1
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Manna P, Hoffmann M, Davies T, Richardson KH, Johnson MP, Schlau-Cohen GS. Energetic driving force for LHCII clustering in plant membranes. SCIENCE ADVANCES 2023; 9:eadj0807. [PMID: 38134273 PMCID: PMC10745693 DOI: 10.1126/sciadv.adj0807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 11/21/2023] [Indexed: 12/24/2023]
Abstract
Plants capture and convert solar energy in a complex network of membrane proteins. Under high light, the luminal pH drops and induces a reorganization of the protein network, particularly clustering of the major light-harvesting complex (LHCII). While the structures of the network have been resolved in exquisite detail, the thermodynamics that control the assembly and reorganization had not been determined, largely because the interaction energies of membrane proteins have been inaccessible. Here, we describe a method to quantify these energies and its application to LHCII. Using single-molecule measurements, LHCII proteoliposomes, and statistical thermodynamic modeling, we quantified the LHCII-LHCII interaction energy as ~-5 kBT at neutral pH and at least -7 kBT at acidic pH. These values revealed an enthalpic thermodynamic driving force behind LHCII clustering. Collectively, this work captures the interactions that drive the organization of membrane protein networks from the perspective of equilibrium statistical thermodynamics, which has a long and rich tradition in biology.
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Affiliation(s)
- Premashis Manna
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Madeline Hoffmann
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Thomas Davies
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
| | | | - Matthew P. Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
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2
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Navakoudis E, Stergiannakos T, Daskalakis V. A perspective on the major light-harvesting complex dynamics under the effect of pH, salts, and the photoprotective PsbS protein. PHOTOSYNTHESIS RESEARCH 2023; 156:163-177. [PMID: 35816266 PMCID: PMC10070230 DOI: 10.1007/s11120-022-00935-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 06/14/2022] [Indexed: 06/15/2023]
Abstract
The photosynthetic apparatus is a highly modular assembly of large pigment-binding proteins. Complexes called antennae can capture the sunlight and direct it from the periphery of two Photosystems (I, II) to the core reaction centers, where it is converted into chemical energy. The apparatus must cope with the natural light fluctuations that can become detrimental to the viability of the photosynthetic organism. Here we present an atomic scale view of the photoprotective mechanism that is activated on this line of defense by several photosynthetic organisms to avoid overexcitation upon excess illumination. We provide a complete macroscopic to microscopic picture with specific details on the conformations of the major antenna of Photosystem II that could be associated with the switch from the light-harvesting to the photoprotective state. This is achieved by combining insight from both experiments and all-atom simulations from our group and the literature in a perspective article.
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Affiliation(s)
- Eleni Navakoudis
- Department of Chemical Engineering, Cyprus University of Technology, 95 Eirinis Street, 3603, Limassol, Cyprus
| | - Taxiarchis Stergiannakos
- Department of Chemical Engineering, Cyprus University of Technology, 95 Eirinis Street, 3603, Limassol, Cyprus
| | - Vangelis Daskalakis
- Department of Chemical Engineering, Cyprus University of Technology, 95 Eirinis Street, 3603, Limassol, Cyprus.
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3
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Zhu L, Zhao H, Wang Y, Yu C, Liu J, Li L, Li Z, Zhang J, Dai H, Wang J, Zhu L. Solubilization, purification, and ligand binding characterization of G protein-coupled receptor SMO in native membrane bilayer using styrene maleic acid copolymer. PeerJ 2022; 10:e13381. [PMID: 35529497 PMCID: PMC9074879 DOI: 10.7717/peerj.13381] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 04/13/2022] [Indexed: 01/13/2023] Open
Abstract
Smoothened (SMO) protein is a member of the G protein-coupled receptor (GPCR) family that is involved in the Hedgehog (Hh) signaling pathway. It is a putative target for treating various cancers, including medulloblastoma and basal cell carcinoma (BCC). Characterizing membrane proteins such as SMO in their native state is highly beneficial for the development of effective pharmaceutical drugs, as their structures and functions are retained to the highest extent in this state. Therefore, although SMO protein is conventionally solubilized in detergent micelles, incorporating the protein in a lipid-based membrane mimic is still required. In this study, we used styrene maleic acid (SMA) copolymer that directly extracted membrane protein and surrounding lipids as well as formed the so-called polymer nanodiscs, to solubilize and purify the SMO transmembrane domain encapsulated by SMA-nanodiscs. The obtained SMA-nanodiscs showed high homogeneity and maintained the physiological activity of SMO protein, thereby enabling the measurement of the dissociation constant (Kd) for SMO ligands SMO-ligands Shh Signaling Antagonist V (SANT-1) and Smoothened Agonist (SAG) using ligand-based solution nuclear magnetic resonance spectroscopy. This work paves the way for investigating the structure, function, and drug development of SMO proteins in a native-like lipid environment.
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Affiliation(s)
- Lina Zhu
- Institute of Physical Science and Information Technology, Anhui University, Hefei, China,High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Hongxin Zhao
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Yizhuo Wang
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China,University of Science and Technology of China, Hefei, China
| | - Chuandi Yu
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China,University of Science and Technology of China, Hefei, China
| | - Juanjuan Liu
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Ling Li
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China,University of Science and Technology of China, Hefei, China
| | - Zehua Li
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China,University of Science and Technology of China, Hefei, China
| | - Jin Zhang
- School of Basic Medical Sciences, Nanchang University, Nanchang, China
| | - Han Dai
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Junfeng Wang
- Institute of Physical Science and Information Technology, Anhui University, Hefei, China,High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China,University of Science and Technology of China, Hefei, China
| | - Lei Zhu
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
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4
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Yamano N, Wang P, Dong FQ, Zhang JP. Lipid-Enhanced Photoprotection of LHCII in Membrane Nanodisc by Reducing Chlorophyll Triplet Production. J Phys Chem B 2022; 126:2669-2676. [PMID: 35377647 DOI: 10.1021/acs.jpcb.1c10557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Carotenoid (Car) quenching chlorophyll triplet state (3Chl a*), an unwanted photosensitizer yielding harmful reactive oxygen species, is crucial for the survival of oxygenic photosynthetic organisms. For the major light-harvesting complex of photosystem II (LHCII) in isolated form, 3Chl a* is deactivated via sub-nanosecond Chl-to-Car triplet excitation energy transfer by lutein in the central domain of LHCII; however, the mechanistic difference from LHCII in vivo remains to be explored. To investigate the intrinsic Car-photoprotection properties of LHCII in a bio-mimicking circumstance, we reconstituted trimeric spinach LHCII into the discoidal membrane of nanosize made from l-α-phosphatidylcholine and examined the triplet excited dynamics. Time-resolved optical absorption combined with circular dichroism spectroscopies revealed that, with reference to LHCII in buffer, LHCII in the membrane nanodisc shows appreciable conformational variation in the neoxanthin and the Lut621 domains and in the Chl a-terminal cluster owing to the lipid-protein interactions, which, in turn, alters the triplet population of Lut620 and Lut621 and their partition. Importantly, the unquenched 3Chl a* population in the complex was reduced by 60%, indicating that LHCII in the membrane adopts a conformation that is optimized for the alleviation of photoinhibition.
