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Krishnarjuna B, Sharma G, Im SC, Auchus R, Anantharamaiah GM, Ramamoorthy A. Characterization of nanodisc-forming peptides for membrane protein studies. J Colloid Interface Sci 2024; 653:1402-1414. [PMID: 37801850 PMCID: PMC10864042 DOI: 10.1016/j.jcis.2023.09.162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 09/11/2023] [Accepted: 09/27/2023] [Indexed: 10/08/2023]
Abstract
Lipid-bilayer nanodiscs provide a stable, native-like membrane environment for the functional and structural studies of membrane proteins and other membrane-binding molecules. Peptide-based nanodiscs having unique properties are developed for membrane protein studies and other biological applications. While the self-assembly process rendering the formation of peptide-nanodiscs is attractive, it is important to understand the stability and suitability of these nanodisc systems for membrane protein studies. In this study, we investigated the nanodiscs formation by the anti-inflammatory and tumor-suppressing peptide AEM28. AEM28 is a chimeric peptide containing a cationic-rich heparan sulfate proteoglycan- (HSPG)-binding domain from human apolipoprotein E (hapoE) (141-150) followed by the 18A peptide's amino acid sequence. AEM28-based nanodiscs made with different types of lipids were characterized using various biophysical techniques and compared with the nanodiscs formed using 2F or 4F peptides. Variable temperature dynamic light-scattering and 31P NMR experiments indicated the fusion and size heterogeneity of nanodiscs at high temperatures. The suitability of AEM28 and Ac-18A-NH2- (2F-) based nanodiscs for studying membrane proteins is demonstrated by reconstituting and characterizing a drug-metabolizing enzyme, cytochrome-P450 (CYP450), or the redox complex CYP450-CYP450 reductase. AEM28 and 2F were also tested for their efficacies in solubilizing E. coli membranes to understand the possibility of using them for detergent-free membrane protein isolation. Our experimental results suggest that AEM28 nanodiscs are suitable for studying membrane proteins with a net positive charge, whereas 2F-based nanodiscs are compatible with any membrane proteins and their complexes irrespective of their charge. Furthermore, both peptides solubilized E. coli cell membranes, indicating their use in membrane protein isolation and other applications related to membrane solubilization.
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Affiliation(s)
- Bankala Krishnarjuna
- Biophysics Program, Department of Chemistry, Biomedical Engineering, Macromolecular Science and Engineering, University of Michigan, Arbor, MI 48109, USA
| | - Gaurav Sharma
- Biophysics Program, Department of Chemistry, Biomedical Engineering, Macromolecular Science and Engineering, University of Michigan, Arbor, MI 48109, USA
| | - Sang-Choul Im
- Department of Pharmacology and Internal Medicine, Division of Metabolism, Endocrinology, & Diabetes, University of Michigan, Ann Arbor, MI 48109, USA
| | - Richard Auchus
- Department of Pharmacology and Internal Medicine, Division of Metabolism, Endocrinology, & Diabetes, University of Michigan, Ann Arbor, MI 48109, USA
| | - G M Anantharamaiah
- Department of Medicine, University of Alabama at Birmingham Medical Center, Birmingham, AL 35294, USA
| | - Ayyalusamy Ramamoorthy
- Biophysics Program, Department of Chemistry, Biomedical Engineering, Macromolecular Science and Engineering, University of Michigan, Arbor, MI 48109, USA; National High Magnetic Field Laboratory, Department of Chemical and Biomedical Engineering, Tallahassee, FL 32310, USA.
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2
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Eggenreich L, Vargas C, Kolar C, Keller S. Lipid exchange among electroneutral Sulfo-DIBMA nanodiscs is independent of ion concentration. Biol Chem 2023:hsz-2022-0319. [PMID: 36921292 DOI: 10.1515/hsz-2022-0319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 02/21/2023] [Indexed: 03/17/2023]
Abstract
Polymer-encapsulated nanodiscs enable membrane proteins to be investigated within a native-like lipid-bilayer environment. Unlike other bilayer-based membrane mimetics, these nanodiscs are equilibrium structures that permit lipid exchange on experimentally relevant timescales. Therefore, examining the kinetics and mechanisms of lipid exchange is of great interest. Since the high charge densities of existing anionic polymers can interfere with protein-protein and protein-lipid interactions as well as charge-sensitive analysis techniques, electroneutral nanodisc-forming polymers have been recently introduced. However, it has remained unclear how the electroneutrality of these polymers affects the lipid-exchange behavior of the nanodiscs. Here, we use time-resolved Förster resonance energy transfer to study the kinetics and the mechanisms of lipid exchange among nanodiscs formed by the electroneutral polymer Sulfo-DIBMA. We also examine the role of coulombic repulsion and specific counterion association in lipid exchange. Our results show that Sulfo-DIBMA nanodiscs exchange lipids on a similar timescale as DIBMA nanodiscs. In contrast with nanodiscs made from polyanionic DIBMA, however, the presence of mono- and divalent cations does not influence lipid exchange among Sulfo-DIBMA nanodiscs, as expected from their electroneutrality. The robustness of Sulfo-DIBMA nanodiscs against varying ion concentrations opens new possibilities for investigating charge-sensitive processes involving membrane proteins.
