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Seneviratne R, Coates G, Xu Z, Cornell CE, Thompson RF, Sadeghpour A, Maskell DP, Jeuken LJC, Rappolt M, Beales PA. High Resolution Membrane Structures within Hybrid Lipid-Polymer Vesicles Revealed by Combining X-Ray Scattering and Electron Microscopy. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2206267. [PMID: 36866488 DOI: 10.1002/smll.202206267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 01/26/2023] [Indexed: 06/02/2023]
Abstract
Hybrid vesicles consisting of phospholipids and block-copolymers are increasingly finding applications in science and technology. Herein, small angle X-ray scattering (SAXS) and cryo-electron tomography (cryo-ET) are used to obtain detailed structural information about hybrid vesicles with different ratios of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and poly(1,2-butadiene-block-ethylene oxide) (PBd22 -PEO14 , Ms = 1800 g mol-1 ). Using single particle analysis (SPA) the authors are able to further interpret the information gained from SAXS and cryo-ET experiments, showing that increasing PBd22 -PEO14 mole fraction increases the membrane thickness from 52 Å for a pure lipid system to 97 Å for pure PBd22 -PEO14 vesicles. Two vesicle populations with different membrane thicknesses in hybrid vesicle samples are found. As these lipids and polymers are reported to homogeneously mix, bistability is inferred between weak and strong interdigitation regimes of PBd22 -PEO14 within the hybrid membranes. It is hypothesized that membranes of intermediate structure are not energetically favorable. Therefore, each vesicle exists in one of these two membrane structures, which are assumed to have comparable free energies. The authors conclude that, by combining biophysical methods, accurate determination of the influence of composition on the structural properties of hybrid membranes is achieved, revealing that two distinct membranes structures can coexist in homogeneously mixed lipid-polymer hybrid vesicles.
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Affiliation(s)
- Rashmi Seneviratne
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Georgina Coates
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Zexi Xu
- School of Food Science and Nutrition, School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Caitlin E Cornell
- Department of Bioengineering, University of California, Berkeley, CA, 94720, USA
| | - Rebecca F Thompson
- School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Amin Sadeghpour
- School of Food Science and Nutrition, University of Leeds, Leeds, LS2 9JT, UK
| | - Daniel P Maskell
- School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Lars J C Jeuken
- Leiden Institute of Chemistry, Leiden University, PC Box 9502, Leiden, 2300 RA, Netherlands
| | - Michael Rappolt
- School of Food Science and Nutrition, University of Leeds, Leeds, LS2 9JT, UK
| | - Paul A Beales
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
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2
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The Assembly of Super-Complexes in the Plant Chloroplast. Biomolecules 2021; 11:biom11121839. [PMID: 34944483 PMCID: PMC8699064 DOI: 10.3390/biom11121839] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 12/02/2021] [Accepted: 12/02/2021] [Indexed: 11/17/2022] Open
Abstract
Increasing evidence has revealed that the enzymes of several biological pathways assemble into larger supramolecular structures called super-complexes. Indeed, those such as association of the mitochondrial respiratory chain complexes play an essential role in respiratory activity and promote metabolic fitness. Dynamically assembled super-complexes are able to alternate between participating in large complexes and existing in a free state. However, the functional significance of the super-complexes is not entirely clear. It has been proposed that the organization of respiratory enzymes into super-complexes could reduce oxidative damage and increase metabolism efficiency. There are several protein complexes that have been revealed in the plant chloroplast, yet little research has been focused on the formation of super-complexes in this organelle. The photosystem I and light-harvesting complex I super-complex’s structure suggests that energy absorbed by light-harvesting complex I could be efficiently transferred to the PSI core by avoiding concentration quenching. Here, we will discuss in detail core complexes of photosystem I and II, the chloroplast ATPase the chloroplast electron transport chain, the Calvin–Benson cycle and a plastid localized purinosome. In addition, we will also describe the methods to identify these complexes.
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Rizvi A, Mulvey JT, Carpenter BP, Talosig R, Patterson JP. A Close Look at Molecular Self-Assembly with the Transmission Electron Microscope. Chem Rev 2021; 121:14232-14280. [PMID: 34329552 DOI: 10.1021/acs.chemrev.1c00189] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Molecular self-assembly is pervasive in the formation of living and synthetic materials. Knowledge gained from research into the principles of molecular self-assembly drives innovation in the biological, chemical, and materials sciences. Self-assembly processes span a wide range of temporal and spatial domains and are often unintuitive and complex. Studying such complex processes requires an arsenal of analytical and computational tools. Within this arsenal, the transmission electron microscope stands out for its unique ability to visualize and quantify self-assembly structures and processes. This review describes the contribution that the transmission electron microscope has made to the field of molecular self-assembly. An emphasis is placed on which TEM methods are applicable to different structures and processes and how TEM can be used in combination with other experimental or computational methods. Finally, we provide an outlook on the current challenges to, and opportunities for, increasing the impact that the transmission electron microscope can have on molecular self-assembly.
