Department of Biophysics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Olomouc 783 71, Czech Republic
- Electron Microscopy Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen 9747 AG, The Netherlands
| | - Francesco Saccon
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Pushan Bag
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå 901 87, Sweden
| | - Avratanu Biswas
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - Claudio Calvaruso
- Institute for Molecular Biosciences, Goethe University of Frankfurt, Frankfurt 60438, Germany
| | - Ahmad Farhan Bhatti
- Laboratory of Biophysics, Wageningen University, Wageningen, the Netherlands
| | - Steffen Grebe
- Department of Life Technologies, MolecularPlant Biology, University of Turku, Turku FI–20520, Finland
| | - Vincenzo Mascoli
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - Moontaha Mahbub
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
- Department of Botany, Jagannath University, Dhaka 1100, Bangladesh
| | - Fernando Muzzopappa
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif sur Yvette 1198, France
| | - Alexandros Polyzois
- Université de Paris, Faculté de Pharmacie de Paris, CiTCoM UMR 8038 CNRS, Paris 75006, France
| | | | - Mirella Sorrentino
- Photon Systems Instruments, spol. s.r.o., Drásov, Czech Republic
- Department of Agricultural Sciences, University of Naples Federico II, Naples 80138, Italy
| | - Simona Streckaité
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif sur Yvette 1198, France
| | | | - Eva-Mari Aro
- Department of Life Technologies, MolecularPlant Biology, University of Turku, Turku FI–20520, Finland
| | - Roberto Bassi
- Dipartimento di Biotecnologie, Università di Verona, Verona, Italy
| | - Egbert J Boekema
- Electron Microscopy Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen 9747 AG, The Netherlands
| | - Roberta Croce
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - Jan Dekker
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - Rienk van Grondelle
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - Stefan Jansson
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå 901 87, Sweden
| | - Diana Kirilovsky
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif sur Yvette 1198, France
| | - Roman Kouřil
- Department of Biophysics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Olomouc 783 71, Czech Republic
| | - Sylvie Michel
- Université de Paris, Faculté de Pharmacie de Paris, CiTCoM UMR 8038 CNRS, Paris 75006, France
| | - Conrad W Mullineaux
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Klára Panzarová
- Photon Systems Instruments, spol. s.r.o., Drásov, Czech Republic
| | - Bruno Robert
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif sur Yvette 1198, France
| | - Alexander V Ruban
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Ivo van Stokkum
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - Emilie Wientjes
- Laboratory of Biophysics, Wageningen University, Wageningen, the Netherlands
| | - Claudia Büchel
- Institute for Molecular Biosciences, Goethe University of Frankfurt, Frankfurt 60438, Germany
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Yang M, Wenner N, Dykes GF, Li Y, Zhu X, Sun Y, Huang F, Hinton JCD, Liu LN. Biogenesis of a bacterial metabolosome for propanediol utilization. Nat Commun 2022; 13:2920. [PMID: 35614058 PMCID: PMC9132943 DOI: 10.1038/s41467-022-30608-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 04/22/2022] [Indexed: 12/24/2022] Open
Abstract
Bacterial metabolosomes are a family of protein organelles in bacteria. Elucidating how thousands of proteins self-assemble to form functional metabolosomes is essential for understanding their significance in cellular metabolism and pathogenesis. Here we investigate the de novo biogenesis of propanediol-utilization (Pdu) metabolosomes and characterize the roles of the key constituents in generation and intracellular positioning of functional metabolosomes. Our results demonstrate that the Pdu metabolosome undertakes both "Shell first" and "Cargo first" assembly pathways, unlike the β-carboxysome structural analog which only involves the "Cargo first" strategy. Shell and cargo assemblies occur independently at the cell poles. The internal cargo core is formed through the ordered assembly of multiple enzyme complexes, and exhibits liquid-like properties within the metabolosome architecture. Our findings provide mechanistic insight into the molecular principles driving bacterial metabolosome assembly and expand our understanding of liquid-like organelle biogenesis.
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Affiliation(s)
- Mengru Yang
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, United Kingdom
| | - Nicolas Wenner
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Crown Street, Liverpool, L69 7ZB, United Kingdom
| | - Gregory F Dykes
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, United Kingdom
| | - Yan Li
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Crown Street, Liverpool, L69 7ZB, United Kingdom
| | - Xiaojun Zhu
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Crown Street, Liverpool, L69 7ZB, United Kingdom
| | - Yaqi Sun
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, United Kingdom
| | - Fang Huang
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, United Kingdom
| | - Jay C D Hinton
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Crown Street, Liverpool, L69 7ZB, United Kingdom
| | - Lu-Ning Liu
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, United Kingdom.
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, 266003, China.
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5
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Biosorption of Zn(II) from Seawater Solution by the Microalgal Biomass of Tetraselmis marina AC16-MESO. Int J Mol Sci 2021; 22:ijms222312799. [PMID: 34884601 PMCID: PMC8657923 DOI: 10.3390/ijms222312799] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/12/2021] [Accepted: 11/14/2021] [Indexed: 02/06/2023] Open
Abstract
Biosorption refers to a physicochemical process where substances are removed from the solution by a biological material (live or dead) via adsorption processes governed by mechanisms such as surface complexation, ion exchange, and precipitation. This study aimed to evaluate the adsorption of Zn2+ in seawater using the microalgal biomass of Tetraselmis marina AC16-MESO “in vivo” and “not alive” at different concentrations of Zn2+ (0, 5, 10, and 20 mg L−1) at 72 h. Analysis was carried out by using the Langmuir isotherms and by evaluating the autofluorescence from microalgae. The maximum adsorption of Zn2+ by the Langmuir model using the Qmax parameter in the living microalgal biomass (Qmax = 0.03051 mg g−1) was more significant than the non-living microalgal biomass of T. marine AC16-MESO (Qmax = 0.02297 mg g−1). Furthermore, a decrease in fluorescence was detected in cells from T. marina AC16-MESO, in the following order: Zn2+ (0 < 20 < 5 < 10) mg L−1. Zn2+ was adsorbed quickly by living cells from T. marine AC16-MESO compared to the non-living microalgal biomass, with a decrease in photosystem II activities from 0 to 20 mg L−1 Zn2+ in living cells.
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6
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Mahbub M, Hemm L, Yang Y, Kaur R, Carmen H, Engl C, Huokko T, Riediger M, Watanabe S, Liu LN, Wilde A, Hess WR, Mullineaux CW. mRNA localization, reaction centre biogenesis and thylakoid membrane targeting in cyanobacteria. NATURE PLANTS 2020; 6:1179-1191. [PMID: 32895528 DOI: 10.1038/s41477-020-00764-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 07/31/2020] [Indexed: 06/11/2023]
Abstract
The thylakoid membranes of cyanobacteria form a complex intracellular membrane system with a distinctive proteome. The sites of biogenesis of thylakoid proteins remain uncertain, as do the signals that direct thylakoid membrane-integral proteins to the thylakoids rather than to the plasma membrane. Here, we address these questions by using fluorescence in situ hybridization to probe the subcellular location of messenger RNA molecules encoding core subunits of the photosystems in two cyanobacterial species. These mRNAs cluster at thylakoid surfaces mainly adjacent to the central cytoplasm and the nucleoid, in contrast to mRNAs encoding proteins with other locations. Ribosome association influences the distribution of the photosynthetic mRNAs on the thylakoid surface, but thylakoid affinity is retained in the absence of ribosome association. However, thylakoid association is disrupted in a mutant lacking two mRNA-binding proteins, which probably play roles in targeting photosynthetic proteins to the thylakoid membrane.
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Affiliation(s)
- Moontaha Mahbub
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
- Department of Botany, Jagannath University, Dhaka, Bangladesh
| | - Luisa Hemm
- Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Yuxiao Yang
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Ramanpreet Kaur
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Helder Carmen
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Christoph Engl
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Tuomas Huokko
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | | | - Satoru Watanabe
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Lu-Ning Liu
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Annegret Wilde
- Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Wolfgang R Hess
- Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Conrad W Mullineaux
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK.