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Affiliation(s)
- Loretta Eggenreich
- Biophysics, Institute of Molecular Biosciences (IMB), NAWI Graz, University of Graz, Humboldtstr. 50/III, A-8010 Graz, Austria.,Field of Excellence BioHealth, University of Graz, Graz, Austria.,BioTechMed-Graz, Graz, Austria
| | - Carolyn Vargas
- Biophysics, Institute of Molecular Biosciences (IMB), NAWI Graz, University of Graz, Humboldtstr. 50/III, A-8010 Graz, Austria.,Field of Excellence BioHealth, University of Graz, Graz, Austria.,BioTechMed-Graz, Graz, Austria
| | - Cenek Kolar
- Glycon Biochemicals GmbH, Im Biotechnologiepark TGZ 1, D-14943 Luckenwalde, Germany
| | - Sandro Keller
- Biophysics, Institute of Molecular Biosciences (IMB), NAWI Graz, University of Graz, Humboldtstr. 50/III, A-8010 Graz, Austria.,Field of Excellence BioHealth, University of Graz, Graz, Austria.,BioTechMed-Graz, Graz, Austria
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3
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Krishnarjuna B, Marte J, Ravula T, Ramamoorthy A. Enhancing the stability and homogeneity of non-ionic polymer nanodiscs by tuning electrostatic interactions. J Colloid Interface Sci 2023; 634:887-896. [PMID: 36566634 PMCID: PMC10838601 DOI: 10.1016/j.jcis.2022.12.112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 12/14/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022]
Abstract
The nanodisc technology is increasingly used for structural studies on membrane proteins and drug delivery. The development of synthetic polymer nanodiscs and the recent discovery of non-ionic inulin-based polymers have significantly broadened the scope of nanodiscs. While the lipid exchange and size flexibility properties of the self-assembled polymer-based nanodiscs are valuable for various applications, the non-ionic polymer nanodiscs are remarkably unique in that they enable the reconstitution of any protein, protein-protein complexes, or drugs irrespective of their charge. However, the non-ionic nature of the belt could influence the stability and size homogeneity of inulin-based polymer nanodiscs. In this study, we investigate the size stability and homogeneity of nanodiscs formed by non-ionic lipid-solubilizing polymers using different biophysical methods. Polymer nanodiscs containing zwitterionic DMPC and different ratios of DMPC:DMPG lipids were made using anionic SMA-EA or non-ionic pentyl-inulin polymers. Non-ionic polymer nanodiscs made using zwitterionic DMPC lipids produced a very broad elution profile on SEC due to their instability in the column, thus affecting sample monodispersity which was confirmed by DLS experiments that showed multiple peaks. However, the inclusion of anionic DMPG lipids improved the stability as observed from SEC and DLS profiles, which was further confirmed by TEM images. Whereas, anionic SMA-EA-based DMPC-nanodiscs showed excellent stability and size homogeneity when solubilizing zwitterionic lipids. The stability of DMPC:DMPG non-ionic polymer nanodiscs is attributed to the inter-nanodisc repulsion by the anionic-DMPG that prevents the uncontrolled collision and fusion of nanodiscs. Thus, the reported results demonstrate the use of electrostatic interactions to tune the solubility, stability, and size homogeneity of non-ionic polymer nanodiscs which are important features for enabling functional and atomic-resolution structural studies of membrane proteins, other lipid-binding molecules, and water-soluble biomolecules including cytosolic proteins, nucleic acids and metabolites.
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Affiliation(s)
- Bankala Krishnarjuna
- Biophysics Program, Department of Chemistry, Macromolecular Science and Engineering, Biomedical Engineering, Michigan Neuroscience Institute, The University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Joseph Marte
- Biophysics Program, Department of Chemistry, Macromolecular Science and Engineering, Biomedical Engineering, Michigan Neuroscience Institute, The University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Thirupathi Ravula
- Biophysics Program, Department of Chemistry, Macromolecular Science and Engineering, Biomedical Engineering, Michigan Neuroscience Institute, The University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Ayyalusamy Ramamoorthy
- Biophysics Program, Department of Chemistry, Macromolecular Science and Engineering, Biomedical Engineering, Michigan Neuroscience Institute, The University of Michigan, Ann Arbor, MI 48109-1055, USA.
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4
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Pusterla J, Scoppola E, Appel C, Mukhina T, Shen C, Brezesinski G, Schneck E. Characterization of lipid bilayers adsorbed to functionalized air/water interfaces. NANOSCALE 2022; 14:15048-15059. [PMID: 36200471 DOI: 10.1039/d2nr03334h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Lipid bilayers immobilized in planar geometries, such as solid-supported or "floating" bilayers, have enabled detailed studies of biological membranes with numerous experimental techniques, notably X-ray and neutron reflectometry. However, the presence of a solid support also has disadvantages as it complicates the use of spectroscopic techniques as well as surface rheological measurements that would require surface deformations. Here, in order to overcome these limitations, we investigate lipid bilayers adsorbed to inherently soft and experimentally well accessible air/water interfaces that are functionalized with Langmuir monolayers of amphiphiles. The bilayers are characterized with ellipsometry, X-ray scattering, and X-ray fluorescence. Grazing-incidence X-ray diffraction reveals that lipid bilayers in a chain-ordered state can have significantly different structural features than regular Langmuir monolayers of the same composition. Our results suggest that bilayers at air/water interfaces may be well suited for fundamental studies in the field of membrane biophysics.
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Affiliation(s)
- Julio Pusterla
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany.
| | - Ernesto Scoppola
- Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Christian Appel
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany.
| | - Tetiana Mukhina
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany.
| | - Chen Shen
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Gerald Brezesinski
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany.
| | - Emanuel Schneck
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany.
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5
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Brady NG, Qian S, Nguyen J, O'Neill HM, Bruce BD. Small angle neutron scattering and lipidomic analysis of a native, trimeric PSI-SMALP from a thermophilic cyanobacteria. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148596. [PMID: 35853496 PMCID: PMC10228149 DOI: 10.1016/j.bbabio.2022.148596] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 06/05/2022] [Accepted: 07/11/2022] [Indexed: 01/21/2023]
Abstract
The use of styrene-maleic acid copolymers (SMAs) to produce membrane protein-containing nanodiscs without the initial detergent isolation has gained significant interest over the last decade. We have previously shown that a Photosystem I SMALP from the thermophilic cyanobacterium, Thermosynechococcus elongatus (PSI-SMALP), has much more rapid energy transfer and charge separation in vitro than detergent isolated PSI complexes. In this study, we have utilized small-angle neutron scattering (SANS) to better understand the geometry of these SMALPs. These techniques allow us to investigate the size and shape of these particles in their fully solvated state. Further, the particle's proteolipid core and detergent shell or copolymer belt can be interrogated separately using contrast variation, a capability unique to SANS. Here we report the dimensions of the Thermosynechococcus elongatus PSI-SMALP containing a PSI trimer. At ~1.5 MDa, PSI-SMALP is the largest SMALP to be isolated; our lipidomic analysis indicates it contains ~1300 lipids/per trimeric particle, >40-fold more than the PSI-DDM particle and > 100 fold more than identified in the 1JB0 crystal structure. Interestingly, the lipid composition to the PSI trimer in the PSI-SMALP differs significantly from bulk thylakoid composition, being enriched ~50 % in the anionic sulfolipid, SQDG. Finally, utilizing the contrast match point for the SMA 1440 copolymer, we also can observe the ~1 nm SMA copolymer belt surrounding this SMALP for the first time, consistent with most models of SMA organization.