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Affiliation(s)
- Aoon Rizvi
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, United States
| | - Justin T Mulvey
- Department of Materials Science and Engineering, University of California, Irvine, Irvine, California 92697-2025, United States
| | - Brooke P Carpenter
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, United States
| | - Rain Talosig
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, United States
| | - Joseph P Patterson
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, United States
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Kouřil R, Nosek L, Opatíková M, Arshad R, Semchonok DA, Chamrád I, Lenobel R, Boekema EJ, Ilík P. Unique organization of photosystem II supercomplexes and megacomplexes in Norway spruce. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 104:215-225. [PMID: 32654240 PMCID: PMC7590091 DOI: 10.1111/tpj.14918] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 06/26/2020] [Indexed: 05/28/2023]
Abstract
Photosystem II (PSII) complexes are organized into large supercomplexes with variable amounts of light-harvesting proteins (Lhcb). A typical PSII supercomplex in plants is formed by four trimers of Lhcb proteins (LHCII trimers), which are bound to the PSII core dimer via monomeric antenna proteins. However, the architecture of PSII supercomplexes in Norway spruce[Picea abies (L.) Karst.] is different, most likely due to a lack of two Lhcb proteins, Lhcb6 and Lhcb3. Interestingly, the spruce PSII supercomplex shares similar structural features with its counterpart in the green alga Chlamydomonas reinhardtii [Kouřil et al. (2016) New Phytol. 210, 808-814]. Here we present a single-particle electron microscopy study of isolated PSII supercomplexes from Norway spruce that revealed binding of a variable amount of LHCII trimers to the PSII core dimer at positions that have never been observed in any other plant species so far. The largest spruce PSII supercomplex, which was found to bind eight LHCII trimers, is even larger than the current largest known PSII supercomplex from C. reinhardtii. We have also shown that the spruce PSII supercomplexes can form various types of PSII megacomplexes, which were also identified in intact grana membranes. Some of these large PSII supercomplexes and megacomplexes were identified also in Pinus sylvestris, another representative of the Pinaceae family. The structural variability and complexity of LHCII organization in Pinaceae seems to be related to the absence of Lhcb6 and Lhcb3 in this family, and may be beneficial for the optimization of light-harvesting under varying environmental conditions.
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Affiliation(s)
- Roman Kouřil
- Department of BiophysicsCentre of the Region Haná for Biotechnological and Agricultural ResearchFaculty of SciencePalacký UniversityŠlechtitelů 27Olomouc783 71Czech Republic
| | - Lukáš Nosek
- Department of BiophysicsCentre of the Region Haná for Biotechnological and Agricultural ResearchFaculty of SciencePalacký UniversityŠlechtitelů 27Olomouc783 71Czech Republic
| | - Monika Opatíková
- Department of BiophysicsCentre of the Region Haná for Biotechnological and Agricultural ResearchFaculty of SciencePalacký UniversityŠlechtitelů 27Olomouc783 71Czech Republic
| | - Rameez Arshad
- Department of BiophysicsCentre of the Region Haná for Biotechnological and Agricultural ResearchFaculty of SciencePalacký UniversityŠlechtitelů 27Olomouc783 71Czech Republic
- Electron Microscopy GroupGroningen Biomolecular Sciences and Biotechnology InstituteUniversity of GroningenNijenborgh 7Groningen9747 AGThe Netherlands
| | - Dmitry A. Semchonok
- Electron Microscopy GroupGroningen Biomolecular Sciences and Biotechnology InstituteUniversity of GroningenNijenborgh 7Groningen9747 AGThe Netherlands
| | - Ivo Chamrád
- Department of Protein Biochemistry and ProteomicsCentre of the Region Haná for Biotechnological and Agricultural ResearchFaculty of SciencePalacký UniversityŠlechtitelů 27Olomouc783 71Czech Republic
| | - René Lenobel
- Department of Protein Biochemistry and ProteomicsCentre of the Region Haná for Biotechnological and Agricultural ResearchFaculty of SciencePalacký UniversityŠlechtitelů 27Olomouc783 71Czech Republic
| | - Egbert J. Boekema
- Electron Microscopy GroupGroningen Biomolecular Sciences and Biotechnology InstituteUniversity of GroningenNijenborgh 7Groningen9747 AGThe Netherlands
| | - Petr Ilík
- Department of BiophysicsCentre of the Region Haná for Biotechnological and Agricultural ResearchFaculty of SciencePalacký UniversityŠlechtitelů 27Olomouc783 71Czech Republic
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Abstract
In vertebrates, immunoglobulins (Igs), commonly known as antibodies, play an integral role in the armamentarium of immune defense against various pathogens. After an antigenic challenge, antibodies are secreted by differentiated B cells called plasma cells. Antibodies have two predominant roles that involve specific binding to antigens to launch an immune response, along with activation of other components of the immune system to fight pathogens. The ability of immunoglobulins to fight against innumerable and diverse pathogens lies in their intrinsic ability to discriminate between different antigens. Due to this specificity and high affinity for their antigens, antibodies have been a valuable and indispensable tool in research, diagnostics and therapy. Although seemingly a simple maneuver, the association between an antibody and its antigen, to make an antigen-antibody complex, is comprised of myriads of non-covalent interactions. Amino acid residues on the antigen binding