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7
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Santamarï A-Gï Mez J, Mariscal V, Luque I. Mechanisms for Protein Redistribution in Thylakoids of Anabaena During Cell Differentiation. PLANT & CELL PHYSIOLOGY 2018; 59:1860-1873. [PMID: 29878163 DOI: 10.1093/pcp/pcy103] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 05/25/2018] [Indexed: 06/08/2023]
Abstract
Thylakoid membranes are far from being homogeneous in composition. On the contrary, compositional heterogeneity of lipid and protein content is well known to exist in these membranes. The mechanisms for the confinement of proteins at a particular membrane domain have started to be unveiled, but we are far from a thorough understanding, and many issues remain to be elucidated. During the differentiation of heterocysts in filamentous cyanobacteria of the Anabaena and Nostoc genera, thylakoids undergo a complete reorganization, separating into two membrane domains of different appearance and subcellular localization. Evidence also indicates different functionality and protein composition for these two membrane domains. In this work, we have addressed the mechanisms that govern the specific localization of proteins at a particular membrane domain. Two classes of proteins were distinguished according to their distribution in the thylakoids. Our results indicate that the specific accumulation of proteins of the CURVATURE THYLAKOID 1 (CURT1) family and proteins containing the homologous CAAD domain at subpolar honeycomb thylakoids is mediated by multiple mechanisms including a previously unnoticed phenomenon of thylakoid membrane migration.
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Affiliation(s)
- Javier Santamarï A-Gï Mez
- Instituto de Bioqu�mica Vegetal y Fotos�ntesis, CSIC and Universidad de Sevilla, Avda Am�rico Vespucio 49, Seville E-41092, Spain
| | - Vicente Mariscal
- Instituto de Bioqu�mica Vegetal y Fotos�ntesis, CSIC and Universidad de Sevilla, Avda Am�rico Vespucio 49, Seville E-41092, Spain
| | - Ignacio Luque
- Instituto de Bioqu�mica Vegetal y Fotos�ntesis, CSIC and Universidad de Sevilla, Avda Am�rico Vespucio 49, Seville E-41092, Spain
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8
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Azadi-Chegeni F, Schiphorst C, Pandit A. In vivo NMR as a tool for probing molecular structure and dynamics in intact Chlamydomonas reinhardtii cells. PHOTOSYNTHESIS RESEARCH 2018; 135:227-237. [PMID: 28646418 PMCID: PMC5783995 DOI: 10.1007/s11120-017-0412-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 06/07/2017] [Indexed: 06/14/2023]
Abstract
We report the application of NMR dynamic spectral editing for probing the structure and dynamics of molecular constituents in fresh, intact cells and in freshly prepared thylakoid membranes of Chlamydomonas reinhardtii (Cr.) green algae. For isotope labeling, wild-type Cr. cells were grown on 13C acetate-enriched minimal medium. 1D 13C J-coupling based and dipolar-based MAS NMR spectra were applied to distinguish 13C resonances of different molecular components. 1D spectra were recorded over a physiological temperature range, and whole-cell spectra were compared to those taken from thylakoid membranes, evaluating their composition and dynamics. A theoretical model for NMR polarization transfer was used to simulate the relative intensities of direct, J-coupling, and dipolar-based polarization from which the degree of lipid segmental order and rotational dynamics of the lipid acyl chains were estimated. We observe that thylakoid lipid signals dominate the lipid spectral profile of whole algae cells, demonstrating that with our novel method, thylakoid membrane characteristics can be detected with atomistic precision inside intact photosynthetic cells. The experimental procedure is rapid and applicable to fresh cell cultures, and could be used as an original approach for detecting chemical profiles, and molecular structure and dynamics of photosynthetic membranes in vivo in functional states.
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Affiliation(s)
- Fatemeh Azadi-Chegeni
- Department of Solid State NMR, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333CC, Leiden, The Netherlands
| | - Christo Schiphorst
- Department of Solid State NMR, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333CC, Leiden, The Netherlands
- Department of Biotechnology, University of Verona, Verona, Italy
| | - Anjali Pandit
- Department of Solid State NMR, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333CC, Leiden, The Netherlands.
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Casella S, Huang F, Mason D, Zhao GY, Johnson GN, Mullineaux CW, Liu LN. Dissecting the Native Architecture and Dynamics of Cyanobacterial Photosynthetic Machinery. MOLECULAR PLANT 2017; 10:1434-1448. [PMID: 29017828 PMCID: PMC5683893 DOI: 10.1016/j.molp.2017.09.019] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Revised: 09/25/2017] [Accepted: 09/29/2017] [Indexed: 05/18/2023]
Abstract
The structural dynamics and flexibility of cell membranes play fundamental roles in the functions of the cells, i.e., signaling, energy transduction, and physiological adaptation. The cyanobacterial thylakoid membrane represents a model membrane that can conduct both oxygenic photosynthesis and respiration simultaneously. In this study, we conducted direct visualization of the global organization and mobility of photosynthetic complexes in thylakoid membranes from a model cyanobacterium, Synechococcus elongatus PCC 7942, using high-resolution atomic force, confocal, and total internal reflection fluorescence microscopy. We visualized the native arrangement and dense packing of photosystem I (PSI), photosystem II (PSII), and cytochrome (Cyt) b6f within thylakoid membranes at the molecular level. Furthermore, we functionally tagged PSI, PSII, Cyt b6f, and ATP synthase individually with fluorescent proteins, and revealed the heterogeneous distribution of these four photosynthetic complexes and determined their dynamic features within the crowding membrane environment using live-cell fluorescence imaging. We characterized red light-induced clustering localization and adjustable diffusion of photosynthetic complexes in thylakoid membranes, representative of the reorganization of photosynthetic apparatus in response to environmental changes. Understanding the organization and dynamics of photosynthetic membranes is essential for rational design and construction of artificial photosynthetic systems to underpin bioenergy development. Knowledge of cyanobacterial thylakoid membranes could also be extended to other cell membranes, such as chloroplast and mitochondrial membranes.
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Affiliation(s)
- Selene Casella
- Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK
| | - Fang Huang
- Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK
| | - David Mason
- Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK; Centre for Cell Imaging, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK
| | - Guo-Yan Zhao
- Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK; College of Life Science, Shandong Normal University, Jinan 250014, P. R. China
| | - Giles N Johnson
- School of Earth and Environmental Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Conrad W Mullineaux
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Lu-Ning Liu
- Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK.
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10
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Bersanini L, Allahverdiyeva Y, Battchikova N, Heinz S, Lespinasse M, Ruohisto E, Mustila H, Nickelsen J, Vass I, Aro EM. Dissecting the Photoprotective Mechanism Encoded by the flv4-2 Operon: a Distinct Contribution of Sll0218 in Photosystem II Stabilization. PLANT, CELL & ENVIRONMENT 2017; 40:378-389. [PMID: 27928824 DOI: 10.1111/pce.12872] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 11/17/2016] [Accepted: 11/20/2016] [Indexed: 06/06/2023]
Abstract
In Synechocystis sp. PCC 6803, the flv4-2 operon encodes the flavodiiron proteins Flv2 and Flv4 together with a small protein, Sll0218, providing photoprotection for Photosystem II (PSII). Here, the distinct roles of Flv2/Flv4 and Sll0218 were addressed, using a number of flv4-2 operon mutants. In the ∆sll0218 mutant, the presence of Flv2/Flv4 rescued PSII functionality as compared with ∆sll0218-flv2, where neither Sll0218 nor the Flv2/Flv4 heterodimer are expressed. Nevertheless, both the ∆sll0218 and ∆sll0218-flv2 mutants demonstrated deficiency in accumulation of PSII proteins suggesting a role for Sll0218 in PSII stabilization, which was further supported by photoinhibition experiments. Moreover, the accumulation of PSII assembly intermediates occurred in Sll0218-lacking mutants. The YFP-tagged Sll0218 protein localized in a few spots per cell at the external side of the thylakoid membrane, and biochemical membrane fractionation revealed clear enrichment of Sll0218 in the PratA-defined membranes, where the early biogenesis steps of PSII occur. Further, the characteristic antenna uncoupling feature of the ∆flv4-2 operon mutants is shown to be related to PSII destabilization in the absence of Sll0218. It is concluded that the Flv2/Flv4 heterodimer supports PSII functionality, while the Sll0218 protein assists PSII assembly and stabilization, including optimization of light harvesting.