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Affiliation(s)
- Nathan G Brady
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Shuo Qian
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA; The Second Target Station Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Jon Nguyen
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Hugh M O'Neill
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Barry D Bruce
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA; Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, USA; Department of Microbiology, University of Tennessee, Knoxville, TN 37996, USA.
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6
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Rieth MD. A new lipid complex has micelle and bicelle-like properties. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183952. [PMID: 35508225 DOI: 10.1016/j.bbamem.2022.183952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 04/19/2022] [Accepted: 04/26/2022] [Indexed: 06/14/2023]
Affiliation(s)
- Monica D Rieth
- Department of Chemistry, 44 S. Circle Dr., Edwardsville, IL 62026, USA; Department of Chemistry, Lehigh University, 6 E. Packer Ave., Bethlehem, PA 18015, USA.
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7
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Lakey JH, Paracini N, Clifton LA. Exploiting neutron scattering contrast variation in biological membrane studies. BIOPHYSICS REVIEWS 2022; 3:021307. [PMID: 38505417 PMCID: PMC10903484 DOI: 10.1063/5.0091372] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 05/03/2022] [Indexed: 03/21/2024]
Abstract
Biological membranes composed of lipids and proteins are central for the function of all cells and individual components, such as proteins, that are readily studied by a range of structural approaches, including x-ray crystallography and cryo-electron microscopy. However, the study of complex molecular mixtures within the biological membrane structure and dynamics requires techniques that can study nanometer thick molecular bilayers in an aqueous environment at ambient temperature and pressure. Neutron methods, including scattering and spectroscopic approaches, are useful since they can measure structure and dynamics while also being able to penetrate sample holders and cuvettes. The structural approaches, such as small angle neutron scattering and neutron reflectometry, detect scattering caused by the difference in neutron contrast (scattering length) between different molecular components such as lipids or proteins. Usually, the bigger the contrast, the clearer the structural data, and this review uses examples from our research to illustrate how contrast can be increased to allow the structures of individual membrane components to be resolved. Most often this relies upon the use of deuterium in place of hydrogen, but we also discuss the use of magnetic contrast and other elements with useful scattering length values.
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Affiliation(s)
- Jeremy H. Lakey
- Institute for Cell and Molecular Bioscience, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Nicolò Paracini
- Biofilms Research Center for Biointerfaces, Malmö University, Per Albin Hanssons väg 35, 21432 Malmö, Sweden
| | - Luke A. Clifton
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
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8
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Hall SCL, Tognoloni C, Campbell RA, Richens J, O'Shea P, Terry AE, Price GJ, Dafforn TR, Edler KJ, Arnold T. The interaction of styrene maleic acid copolymers with phospholipids in Langmuir monolayers, vesicles and nanodiscs; a structural study. J Colloid Interface Sci 2022; 625:220-236. [PMID: 35716617 DOI: 10.1016/j.jcis.2022.03.102] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 03/21/2022] [Accepted: 03/22/2022] [Indexed: 10/31/2022]
Abstract
HYPOTHESIS Self-assembly of amphipathic styrene maleic acid copolymers with phospholipids in aqueous solution results in the formation of 'nanodiscs' containing a planar segment of phospholipid bilayer encapsulated by a polymer belt. Recently, studies have reported that lipids rapidly exchange between both nanodiscs in solution and external sources of lipids. Outstanding questions remain regarding details of polymer-lipid interactions, factors influencing lipid exchange and structural effects of such exchange processes. Here, the dynamic behaviour of nanodiscs is investigated, specifically the role of membrane charge and polymer chemistry. EXPERIMENTS Two model systems are investigated: fluorescently labelled phospholipid vesicles, and Langmuir monolayers of phospholipids. Using fluorescence spectroscopy and time-resolved neutron reflectometry, the membrane potential, monolayer structure and composition are monitored with respect to time upon polymer and nanodisc interactions. FINDINGS In the presence of external lipids, polymer chains embed throughout lipid membranes, the extent of which is governed by the net membrane charge. Nanodiscs stabilised by three different polymers will all exchange lipids and polymer with monolayers to differing extents, related to the properties of the stabilising polymer belt. These results demonstrate the dynamic nature of nanodiscs which interact with the local environment and are likely to deposit both lipids and polymer at all stages of use.
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Affiliation(s)
- Stephen C L Hall
- School of Biosciences, University of Birmingham, Edgbaston, B15 2TT, UK; Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 ODE, UK; ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK.