site, the epitope, and on the antibody binding site, the paratope, intimately contribute to the energetics needed for the antigen-antibody complex stability. Structural biology methods to study antigen-antibody complexes are extremely valuable tools to visualize antigen-antibody interactions in detail; this helps to elucidate the basis of molecular recognition between an antibody and its specific antigen. The main scope of this chapter is to discuss the structure and function of different classes of antibodies and the various aspects of antigen-antibody interactions including antigen-antibody interfaces-with a special focus on paratopes, complementarity determining regions (CDRs) and other non-CDR residues important for antigen binding and recognition. Herein, we also discuss methods used to study antigen-antibody complexes, antigen recognition by antibodies, types of antigens in complexes, and how antigen-antibody complexes play a role in modern day medicine and human health. Understanding the molecular basis of antigen binding and recognition by antibodies helps to facilitate the production of better and more potent antibodies for immunotherapy, vaccines and various other applications.
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Affiliation(s)
- A Brenda Kapingidza
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, 29208, USA
| | - Krzysztof Kowal
- Department of Allergology and Internal Medicine, Medical University of Bialystok, Bialystok, Poland
- Department of Experimental Allergology and Immunology, Medical University of Bialystok, Bialystok, Poland
| | - Maksymilian Chruszcz
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, 29208, USA.
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6
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Kouřil R, Nosek L, Semchonok D, Boekema EJ, Ilík P. Organization of Plant Photosystem II and Photosystem I Supercomplexes. Subcell Biochem 2018; 87:259-286. [PMID: 29464563 DOI: 10.1007/978-981-10-7757-9_9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
In nature, plants are continuously exposed to varying environmental conditions. They have developed a wide range of adaptive mechanisms, which ensure their survival and maintenance of stable photosynthetic performance. Photosynthesis is delicately regulated at the level of the thylakoid membrane of chloroplasts and the regulatory mechanisms include a reversible formation of a large variety of specific protein-protein complexes, supercomplexes or even larger assemblies known as megacomplexes. Revealing their structures is crucial for better understanding of their function and relevance in photosynthesis. Here we focus our attention on the isolation and a structural characterization of various large protein supercomplexes and megacomplexes, which involve Photosystem II and Photosystem I, the key constituents of photosynthetic apparatus. The photosystems are often attached to other protein complexes in thylakoid membranes such as light harvesting complexes, cytochrome b 6 f complex, and NAD(P)H dehydrogenase. Structural models of individual supercomplexes and megacomplexes provide essential details of their architecture, which allow us to discuss their function as well as physiological significance.
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Affiliation(s)
- Roman Kouřil
- Department of Biophysics, Faculty of Science, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University, Olomouc, Czech Republic.
| | - Lukáš Nosek
- Department of Biophysics, Faculty of Science, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University, Olomouc, Czech Republic
| | - Dmitry Semchonok
- Electron Microscopy Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
| | - Egbert J Boekema
- Electron Microscopy Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
| | - Petr Ilík
- Department of Biophysics, Faculty of Science, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University, Olomouc, Czech Republic
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7
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Sömmer A, Behrends S. Methods to investigate structure and activation dynamics of GC-1/GC-2. Nitric Oxide 2018; 78:S1089-8603(17)30348-8. [PMID: 29705716 DOI: 10.1016/j.niox.2018.04.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 04/19/2018] [Accepted: 04/23/2018] [Indexed: 12/18/2022]
Abstract
Soluble guanylyl cyclase (sGC) is a heterodimeric enzyme consisting of one α and one β subunit. The α1β1 (GC-1) and α2β1 (GC-2) heterodimers are important for NO signaling in humans and catalyse the conversion from GTP to cGMP. Each sGC subunit consists of four domains. Several crystal structures of the isolated domains are available. However, crystals of full-length sGC have failed to materialise. In consequence, the detailed three dimensional structure of sGC remains unknown to date. Different techniques including stopped-flow spectroscopy, Förster-resonance energy transfer, direct fluorescence, analytical ultracentrifugation, chemical cross-linking, small-angle X-ray scattering, electron microscopy, hydrogen-deuterium exchange and protein thermal shift assays, were used to collect indirect information. Taken together, this circumstantial evidence from different groups brings forth a plausible model of sGC domain arrangement, spatial orientation and dynamic rearrangement upon activation. For analysis of the active conformation the stable binding mode of sGC activators has a significant methodological advantage over the transient, elusive, complex and highly concentration dependent effects of NO in many applications. The methods used and the results obtained are reviewed and discussed in this article.