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Affiliation(s)
- Luca Bersanini
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Yagut Allahverdiyeva
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Natalia Battchikova
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Steffen Heinz
- Molecular Plant Sciences, Ludwig-Maximillians-Universität München, Biozentrum, Grosshaderner Straße 2-4, 82152, Planegg-Martinsried, Germany
| | - Maija Lespinasse
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Essi Ruohisto
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Henna Mustila
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Jörg Nickelsen
- Molecular Plant Sciences, Ludwig-Maximillians-Universität München, Biozentrum, Grosshaderner Straße 2-4, 82152, Planegg-Martinsried, Germany
| | - Imre Vass
- Institute of Plant Biology, Biological Research Centre of the Hungarian Academy of Sciences, P.O. Box 521, H-6701, Szeged, Hungary
| | - Eva-Mari Aro
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
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11
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Liu LN. Distribution and dynamics of electron transport complexes in cyanobacterial thylakoid membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1857:256-65. [PMID: 26619924 PMCID: PMC4756276 DOI: 10.1016/j.bbabio.2015.11.010] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 11/17/2015] [Accepted: 11/19/2015] [Indexed: 12/24/2022]
Abstract
The cyanobacterial thylakoid membrane represents a system that can carry out both oxygenic photosynthesis and respiration simultaneously. The organization, interactions and mobility of components of these two electron transport pathways are indispensable to the biosynthesis of thylakoid membrane modules and the optimization of bioenergetic electron flow in response to environmental changes. These are of fundamental importance to the metabolic robustness and plasticity of cyanobacteria. This review summarizes our current knowledge about the distribution and dynamics of electron transport components in cyanobacterial thylakoid membranes. Global understanding of the principles that govern the dynamic regulation of electron transport pathways in nature will provide a framework for the design and synthetic engineering of new bioenergetic machinery to improve photosynthesis and biofuel production. This article is part of a Special Issue entitled: Organization and dynamics of bioenergetic systems in bacteria, edited by Conrad Mullineaux. Cyanobacterial thylakoid membranes carry out both oxygenic photosynthesis and respiration. Electron transport components are located in the thylakoid membrane and functionally coordinate with each other. Distribution and dynamics of electron transport components are physiologically regulated in response to environmental change.
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Affiliation(s)
- Lu-Ning Liu
- Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, United Kingdom.
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12
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Sacharz J, Bryan SJ, Yu J, Burroughs NJ, Spence EM, Nixon PJ, Mullineaux CW. Sub-cellular location of FtsH proteases in the cyanobacterium Synechocystis sp. PCC 6803 suggests localised PSII repair zones in the thylakoid membranes. Mol Microbiol 2015; 96:448-62. [PMID: 25601560 PMCID: PMC4949578 DOI: 10.1111/mmi.12940] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/18/2015] [Indexed: 12/21/2022]
Abstract
In cyanobacteria and chloroplasts, exposure to HL damages the photosynthetic apparatus, especially the D1 subunit of Photosystem II. To avoid chronic photoinhibition, a PSII repair cycle operates to replace damaged PSII subunits with newly synthesised versions. To determine the sub-cellular location of this process, we examined the localisation of FtsH metalloproteases, some of which are directly involved in degrading damaged D1. We generated transformants of the cyanobacterium Synechocystis sp. PCC6803 expressing GFP-tagged versions of its four FtsH proteases. The ftsH2-gfp strain was functional for PSII repair under our conditions. Confocal microscopy shows that FtsH1 is mainly in the cytoplasmic membrane, while the remaining FtsH proteins are in patches either in the thylakoid or at the interface between the thylakoid and cytoplasmic membranes. HL exposure which increases the activity of the Photosystem II repair cycle led to no detectable changes in FtsH distribution, with the FtsH2 protease involved in D1 degradation retaining its patchy distribution in the thylakoid membrane. We discuss the possibility that the FtsH2-GFP patches represent Photosystem II 'repair zones' within the thylakoid membranes, and the possible advantages of such functionally specialised membrane zones. Anti-GFP affinity pull-downs provide the first indication of the composition of the putative repair zones.
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Affiliation(s)
- Joanna Sacharz
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
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13
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Burroughs NJ, Boehm M, Eckert C, Mastroianni G, Spence EM, Yu J, Nixon PJ, Appel J, Mullineaux CW, Bryan SJ. Solar powered biohydrogen production requires specific localization of the hydrogenase. ENERGY & ENVIRONMENTAL SCIENCE 2014; 7:3791-3800. [PMID: 26339289 PMCID: PMC4535174 DOI: 10.1039/c4ee02502d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 09/04/2014] [Indexed: 05/15/2023]
Abstract
Cyanobacteria contain a bidirectional [NiFe] hydrogenase which transiently produces hydrogen upon exposure of anoxic cells to light, potentially acting as a "valve" releasing excess electrons from the electron transport chain. However, its interaction with the photosynthetic electron transport chain remains unclear. By GFP-tagging the HoxF diaphorase subunit we show that the hydrogenase is thylakoid associated, comprising a population dispersed uniformly through the thylakoids and a subpopulation localized to discrete puncta in the distal thylakoid. Thylakoid localisation of both the HoxH and HoxY hydrogenase subunits is confirmed by immunogold electron microscopy. The diaphorase HoxE subunit is essential for recruitment to the dispersed thylakoid population, potentially anchoring the hydrogenase to the membrane, but aggregation to puncta occurs through a distinct HoxE-independent mechanism. Membrane association does not require NDH-1. Localization is dynamic on a scale of minutes, with anoxia and high light inducing a significant redistribution between these populations in favour of puncta. Since HoxE is essential for access to its electron donor, electron supply to the hydrogenase depends on a physiologically controlled localization, potentially offering a new avenue to enhance photosynthetic hydrogen production by exploiting localization/aggregation signals.
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Affiliation(s)
- Nigel J Burroughs
- Systems Biology Centre , Coventry House , University of Warwick , Coventry , CV4 7AL , UK
| | - Marko Boehm
- Imperial College London , South Kensington Campus , London , SW7 2AZ , UK
| | - Carrie Eckert
- Biosciences Centre , National Renewable Energy Laboratory , Golden , Colorado 80401 , USA ; Renewable and Sustainable Energy Institute, University of Colorado Boulder , Boulder , CO 80309 , USA
| | - Giulia Mastroianni
- School of Biological and Chemical Sciences , Queen Mary University of London , Mile End Road , London , E1 4NS , UK .
| | - Edward M Spence
- Pharmaceutical Science Division , King's College London , Franklin-Wilkins Building, 150 Stamford Street , London , SE1 9NH , UK
| | - Jianfeng Yu
- Imperial College London , South Kensington Campus , London , SW7 2AZ , UK
| | - Peter J Nixon
- Imperial College London , South Kensington Campus , London , SW7 2AZ , UK
| | - Jens Appel
- Botanical Institute , University of Kiel , Am Botanischen Garten 1-9 , 24118 Kiel , Germany
| | - Conrad W Mullineaux
- School of Biological and Chemical Sciences , Queen Mary University of London , Mile End Road , London , E1 4NS , UK .
| | - Samantha J Bryan
- School of Biological and Chemical Sciences , Queen Mary University of London , Mile End Road , London , E1 4NS , UK .
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14
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Bryan SJ, Burroughs NJ, Shevela D, Yu J, Rupprecht E, Liu LN, Mastroianni G, Xue Q, Llorente-Garcia I, Leake MC, Eichacker LA, Schneider D, Nixon PJ, Mullineaux CW. Localisation and interactions of the Vipp1 protein in cyanobacteria. Mol Microbiol 2014; 94:1179-1195. [PMID: 25308470 PMCID: PMC4297356 DOI: 10.1111/mmi.12826] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/09/2014] [Indexed: 12/22/2022]
Abstract
The Vipp1 protein is essential in cyanobacteria and chloroplasts for the maintenance of photosynthetic function and thylakoid membrane architecture. To investigate its mode of action we generated strains of the cyanobacteria Synechocystis sp. PCC6803 and Synechococcus sp. PCC7942 in which Vipp1 was tagged with green fluorescent protein at the C-terminus and expressed from the native chromosomal locus. There was little perturbation of function. Live-cell fluorescence imaging shows dramatic relocalisation of Vipp1 under high light. Under low light, Vipp1 is predominantly dispersed in the cytoplasm with occasional concentrations at the outer periphery of the thylakoid membranes. High light induces Vipp1 coalescence into localised puncta within minutes, with net relocation of Vipp1 to the vicinity of the cytoplasmic membrane and the thylakoid membranes. Pull-downs and mass spectrometry identify an extensive collection of proteins that are directly or indirectly associated with Vipp1 only after high-light exposure. These include not only photosynthetic and stress-related proteins but also RNA-processing, translation and protein assembly factors. This suggests that the Vipp1 puncta could be involved in protein assembly. One possibility is that Vipp1 is involved in the formation of stress-induced localised protein assembly centres, enabling enhanced protein synthesis and delivery to membranes under stress conditions.