| | - Cecilia Tognoloni
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Richard A Campbell
- Institut Laue-Langevin, 71 Avenue des Martyrs, 38042 Grenoble, France; Division of Pharmacy and Optometry, University of Manchester, Manchester M13 9PT, UK
| | - Joanna Richens
- School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK
| | - Paul O'Shea
- School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK; Biomedical and Life Sciences, Lancaster University, Lancaster LA1 4YG, UK
| | - Ann E Terry
- MAX IV Laboratory, Lund University, SE-221 00 Lund, Sweden
| | - Gareth J Price
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Tim R Dafforn
- School of Biosciences, University of Birmingham, Edgbaston, B15 2TT, UK
| | - Karen J Edler
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Thomas Arnold
- ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK; ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK; Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK; European Spallation Source ERIC, P.O Box 176, SE-221 00 Lund, Sweden
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Danielczak B, Rasche M, Lenz J, Pérez Patallo E, Weyrauch S, Mahler F, Agbadaola MT, Meister A, Babalola JO, Vargas C, Kolar C, Keller S. A bioinspired glycopolymer for capturing membrane proteins in native-like lipid-bilayer nanodiscs. NANOSCALE 2022; 14:1855-1867. [PMID: 35040850 DOI: 10.1039/d1nr03811g] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Amphiphilic copolymers that directly extract membrane proteins and lipids from cellular membranes to form nanodiscs combine the advantages of harsher membrane mimics with those of a native-like membrane environment. Among the few commercial polymers that are capable of forming nanodiscs, alternating diisobutylene/maleic acid (DIBMA) copolymers have gained considerable popularity as gentle and UV-transparent alternatives to aromatic polymers. However, their moderate hydrophobicities and high electric charge densities render all existing aliphatic copolymers rather inefficient under near-physiological conditions. Here, we introduce Glyco-DIBMA, a bioinspired glycopolymer that possesses increased hydrophobicity and reduced charge density but nevertheless retains excellent solubility in aqueous solutions. Glyco-DIBMA outperforms established aliphatic copolymers in that it solubilizes lipid vesicles of various compositions much more efficiently, thereby furnishing smaller, more narrowly distributed nanodiscs that preserve a bilayer architecture and exhibit rapid lipid exchange. We demonstrate the superior performance of Glyco-DIBMA in preparative and analytical applications by extracting a broad range of integral membrane proteins from cellular membranes and further by purifying a membrane-embedded voltage-gated K+ channel, which was fluorescently labeled and analyzed with the aid of microfluidic diffusional sizing (MDS) directly within native-like lipid-bilayer nanodiscs.
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Affiliation(s)
- Bartholomäus Danielczak
- Molecular Biophysics, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 13, 67663 Kaiserslautern, Germany
| | - Marie Rasche
- Glycon Biochemicals GmbH, Im Biotechnologiepark TGZ 1, 14943 Luckenwalde, Germany
| | - Julia Lenz
- Molecular Biophysics, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 13, 67663 Kaiserslautern, Germany
| | - Eugenio Pérez Patallo
- Molecular Biophysics, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 13, 67663 Kaiserslautern, Germany
| | - Sophie Weyrauch
- Molecular Biophysics, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 13, 67663 Kaiserslautern, Germany
| | - Florian Mahler
- Molecular Biophysics, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 13, 67663 Kaiserslautern, Germany
| | - Michael Tope Agbadaola
- Molecular Biophysics, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 13, 67663 Kaiserslautern, Germany
- Department of Chemistry, University of Ibadan, 200284, Ibadan, Nigeria
| | - Annette Meister
- Institute of Biochemistry and Biotechnology, and ZIK HALOmem, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3a, 06120 Halle (Saale), Germany
| | | | - Carolyn Vargas
- Molecular Biophysics, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 13, 67663 Kaiserslautern, Germany
- Biophysics, Institute of Molecular Biosciences (IMB), NAWI Graz, University of Graz, Humboldtstr. 50/III, 8010 Graz, Austria.
- Field of Excellence BioHealth, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Cenek Kolar
- Glycon Biochemicals GmbH, Im Biotechnologiepark TGZ 1, 14943 Luckenwalde, Germany
| | - Sandro Keller
- Molecular Biophysics, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 13, 67663 Kaiserslautern, Germany
- Biophysics, Institute of Molecular Biosciences (IMB), NAWI Graz, University of Graz, Humboldtstr. 50/III, 8010 Graz, Austria.
- Field of Excellence BioHealth, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
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10
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Majeed S, Ahmad AB, Sehar U, Georgieva ER. Lipid Membrane Mimetics in Functional and Structural Studies of Integral Membrane Proteins. MEMBRANES 2021; 11:685. [PMID: 34564502 PMCID: PMC8470526 DOI: 10.3390/membranes11090685] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/18/2021] [Accepted: 08/30/2021] [Indexed: 12/12/2022]
Abstract
Integral membrane proteins (IMPs) fulfill important physiological functions by providing cell-environment, cell-cell and virus-host communication; nutrients intake; export of toxic compounds out of cells; and more. However, some IMPs have obliterated functions due to polypeptide mutations, modifications in membrane properties and/or other environmental factors-resulting in damaged binding to ligands and the adoption of non-physiological conformations that prevent the protein from returning to its physiological state. Thus, elucidating IMPs' mechanisms of function and malfunction at the molecular level is important for enhancing our understanding of cell and organism physiology. This understanding also helps pharmaceutical developments for restoring or inhibiting protein activity. To this end, in vitro studies provide invaluable information about IMPs' structure and the relation between structural dynamics and function. Typically, these studies are conducted on transferred from native membranes to membrane-mimicking nano-platforms (membrane mimetics) purified IMPs. Here, we review the most widely used membrane mimetics in structural and functional studies of IMPs. These membrane mimetics are detergents, liposomes, bicelles, nanodiscs/Lipodisqs, amphipols, and lipidic cubic phases. We also discuss the protocols for IMPs reconstitution in membrane mimetics as well as the applicability of these membrane mimetic-IMP complexes in studies via a variety of biochemical, biophysical, and structural biology techniques.