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Affiliation(s)
- Anne Sömmer
- Department of Pharmacology, Toxicology and Clinical Pharmacy, University of Braunschweig - Institute of Technology, Germany.
| | - Sönke Behrends
- Department of Pharmacology, Toxicology and Clinical Pharmacy, University of Braunschweig - Institute of Technology, Germany.
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8
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Haniewicz P, Abram M, Nosek L, Kirkpatrick J, El-Mohsnawy E, Olmos JDJ, Kouřil R, Kargul JM. Molecular Mechanisms of Photoadaptation of Photosystem I Supercomplex from an Evolutionary Cyanobacterial/Algal Intermediate. PLANT PHYSIOLOGY 2018; 176:1433-1451. [PMID: 29187568 PMCID: PMC5813541 DOI: 10.1104/pp.17.01022] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 11/28/2017] [Indexed: 05/28/2023]
Abstract
The monomeric photosystem I-light-harvesting antenna complex I (PSI-LHCI) supercomplex from the extremophilic red alga Cyanidioschyzon merolae represents an intermediate evolutionary link between the cyanobacterial PSI reaction center and its green algal/higher plant counterpart. We show that the C. merolae PSI-LHCI supercomplex is characterized by robustness in various extreme conditions. By a combination of biochemical, spectroscopic, mass spectrometry, and electron microscopy/single particle analyses, we dissected three molecular mechanisms underlying the inherent robustness of the C. merolae PSI-LHCI supercomplex: (1) the accumulation of photoprotective zeaxanthin in the LHCI antenna and the PSI reaction center; (2) structural remodeling of the LHCI antenna and adjustment of the effective absorption cross section; and (3) dynamic readjustment of the stoichiometry of the two PSI-LHCI isomers and changes in the oligomeric state of the PSI-LHCI supercomplex, accompanied by dissociation of the PsaK core subunit. We show that the largest low light-treated C. merolae PSI-LHCI supercomplex can bind up to eight Lhcr antenna subunits, which are organized as two rows on the PsaF/PsaJ side of the core complex. Under our experimental conditions, we found no evidence of functional coupling of the phycobilisomes with the PSI-LHCI supercomplex purified from various light conditions, suggesting that the putative association of this antenna with the PSI supercomplex is absent or may be lost during the purification procedure.
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Affiliation(s)
- Patrycja Haniewicz
- Solar Fuels Laboratory, Center of New Technologies, University of Warsaw, 02-097 Warsaw, Poland
| | - Mateusz Abram
- Solar Fuels Laboratory, Center of New Technologies, University of Warsaw, 02-097 Warsaw, Poland
- Faculty of Biology, University of Warsaw, 02-096 Warsaw, Poland
| | - Lukáš Nosek
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Biophysics, Faculty of Science, Palacký University, 783 71 Olomouc, Czech Republic
| | | | - Eithar El-Mohsnawy
- Botany Department, Faculty of Science, Kafrelsheikh University, 33516, Kafr El-Sheikh, Egypt
- Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr University, D-44780 Bochum, Germany
| | - Julian D Janna Olmos
- Solar Fuels Laboratory, Center of New Technologies, University of Warsaw, 02-097 Warsaw, Poland
- Faculty of Biology, University of Warsaw, 02-096 Warsaw, Poland
| | - Roman Kouřil
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Biophysics, Faculty of Science, Palacký University, 783 71 Olomouc, Czech Republic
| | - Joanna M Kargul
- Solar Fuels Laboratory, Center of New Technologies, University of Warsaw, 02-097 Warsaw, Poland
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9
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Overcoming bottlenecks in the membrane protein structural biology pipeline. Biochem Soc Trans 2017; 44:838-44. [PMID: 27284049 DOI: 10.1042/bst20160049] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Indexed: 02/07/2023]
Abstract
Membrane proteins account for a third of the eukaryotic proteome, but are greatly under-represented in the Protein Data Bank. Unfortunately, recent technological advances in X-ray crystallography and EM cannot account for the poor solubility and stability of membrane protein samples. A limitation of conventional detergent-based methods is that detergent molecules destabilize membrane proteins, leading to their aggregation. The use of orthologues, mutants and fusion tags has helped improve protein stability, but at the expense of not working with the sequence of interest. Novel detergents such as glucose neopentyl glycol (GNG), maltose neopentyl glycol (MNG) and calixarene-based detergents can improve protein stability without compromising their solubilizing properties. Styrene maleic acid lipid particles (SMALPs) focus on retaining the native lipid bilayer of a membrane protein during purification and biophysical analysis. Overcoming bottlenecks in the membrane protein structural biology pipeline, primarily by maintaining protein stability, will facilitate the elucidation of many more membrane protein structures in the near future.