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Affiliation(s)
- Samantha J Bryan
- School of Biological and Chemical Sciences, Queen Mary University of LondonMile End Road, London, E1 4NS, UK
| | - Nigel J Burroughs
- Mathematics Institute and Warwick Systems Biology Centre, University of WarwickCoventry, CV4 7AL, UK
| | - Dmitriy Shevela
- Department of Mathematics and Natural Science, University of Stavanger4036, Stavanger, Norway
| | - Jianfeng Yu
- Department of Life Sciences, Imperial College LondonLondon, SW7 2AZ, UK
| | - Eva Rupprecht
- Institut für Biochemie und Molekularbiologie, ZBMZ, Albert-Ludwigs-UniversitätStefan-Meier-Strasse 17, 79104, Freiburg, Germany
| | - Lu-Ning Liu
- School of Biological and Chemical Sciences, Queen Mary University of LondonMile End Road, London, E1 4NS, UK
| | - Giulia Mastroianni
- School of Biological and Chemical Sciences, Queen Mary University of LondonMile End Road, London, E1 4NS, UK
| | - Quan Xue
- Clarendon Laboratory, Department of Physics, University of OxfordParks Road, Oxford, OX1 3PU, UK
| | - Isabel Llorente-Garcia
- Clarendon Laboratory, Department of Physics, University of OxfordParks Road, Oxford, OX1 3PU, UK
- Department of Physics and Astronomy, University College LondonGower St., London, WC1E 6BT, UK
| | - Mark C Leake
- Biological Physical Sciences Institute (BPSI), Departments of Physics and Biology, University of YorkYork, YO105DD, UK
| | - Lutz A Eichacker
- Department of Mathematics and Natural Science, University of Stavanger4036, Stavanger, Norway
| | - Dirk Schneider
- Institut für Biochemie und Molekularbiologie, ZBMZ, Albert-Ludwigs-UniversitätStefan-Meier-Strasse 17, 79104, Freiburg, Germany
- Institut für Pharmazie und Biochemie, Johannes Gutenberg-Universität Mainz55128, Mainz, Germany
| | - Peter J Nixon
- Department of Life Sciences, Imperial College LondonLondon, SW7 2AZ, UK
| | - Conrad W Mullineaux
- School of Biological and Chemical Sciences, Queen Mary University of LondonMile End Road, London, E1 4NS, UK
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15
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Mechanisms Modulating Energy Arriving at Reaction Centers in Cyanobacteria. ADVANCES IN PHOTOSYNTHESIS AND RESPIRATION 2014. [DOI: 10.1007/978-94-017-9032-1_22] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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16
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Mullineaux CW. Co-existence of photosynthetic and respiratory activities in cyanobacterial thylakoid membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1837:503-11. [PMID: 24316145 DOI: 10.1016/j.bbabio.2013.11.017] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 11/15/2013] [Accepted: 11/24/2013] [Indexed: 01/10/2023]
Abstract
The thylakoid membranes of cyanobacteria are the major sites of respiratory electron transport as well as photosynthetic light reactions. The photosynthetic and respiratory electron transport chains share some components, and their presence in the same membrane opens up the possibility for a variety of "unorthodox" electron transport routes. Many of the theoretically possible electron transport pathways have indeed been detected in particular species and circumstances. Electron transport has a crucial impact on the redox balance of the cell and therefore the pathways of electron flow in the cyanobacterial thylakoid membrane must be tightly regulated. This review summarises what is known of cyanobacterial electron transport components, their interactions and their sub-cellular location. The role of thylakoid membrane organisation in controlling electron transport pathways is discussed with respect to recent evidence that the larger-scale distribution of complexes in the membrane is important for controlling electron exchange between the photosynthetic and respiratory complexes. The distribution of complexes on scales of 100nm or more is under physiological control, showing that larger-scale thylakoid membrane re-arrangement is a key factor in controlling the crosstalk between photosynthetic and respiratory electron transport. This article is part of a Special Issue entitled: Dynamic and ultrastructure of bioenergetic membranes and their components.
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Affiliation(s)
- Conrad W Mullineaux
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK.
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17
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Ogata K, Yuki T, Hatakeyama M, Uchida W, Nakamura S. All-Atom Molecular Dynamics Simulation of Photosystem II Embedded in Thylakoid Membrane. J Am Chem Soc 2013; 135:15670-3. [DOI: 10.1021/ja404317d] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Koji Ogata
- Nakamura
Laboratory, RIKEN Innovation Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Taichi Yuki
- Department
of Biomolecular Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
| | - Makoto Hatakeyama
- Nakamura
Laboratory, RIKEN Innovation Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Waka Uchida
- Department
of Biomolecular Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
| | - Shinichiro Nakamura
- Nakamura
Laboratory, RIKEN Innovation Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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18
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Kaňa R. Mobility of photosynthetic proteins. PHOTOSYNTHESIS RESEARCH 2013; 116:465-79. [PMID: 23955784 DOI: 10.1007/s11120-013-9898-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 07/18/2013] [Indexed: 05/03/2023]
Abstract
The mobility of photosynthetic proteins represents an important factor that affects light-energy conversion in photosynthesis. The specific feature of photosynthetic proteins mobility can be currently measured in vivo using advanced microscopic methods, such as fluorescence recovery after photobleaching which allows the direct observation of photosynthetic proteins mobility on a single cell level. The heterogeneous organization of thylakoid membrane proteins results in heterogeneity in protein mobility. The thylakoid membrane contains both, protein-crowded compartments with immobile proteins and fluid areas (less crowded by proteins), allowing restricted diffusion of proteins. This heterogeneity represents an optimal balance as protein crowding is necessary for efficient light-energy conversion, and protein mobility plays an important role in the regulation of photosynthesis. The mobility is required for an optimal light-harvesting process (e.g., during state transitions), and also for transport of proteins during their synthesis or repair. Protein crowding is then a key limiting factor of thylakoid membrane protein mobility; the less thylakoid membranes are crowded by proteins, the higher protein mobility is observed. Mobility of photosynthetic proteins outside the thylakoid membrane (lumen and stroma/cytosol) is less understood. Cyanobacterial phycobilisomes attached to the stromal side of the thylakoid can move relatively fast. Therefore, it seems that stroma with their active enzymes of the Calvin-Benson cycle, are a more fluid compartment in comparison to the rather rigid thylakoid lumen. In conclusion, photosynthetic protein diffusion is generally slower in comparison to similarly sized proteins from other eukaryotic membranes or organelles. Mobility of photosynthetic proteins resembles restricted protein diffusion in bacteria, and has been rationalized by high protein crowding similar to that of thylakoids.
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Affiliation(s)
- Radek Kaňa
- Department of photothrophic microorganisms - Algatech, Institute of Microbiology, Academy of Sciences of the Czech Republic, Opatovický mlýn, 379 81, Třeboň, Czech Republic,
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19
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Control of electron transport routes through redox-regulated redistribution of respiratory complexes. Proc Natl Acad Sci U S A 2012; 109:11431-6. [PMID: 22733774 DOI: 10.1073/pnas.1120960109] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In cyanobacteria, respiratory electron transport takes place in close proximity to photosynthetic electron transport, because the complexes required for both processes are located within the thylakoid membranes. The balance of electron transport routes is crucial for cell physiology, yet the factors that control the predominance of particular pathways are poorly understood. Here we use a combination of tagging with green fluorescent protein and confocal fluorescence microscopy in live cells of the cyanobacterium Synechococcus elongatus PCC 7942 to investigate the distribution on submicron scales of two key respiratory electron donors, type-I NAD(P)H dehydrogenase (NDH-1) and succinate dehydrogenase (SDH). When cells are grown under low light, both complexes are concentrated in discrete patches in the thylakoid membranes, about 100-300 nm in diameter and containing tens to hundreds of complexes. Exposure to moderate light leads to redistribution of both NDH-1 and SDH such that they become evenly distributed within the thylakoid membranes. The effects of electron transport inhibitors indicate that redistribution of respiratory complexes is triggered by changes in the redox state of an electron carrier close to plastoquinone. Redistribution does not depend on de novo protein synthesis, and it is accompanied by a major increase in the probability that respiratory electrons are transferred to photosystem I rather than to a terminal oxidase. These results indicate that the distribution of complexes on the scale of 100-300 nm controls the partitioning of reducing power and that redistribution of electron transport complexes on these scales is a physiological mechanism to regulate the pathways of electron flow.