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Affiliation(s)
- Saman Majeed
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
| | - Akram Bani Ahmad
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
| | - Ujala Sehar
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
| | - Elka R Georgieva
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
- Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Science Center, Lubbock, TX 79409, USA
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11
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Hoffmann M, Haselberger D, Hofmann T, Müller L, Janson K, Meister A, Das M, Vargas C, Keller S, Kastritis PL, Schmidt C, Hinderberger D. Nanoscale Model System for the Human Myelin Sheath. Biomacromolecules 2021; 22:3901-3912. [PMID: 34324309 DOI: 10.1021/acs.biomac.1c00714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Neurodegenerative disorders are among the most common diseases in modern society. However, the molecular bases of diseases such as multiple sclerosis or Charcot-Marie-Tooth disease remain far from being fully understood. Research in this field is limited by the complex nature of native myelin and by difficulties in obtaining good in vitro model systems of myelin. Here, we introduce an easy-to-use model system of the myelin sheath that can be used to study myelin proteins in a native-like yet well-controlled environment. To this end, we present myelin-mimicking nanodiscs prepared through one of the amphiphilic copolymers styrene/maleic acid (SMA), diisobutylene/maleic acid (DIBMA), and styrene/maleimide sulfobetaine (SMA-SB). These nanodiscs were tested for their lipid composition using chromatographic (HPLC) and mass spectrometric (MS) methods and, utilizing spin probes within the nanodisc, their comparability with liposomes was studied. In addition, their binding behavior with bovine myelin basic protein (MBP) was scrutinized to ensure that the nanodiscs represent a suitable model system of myelin. Our results suggest that both SMA and SMA-SB are able to solubilize the myelin-like (cytoplasmic) liposomes without preferences for specific lipid headgroups or fatty acyl chains. In nanodiscs of both SMA and SMA-SB (called SMA(-SB)-lipid particles, short SMALPs or SMA-SBLPs, respectively), the polymers restrict the lipids' motion in the hydrophobic center of the bilayer. The headgroups of the lipids, however, are sterically less hindered in nanodiscs when compared with liposomes. Myelin-like SMALPs are able to bind bovine MBP, which can stack the lipid bilayers like in native myelin, showing the usability of these simple, well-controlled systems in further studies of protein-lipid interactions of native myelin.
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Affiliation(s)
- Matthias Hoffmann
- Interdisciplinary Research Center HALOmem, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany.,Institute of Chemistry, Martin Luther University (MLU) Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - David Haselberger
- Interdisciplinary Research Center HALOmem, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany.,Institute of Chemistry, Martin Luther University (MLU) Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - Tommy Hofmann
- Interdisciplinary Research Center HALOmem, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany.,Institute of Biochemistry and Biotechnology, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany
| | - Lisa Müller
- Institute of Pharmacy, Martin Luther University (MLU) Halle-Wittenberg, Wolfgang-Langenbeck-Straße 4, 06120 Halle (Saale), Germany
| | - Kevin Janson
- Interdisciplinary Research Center HALOmem, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany.,Institute of Biochemistry and Biotechnology, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany
| | - Annette Meister
- Interdisciplinary Research Center HALOmem, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany.,Institute of Biochemistry and Biotechnology, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany
| | - Manabendra Das
- Molecular Biophysics, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Straße 13, 67663 Kaiserslautern, Germany
| | - Carolyn Vargas
- Molecular Biophysics, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Straße 13, 67663 Kaiserslautern, Germany.,Biophysics, Institute of Molecular Biosciences (IMB), NAWI Graz, University of Graz, Humboldtstraße 50/III, 8010 Graz, Austria.,Field of Excellence BioHealth, University of Graz, 8010 Graz, Austria.,BioTechMed-Graz, 8010 Graz, Austria
| | - Sandro Keller
- Molecular Biophysics, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Straße 13, 67663 Kaiserslautern, Germany.,Biophysics, Institute of Molecular Biosciences (IMB), NAWI Graz, University of Graz, Humboldtstraße 50/III, 8010 Graz, Austria.,Field of Excellence BioHealth, University of Graz, 8010 Graz, Austria.,BioTechMed-Graz, 8010 Graz, Austria
| | - Panagiotis L Kastritis
- Interdisciplinary Research Center HALOmem, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany.,Institute of Biochemistry and Biotechnology, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany
| | - Carla Schmidt
- Interdisciplinary Research Center HALOmem, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany.,Institute of Biochemistry and Biotechnology, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany
| | - Dariush Hinderberger
- Interdisciplinary Research Center HALOmem, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany.,Institute of Chemistry, Martin Luther University (MLU) Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
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12
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Unravelling the structural complexity of protein-lipid interactions with neutron reflectometry. Biochem Soc Trans 2021; 49:1537-1546. [PMID: 34240735 DOI: 10.1042/bst20201071] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 06/02/2021] [Accepted: 06/14/2021] [Indexed: 11/17/2022]
Abstract
Neutron reflectometry (NR) is a large-facility technique used to examine structure at interfaces. In this brief review an introduction to the utilisation of NR in the study of protein-lipid interactions is given. Cold neutron beams penetrate matter deeply, have low energies, wavelengths in the Ångstrom regime and are sensitive to light elements. High differential hydrogen sensitivity (between protium and deuterium) enables solution and sample isotopic labelling to be utilised to enhance or diminish the scattering signal of individual components within complex biological structures. The combination of these effects means NR can probe buried structures such as those at the solid-liquid interface and encode molecular level structural information on interfacial protein-lipid complexes revealing the relative distribution of components as well as the overall structure. Model biological membrane sample systems can be structurally probed to examine phenomena such as antimicrobial mode of activity, as well as structural and mechanistic properties peripheral/integral proteins within membrane complexes. Here, the example of the antimicrobial protein α1-purothionin binding to a model Gram negative bacterial outer membrane is used to highlight the utilisation of this technique, detailing how changes in the protein/lipid distributions across the membrane before and after the protein interaction can be easily encoded using hydrogen isotope labelling.