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Affiliation(s)
- Nami Yamano
- Key Laboratory of Advanced Light Conversion Materials and Biophotonics, Department of Chemistry, Renmin University of China, Beijing, 100872 Beijing, China
| | - Peng Wang
- Key Laboratory of Advanced Light Conversion Materials and Biophotonics, Department of Chemistry, Renmin University of China, Beijing, 100872 Beijing, China
| | - Feng-Qin Dong
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Jian-Ping Zhang
- Key Laboratory of Advanced Light Conversion Materials and Biophotonics, Department of Chemistry, Renmin University of China, Beijing, 100872 Beijing, China
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5
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Azadi-Chegeni F, Thallmair S, Ward ME, Perin G, Marrink SJ, Baldus M, Morosinotto T, Pandit A. Protein dynamics and lipid affinity of monomeric, zeaxanthin-binding LHCII in thylakoid membranes. Biophys J 2022; 121:396-409. [PMID: 34971616 PMCID: PMC8822613 DOI: 10.1016/j.bpj.2021.12.039] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 12/02/2021] [Accepted: 12/23/2021] [Indexed: 02/03/2023] Open
Abstract
The xanthophyll cycle in the antenna of photosynthetic organisms under light stress is one of the most well-known processes in photosynthesis, but its role is not well understood. In the xanthophyll cycle, violaxanthin (Vio) is reversibly transformed to zeaxanthin (Zea) that occupies Vio binding sites of light-harvesting antenna proteins. Higher monomer/trimer ratios of the most abundant light-harvesting protein, the light-harvesting complex II (LHCII), usually occur in Zea accumulating membranes and have been observed in plants after prolonged illumination and during high-light acclimation. We present a combined NMR and coarse-grained simulation study on monomeric LHCII from the npq2 mutant that constitutively binds Zea in the Vio binding pocket. LHCII was isolated from 13C-enriched npq2 Chlamydomonas reinhardtii (Cr) cells and reconstituted in thylakoid lipid membranes. NMR results reveal selective changes in the fold and dynamics of npq2 LHCII compared with the trimeric, wild-type and show that npq2 LHCII contains multiple mono- or digalactosyl diacylglycerol lipids (MGDG and DGDG) that are strongly protein bound. Coarse-grained simulations on npq2 LHCII embedded in a thylakoid lipid membrane agree with these observations. The simulations show that LHCII monomers have more extensive lipid contacts than LHCII trimers and that protein-lipid contacts are influenced by Zea. We propose that both monomerization and Zea binding could have a functional role in modulating membrane fluidity and influence the aggregation and conformational dynamics of LHCII with a likely impact on photoprotection ability.
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Affiliation(s)
- Fatemeh Azadi-Chegeni
- Leiden Institute of Chemistry, Department of Solid-State NMR, Leiden University, Leiden, the Netherlands
| | - Sebastian Thallmair
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands; Frankfurt Institute for Advanced Studies, Frankfurt am Main, Germany
| | - Meaghan E Ward
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, the Netherlands
| | - Giorgio Perin
- Department of Biology, University of Padua, Padua, Italy
| | - Siewert J Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands
| | - Marc Baldus
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, the Netherlands
| | | | - Anjali Pandit
- Leiden Institute of Chemistry, Department of Solid-State NMR, Leiden University, Leiden, the Netherlands.
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6
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Kirchhoff H. Proteoliposomes for Studying Lipid-protein Interactions in Membranes in vitro. Bio Protoc 2021; 11:e4197. [PMID: 34761069 DOI: 10.21769/bioprotoc.4197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Accepted: 07/21/2021] [Indexed: 11/02/2022] Open
Abstract
Lipids in biomembranes can control the structure and, therefore, the functionality of membrane-embedded protein complexes. Unraveling how the lipid composition determines the mode of operation of membrane proteins provides mechanistic insights into their functionality. We applied a proteoliposome technique for studying how proteins function in biomembranes. The incorporation of isolated membrane proteins in preformed liposomes made from a well-defined lipid composition (proteoliposomes) is a powerful tool for studying lipid-protein interactions. Over several decades, the proteoliposome technique was employed for many different membrane proteins. Recently, it was recognized that different lipid compositions control the light-harvesting functionality of the major photosynthetic light-harvesting complex II (LHCII) isolated from plant thylakoid membranes in vitro. This technique allows systematic examination of the role of so-called non-bilayer lipids on light-harvesting characteristics of LHCII. This protocol describes the isolation of LHCII from leaves and details a four-step procedure to incorporate the detergent-solubilized membrane protein in large unilamellar vesicles (LUV). The protocol was optimized to ensure a very high lipid/protein ratio, designed to specifically examine lipid-protein interactions by minimizing LHCII aggregation. The procedure provides structurally and functionally highly intact LHCII in a detergent-free lipid bilayer with a defined composition.
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Affiliation(s)
- Helmut Kirchhoff
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
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7
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Hancock AM, Son M, Nairat M, Wei T, Jeuken LJC, Duffy CDP, Schlau-Cohen GS, Adams PG. Ultrafast energy transfer between lipid-linked chromophores and plant light-harvesting complex II. Phys Chem Chem Phys 2021; 23:19511-19524. [PMID: 34524278 PMCID: PMC8442836 DOI: 10.1039/d1cp01628h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Light-Harvesting Complex II (LHCII) is a membrane protein found in plant chloroplasts that has the crucial role of absorbing solar energy and subsequently performing excitation energy transfer to the reaction centre subunits of Photosystem II. LHCII provides strong absorption of blue and red light, however, it has minimal absorption in the green spectral region where solar irradiance is maximal. In a recent proof-of-principle study, we enhanced the absorption in this spectral range by developing a biohybrid system where LHCII proteins together with lipid-linked Texas Red (TR) chromophores were assembled into lipid membrane vesicles. The utility of these systems was limited by significant LHCII quenching due to protein-protein interactions and heterogeneous lipid structures. Here, we organise TR and LHCII into a lipid nanodisc, which provides a homogeneous, well-controlled platform to study the interactions between TR molecules and single LHCII complexes. Fluorescence spectroscopy determined that TR-to-LHCII energy transfer has an efficiency of at least 60%, resulting in a 262% enhancement of LHCII fluorescence in the 525-625 nm range, two-fold greater than in the previous system. Ultrafast transient absorption spectroscopy revealed two time constants of 3.7 and 128 ps for TR-to-LHCII energy transfer. Structural modelling and theoretical calculations indicate that these timescales correspond to TR-lipids that are loosely- or tightly-associated with the protein, respectively, with estimated TR-to-LHCII separations of ∼3.5 nm and ∼1 nm. Overall, we demonstrate that a nanodisc-based biohybrid system provides an idealised platform to explore the photophysical interactions between extrinsic chromophores and membrane proteins with potential applications in understanding more complex natural or artificial photosynthetic systems.