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10
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Nosek L, Semchonok D, Boekema EJ, Ilík P, Kouřil R. Structural variability of plant photosystem II megacomplexes in thylakoid membranes. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 89:104-111. [PMID: 27598242 DOI: 10.1111/tpj.13325] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 07/21/2016] [Accepted: 08/26/2016] [Indexed: 05/27/2023]
Abstract
Plant photosystem II (PSII) is organized into large supercomplexes with variable levels of membrane-bound light-harvesting proteins (LHCIIs). The largest stable form of the PSII supercomplex involves four LHCII trimers, which are specifically connected to the PSII core dimer via monomeric antenna proteins. The PSII supercomplexes can further interact in the thylakoid membrane, forming PSII megacomplexes. So far, only megacomplexes consisting of two PSII supercomplexes associated in parallel have been observed. Here we show that the forms of PSII megacomplexes can be much more variable. We performed single particle electron microscopy (EM) analysis of PSII megacomplexes isolated from Arabidopsis thaliana using clear-native polyacrylamide gel electrophoresis. Extensive image analysis of a large data set revealed that besides the known PSII megacomplexes, there are distinct groups of megacomplexes with non-parallel association of supercomplexes. In some of them, we have found additional LHCII trimers, which appear to stabilize the non-parallel assemblies. We also performed EM analysis of the PSII supercomplexes on the level of whole grana membranes and successfully identified several types of megacomplexes, including those with non-parallel supercomplexes, which strongly supports their natural origin. Our data demonstrate a remarkable ability of plant PSII to form various larger assemblies, which may control photochemical usage of absorbed light energy in plants in a changing environment.
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Affiliation(s)
- Lukáš Nosek
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Biophysics, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71, Olomouc, Czech Republic
| | - Dmitry Semchonok
- Electron Microscopy Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Egbert J Boekema
- Electron Microscopy Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Petr Ilík
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Biophysics, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71, Olomouc, Czech Republic
| | - Roman Kouřil
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Biophysics, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71, Olomouc, Czech Republic
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11
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Alboresi A, Le Quiniou C, Yadav SKN, Scholz M, Meneghesso A, Gerotto C, Simionato D, Hippler M, Boekema EJ, Croce R, Morosinotto T. Conservation of core complex subunits shaped the structure and function of photosystem I in the secondary endosymbiont alga Nannochloropsis gaditana. THE NEW PHYTOLOGIST 2017; 213:714-726. [PMID: 27620972 PMCID: PMC5216901 DOI: 10.1111/nph.14156] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 07/13/2016] [Indexed: 05/03/2023]
Abstract
Photosystem I (PSI) is a pigment protein complex catalyzing the light-driven electron transport from plastocyanin to ferredoxin in oxygenic photosynthetic organisms. Several PSI subunits are highly conserved in cyanobacteria, algae and plants, whereas others are distributed differentially in the various organisms. Here we characterized the structural and functional properties of PSI purified from the heterokont alga Nannochloropsis gaditana, showing that it is organized as a supercomplex including a core complex and an outer antenna, as in plants and other eukaryotic algae. Differently from all known organisms, the N. gaditana PSI supercomplex contains five peripheral antenna proteins, identified by proteome analysis as type-R light-harvesting complexes (LHCr4-8). Two antenna subunits are bound in a conserved position, as in PSI in plants, whereas three additional antennae are associated with the core on the other side. This peculiar antenna association correlates with the presence of PsaF/J and the absence of PsaH, G and K in the N. gaditana genome and proteome. Excitation energy transfer in the supercomplex is highly efficient, leading to a very high trapping efficiency as observed in all other PSI eukaryotes, showing that although the supramolecular organization of PSI changed during evolution, fundamental functional properties such as trapping efficiency were maintained.