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13
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Biological insights from SMA-extracted proteins. Biochem Soc Trans 2021; 49:1349-1359. [PMID: 34110372 PMCID: PMC8286838 DOI: 10.1042/bst20201067] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 05/12/2021] [Accepted: 05/17/2021] [Indexed: 02/08/2023]
Abstract
In the twelve years since styrene maleic acid (SMA) was first used to extract and purify a membrane protein within a native lipid bilayer, this technological breakthrough has provided insight into the structural and functional details of protein–lipid interactions. Most recently, advances in cryo-EM have demonstrated that SMA-extracted membrane proteins are a rich-source of structural data. For example, it has been possible to resolve the details of annular lipids and protein–protein interactions within complexes, the nature of lipids within central cavities and binding pockets, regions involved in stabilising multimers, details of terminal residues that would otherwise remain unresolved and the identification of physiologically relevant states. Functionally, SMA extraction has allowed the analysis of membrane proteins that are unstable in detergents, the characterization of an ultrafast component in the kinetics of electron transfer that was not possible in detergent-solubilised samples and quantitative, real-time measurement of binding assays with low concentrations of purified protein. While the use of SMA comes with limitations such as its sensitivity to low pH and divalent cations, its major advantage is maintenance of a protein's lipid bilayer. This has enabled researchers to view and assay proteins in an environment close to their native ones, leading to new structural and mechanistic insights.
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14
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Di Mauro GM, La Rosa C, Condorelli M, Ramamoorthy A. Benchmarks of SMA-Copolymer Derivatives and Nanodisc Integrity. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:3113-3121. [PMID: 33645999 DOI: 10.1021/acs.langmuir.0c03554] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Poly(styrene-co-maleic acid) or SMA and its derivatives, a family of synthetic amphipathic copolymers, are increasingly used to directly solubilize cell membranes to functionally reconstitute membrane proteins in native-like copolymer-lipid nanodiscs. Although these copolymers act, de facto, like a "macromolecular detergent", the polymer-based lipid-nanodiscs has been demonstrated to be an excellent membrane mimetic for structural and functional studies of membrane proteins and their complexes by a variety of biophysical and biochemical approaches. In many studies reported in the literature, the choice of the right SMA formulation can depend on a number of factors, and the experimental conditions are typically developed according to a trial-and-error process since each studied system requires adapted protocols. While increasing number of nanodisc-forming copolymers are reported to be useful and they provide flexibilities in optimizing the sample preparation conditions, it is important to develop a systematic protocol that can be used for various applications. In this context, there is a vital necessity of benchmarking the performances of existing copolymer formulations, assessing crucial parameters for the successful extraction, isolation, and stabilization of membrane proteins. In this study, we compare both copolymers and copolymer-lipid nanodiscs obtained by SMA-EA with a set of anionic XIRAN copolymer formulations commercially available under the names of SL25010 P, SL30010 P, and SL40005 P. The reported results show how the critical micellar concentration (c.m.c.) of each copolymer is significantly altered in the presence of lipids and confirms the existence of an equilibrium between nanodisc-bound and "free" or "micellar" copolymer chains in the solution. We believe that these findings can be exploited to optimize studies that involve the necessity of special copolymers, which would not only simplify the applications but also broaden the scope of polymer-based nanodiscs.
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Affiliation(s)
- Giacomo M Di Mauro
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Carmelo La Rosa
- Department of Chemistry, University of Catania, Catania 95125, Italy
| | | | - Ayyalusamy Ramamoorthy
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
- Biophysics and Chemistry Department, Macromolecular Science and Engineering, and Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
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15
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Geisler R, Pedersen MC, Preisig N, Hannappel Y, Prévost S, Dattani R, Arleth L, Hellweg T. Aescin - a natural soap for the formation of lipid nanodiscs with tunable size. SOFT MATTER 2021; 17:1888-1900. [PMID: 33410858 DOI: 10.1039/d0sm02043e] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The saponin β-aescin from the seed extract of the horse chestnut tree Aesculus hippocastanum has demonstrated a beneficial role in clinical therapy which is in part related to its strong interaction with biological membranes. In this context the present work investigates the self-assembly of nm-sized discoidal lipid nanoparticles composed of β-aescin and the phospholipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC). The discoidal lipid nanoparticles reassemble from small discs into larger discs, ribbons and finally stacks of sheets upon heating from gel-phase to fluid phase DMPC. The morphological transition of the lipid nano-particles is mainly triggered by the phospholipid phase state change. The final morphology depends on the phospholipid-to-saponin ratio and the actual temperature. The study is conducted by small-angle X-ray scattering (SAXS) and transmission (TEM) and freeze fracture electron microscopy (FFEM) are used to cover larger length scales. Two different models, representing a disc and ribbon-like shape are applied to the SAXS data, evaluating possible geometries and molecular mixing of the nano-particles. The stacked sheets are analysed by the Caillé theory.
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Affiliation(s)
- Ramsia Geisler
- Physical and Biophysical Chemistry, Bielefeld University, Universitätsstr. 25, 33615 Bielefeld, Germany.
| | - Martin Cramer Pedersen
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Natalie Preisig
- Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Yvonne Hannappel
- Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Sylvain Prévost
- ESRF-The European Synchrotron, 71, Avenue des Martyrs, 38000 Grenoble Cedex 9, France
| | - Rajeev Dattani
- ESRF-The European Synchrotron, 71, Avenue des Martyrs, 38000 Grenoble Cedex 9, France
| | - Lise Arleth
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Thomas Hellweg
- Physical and Biophysical Chemistry, Bielefeld University, Universitätsstr. 25, 33615 Bielefeld, Germany.
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16
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Lipidomic and in-gel analysis of maleic acid co-polymer nanodiscs reveals differences in composition of solubilized membranes. Commun Biol 2021; 4:218. [PMID: 33594255 PMCID: PMC7886889 DOI: 10.1038/s42003-021-01711-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 01/12/2021] [Indexed: 01/30/2023] Open
Abstract
Membrane proteins are key in a large number of physiological and pathological processes. Their study often involves a prior detergent solubilization step, which strips away the membrane and can jeopardize membrane protein integrity. A recent alternative to detergents encompasses maleic acid based copolymers (xMAs), which disrupt the lipid bilayer and form lipid protein nanodiscs (xMALPs) soluble in aqueous buffer. Although xMALPs are often referred to as native nanodiscs, little is known about the resemblance of their lipid and protein content to the native bilayer. Here we have analyzed prokaryotic and eukaryotic xMALPs using lipidomics and in-gel analysis. Our results show that the xMALPs content varies with the chemical properties of the used xMA.