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Affiliation(s)
- Ashley M Hancock
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK. .,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Minjung Son
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA.
| | - Muath Nairat
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA.
| | - Tiejun Wei
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Lars J C Jeuken
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK.,Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.,Leiden Institute of Chemistry, Leiden University, 2300 RA Leiden, The Netherlands
| | - Christopher D P Duffy
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Gabriela S Schlau-Cohen
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA.
| | - Peter G Adams
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK. .,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
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8
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Manna P, Davies T, Hoffmann M, Johnson MP, Schlau-Cohen GS. Membrane-dependent heterogeneity of LHCII characterized using single-molecule spectroscopy. Biophys J 2021; 120:3091-3102. [PMID: 34214527 DOI: 10.1016/j.bpj.2021.06.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/16/2021] [Accepted: 06/08/2021] [Indexed: 10/21/2022] Open
Abstract
In green plants, light harvesting complex of Photosystem II (LHCII) absorbs and transports excitation energy toward the photosynthetic reaction centers and serves as a site for energy-dependent nonphotochemical quenching (qE), the photoprotective dissipation of energy as heat. LHCII is thought to activate dissipation through conformational changes that change the photophysical behaviors. Understanding this balance requires a characterization of how the conformations of LHCII, and thus its photophysics, are influenced by individual factors within the membrane environment. Here, we used ensemble and single-molecule fluorescence to characterize the excited-state lifetimes and switching kinetics of LHCII embedded in nanodisc- and liposome-based model membranes of various sizes and lipid compositions. As the membrane area decreased, the quenched population and the rate of conformational dynamics both increased because of interactions with other proteins, the aqueous solution, and/or disordered lipids. Although the conformational states and dynamics were similar in both thylakoid and asolectin lipids, photodegradation increased with thylakoid lipids, likely because of their charge and pressure properties. Collectively, these findings demonstrate the ability of membrane environments to tune the conformations and photophysics of LHCII.
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Affiliation(s)
- Premashis Manna
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Thomas Davies
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | - Madeline Hoffmann
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Matthew P Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
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9
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Meredith SA, Yoneda T, Hancock AM, Connell SD, Evans SD, Morigaki K, Adams PG. Model Lipid Membranes Assembled from Natural Plant Thylakoids into 2D Microarray Patterns as a Platform to Assess the Organization and Photophysics of Light-Harvesting Proteins. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2006608. [PMID: 33690933 DOI: 10.1002/smll.202006608] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 01/14/2021] [Indexed: 06/12/2023]
Abstract
Natural photosynthetic "thylakoid" membranes found in green plants contain a large network of light-harvesting (LH) protein complexes. Rearrangement of this photosynthetic machinery, laterally within stacked membranes called "grana", alters protein-protein interactions leading to changes in the energy balance within the system. Preparation of an experimentally accessible model system that allows the detailed investigation of these complex interactions can be achieved by interfacing thylakoid membranes and synthetic lipids into a template comprised of polymerized lipids in a 2D microarray pattern on glass surfaces. This paper uses this system to interrogate the behavior of LH proteins at the micro- and nanoscale and assesses the efficacy of this model. A combination of fluorescence lifetime imaging and atomic force microscopy reveals the differences in photophysical state and lateral organization between native thylakoid and hybrid membranes, the mechanism of LH protein incorporation into the developing hybrid membranes, and the nanoscale structure of the system. The resulting model system within each corral is a high-quality supported lipid bilayer that incorporates laterally mobile LH proteins. Photosynthetic activity is assessed in the hybrid membranes versus proteoliposomes, revealing that commonly used photochemical assays to test the electron transfer activity of photosystem II may actually produce false-positive results.
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Affiliation(s)
- Sophie A Meredith
- School of Physics and Astronomy and The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Takuro Yoneda
- Graduate School of Agricultural Science and Biosignal Research Center, Kobe University, Rokkodaicho 1-1, Nada, Kobe, 657-8501, Japan
| | - Ashley M Hancock
- School of Physics and Astronomy and The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Simon D Connell
- School of Physics and Astronomy and The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Stephen D Evans
- School of Physics and Astronomy and The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Kenichi Morigaki
- Graduate School of Agricultural Science and Biosignal Research Center, Kobe University, Rokkodaicho 1-1, Nada, Kobe, 657-8501, Japan
| | - Peter G Adams
- School of Physics and Astronomy and The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
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10
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Nicol L, Croce R. The PsbS protein and low pH are necessary and sufficient to induce quenching in the light-harvesting complex of plants LHCII. Sci Rep 2021; 11:7415. [PMID: 33795805 PMCID: PMC8016914 DOI: 10.1038/s41598-021-86975-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 03/11/2021] [Indexed: 11/10/2022] Open
Abstract
Photosynthesis is tightly regulated in order to withstand dynamic light environments. Under high light intensities, a mechanism known as non-photochemical quenching (NPQ) dissipates excess excitation energy, protecting the photosynthetic machinery from damage. An obstacle that lies in the way of understanding the molecular mechanism of NPQ is the large gap between in vitro and in vivo studies. On the one hand, the complexity of the photosynthetic membrane makes it challenging to obtain molecular information from in vivo experiments. On the other hand, a suitable in vitro system for the study of quenching is not available. Here we have developed a minimal NPQ system using proteoliposomes. With this, we demonstrate that the combination of low pH and PsbS is both necessary and sufficient to induce quenching in LHCII, the main antenna complex of plants. This proteoliposome system can be further exploited to gain more insight into how PsbS and other factors (e.g. zeaxanthin) influence the quenching mechanism observed in LHCII.
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Affiliation(s)
- Lauren Nicol
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Roberta Croce
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands.