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20
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Rexroth S, Mullineaux CW, Ellinger D, Sendtko E, Rögner M, Koenig F. The plasma membrane of the cyanobacterium Gloeobacter violaceus contains segregated bioenergetic domains. THE PLANT CELL 2011; 23:2379-90. [PMID: 21642550 PMCID: PMC3160022 DOI: 10.1105/tpc.111.085779] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 04/01/2011] [Accepted: 05/14/2011] [Indexed: 05/18/2023]
Abstract
The light reactions of oxygenic photosynthesis almost invariably take place in the thylakoid membranes, a highly specialized internal membrane system located in the stroma of chloroplasts and the cytoplasm of cyanobacteria. The only known exception is the primordial cyanobacterium Gloeobacter violaceus, which evolved before the appearance of thylakoids and harbors the photosynthetic complexes in the plasma membrane. Thus, studies on G. violaceus not only shed light on the evolutionary origin and the functional advantages of thylakoid membranes but also might include insights regarding thylakoid formation during chloroplast differentiation. Based on biochemical isolation and direct in vivo characterization, we report here structural and functional domains in the cytoplasmic membrane of a cyanobacterium. Although G. violaceus has no internal membranes, it does have localized domains with apparently specialized functions in its plasma membrane, in which both the photosynthetic and the respiratory complexes are concentrated. These bioenergetic domains can be visualized by confocal microscopy, and they can be isolated by a simple procedure. Proteomic analysis of these domains indicates their physiological function and suggests a protein sorting mechanism via interaction with membrane-intrinsic terpenoids. Based on these results, we propose specialized domains in the plasma membrane as evolutionary precursors of thylakoids.
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Affiliation(s)
- Sascha Rexroth
- Plant Biochemistry, Ruhr-University Bochum, 44780 Bochum, Germany.
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21
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Nixon PJ, Michoux F, Yu J, Boehm M, Komenda J. Recent advances in understanding the assembly and repair of photosystem II. ANNALS OF BOTANY 2010; 106:1-16. [PMID: 20338950 PMCID: PMC2889791 DOI: 10.1093/aob/mcq059] [Citation(s) in RCA: 382] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 02/01/2010] [Accepted: 02/09/2010] [Indexed: 05/18/2023]
Abstract
BACKGROUND Photosystem II (PSII) is the light-driven water:plastoquinone oxidoreductase of oxygenic photosynthesis and is found in the thylakoid membrane of chloroplasts and cyanobacteria. Considerable attention is focused on how PSII is assembled in vivo and how it is repaired following irreversible damage by visible light (so-called photoinhibition). Understanding these processes might lead to the development of plants with improved growth characteristics especially under conditions of abiotic stress. SCOPE Here we summarize recent results on the assembly and repair of PSII in cyanobacteria, which are excellent model organisms to study higher plant photosynthesis. CONCLUSIONS Assembly of PSII is highly co-ordinated and proceeds through a number of distinct assembly intermediates. Associated with these assembly complexes are proteins that are not found in the final functional PSII complex. Structural information and possible functions are beginning to emerge for several of these 'assembly' factors, notably Ycf48/Hcf136, Psb27 and Psb28. A number of other auxiliary proteins have been identified that appear to have evolved since the divergence of chloroplasts and cyanobacteria. The repair of PSII involves partial disassembly of the damaged complex, the selective replacement of the damaged sub-unit (predominantly the D1 sub-unit) by a newly synthesized copy, and reassembly. It is likely that chlorophyll released during the repair process is temporarily stored by small CAB-like proteins (SCPs). A model is proposed in which damaged D1 is removed in Synechocystis sp. PCC 6803 by a hetero-oligomeric complex composed of two different types of FtsH sub-unit (FtsH2 and FtsH3), with degradation proceeding from the N-terminus of D1 in a highly processive reaction. It is postulated that a similar mechanism of D1 degradation also operates in chloroplasts. Deg proteases are not required for D1 degradation in Synechocystis 6803 but members of this protease family might play a supplementary role in D1 degradation in chloroplasts under extreme conditions.
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Affiliation(s)
- Peter J Nixon
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK.
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22
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Goral TK, Johnson MP, Brain APR, Kirchhoff H, Ruban AV, Mullineaux CW. Visualizing the mobility and distribution of chlorophyll proteins in higher plant thylakoid membranes: effects of photoinhibition and protein phosphorylation. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010. [PMID: 20230505 DOI: 10.1111/j.1365-313x.2010.04207.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The diffusion of proteins in chloroplast thylakoid membranes is believed to be important for processes including the photosystem-II repair cycle and the regulation of light harvesting. However, to date there is very little direct information on the mobility of thylakoid proteins. We have used fluorescence recovery after photobleaching in a laser-scanning confocal microscope to visualize in real time the exchange of chlorophyll proteins between grana in intact spinach (Spinacia oleracea L.) and Arabidopsis chloroplasts. Most chlorophyll proteins in the grana appear immobile on the 10-min timescale of our measurements. However, a limited population of chlorophyll proteins (accounting for around 15% of chlorophyll fluorescence) can exchange between grana on this timescale. In intact, wild-type chloroplasts this mobile population increases significantly after photoinhibition, consistent with a role for protein diffusion in the photosystem-II repair cycle. No such increase in mobility is seen in isolated grana membranes, or in the Arabidopsis stn8 and stn7 stn8 mutants, which lack the protein kinases required for phosphorylation of photosystem II core proteins and light-harvesting complexes. Furthermore, mobility under low-light conditions is significantly lower in stn8 and stn7 stn8 plants than in wild-type Arabidopsis. The changes in protein mobility correlate with changes in the packing density and size of thylakoid protein complexes, as observed by freeze-fracture electron microscopy. We conclude that protein phosphorylation switches the membrane system to a more fluid state, thus facilitating the photosystem-II repair cycle.
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Affiliation(s)
- Tomasz K Goral
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
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23
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Liu LN, Aartsma TJ, Thomas JC, Zhou BC, Zhang YZ. FRAP analysis on red alga reveals the fluorescence recovery is ascribed to intrinsic photoprocesses of phycobilisomes than large-scale diffusion. PLoS One 2009; 4:e5295. [PMID: 19381335 PMCID: PMC2667670 DOI: 10.1371/journal.pone.0005295] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2009] [Accepted: 03/26/2009] [Indexed: 11/28/2022] Open
Abstract
Background Phycobilisomes (PBsomes) are the extrinsic antenna complexes upon the photosynthetic membranes in red algae and most cyanobacteria. The PBsomes in the cyanobacteria has been proposed to present high lateral mobility on the thylakoid membrane surface. In contrast, direct measurement of PBsome motility in red algae has been lacking so far. Methodology/Principal Findings In this work, we investigated the dynamics of PBsomes in the unicellular red alga Porphyridium cruentum in vivo and in vitro, using fluorescence recovery after photobleaching (FRAP). We found that part of the fluorescence recovery could be detected in both partially- and wholly-bleached wild-type and mutant F11 (UTEX 637) cells. Such partial fluorescence recovery was also observed in glutaraldehyde-treated and betaine-treated cells in which PBsome diffusion should be restricted by cross-linking effect, as well as in isolated PBsomes immobilized on the glass slide. Conclusions/Significance On the basis of our previous structural results showing the PBsome crowding on the native photosynthetic membrane as well as the present FRAP data, we concluded that the fluorescence recovery observed during FRAP experiment in red algae is mainly ascribed to the intrinsic photoprocesses of the bleached PBsomes in situ, rather than the rapid diffusion of PBsomes on thylakoid membranes in vivo. Furthermore, direct observations of the fluorescence dynamics of phycoerythrins using FRAP demonstrated the energetic decoupling of phycoerythrins in PBsomes against strong excitation light in vivo, which is proposed as a photoprotective mechanism in red algae attributed by the PBsomes in response to excess light energy.