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Affiliation(s)
- Alessandro Alboresi
- Dipartimento di BiologiaUniversità di PadovaVia U. Bassi 58/B35121PadovaItaly
| | - Clotilde Le Quiniou
- Department of Physics and Astronomy and Institute for Lasers, Life and BiophotonicsFaculty of SciencesVU University AmsterdamDe Boelelaan 10811081 HVAmsterdamthe Netherlands
| | - Sathish K. N. Yadav
- Electron Microscopy GroupGroningen Biomolecular Sciences and Biotechnology InstituteUniversity of GroningenNijenborgh 79747 AGGroningenthe Netherlands
| | - Martin Scholz
- Institute of Plant Biology and BiotechnologyUniversity of MünsterMünster48143Germany
| | - Andrea Meneghesso
- Dipartimento di BiologiaUniversità di PadovaVia U. Bassi 58/B35121PadovaItaly
| | - Caterina Gerotto
- Dipartimento di BiologiaUniversità di PadovaVia U. Bassi 58/B35121PadovaItaly
| | - Diana Simionato
- Dipartimento di BiologiaUniversità di PadovaVia U. Bassi 58/B35121PadovaItaly
| | - Michael Hippler
- Institute of Plant Biology and BiotechnologyUniversity of MünsterMünster48143Germany
| | - Egbert J. Boekema
- Electron Microscopy GroupGroningen Biomolecular Sciences and Biotechnology InstituteUniversity of GroningenNijenborgh 79747 AGGroningenthe Netherlands
| | - Roberta Croce
- Department of Physics and Astronomy and Institute for Lasers, Life and BiophotonicsFaculty of SciencesVU University AmsterdamDe Boelelaan 10811081 HVAmsterdamthe Netherlands
| | - Tomas Morosinotto
- Dipartimento di BiologiaUniversità di PadovaVia U. Bassi 58/B35121PadovaItaly
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12
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Kye M, Lim YB. Reciprocal Self-Assembly of Peptide-DNA Conjugates into a Programmable Sub-10-nm Supramolecular Deoxyribonucleoprotein. Angew Chem Int Ed Engl 2016; 55:12003-7. [DOI: 10.1002/anie.201605696] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 07/22/2016] [Indexed: 02/03/2023]
Affiliation(s)
- Mahnseok Kye
- Department of Materials Science and Engineering; Yonsei University; 50 Yonsei-ro Seoul 03722 Korea
| | - Yong-beom Lim
- Department of Materials Science and Engineering; Yonsei University; 50 Yonsei-ro Seoul 03722 Korea
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Kye M, Lim YB. Reciprocal Self-Assembly of Peptide-DNA Conjugates into a Programmable Sub-10-nm Supramolecular Deoxyribonucleoprotein. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201605696] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Mahnseok Kye
- Department of Materials Science and Engineering; Yonsei University; 50 Yonsei-ro Seoul 03722 Korea
| | - Yong-beom Lim
- Department of Materials Science and Engineering; Yonsei University; 50 Yonsei-ro Seoul 03722 Korea
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14
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Le Borne S, Eisenschmidt H, Sundmacher K. Image-based analytical crystal shape computation exemplified for potassium dihydrogen phosphate (KDP). Chem Eng Sci 2016. [DOI: 10.1016/j.ces.2015.09.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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15
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The Effects of Electron Beam Exposure Time on Transmission Electron Microscopy Imaging of Negatively Stained Biological Samples. Appl Microsc 2015. [DOI: 10.9729/am.2015.45.3.150] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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16
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Towards structural and functional characterization of photosynthetic and mitochondrial supercomplexes. Micron 2015; 72:39-51. [PMID: 25841081 DOI: 10.1016/j.micron.2015.03.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 01/23/2015] [Accepted: 03/04/2015] [Indexed: 11/23/2022]
Abstract
Bioenergetic reactions in chloroplasts and mitochondria are catalyzed by large multi-subunit membrane proteins. About two decades ago it became clear that several of these large membrane proteins further associate into supercomplexes and since then a number of new ones have been described. In this review we focus on supercomplexes involved in light harvesting and electron transfer in the primary reactions of oxygenic photosynthesis and on the mitochondrial supercomplexes that catalyze electron transfer and ATP synthesis in oxidative phosphorylation. Functional and structural aspects are overviewed. In addition, several relevant technical aspects are discussed, including membrane solubilization with suitable detergents and methods of purification. Some open questions are addressed, such as the lack of high-resolution structures, the outstanding gaps in the knowledge about supercomplexes involved in cyclic electron transport in photosynthesis and the unusual mitochondrial protein complexes of protists and in particular of ciliates.