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11
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Aggregation-related quenching of LHCII fluorescence in liposomes revealed by single-molecule spectroscopy. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2021; 218:112174. [PMID: 33799009 DOI: 10.1016/j.jphotobiol.2021.112174] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 02/04/2021] [Accepted: 03/21/2021] [Indexed: 11/20/2022]
Abstract
Incorporation of membrane proteins into reconstituted lipid membranes is a common approach for studying their structure and function relationship in a native-like environment. In this work, we investigated fluorescence properties of liposome-reconstituted major light-harvesting complexes of plants (LHCII). By utilizing liposome labelling with the fluorescent dye molecules and single-molecule microscopy techniques, we were able to study truly liposome-reconstituted LHCII and compare them with bulk measurements and liposome-free LHCII aggregates bound to the surface. Our results showed that fluorescence lifetime obtained in bulk and in single liposome measurements were correlated. The fluorescence lifetimes of LHCII were shorter for liposome-free LHCII than for reconstituted LHCII. In the case of liposome-reconstituted LHCII, fluorescence lifetime showed dependence on the protein density reminiscent to concentration quenching. The dependence of fluorescence lifetime of LHCII on the liposome size was not significant. Our results demonstrated that fluorescence quenching can be induced by LHCII - LHCII interactions in reconstituted membranes, most likely occurring via the same mechanism as photoprotective non-photochemical quenching in vivo.
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12
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Li F, Liu C, Streckaite S, Yang C, Xu P, Llansola-Portoles MJ, Ilioaia C, Pascal AA, Croce R, Robert B. A new, unquenched intermediate of LHCII. J Biol Chem 2021; 296:100322. [PMID: 33493515 PMCID: PMC7949128 DOI: 10.1016/j.jbc.2021.100322] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/18/2021] [Accepted: 01/20/2021] [Indexed: 11/23/2022] Open
Abstract
When plants are exposed to high-light conditions, the potentially harmful excess energy is dissipated as heat, a process called non-photochemical quenching. Efficient energy dissipation can also be induced in the major light-harvesting complex of photosystem II (LHCII) in vitro, by altering the structure and interactions of several bound cofactors. In both cases, the extent of quenching has been correlated with conformational changes (twisting) affecting two bound carotenoids, neoxanthin, and one of the two luteins (in site L1). This lutein is directly involved in the quenching process, whereas neoxanthin senses the overall change in state without playing a direct role in energy dissipation. Here we describe the isolation of an intermediate state of LHCII, using the detergent n-dodecyl-α-D-maltoside, which exhibits the twisting of neoxanthin (along with changes in chlorophyll–protein interactions), in the absence of the L1 change or corresponding quenching. We demonstrate that neoxanthin is actually a reporter of the LHCII environment—probably reflecting a large-scale conformational change in the protein—whereas the appearance of excitation energy quenching is concomitant with the configuration change of the L1 carotenoid only, reflecting changes on a smaller scale. This unquenched LHCII intermediate, described here for the first time, provides for a deeper understanding of the molecular mechanism of quenching.
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Affiliation(s)
- Fei Li
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Cheng Liu
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Simona Streckaite
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Chunhong Yang
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Pengqi Xu
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands
| | - Manuel J Llansola-Portoles
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Cristian Ilioaia
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France.
| | - Andrew A Pascal
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Roberta Croce
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands
| | - Bruno Robert
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France.
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13
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Conformational Dynamics of Light-Harvesting Complex II in a Native Membrane Environment. Biophys J 2020; 120:270-283. [PMID: 33285116 DOI: 10.1016/j.bpj.2020.11.2265] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 11/17/2020] [Accepted: 11/24/2020] [Indexed: 12/14/2022] Open
Abstract
Photosynthetic light-harvesting complexes (LHCs) of higher plants, moss, and green algae can undergo dynamic conformational transitions, which have been correlated to their ability to adapt to fluctuations in the light environment. Herein, we demonstrate the application of solid-state NMR spectroscopy on native, heterogeneous thylakoid membranes of Chlamydomonas reinhardtii (Cr) and on Cr light-harvesting complex II (LHCII) in thylakoid lipid bilayers to detect LHCII conformational dynamics in its native membrane environment. We show that membrane-reconstituted LHCII contains selective sites that undergo fast, large-amplitude motions, including the phytol tails of two chlorophylls. Protein plasticity is also observed in the N-terminal stromal loop and in protein fragments facing the lumen, involving sites that stabilize the xanthophyll-cycle carotenoid violaxanthin and the two luteins. The results report on the intrinsic flexibility of LHCII pigment-protein complexes in a membrane environment, revealing putative sites for conformational switching. In thylakoid membranes, fast dynamics of protein and pigment sites is significantly reduced, which suggests that in their native organelle membranes, LHCII complexes are locked in specific conformational states.
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14
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Sligar SG, Denisov IG. Nanodiscs: A toolkit for membrane protein science. Protein Sci 2020; 30:297-315. [PMID: 33165998 DOI: 10.1002/pro.3994] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 10/30/2020] [Accepted: 10/30/2020] [Indexed: 12/25/2022]
Abstract
Membrane proteins are involved in numerous vital biological processes, including transport, signal transduction and the enzymes in a variety of metabolic pathways. Integral membrane proteins account for up to 30% of the human proteome and they make up more than half of all currently marketed therapeutic targets. Unfortunately, membrane proteins are inherently recalcitrant to study using the normal toolkit available to scientists, and one is most often left with the challenge of finding inhibitors, activators and specific antibodies using a denatured or detergent solubilized aggregate. The Nanodisc platform circumvents these challenges by providing a self-assembled system that renders typically insoluble, yet biologically and pharmacologically significant, targets such as receptors, transporters, enzymes, and viral antigens soluble in aqueous media in a native-like bilayer environment that maintain a target's functional activity. By providing a bilayer surface of defined composition and structure, Nanodiscs have found great utility in the study of cellular signaling complexes that assemble on a membrane surface. Nanodiscs provide a nanometer scale vehicle for the in vivo delivery of amphipathic drugs, therapeutic lipids, tethered nucleic acids, imaging agents and active protein complexes. This means for generating nanoscale lipid bilayers has spawned the successful use of numerous other polymer and peptide amphipathic systems. This review, in celebration of the Anfinsen Award, summarizes some recent results and provides an inroad into the current and historical literature.