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Affiliation(s)
- Lu-Ning Liu
- State Key Lab of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Jinan, People's Republic of China
- Department of Biophysics, Huygens Laboratory, Leiden University, Leiden, The Netherlands
| | - Thijs J. Aartsma
- Department of Biophysics, Huygens Laboratory, Leiden University, Leiden, The Netherlands
| | - Jean-Claude Thomas
- UMR 8186 CNRS & Ecole Normale Supérieure, Biologie Moléculaire des Organismes Photosynthétiques, Paris, France
| | - Bai-Cheng Zhou
- State Key Lab of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Jinan, People's Republic of China
| | - Yu-Zhong Zhang
- State Key Lab of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Jinan, People's Republic of China
- * E-mail:
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24
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Abstract
Protein diffusion in and around the photosynthetic membrane must play a crucial role in photosynthetic functions including electron transport, regulation of light-harvesting, and biogenesis, turnover and repair of membrane components. Protein mobility is controlled by a complex web of specific interactions, plus the viscosity of the environment and the extent of macromolecular crowding. I discuss the techniques that can be used to measure protein mobility in photosynthetic membranes. I then summarize what we know about the constraints on protein mobility imposed by macromolecular aggregation and crowding in and around the thylakoid membranes of green plants and cyanobacteria, with particular reference to the fluidity of the thylakoid membrane and the aqueous phases on either side of the membrane (the stroma/cytoplasm and the thylakoid lumen). Current indications are that the stroma/cytoplasm is a relatively fluid environment, whereas protein mobility in the lumen may be extremely restricted. The thylakoid membrane itself has an intermediate fluidity: some protein complexes are virtually immobile, probably due to their incorporation into large, stable macromolecular aggregates. However, there is sufficient free space to allow the long-range diffusion of some complexes. Finally, I discuss some future directions for research in this area.
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Affiliation(s)
- Conrad W Mullineaux
- School of Biological and Chemical Sciences, Queen Mary, University of London, London, UK.
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25
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Mullineaux CW, Mariscal V, Nenninger A, Khanum H, Herrero A, Flores E, Adams DG. Mechanism of intercellular molecular exchange in heterocyst-forming cyanobacteria. EMBO J 2008; 27:1299-308. [PMID: 18388860 DOI: 10.1038/emboj.2008.66] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Accepted: 03/04/2008] [Indexed: 11/09/2022] Open
Abstract
Heterocyst-forming filamentous cyanobacteria are true multicellular prokaryotes, in which heterocysts and vegetative cells have complementary metabolism and are mutually dependent. The mechanism for metabolite exchange between cells has remained unclear. To gain insight into the mechanism and kinetics of metabolite exchange, we introduced calcein, a 623-Da fluorophore, into the Anabaena cytoplasm. We used fluorescence recovery after photobleaching to quantify rapid diffusion of this molecule between the cytoplasms of all the cells in the filament. This indicates nonspecific intercellular channels allowing the movement of molecules from cytoplasm to cytoplasm. We quantify rates of molecular exchange as filaments adapt to diazotrophic growth. Exchange among vegetative cells becomes faster as filaments differentiate, becoming considerably faster than exchange with heterocysts. Slower exchange is probably a price paid to maintain a microaerobic environment in the heterocyst. We show that the slower exchange is partly due to the presence of cyanophycin polar nodules in heterocysts. The phenotype of a null mutant identifies FraG (SepJ), a membrane protein localised at the cell-cell interface, as a strong candidate for the channel-forming protein.
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Affiliation(s)
- Conrad W Mullineaux
- School of Biological and Chemical Sciences, Queen Mary, University of London, London, UK.
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26
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Kirilovsky D. Photoprotection in cyanobacteria: the orange carotenoid protein (OCP)-related non-photochemical-quenching mechanism. PHOTOSYNTHESIS RESEARCH 2007; 93:7-16. [PMID: 17486426 DOI: 10.1007/s11120-007-9168-y] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2006] [Accepted: 04/12/2007] [Indexed: 05/15/2023]
Abstract
Plants and algae have developed multiple protective mechanisms to survive under high light conditions. Thermal dissipation of excitation energy in the membrane-bound chlorophyll-antenna of photosystem II (PSII) decreases the energy arriving at the reaction center and thus reduces the generation of toxic photo-oxidative species. This process results in a decrease of PSII-related fluorescence emission, known as non-photochemical quenching (NPQ). It has always been assumed that cyanobacteria, the progenitor of the chloroplast, lacked an equivalent photoprotective mechanism. Recently, however, evidence has been presented for the existence of at least three distinct mechanisms for dissipating excess absorbed energy in cyanobacteria. One of these mechanisms, characterized by a blue-light-induced fluorescence quenching, is related to the phycobilisomes, the extramembranal antenna of cyanobacterial PSII. In this photoprotective mechanism the soluble carotenoid-binding protein (OCP) encoded by the slr1963 gene in Synechocystis sp. PCC 6803, of previously unknown function, plays an essential role. The amount of energy transferred from the phycobilisomes to the photosystems is reduced and the OCP acts as the photoreceptor and as the mediator of this antenna-related process. These are novel roles for a soluble carotenoid protein.
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Affiliation(s)
- Diana Kirilovsky
- CEA, SB2SM, iBiTecS, URA 2096, CNRS, 91191, Gif sur Yvette, France.
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27
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Volkmer T, Schneider D, Bernát G, Kirchhoff H, Wenk SO, Rögner M. Ssr2998 of Synechocystis sp. PCC 6803 is involved in regulation of cyanobacterial electron transport and associated with the cytochrome b6f complex. J Biol Chem 2006; 282:3730-7. [PMID: 17166849 DOI: 10.1074/jbc.m604948200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To analyze the function of a protein encoded by the open reading frame ssr2998 in Synechocystis sp. PCC 6803, the corresponding gene was disrupted, and the generated mutant strain was analyzed. Loss of the 7.2-kDa protein severely reduced the growth of Synechocystis, especially under high light conditions, and appeared to impair the function of the cytochrome b6 f complex. This resulted in slower electron donation to cytochrome f and photosystem 1 and, concomitantly, over-reduction of the plastoquinone pool, which in turn had an impact on the photosystem 1 to photosystem 2 stoichiometry and state transition. Furthermore, a 7.2-kDa protein, encoded by the open reading frame ssr2998, was co-isolated with the cytochrome b6 f complex from the cyanobacterium Synechocystis sp. PCC 6803. ssr2998 seems to be structurally and functionally associated with the cytochrome b6 f complex from Synechocystis, and the protein could be involved in regulation of electron transfer processes in Synechocystis sp. PCC 6803.
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Affiliation(s)
- Thomas Volkmer
- Biochemie der Pflanzen, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
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28
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Fowlkes JD, Hullander ED, Fletcher BL, Retterer ST, Melechko AV, Hensley DK, Simpson ML, Doktycz MJ. Molecular transport in a crowded volume created from vertically aligned carbon nanofibres: a fluorescence recovery after photobleaching study. NANOTECHNOLOGY 2006; 17:5659-68. [PMID: 21727339 DOI: 10.1088/0957-4484/17/22/021] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Rapid and selective molecular exchange across a barrier is essential for emulating the properties of biological membranes. Vertically-aligned carbon nanofibre (VACNF) forests have shown great promise as membrane mimics, owing to their mechanical stability, their ease of integration with microfabrication technologies and the ability to tailor their morphology and surface properties. However, quantifying transport through synthetic membranes having micro- and nanoscale features is challenging. Here, fluorescence recovery after photobleaching (FRAP) is coupled with finite difference and Monte Carlo simulations to quantify diffusive transport in microfluidic structures containing VACNF forests. Anomalous subdiffusion was observed for FITC (hydrodynamic radius of 0.54 nm) diffusion through both VACNFs and SiO(2)-coated VACNFS (oxVACNFs). Anomalous subdiffusion can be attributed to multiple FITC-nanofibre interactions for the case of diffusion through the VACNF forest. Volume crowding was identified as the cause of anomalous subdiffusion in the oxVACNF forest. In both cases the diffusion mode changes to a time-independent, Fickian mode of transport that can be defined by a crossover length (R(CR)). By identifying the space-and time-dependent transport characteristics of the VACNF forest, the dimensional features of membranes can be tailored to achieve predictable molecular exchange.