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Koshy C, Ziegler C. Structural insights into functional lipid-protein interactions in secondary transporters. Biochim Biophys Acta Gen Subj 2014; 1850:476-87. [PMID: 24859688 DOI: 10.1016/j.bbagen.2014.05.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 05/09/2014] [Accepted: 05/12/2014] [Indexed: 12/22/2022]
Abstract
BACKGROUND Structural evidences with functional corroborations have revealed distinct features of lipid-protein interactions especially in channels and receptors. Many membrane embedded transporters are also known to require specific lipids for their functions and for some of them cellular and biochemical data suggest tight regulation by the lipid bilayer. However, molecular details on lipid-protein interactions in transporters are sparse since lipids are either depleted from the detergent solubilized transporters in three-dimensional crystals or not readily resolved in crystal structures. Nevertheless the steady increase in the progress of transporter structure determination contributed more examples of structures with resolved lipids. SCOPE OF REVIEW This review gives an overview on transporter structures in complex with lipids reported to date and discusses commonly encountered difficulties in the identification of functionally significant lipid-protein interactions based on those structures and functional in vitro data. Recent structures provided molecular details into regulation mechanism of transporters by specific lipids. The review highlights common findings and conserved patterns for distantly related transporter families to draw a more general picture on the regulatory role of lipid-protein interactions. MAJOR CONCLUSIONS Several common themes of the manner in which lipids directly influence membrane-mediated folding, oligomerization and structure stability can be found. Especially for LeuT-like fold transporters similarities in structurally resolved lipid-protein interactions suggest a common way in which transporter conformations are affected by lipids even in evolutionarily distinct transporters. Lipids appear to play an additional role as joints mechanically reinforcing the inverted repeat topology, which is a major determinant in the alternating access mechanism of secondary transporters. GENERAL SIGNIFICANCE This review brings together and adds to the repertoire of knowledge on lipid-protein interactions of functional significance presented in structures of membrane transporters. Knowledge of specific lipid-binding sites and modes of lipid influence on these proteins not only accomplishes the molecular description of transport cycle further, but also sheds light into localization dependent differences of transporter function. This article is part of a Special Issue entitled Structural biochemistry and biophysics of membrane proteins.
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Affiliation(s)
- Caroline Koshy
- Max Planck Institute of Biophysics, Structural Biology Department, Frankfurt am Main, Germany; Max-Planck Institute of Biophysics, Computational Structural Biology Group, Frankfurt am Main, Germany
| | - Christine Ziegler
- Max Planck Institute of Biophysics, Structural Biology Department, Frankfurt am Main, Germany; Institute of Biophysics and Physical Biochemistry, University of Regensburg, Regensburg, Germany.
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18
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McDonald KL. Out with the old and in with the new: rapid specimen preparation procedures for electron microscopy of sectioned biological material. PROTOPLASMA 2014; 251:429-448. [PMID: 24258967 DOI: 10.1007/s00709-013-0575-y] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 10/22/2013] [Indexed: 06/02/2023]
Abstract
This article presents the best current practices for preparation of biological samples for examination as thin sections in an electron microscope. The historical development of fixation, dehydration, and embedding procedures for biological materials are reviewed for both conventional and low temperature methods. Conventional procedures for processing cells and tissues are usually done over days and often produce distortions, extractions, and other artifacts that are not acceptable for today's structural biology standards. High-pressure freezing and freeze substitution can minimize some of these artifacts. New methods that reduce the times for freeze substitution and resin embedding to a few hours are discussed as well as a new rapid room temperature method for preparing cells for on-section immunolabeling without the use of aldehyde fixatives.
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Affiliation(s)
- Kent L McDonald
- Electron Microscope Laboratory, University of California, 26 Giannini Hall, Berkeley, CA, 94720, USA,
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Boekema EJ, Scheffers DJ, van Bezouwen LS, Bolhuis H, Folea IM. Focus on membrane differentiation and membrane domains in the prokaryotic cell. J Mol Microbiol Biotechnol 2013; 23:345-56. [PMID: 23920497 DOI: 10.1159/000351361] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
A summary is presented of membrane differentiation in the prokaryotic cell, with an emphasis on the organization of proteins in the plasma/cell membrane. Many species belonging to the Eubacteria and Archaea have special membrane domains and/or membrane proliferation, which are vital for different cellular processes. Typical membrane domains are found in bacteria where a specific membrane protein is abundantly expressed. Lipid rafts form another example. Despite the rareness of conventional organelles as found in eukaryotes, some bacteria are known to have an intricate internal cell membrane organization. Membrane proliferation can be divided into curvature and invaginations which can lead to internal compartmentalization. This study discusses some of the clearest examples of bacteria with such domains and internal membranes. The need for membrane specialization is highest among the heterogeneous group of bacteria which harvest light energy, such as photosynthetic bacteria and halophilic archaea. Most of the highly specialized membranes and domains, such as the purple membrane, chromatophore and chlorosome, are found in these autotrophic organisms. Otherwise the need for membrane differentiation is lower and variable, except for those structures involved in cell division. Microscopy techniques have given essential insight into bacterial membrane morphology. As microscopy will further contribute to the unraveling of membrane organization in the years to come, past and present technology in electron microscopy and light microscopy is discussed. Electron microscopy was the first to unravel bacterial morphology because it can directly visualize membranes with inserted proteins, which no other technique can do. Electron microscopy techniques developed in the 1950s and perfected in the following decades involve the thin sectioning and freeze fractioning of cells. Several studies from the golden age of these techniques show amazing examples of cell membrane morphology. More recently, light microscopy in combination with the use of fluorescent dyes has become an attractive technique for protein localization with the natural membrane. However, the resolution problem in light microscopy remains and overinterpretation of observed phenomena is a pitfall. Thus, light microscopy as a stand-alone technique is not sufficient to prove, for instance, the long-range helical distribution of proteins in membrane such as MinD spirals in Bacillus subtilis. Electron tomography is an emerging electron microscopy technique that can provide three-dimensional reconstructions of small, nonchemically fixed bacteria. It will become a useful tool for studying prokaryotic membranes in more detail and is expected to collect information complementary to those of advanced light microscopy. Together, microscopy techniques can meet the challenge of the coming years: to specify membrane structures in more detail and to bring them to the level of specific protein-protein interactions.