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Affiliation(s)
- Stephen G Sligar
- Departments of Biochemistry Chemistry, University of Illinois, Urbana-Champaign, Urbana, Illinois, USA
| | - Ilia G Denisov
- Departments of Biochemistry Chemistry, University of Illinois, Urbana-Champaign, Urbana, Illinois, USA
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15
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Lingvay M, Akhtar P, Sebők-Nagy K, Páli T, Lambrev PH. Photobleaching of Chlorophyll in Light-Harvesting Complex II Increases in Lipid Environment. FRONTIERS IN PLANT SCIENCE 2020; 11:849. [PMID: 32670321 PMCID: PMC7327537 DOI: 10.3389/fpls.2020.00849] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 05/26/2020] [Indexed: 05/18/2023]
Abstract
Excess light causes damage to the photosynthetic apparatus of plants and algae primarily via reactive oxygen species. Singlet oxygen can be formed by interaction of chlorophyll (Chl) triplet states, especially in the Photosystem II reaction center, with oxygen. Whether Chls in the light-harvesting antenna complexes play direct role in oxidative photodamage is less clear. In this work, light-induced photobleaching of Chls in the major trimeric light-harvesting complex II (LHCII) is investigated in different molecular environments - protein aggregates, embedded in detergent micelles or in reconstituted membranes (proteoliposomes). The effects of intense light treatment were analyzed by absorption and circular dichroism spectroscopy, steady-state and time-resolved fluorescence and EPR spectroscopy. The rate and quantum yield of photobleaching was estimated from the light-induced Chl absorption changes. Photobleaching occurred mainly in Chl a and was accompanied by strong fluorescence quenching of the remaining unbleached Chls. The rate of photobleaching increased by 140% when LHCII was embedded in lipid membranes, compared to detergent-solubilized LHCII. Removing oxygen from the medium or adding antioxidants largely suppressed the bleaching, confirming its oxidative mechanism. Singlet oxygen formation was monitored by EPR spectroscopy using spin traps and spin labels to detect singlet oxygen directly and indirectly, respectively. The quantum yield of Chl a photobleaching in membranes and detergent was found to be 3.4 × 10-5 and 1.4 × 10-5, respectively. These values compare well with the yields of ROS production estimated from spin-trap EPR spectroscopy (around 4 × 10-5 and 2 × 10-5). A kinetic model is proposed, quantifying the generation of Chl and carotenoid triplet states and singlet oxygen. The high quantum yield of photobleaching, especially in the lipid membrane, suggest that direct photodamage of the antenna occurs with rates relevant to photoinhibition in vivo. The results represent further evidence that the molecular environment of LHCII has profound impact on its functional characteristics, including, among others, the susceptibility to photodamage.
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Affiliation(s)
- Mónika Lingvay
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
- Doctoral School of Physics, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Parveen Akhtar
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
| | | | - Tibor Páli
- Institute of Biophysics, Biological Research Centre, Szeged, Hungary
| | - Petar H. Lambrev
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
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16
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Son M, Pinnola A, Schlau-Cohen GS. Zeaxanthin independence of photophysics in light-harvesting complex II in a membrane environment. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148115. [DOI: 10.1016/j.bbabio.2019.148115] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 10/21/2019] [Accepted: 11/08/2019] [Indexed: 11/15/2022]
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17
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Observation of dissipative chlorophyll-to-carotenoid energy transfer in light-harvesting complex II in membrane nanodiscs. Nat Commun 2020; 11:1295. [PMID: 32157079 PMCID: PMC7064482 DOI: 10.1038/s41467-020-15074-6] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 02/17/2020] [Indexed: 11/08/2022] Open
Abstract
Plants prevent photodamage under high light by dissipating excess energy as heat. Conformational changes of the photosynthetic antenna complexes activate dissipation by leveraging the sensitivity of the photophysics to the protein structure. The mechanisms of dissipation remain debated, largely due to two challenges. First, because of the ultrafast timescales and large energy gaps involved, measurements lacked the temporal or spectral requirements. Second, experiments have been performed in detergent, which can induce non-native conformations, or in vivo, where contributions from homologous antenna complexes cannot be disentangled. Here, we overcome both challenges by applying ultrabroadband two-dimensional electronic spectroscopy to the principal antenna complex, LHCII, in a near-native membrane. Our data provide evidence that the membrane enhances two dissipative pathways, one of which is a previously uncharacterized chlorophyll-to-carotenoid energy transfer. Our results highlight the sensitivity of the photophysics to local environment, which may control the balance between light harvesting and dissipation in vivo.
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18
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Tietz S, Leuenberger M, Höhner R, Olson AH, Fleming GR, Kirchhoff H. A proteoliposome-based system reveals how lipids control photosynthetic light harvesting. J Biol Chem 2020; 295:1857-1866. [PMID: 31929108 DOI: 10.1074/jbc.ra119.011707] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 01/09/2020] [Indexed: 11/06/2022] Open
Abstract
Integral membrane proteins are exposed to a complex and dynamic lipid environment modulated by nonbilayer lipids that can influence protein functions by lipid-protein interactions. The nonbilayer lipid monogalactosyldiacylglycerol (MGDG) is the most abundant lipid in plant photosynthetic thylakoid membranes, but its impact on the functionality of energy-converting membrane protein complexes is unknown. Here, we optimized a detergent-based reconstitution protocol to develop a proteoliposome technique that incorporates the major light-harvesting complex II (LHCII) into compositionally well-defined large unilamellar lipid bilayer vesicles to study the impact of MGDG on light harvesting by LHCII. Using steady-state fluorescence spectroscopy, CD spectroscopy, and time-correlated single-photon counting, we found that both chlorophyll fluorescence quantum yields and fluorescence lifetimes clearly indicate that the presence of MGDG in lipid bilayers switches LHCII from a light-harvesting to a more energy-quenching mode that dissipates harvested light into heat. It is hypothesized that in the in vitro system developed here, MGDG controls light harvesting of LHCII by modulating the hydrostatic lateral membrane pressure profile in the lipid bilayer sensed by LHCII-bound peripheral pigments.
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Affiliation(s)
- Stefanie Tietz
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, 99164-6340
| | - Michelle Leuenberger
- Department of Chemistry, University of California, Berkeley, California 94720; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Ricarda Höhner
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, 99164-6340
| | - Alice H Olson
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, 99164-6340
| | - Graham R Fleming
- Department of Chemistry, University of California, Berkeley, California 94720; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Helmut Kirchhoff
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, 99164-6340.