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Affiliation(s)
- J D Fowlkes
- Molecular-Scale Engineering and Nanoscale Technologies Research Group, Condensed Matter Sciences Division, Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831-6006, USA. Materials Science and Engineering Department, The University of Tennessee, Knoxville, TN 37996-2200, USA. Biological and Nanoscale Systems Group, Life Sciences Division, Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831-6123, USA
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29
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Leake MC, Chandler JH, Wadhams GH, Bai F, Berry RM, Armitage JP. Stoichiometry and turnover in single, functioning membrane protein complexes. Nature 2006; 443:355-8. [PMID: 16971952 DOI: 10.1038/nature05135] [Citation(s) in RCA: 443] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2006] [Accepted: 07/24/2006] [Indexed: 11/09/2022]
Abstract
Many essential cellular processes are carried out by complex biological machines located in the cell membrane. The bacterial flagellar motor is a large membrane-spanning protein complex that functions as an ion-driven rotary motor to propel cells through liquid media. Within the motor, MotB is a component of the stator that couples ion flow to torque generation and anchors the stator to the cell wall. Here we have investigated the protein stoichiometry, dynamics and turnover of MotB with single-molecule precision in functioning bacterial flagellar motors in Escherichia coli. We monitored motor function by rotation of a tethered cell body, and simultaneously measured the number and dynamics of MotB molecules labelled with green fluorescent protein (GFP-MotB) in the motor by total internal reflection fluorescence microscopy. Counting fluorophores by the stepwise photobleaching of single GFP molecules showed that each motor contains approximately 22 copies of GFP-MotB, consistent with approximately 11 stators each containing two MotB molecules. We also observed a membrane pool of approximately 200 GFP-MotB molecules diffusing at approximately 0.008 microm2 s(-1). Fluorescence recovery after photobleaching and fluorescence loss in photobleaching showed turnover of GFP-MotB between the membrane pool and motor with a rate constant of the order of 0.04 s(-1): the dwell time of a given stator in the motor is only approximately 0.5 min. This is the first direct measurement of the number and rapid turnover of protein subunits within a functioning molecular machine.
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Affiliation(s)
- Mark C Leake
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK
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30
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Mullineaux CW, Nenninger A, Ray N, Robinson C. Diffusion of green fluorescent protein in three cell environments in Escherichia coli. J Bacteriol 2006; 188:3442-8. [PMID: 16672597 PMCID: PMC1482841 DOI: 10.1128/jb.188.10.3442-3448.2006] [Citation(s) in RCA: 149] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Surprisingly little is known about the physical environment inside a prokaryotic cell. Knowledge of the rates at which proteins and other cell components can diffuse is crucial for the understanding of a cell as a physical system. There have been numerous measurements of diffusion coefficients in eukaryotic cells by using fluorescence recovery after photobleaching (FRAP) and related techniques. Much less information is available about diffusion coefficients in prokaryotic cells, which differ from eukaryotic cells in a number of significant respects. We have used FRAP to observe the diffusion of green fluorescent protein (GFP) in cells of Escherichia coli elongated by growth in the presence of cephalexin. GFP was expressed in the cytoplasm, exported into the periplasm using the twin-arginine translocation (Tat) system, or fused to an integral plasma membrane protein (TatA). We show that TatA-GFP diffuses in the plasma membrane with a diffusion coefficient comparable to that of a typical eukaryotic membrane protein. A previous report showed a very low rate of protein diffusion in the E. coli periplasm. However, we measured a GFP diffusion coefficient only slightly smaller in the periplasm than that in the cytoplasm, showing that both cell compartments are relatively fluid environments.
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Affiliation(s)
- Conrad W Mullineaux
- School of Biological and Chemical Sciences, Queen Mary, University of London, UK.
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Liberton M, Howard Berg R, Heuser J, Roth R, Pakrasi HB. Ultrastructure of the membrane systems in the unicellular cyanobacterium Synechocystis sp. strain PCC 6803. PROTOPLASMA 2006; 227:129-38. [PMID: 16736255 DOI: 10.1007/s00709-006-0145-7] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2005] [Accepted: 07/05/2005] [Indexed: 05/09/2023]
Abstract
Among prokaryotes, cyanobacteria are unique in having highly differentiated internal membrane systems. Like other Gram-negative bacteria, cyanobacteria such as Synechocystis sp. strain PCC 6803 have a cell envelope consisting of a plasma membrane, peptidoglycan layer, and outer membrane. In addition, these organisms have an internal system of thylakoid membranes where the electron transfer reactions of photosynthesis and respiration occur. A long-standing controversy concerning the cellular ultrastructures of these organisms has been whether the thylakoid membranes exist inside the cell as separate compartments, or if they have physical continuity with the plasma membrane. Advances in cellular preservation protocols as well as in image acquisition and manipulation techniques have facilitated a new examination of this topic. We have used a combination of electron microscopy techniques, including freeze-etched as well as freeze-substituted preparations, in conjunction with computer-aided image processing to generate highly detailed images of the membrane systems in Synechocystis cells. We show that the thylakoid membranes are in fact physically discontinuous from the plasma membrane in this cyanobacterium. Thylakoid membranes in Synechocystis sp. strain PCC 6803 thus represent bona fide intracellular organelles, the first example of such compartments in prokaryotic cells.
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Affiliation(s)
- Michelle Liberton
- Department of Biology, Washington University, St. Louis, Missouri 63130, USA
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Joshua S, Mullineaux CW. The rpaC gene product regulates phycobilisome-photosystem II interaction in cyanobacteria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2005; 1709:58-68. [PMID: 16023072 DOI: 10.1016/j.bbabio.2005.06.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2005] [Revised: 06/01/2005] [Accepted: 06/19/2005] [Indexed: 11/23/2022]
Abstract
State transitions in cyanobacteria are a physiological adaptation mechanism that changes the interaction of the phycobilisomes with the Photosystem I and Photosystem II core complexes. A random mutagenesis study in the cyanobacterium Synechocystis sp. PCC6803 identified a gene named rpaC which appeared to be specifically required for state transitions. rpaC is a conserved cyanobacterial gene which was tentatively suggested to code for a novel signal transduction factor. The predicted gene product is a 9-kDa integral membrane protein. We have further examined the role of rpaC by overexpressing the gene in Synechocystis 6803 and by inactivating the ortholog in a second cyanobacterium, Synechococcus sp. PCC7942. Unlike the Synechocystis 6803 null mutant, the Synechococcus 7942 null mutant is unable to segregate, indicating that the gene is essential for cell viability in this cyanobacterium. The Synechocystis 6803 overexpressor is also unable to segregate, indicating that the cells can only tolerate a limited gene copy number. The non-segregated Synechococcus 7942 mutant can perform state transitions but shows a perturbed phycobilisome-Photosystem II interaction. Based on these results, we propose that the rpaC gene product controls the stability of the phycobilisome-Photosystem II supercomplex, and is probably a structural component of the complex.
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Affiliation(s)
- Sarah Joshua
- Department of Biology, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
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33
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Tychinsky VP, Kretushev AV, Vyshenskaya TV, Tikhonov AN. Coherent phase microscopy in cell biology: visualization of metabolic states. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2005; 1708:362-6. [PMID: 15950927 DOI: 10.1016/j.bbabio.2005.04.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2005] [Accepted: 04/27/2005] [Indexed: 11/25/2022]
Abstract
Visualization of functional properties of individual cells and intracellular organelles still remains an experimental challenge in cell biology. The coherent phase microscopy (CPM) provides a convenient and non-invasive tool for imaging cells and intracellular organelles. In this work, we report results of statistical analysis of CPM images of cyanobacterial cells (Synechocystis sp. PCC 6803) and spores (Bacillus licheniformis). It has been shown that CPM images of cyanobacterial cells and spores are sensitive to variations of their metabolic states. We found a correlation between one of optical parameters of the CPM image ('phase thicknesses' Deltah) and cell energization. It was demonstrated that the phase thickness Deltah decreased after cell treatment with the uncoupler CCCP or inhibitors of electron transport (KCN or DCMU). Statistical analysis of distributions of parameter Deltah and cell diameter d demonstrated that a decrease in the phase thickness Deltah could not be attributed entirely to a decrease in geometrical sizes of cells. This finding demonstrates that the CPM technique may be a convenient tool for fast and non-invasive diagnosis of metabolic states of individual cells and intracellular organelles.