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Affiliation(s)
- Egbert J Boekema
- Department of Electron Microscopy, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, NL–9747 AG Groningen, The Netherlands.
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Huang TW, Liu SY, Chuang YJ, Hsieh HY, Tsai CY, Huang YT, Mirsaidov U, Matsudaira P, Tseng FG, Chang CS, Chen FR. Self-aligned wet-cell for hydrated microbiology observation in TEM. LAB ON A CHIP 2012; 12:340-7. [PMID: 22130521 DOI: 10.1039/c1lc20647h] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
This paper describes a Self-Aligned Wet (SAW) cell suitable for direct-cell or bacteria incubation and observation in a wet environment inside a transmission electron microscope. This SAW cell is fabricated by a bulk-micromachining process and composed of two structurally complementary counterparts (an out-frame and an in-frame), where each contain a silicon nitride film based observation window. The in- and out-frames can be self-aligned via a mechanism of surface tension from a bio-sample droplet without the aid of positioning stages. The liquid chamber is enclosed between two silicon nitride membranes that are thin enough to allow high energy electrons to penetrate while also sustaining the pressure difference between the TEM vacuum and the vapor pressure within the liquid chamber. A large field of view (150 μm × 150 μm) in a SAW cell is favored and formed from a larger sized observation window in the out-frame, which is fabricated using a unique circular membrane formation process. In this paper, we introduce a novel design to circumvent the challenges of charging/heating problems in silicon nitride that arise from interactions with an electron beam. This paper also demonstrates TEM observations of D. Radiodurans growth in a liquid environment within a thicker chamber (20 μm) within a SAW cell.
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Affiliation(s)
- Tsu-Wei Huang
- Department of Engineering and System Science, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu, 30013, Taiwan
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Supramolecular organization of photosystem II in green plants. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1817:2-12. [PMID: 21723248 DOI: 10.1016/j.bbabio.2011.05.024] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Revised: 05/23/2011] [Accepted: 05/26/2011] [Indexed: 01/24/2023]
Abstract
Green plant photosystem II (PSII) is involved in the light reactions of photosynthesis, which take place in the thylakoid membrane of the chloroplast. PSII is organized into large supercomplexes with variable amounts of membrane-bound peripheral antenna complexes. These supercomplexes are dimeric and contain usually 2-4 copies of trimeric LHCII complexes and have a further tendency to associate into megacomplexes or into crystalline domains, of which several types have been characterized. This review focuses on the overall composition and structure of the PSII supercomplex of green plants and its organization and interactions within the photosynthetic membrane. Further, we present the current knowledge how the thylakoid membrane is three-dimensionally organized within the chloroplast. We also discuss how the supramolecular organization in the thylakoid membrane and the PSII flexibility may play roles in various short-term regulatory mechanisms of green plant photosynthesis. This article is part of a Special Issue entitled: Photosystem II.
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Dudkina NV, Kouril R, Bultema JB, Boekema EJ. Imaging of organelles by electron microscopy reveals protein-protein interactions in mitochondria and chloroplasts. FEBS Lett 2010; 584:2510-5. [PMID: 20303958 DOI: 10.1016/j.febslet.2010.03.027] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Accepted: 03/15/2010] [Indexed: 11/30/2022]
Abstract
Ongoing progress in electron microscopy (EM) offers now an opening to visualize cells at the nanoscale by cryo-electron tomography (ET). Large protein complexes can be resolved at near-atomic resolution by single particle averaging. Some examples from mitochondria and chloroplasts illustrate the possibilities with an emphasis on the membrane organization. Cryo-ET performed on non-chemically fixed, unstained, ice-embedded material can visualize specific large membrane protein complexes. In combination with averaging methods, 3D structures were calculated of mitochondrial ATP synthase at 6 nm resolution and of chloroplast photosystem II at 3.5 nm.
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Affiliation(s)
- Natalya V Dudkina
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
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Boekema EJ. Introduction to imaging methods in photosynthesis. PHOTOSYNTHESIS RESEARCH 2009; 102:107-9. [PMID: 19757143 PMCID: PMC2777216 DOI: 10.1007/s11120-009-9488-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Accepted: 08/10/2009] [Indexed: 05/28/2023]
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