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19
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Macroorganisation and flexibility of thylakoid membranes. Biochem J 2019; 476:2981-3018. [DOI: 10.1042/bcj20190080] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 09/19/2019] [Accepted: 10/03/2019] [Indexed: 02/07/2023]
Abstract
Abstract
The light reactions of photosynthesis are hosted and regulated by the chloroplast thylakoid membrane (TM) — the central structural component of the photosynthetic apparatus of plants and algae. The two-dimensional and three-dimensional arrangement of the lipid–protein assemblies, aka macroorganisation, and its dynamic responses to the fluctuating physiological environment, aka flexibility, are the subject of this review. An emphasis is given on the information obtainable by spectroscopic approaches, especially circular dichroism (CD). We briefly summarise the current knowledge of the composition and three-dimensional architecture of the granal TMs in plants and the supramolecular organisation of Photosystem II and light-harvesting complex II therein. We next acquaint the non-specialist reader with the fundamentals of CD spectroscopy, recent advances such as anisotropic CD, and applications for studying the structure and macroorganisation of photosynthetic complexes and membranes. Special attention is given to the structural and functional flexibility of light-harvesting complex II in vitro as revealed by CD and fluorescence spectroscopy. We give an account of the dynamic changes in membrane macroorganisation associated with the light-adaptation of the photosynthetic apparatus and the regulation of the excitation energy flow by state transitions and non-photochemical quenching.
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20
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Hancock AM, Meredith SA, Connell SD, Jeuken LJC, Adams PG. Proteoliposomes as energy transferring nanomaterials: enhancing the spectral range of light-harvesting proteins using lipid-linked chromophores. NANOSCALE 2019; 11:16284-16292. [PMID: 31465048 DOI: 10.1039/c9nr04653d] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Bio-hybrid nanomaterials have great potential for combining the most desirable aspects of biomolecules and the contemporary concepts of nanotechnology to create highly efficient light-harvesting materials. Light-harvesting proteins are optimized to absorb and transfer solar energy with remarkable efficiency but have a spectral range that is limited by their natural pigment complement. Herein, we present the development of model membranes ("proteoliposomes") in which the absorption range of the membrane protein Light-Harvesting Complex II (LHCII) is effectively enhanced by the addition of lipid-tethered Texas Red (TR) chromophores. Energy transfer from TR to LHCII is observed with up to 94% efficiency and increased LHCII fluorescence of up to three-fold when excited in the region of lowest natural absorption. The new self-assembly procedure offers the modularity to control the concentrations incorporated of TR and LHCII, allowing energy transfer and fluorescence to be tuned. Fluorescence Lifetime Imaging Microscopy provides single-proteoliposome-level quantification of energy transfer efficiency and confirms that functionality is retained on surfaces. Designer proteoliposomes could act as a controllable light-harvesting nanomaterial and are a promising step in the development of bio-hybrid light-harvesting systems.
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Affiliation(s)
- Ashley M Hancock
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK. and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Sophie A Meredith
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK. and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Simon D Connell
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK. and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Lars J C Jeuken
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK and School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Peter G Adams
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK. and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
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21
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Fine tuning of the photosystem II major antenna mobility within the thylakoid membrane of higher plants. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:183059. [PMID: 31518553 DOI: 10.1016/j.bbamem.2019.183059] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 08/16/2019] [Accepted: 09/04/2019] [Indexed: 12/15/2022]
Abstract
Depending on the amount of light, the photosystem II (PSII) antennae or Light Harvesting Complexes (LHCII) switch between two states within the thylakoid membranes of higher plants, i.e., a light-harvesting and a photoprotective mode. This switch is co-regulated by a pH gradient (ΔpH) across the membrane and the interaction with the PSII subunit S (PsbS) that is proposed to induce LHCII aggregation. Herein we employ all-atom and coarse-grained molecular simulations of the major LHCII trimer at low and excess ΔpH, as well as in complexation with PsbS within a native thylakoid membrane model. Our results demonstrate the aggregation potential of LHCII and, consistent with the experimental literature, reveal the role of PsbS at atomic resolution. PsbS alters the LHCII-thylakoid lipid interactions and restores the LHCII mobility that is lost in the transition to photoprotective conditions (low lumenal pH). In agreement with this finding, diffusion of the integral membrane protein LHCII is dependent on both, electrostatic interactions and hydrophobic mismatch, while it does not obey the Saffman-Delbrück diffusion model.
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22
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Strašková A, Steinbach G, Konert G, Kotabová E, Komenda J, Tichý M, Kaňa R. Pigment-protein complexes are organized into stable microdomains in cyanobacterial thylakoids. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:148053. [PMID: 31344362 DOI: 10.1016/j.bbabio.2019.07.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 06/28/2019] [Accepted: 07/18/2019] [Indexed: 02/03/2023]
Abstract
Thylakoids are the place of the light-photosynthetic reactions. To gain maximal efficiency, these reactions are conditional to proper pigment-pigment and protein-protein interactions. In higher plants thylakoids, the interactions lead to a lateral asymmetry in localization of protein complexes (i.e. granal/stromal thylakoids) that have been defined as a domain-like structures characteristic by different biochemical composition and function (Albertsson P-Å. 2001,Trends Plant Science 6: 349-354). We explored this complex organization of thylakoid pigment-proteins at single cell level in the cyanobacterium Synechocystis sp. PCC 6803. Our 3D confocal images captured heterogeneous distribution of all main photosynthetic pigment-protein complexes (PPCs), Photosystem I (fluorescently tagged by YFP), Photosystem II and Phycobilisomes. The acquired images depicted cyanobacterial thylakoid membrane as a stable, mosaic-like structure formed by microdomains (MDs). These microcompartments are of sub-micrometer in sizes (~0.5-1.5 μm), typical by particular PPCs ratios and importantly without full segregation of observed complexes. The most prevailing MD is represented by MD with high Photosystem I content which allows also partial separation of Photosystems like in higher plants thylakoids. We assume that MDs stability (in minutes) provides optimal conditions for efficient excitation/electron transfer. The cyanobacterial MDs thus define thylakoid membrane organization as a system controlled by co-localization of three main PPCs leading to formation of thylakoid membrane mosaic. This organization might represent evolutional and functional precursor for the granal/stromal spatial heterogeneity in photosystems that is typical for higher plant thylakoids.