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17
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Lavington S, Watts A. Lipid nanoparticle technologies for the study of G protein-coupled receptors in lipid environments. Biophys Rev 2020; 12:10.1007/s12551-020-00775-5. [PMID: 33215301 PMCID: PMC7755959 DOI: 10.1007/s12551-020-00775-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 11/06/2020] [Indexed: 12/12/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are a large family of integral membrane proteins which conduct a wide range of biological roles and represent significant drug targets. Most biophysical and structural studies of GPCRs have been conducted on detergent-solubilised receptors, and it is clear that detergents can have detrimental effects on GPCR function. Simultaneously, there is increasing appreciation of roles for specific lipids in modulation of GPCR function. Lipid nanoparticles such as nanodiscs and styrene maleic acid lipid particles (SMALPs) offer opportunities to study integral membrane proteins in lipid environments, in a form that is soluble and amenable to structural and biophysical experiments. Here, we review the application of lipid nanoparticle technologies to the study of GPCRs, assessing the relative merits and limitations of each system. We highlight how these technologies can provide superior platforms to detergents for structural and biophysical studies of GPCRs and inform on roles for protein-lipid interactions in GPCR function.
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Affiliation(s)
- Steven Lavington
- Biochemistry Department, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Anthony Watts
- Biochemistry Department, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
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18
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Hothersall JD, Jones AY, Dafforn TR, Perrior T, Chapman KL. Releasing the technical 'shackles' on GPCR drug discovery: opportunities enabled by detergent-free polymer lipid particle (PoLiPa) purification. Drug Discov Today 2020; 25:S1359-6446(20)30337-8. [PMID: 32835806 DOI: 10.1016/j.drudis.2020.08.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 07/04/2020] [Accepted: 08/13/2020] [Indexed: 12/19/2022]
Abstract
G-protein-coupled receptor (GPCR) drug research is presently hindered by the technical challenges associated with generating purified receptors. Consequently, the application of critical modern discovery technologies has been limited, and the vast untapped opportunity for new GPCR-directed medicines is not being realised. A simple but transformative solution is to purify receptors without removing them from their native phospholipid environment by using polymer lipid particle (PoLiPa) technology, with reagents such as styrene-maleic acid co-polymer (SMA). Compared with contemporary detergent-based and stabilising mutagenesis methods, the PoLiPa approach is simple and generic and, therefore, offers huge advantages, with the potential to revolutionise GPCR research by facilitating the availability of the purified receptors that are required for structural biology, biophysical, and panning technologies.
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Affiliation(s)
- J Daniel Hothersall
- Domainex Ltd, Chesterford Research Park, Little Chesterford, Saffron Walden, CB10 1XL, UK.
| | - Andrew Y Jones
- Domainex Ltd, Chesterford Research Park, Little Chesterford, Saffron Walden, CB10 1XL, UK
| | - Tim R Dafforn
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Trevor Perrior
- Domainex Ltd, Chesterford Research Park, Little Chesterford, Saffron Walden, CB10 1XL, UK
| | - Kathryn L Chapman
- Domainex Ltd, Chesterford Research Park, Little Chesterford, Saffron Walden, CB10 1XL, UK
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19
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Danielczak B, Keller S. Lipid exchange among polymer-encapsulated nanodiscs by time-resolved Förster resonance energy transfer. Methods 2020; 180:27-34. [DOI: 10.1016/j.ymeth.2020.04.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 04/20/2020] [Accepted: 04/28/2020] [Indexed: 12/30/2022] Open
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20
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Cunningham RD, Kopf AH, Elenbaas BOW, Staal BB, Pfukwa R, Killian JA, Klumperman B. Iterative RAFT-Mediated Copolymerization of Styrene and Maleic Anhydride toward Sequence- and Length-Controlled Copolymers and Their Applications for Solubilizing Lipid Membranes. Biomacromolecules 2020; 21:3287-3300. [DOI: 10.1021/acs.biomac.0c00736] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Randy D. Cunningham
- Department of Chemistry and Polymer Science, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa
| | - Adrian H. Kopf
- Membrane Biochemistry & Biophysics, Bijvoet Center for Biomolecular Research and Institute of Biomembranes, Utrecht University, Padualaan 8, Utrecht 3584 CH, the Netherlands
| | - Barend O. W. Elenbaas
- Membrane Biochemistry & Biophysics, Bijvoet Center for Biomolecular Research and Institute of Biomembranes, Utrecht University, Padualaan 8, Utrecht 3584 CH, the Netherlands
| | - Bastiaan B.P. Staal
- BASF SE, RAA/AC, E210, Carl-Bosch-Strasse 38, Ludwigshafen am Rhein 67056, Germany
| | - Rueben Pfukwa
- Department of Chemistry and Polymer Science, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa
| | - J. Antoinette Killian
- Membrane Biochemistry & Biophysics, Bijvoet Center for Biomolecular Research and Institute of Biomembranes, Utrecht University, Padualaan 8, Utrecht 3584 CH, the Netherlands
| | - Bert Klumperman
- Department of Chemistry and Polymer Science, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa
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21
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Grime RL, Goulding J, Uddin R, Stoddart LA, Hill SJ, Poyner DR, Briddon SJ, Wheatley M. Single molecule binding of a ligand to a G-protein-coupled receptor in real time using fluorescence correlation spectroscopy, rendered possible by nano-encapsulation in styrene maleic acid lipid particles. NANOSCALE 2020; 12:11518-11525. [PMID: 32428052 DOI: 10.1039/d0nr01060j] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The fundamental importance of membrane proteins in cellular processes has driven a marked increase in the use of membrane mimetic approaches for studying and exploiting these proteins. Nano-encapsulation strategies which preserve the native lipid bilayer environment are particularly attractive. Consequently, the use of poly(styrene co-maleic acid) (SMA) has been widely adopted to solubilise proteins directly from cell membranes by spontaneously forming "SMA Lipid Particles" (SMALPs). G-protein-coupled receptors (GPCRs) are ubiquitous "chemical switches", are central to cell signalling throughout the evolutionary tree, form the largest family of membrane proteins in humans and are a major drug discovery target. GPCR-SMALPs that retain binding capability would be a versatile platform for a wide range of down-stream applications. Here, using the adenosine A2A receptor (A2AR) as an archetypical GPCR, we show for the first time the utility of fluorescence correlation spectroscopy (FCS) to characterise the binding capability of GPCRs following nano-encapsulation. Unbound fluorescent ligand CA200645 exhibited a monophasic autocorrelation curve (dwell time, τD = 68 ± 2 μs; diffusion coefficient, D = 287 ± 15 μm2 s-1). In the presence of A2AR-SMALP, bound ligand was also evident (τD = 625 ± 23 μs; D = 30 ± 4 μm2 s-1). Using a non-receptor control (ZipA-SMALP) plus competition binding confirmed that this slower component represented binding to the encapsulated A2AR. Consequently, the combination of GPCR-SMALP and FCS is an effective platform for the quantitative real-time characterisation of nano-encapsulated receptors, with single molecule sensitivity, that will have widespread utility for future exploitation of GPCR-SMALPs in general.