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Affiliation(s)
- Vladimir P Tychinsky
- Moscow State Institute for Radioengineering, Electronics and Automation, prosp. Vernadskogo 78, 119454 Moscow, Russia
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Joshua S, Bailey S, Mann NH, Mullineaux CW. Involvement of phycobilisome diffusion in energy quenching in cyanobacteria. PLANT PHYSIOLOGY 2005; 138:1577-85. [PMID: 15908597 PMCID: PMC1176427 DOI: 10.1104/pp.105.061168] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2005] [Revised: 03/14/2005] [Accepted: 03/14/2005] [Indexed: 05/02/2023]
Abstract
Nonphotochemical quenching (NPQ) of excitation energy is a well-established phenomenon in green plants, where it serves to protect the photosynthetic apparatus from photodamage under excess illumination. The induction of NPQ involves a change in the function of the light-harvesting apparatus, with the formation of quenching centers that convert excitation energy into heat. Recently, a comparable phenomenon was demonstrated in cyanobacteria grown under iron-starvation. Under these conditions, an additional integral membrane chlorophyll-protein, IsiA, is synthesized, and it is therefore likely that IsiA is required for NPQ in cyanobacteria. We have previously used fluorescence recovery after photobleaching to show that phycobilisomes diffuse rapidly on the membrane surface, but are immobilized when cells are immersed in high-osmotic strength buffers, apparently because the interaction between phycobilisomes and reaction centers is stabilized. Here, we show that when cells of the cyanobacterium Synechocystis sp. PCC 6803 subjected to prolonged iron-deprivation are immersed in 1 m phosphate buffer, NPQ can still be induced as normal by high light. However, the formation of the quenched state is irreversible under these conditions, suggesting that it involves the coupling of free phycobilisomes to an integral-membrane complex, an interaction that is stabilized by 1 m phosphate. Fluorescence spectra are consistent with this idea. Fluorescence recovery after photobleaching measurements confirm that the induction of NPQ in the presence of 1 m phosphate is accompanied by immobilization of the phycobilisomes. We propose as a working hypothesis that a major component of the fluorescence quenching observed in iron-starved cyanobacteria arises from the coupling of free phycobilisomes to IsiA.
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Affiliation(s)
- Sarah Joshua
- Department of Biology, University College London, London WC1E 6BT United Kingdom
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35
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Joshua S, Mullineaux CW. Phycobilisome diffusion is required for light-state transitions in cyanobacteria. PLANT PHYSIOLOGY 2004; 135:2112-9. [PMID: 15286286 PMCID: PMC520783 DOI: 10.1104/pp.104.046110] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2004] [Revised: 05/28/2004] [Accepted: 05/28/2004] [Indexed: 05/18/2023]
Abstract
Phycobilisomes are the major accessory light-harvesting complexes of cyanobacteria and red algae. Studies using fluorescence recovery after photobleaching on cyanobacteria in vivo have shown that the phycobilisomes are mobile complexes that rapidly diffuse on the thylakoid membrane surface. By contrast, the PSII core complexes are completely immobile. This indicates that the association of phycobilisomes with reaction centers must be transient and unstable. Here, we show that when cells of the cyanobacterium Synechococcus sp. PCC7942 are immersed in buffers of high osmotic strength, the diffusion coefficient for the phycobilisomes is greatly decreased. This suggests that the interaction between phycobilisomes and reaction centers becomes much less transient under these conditions. We discuss the possible reasons for this. State transitions are a rapid physiological adaptation mechanism that regulates the way in which absorbed light energy is distributed between PSI and PSII. Immersing cells in high osmotic strength buffers inhibits state transitions by locking cells into whichever state they were in prior to addition of the buffer. The effect on state transitions is induced at the same buffer concentrations as the effect on phycobilisome diffusion. This implies that phycobilisome diffusion is required for state transitions. The main physiological role for phycobilisome mobility may be to allow such flexibility in light harvesting.
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Affiliation(s)
- Sarah Joshua
- Department of Biology, University College London, London WC1E 6BT, United Kingdom
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36
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Sarcina M, Mullineaux CW. Mobility of the IsiA Chlorophyll-binding Protein in Cyanobacterial Thylakoid Membranes. J Biol Chem 2004; 279:36514-8. [PMID: 15218021 DOI: 10.1074/jbc.m405881200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We are using fluorescence recovery after photobleaching (FRAP) to probe the dynamics of thylakoid membranes in vivo in cells of the cyanobacterium Synechococcus sp. PCC7942. We have shown previously that the light-harvesting phycobilisomes diffuse quite rapidly on the thylakoid membrane surface. However, the photosystem II core complexes appear completely immobile. This raises the possibility that all of the membrane integral protein complexes in the thylakoid membrane are locked into a rather rigid array. Alternatively, it is possible that photosystem II is specifically anchored in the membrane, with other membrane proteins able to diffuse around it. We have now resolved this question by studying the diffusion of a second integral membrane protein, the IsiA chlorophyll-binding protein. IsiA is induced under iron starvation and some other stress conditions. In iron-stressed cyanobacterial cells, a high proportion of chlorophyll fluorescence comes from IsiA. This makes it straightforward to examine the diffusion of IsiA by FRAP. We find that the complex is mobile with a mean diffusion coefficient of approximately 3 x 10(-11) cm(2) s(-1). Thus it is clear that some thylakoid membrane proteins are mobile and that there must be a specific anchor that prevents photosystem II diffusion. We discuss the implications for the structure and function of the cyanobacterial thylakoid membrane.
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Affiliation(s)
- Mary Sarcina
- Department of Biology, University College London, Darwin Building, Gower Street, London WC1E 6BT, United Kingdom
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Mullineaux CW. FRAP analysis of photosynthetic membranes. JOURNAL OF EXPERIMENTAL BOTANY 2004; 55:1207-1211. [PMID: 15020635 DOI: 10.1093/jxb/erh106] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Fluorescence Recovery after Photobleaching (FRAP) is a technique widely used in cell biology to observe the dynamics of biological systems, including the diffusion of membrane components. More information is needed on the dynamics of photosynthetic membranes in order to help to understand processes such as photosynthetic electron transport, regulation of light-harvesting, and biogenesis and turnover of the photosynthetic apparatus. FRAP has the potential to provide this information, although applying the technique to photosynthetic membranes is not always straightforward. This review explains the potential and the problems, and gives a brief guide to performing FRAP measurements and analysing the data.
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Affiliation(s)
- Conrad W Mullineaux
- Department of Biology, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK.
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Sarcina M, Murata N, Tobin MJ, Mullineaux CW. Lipid diffusion in the thylakoid membranes of the cyanobacterium Synechococcus sp.: effect of fatty acid desaturation. FEBS Lett 2003; 553:295-8. [PMID: 14572639 DOI: 10.1016/s0014-5793(03)01031-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Thylakoid membranes are crucial to photosynthesis in cyanobacteria and plants. In cyanobacteria, genetic modification of membrane lipid composition strongly influences cold tolerance and susceptibility to photoinhibition. We have used fluorescence recovery after photobleaching to measure the diffusion of a lipid-soluble fluorescent marker in cells of the cyanobacterium Synechococcus sp. PCC 7942. We have compared the wild-type strain with a transformant with an increased level of fatty acid unsaturation. The transformant showed a six-fold increase in the diffusion coefficient for the fluorescent marker at growth temperature. This is the first direct measurement of lipid diffusion in a photosynthetic membrane.
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Affiliation(s)
- Mary Sarcina
- Department of Biology, University College London, Darwin Building, Gower Street, WC1E 6BT London, UK
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