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Affiliation(s)
- A Strašková
- Institute of Microbiology, Czech Academy of Sciences, Centre Algatech, Novohradská 237, 379 81 Třeboň, Czech Republic
| | - G Steinbach
- Institute of Microbiology, Czech Academy of Sciences, Centre Algatech, Novohradská 237, 379 81 Třeboň, Czech Republic
| | - G Konert
- Institute of Microbiology, Czech Academy of Sciences, Centre Algatech, Novohradská 237, 379 81 Třeboň, Czech Republic
| | - E Kotabová
- Institute of Microbiology, Czech Academy of Sciences, Centre Algatech, Novohradská 237, 379 81 Třeboň, Czech Republic
| | - J Komenda
- Institute of Microbiology, Czech Academy of Sciences, Centre Algatech, Novohradská 237, 379 81 Třeboň, Czech Republic
| | - M Tichý
- Institute of Microbiology, Czech Academy of Sciences, Centre Algatech, Novohradská 237, 379 81 Třeboň, Czech Republic
| | - R Kaňa
- Institute of Microbiology, Czech Academy of Sciences, Centre Algatech, Novohradská 237, 379 81 Třeboň, Czech Republic.
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23
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Cell-free soluble expression of the membrane protein PsbS. Protein Expr Purif 2019; 159:17-20. [DOI: 10.1016/j.pep.2019.02.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 02/13/2019] [Accepted: 02/13/2019] [Indexed: 11/20/2022]
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24
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Tutkus M, Akhtar P, Chmeliov J, Görföl F, Trinkunas G, Lambrev PH, Valkunas L. Fluorescence Microscopy of Single Liposomes with Incorporated Pigment-Proteins. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:14410-14418. [PMID: 30380887 DOI: 10.1021/acs.langmuir.8b02307] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Reconstitution of transmembrane proteins into liposomes is a widely used method to study their behavior under conditions closely resembling the natural ones. However, this approach does not allow precise control of the liposome size, reconstitution efficiency, and the actual protein-to-lipid ratio in the formed proteoliposomes, which might be critical for some applications and/or interpretation of data acquired during the spectroscopic measurements. Here, we present a novel strategy employing methods of proteoliposome preparation, fluorescent labeling, purification, and surface immobilization that allow us to quantify these properties using fluorescence microscopy at the single-liposome level and for the first time apply it to study photosynthetic pigment-protein complexes LHCII. We show that LHCII proteoliposome samples, even after purification with a density gradient, always contain a fraction of nonreconstituted protein and are extremely heterogeneous in both protein density and liposome sizes. This strategy enables quantitative analysis of the reconstitution efficiency of different protocols and precise fluorescence spectroscopic study of various transmembrane proteins in a controlled nativelike environment.
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Affiliation(s)
- Marijonas Tutkus
- Department of Molecular Compound Physics , Centre for Physical Sciences and Technology , Saulėtekio Avenue 3 , LT-10257 Vilnius , Lithuania
| | - Parveen Akhtar
- Biological Research Centre , Hungarian Academy of Sciences , Temesvári körút 62 , 6726 Szeged , Hungary
| | - Jevgenij Chmeliov
- Department of Molecular Compound Physics , Centre for Physical Sciences and Technology , Saulėtekio Avenue 3 , LT-10257 Vilnius , Lithuania
- Institute of Chemical Physics, Faculty of Physics , Vilnius University , Saulėtekio Avenue 9-III , LT-10222 Vilnius , Lithuania
| | - Fanni Görföl
- Biological Research Centre , Hungarian Academy of Sciences , Temesvári körút 62 , 6726 Szeged , Hungary
| | - Gediminas Trinkunas
- Department of Molecular Compound Physics , Centre for Physical Sciences and Technology , Saulėtekio Avenue 3 , LT-10257 Vilnius , Lithuania
| | - Petar H Lambrev
- Biological Research Centre , Hungarian Academy of Sciences , Temesvári körút 62 , 6726 Szeged , Hungary
| | - Leonas Valkunas
- Department of Molecular Compound Physics , Centre for Physical Sciences and Technology , Saulėtekio Avenue 3 , LT-10257 Vilnius , Lithuania
- Institute of Chemical Physics, Faculty of Physics , Vilnius University , Saulėtekio Avenue 9-III , LT-10222 Vilnius , Lithuania
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25
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Adams PG, Vasilev C, Hunter CN, Johnson MP. Correlated fluorescence quenching and topographic mapping of Light-Harvesting Complex II within surface-assembled aggregates and lipid bilayers. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2018; 1859:1075-1085. [PMID: 29928860 PMCID: PMC6135645 DOI: 10.1016/j.bbabio.2018.06.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 06/11/2018] [Accepted: 06/15/2018] [Indexed: 01/30/2023]
Abstract
Light-Harvesting Complex II (LHCII) is a chlorophyll-protein antenna complex that efficiently absorbs solar energy and transfers electronic excited states to photosystems I and II. Under excess light intensity LHCII can adopt a photoprotective state in which excitation energy is safely dissipated as heat, a process known as Non-Photochemical Quenching (NPQ). In vivo NPQ is triggered by combinatorial factors including transmembrane ΔpH, PsbS protein and LHCII-bound zeaxanthin, leading to dramatically shortened LHCII fluorescence lifetimes. In vitro, LHCII in detergent solution or in proteoliposomes can reversibly adopt an NPQ-like state, via manipulation of detergent/protein ratio, lipid/protein ratio, pH or pressure. Previous spectroscopic investigations revealed changes in exciton dynamics and protein conformation that accompany quenching, however, LHCII-LHCII interactions have not been extensively studied. Here, we correlated fluorescence lifetime imaging microscopy (FLIM) and atomic force microscopy (AFM) of trimeric LHCII adsorbed to mica substrates and manipulated the environment to cause varying degrees of quenching. AFM showed that LHCII self-assembled onto mica forming 2D-aggregates (25-150 nm width). FLIM determined that LHCII in these aggregates were in a quenched state, with much lower fluorescence lifetimes (~0.25 ns) compared to free LHCII in solution (2.2-3.9 ns). LHCII-LHCII interactions were disrupted by thylakoid lipids or phospholipids, leading to intermediate fluorescent lifetimes (0.6-0.9 ns). To our knowledge, this is the first in vitro correlation of nanoscale membrane imaging with LHCII quenching. Our findings suggest that lipids could play a key role in modulating the extent of LHCII-LHCII interactions within the thylakoid membrane and so the propensity for NPQ activation.
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Affiliation(s)
- Peter G Adams
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK; Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK.
| | - Cvetelin Vasilev
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Matthew P Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
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26
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Kuthanová Trsková E, Belgio E, Yeates AM, Sobotka R, Ruban AV, Kaňa R. Antenna proton sensitivity determines photosynthetic light harvesting strategy. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:4483-4493. [PMID: 29955883 PMCID: PMC6093471 DOI: 10.1093/jxb/ery240] [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: 03/07/2018] [Accepted: 06/26/2018] [Indexed: 05/25/2023]
Abstract
Photoprotective non-photochemical quenching (NPQ) represents an effective way to dissipate the light energy absorbed in excess by most phototrophs. It is often claimed that NPQ formation/relaxation kinetics are determined by xanthophyll composition. We, however, found that, for the alveolate alga Chromera velia, this is not the case. In the present paper, we investigated the reasons for the constitutive high rate of quenching displayed by the alga by comparing its light harvesting strategies with those of a model phototroph, the land plant Spinacia oleracea. Experimental results and in silico studies support the idea that fast quenching is due not to xanthophylls, but to intrinsic properties of the Chromera light harvesting complex (CLH) protein, related to amino acid composition and protein folding. The pKa for CLH quenching was shifted by 0.5 units to a higher pH compared with higher plant antennas (light harvesting complex II; LHCII). We conclude that, whilst higher plant LHCIIs are better suited for light harvesting, CLHs are 'natural quenchers' ready to switch into a dissipative state. We propose that organisms with antenna proteins intrinsically more sensitive to protons, such as C. velia, carry a relatively high concentration of violaxanthin to improve their light harvesting. In contrast, higher plants need less violaxanthin per chlorophyll because LHCII proteins are more efficient light harvesters and instead require co-factors such as zeaxanthin and PsbS to accelerate and enhance quenching.
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Affiliation(s)
- Eliška Kuthanová Trsková
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Opatovický mlýn, Třeboň, Czech Republic
- University of South Bohemia in České Budějovice, Faculty of Science, Branišovská, České Budějovice, Czech republic
| | - Erica Belgio
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Opatovický mlýn, Třeboň, Czech Republic
| | - Anna M Yeates
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Opatovický mlýn, Třeboň, Czech Republic
| | - Roman Sobotka
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Opatovický mlýn, Třeboň, Czech Republic
- University of South Bohemia in České Budějovice, Faculty of Science, Branišovská, České Budějovice, Czech republic
| | - Alexander V Ruban
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Radek Kaňa
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Opatovický mlýn, Třeboň, Czech Republic
- University of South Bohemia in České Budějovice, Faculty of Science, Branišovská, České Budějovice, Czech republic
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Ogren JI, Tong AL, Gordon SC, Chenu A, Lu Y, Blankenship RE, Cao J, Schlau-Cohen GS. Impact of the lipid bilayer on energy transfer kinetics in the photosynthetic protein LH2. Chem Sci 2018; 9:3095-3104. [PMID: 29732092 PMCID: PMC5914429 DOI: 10.1039/c7sc04814a] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 02/05/2018] [Indexed: 01/28/2023] Open
Abstract
Photosynthetic purple bacteria convert solar energy to chemical energy with near unity quantum efficiency. The light-harvesting process begins with absorption of solar energy by an antenna protein called Light-Harvesting Complex 2 (LH2). Energy is subsequently transferred within LH2 and then through a network of additional light-harvesting proteins to a central location, termed the reaction center, where charge separation occurs. The energy transfer dynamics of LH2 are highly sensitive to intermolecular distances and relative organizations. As a result, minor structural perturbations can cause significant changes in these dynamics. Previous experiments have primarily been performed in two ways. One uses non-native samples where LH2 is solubilized in detergent, which can alter protein structure. The other uses complex membranes that contain multiple proteins within a large lipid area, which make it difficult to identify and distinguish perturbations caused by protein-protein interactions and lipid-protein interactions. Here, we introduce the use of the biochemical platform of model membrane discs to study the energy transfer dynamics of photosynthetic light-harvesting complexes in a near-native environment. We incorporate a single LH2 from Rhodobacter sphaeroides into membrane discs that provide a spectroscopically amenable sample in an environment more physiological than detergent but less complex than traditional membranes. This provides a simplified system to understand an individual protein and how the lipid-protein interaction affects energy transfer dynamics. We compare the energy transfer rates of detergent-solubilized LH2 with those of LH2 in membrane discs using transient absorption spectroscopy and transient absorption anisotropy. For one key energy transfer step in LH2, we observe a 30% enhancement of the rate for LH2 in membrane discs compared to that in detergent. Based on experimental results and theoretical modeling, we attribute this difference to tilting of the peripheral bacteriochlorophyll in the B800 band. These results highlight the importance of well-defined systems with near-native membrane conditions for physiologically-relevant measurements.
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Affiliation(s)
- John I Ogren
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , MA 02139 , USA .
| | - Ashley L Tong
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , MA 02139 , USA .
| | - Samuel C Gordon
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , MA 02139 , USA .
| | - Aurélia Chenu
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , MA 02139 , USA .
| | - Yue Lu
- Department of Biology and Chemistry , Washington University in St. Louis , St. Louis , MO 63130 , USA
| | - Robert E Blankenship
- Department of Biology and Chemistry , Washington University in St. Louis , St. Louis , MO 63130 , USA
| | - Jianshu Cao
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , MA 02139 , USA .
| | - Gabriela S Schlau-Cohen
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , MA 02139 , USA .
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28
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Kirchhoff H. Structure-function relationships in photosynthetic membranes: Challenges and emerging fields. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 266:76-82. [PMID: 29241569 DOI: 10.1016/j.plantsci.2017.09.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 09/26/2017] [Accepted: 09/29/2017] [Indexed: 05/17/2023]
Abstract
Oxygenic photosynthesis is a fundamental biological process that shaped the earth's biosphere. The process of energy transformation is hosted in highly specialized thylakoid membranes that adjust their architecture in response to environmental cues at different structural levels leading to the adjustment of photosynthetic functions. This review presents structure-function dynamics ranging from the whole membrane system over the mesoscopic level (protein ensembles) down to interactions between lipids and protein complexes. On the whole membrane level, thylakoid membranes constantly change their overall shape (e.g. membranes swell and shrink or destack and stack) that controls vital functions of energy transformation. Furthermore, the physical connection and transition between stacked grana thylakoid and unstacked membrane regions that determines mass transport between these sub-compartments is a crucial open question. On the mesoscopic level, it turns out that reorganizations between disordered and ordered protein arrangements is central for light harvesting and lateral diffusion processes. It has to be unraveled how changes in mesoscopic protein organization are controlled. Finally, dynamic physicochemical properties of the lipid bilayer can determine the structure and organization of photosynthetic membrane proteins, a field that is highly neglected so far. This review focusses on open questions and challenging problems in photosynthesis research.
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Affiliation(s)
- Helmut Kirchhoff
- Institute of Biological Chemistry, Washington State University, P.O. Box 646340, Pullman, 99164, WA, USA.
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