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Affiliation(s)
- Rachael L Grime
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Joelle Goulding
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK and Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Romez Uddin
- Life and Health Sciences, Aston University, Birmingham B4 7ET, UK
| | - Leigh A Stoddart
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK and Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Stephen J Hill
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK and Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - David R Poyner
- Life and Health Sciences, Aston University, Birmingham B4 7ET, UK
| | - Stephen J Briddon
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK and Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Mark Wheatley
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK and Centre for Sport, Exercise and Life Sciences, Faculty of Health and Life Sciences, Alison Gingell Building, Coventry University, Coventry, CV1 2DS, UK.
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22
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Hall SCL, Clifton LA, Tognoloni C, Morrison KA, Knowles TJ, Kinane CJ, Dafforn TR, Edler KJ, Arnold T. Adsorption of a styrene maleic acid (SMA) copolymer-stabilized phospholipid nanodisc on a solid-supported planar lipid bilayer. J Colloid Interface Sci 2020; 574:272-284. [PMID: 32330753 PMCID: PMC7276985 DOI: 10.1016/j.jcis.2020.04.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 04/02/2020] [Accepted: 04/03/2020] [Indexed: 12/12/2022]
Abstract
Over recent years, there has been a rapid development of membrane-mimetic systems to encapsulate and stabilize planar segments of phospholipid bilayers in solution. One such system has been the use of amphipathic copolymers to solubilize lipid bilayers into nanodiscs. The attractiveness of this system, in part, stems from the capability of these polymers to solubilize membrane proteins directly from the host cell membrane. The assumption has been that the native lipid annulus remains intact, with nanodiscs providing a snapshot of the lipid environment. Recent studies have provided evidence that phospholipids can exchange from the nanodiscs with either lipids at interfaces, or with other nanodiscs in bulk solution. Here we investigate kinetics of lipid exchange between three recently studied polymer-stabilized nanodiscs and supported lipid bilayers at the silicon-water interface. We show that lipid and polymer exchange occurs in all nanodiscs tested, although the rate and extent differs between different nanodisc types. Furthermore, we observe adsorption of nanodiscs to the supported lipid bilayer for one nanodisc system which used a polymer made using reversible addition-fragmentation chain transfer polymerization. These results have important implications in applications of polymer-stabilized nanodiscs, such as in the fabrication of solid-supported films containing membrane proteins.
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Affiliation(s)
- Stephen C L Hall
- School of Biosciences, University of Birmingham, Edgbaston, B15 2TT, UK; Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 ODE, UK
| | - Luke A Clifton
- ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Didcot, OX11 0QX, UK
| | - Cecilia Tognoloni
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Kerrie A Morrison
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Timothy J Knowles
- School of Biosciences, University of Birmingham, Edgbaston, B15 2TT, UK
| | - Christian J Kinane
- ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Didcot, OX11 0QX, UK
| | - Tim R Dafforn
- School of Biosciences, University of Birmingham, Edgbaston, B15 2TT, UK
| | - Karen J Edler
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Thomas Arnold
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 ODE, UK; ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Didcot, OX11 0QX, UK; Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK; European Spallation Source ERIC, P.O Box 176, SE-221 00 Lund, Sweden.
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Zhang G, Keener JE, Marty MT. Measuring Remodeling of the Lipid Environment Surrounding Membrane Proteins with Lipid Exchange and Native Mass Spectrometry. Anal Chem 2020; 92:5666-5669. [PMID: 32250609 DOI: 10.1021/acs.analchem.0c00786] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Due to their crucial biochemical roles, membrane proteins are important drug targets. Although it is clear that lipids can influence membrane protein function, the chemistry of lipid binding remains difficult to study because protein-lipid interactions are polydisperse, competitive, and transient. Furthermore, detergents, which are often used to solubilize membrane proteins in micelles, may disrupt lipid interactions that occur in bilayers. Here, we present two new approaches to quantify protein-lipid interactions in bilayers and understand how membrane proteins remodel their surrounding lipid environment. First, we used mass spectrometry (MS) to measure the exchange of lipids between lipoprotein nanodiscs with and without an embedded membrane protein. Shifts in the lipid distribution toward the membrane protein nanodiscs revealed lipid binding, and titrations allowed measurement of the optimal lipid composition for the membrane protein. Second, we used native or nondenaturing MS to ionize membrane protein nanodiscs with heterogeneous lipids. Ejecting the membrane protein complex with bound lipids in the mass spectrometer revealed enrichment of specific lipids around the membrane protein. Both new approaches showed that the E. coli ammonium transporter AmtB prefers phosphatidylglycerol lipids overall but has a minor affinity for phosphatidylcholine lipids.
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Routledge SJ, Jamshad M, Little HA, Lin YP, Simms J, Thakker A, Spickett CM, Bill RM, Dafforn TR, Poyner DR, Wheatley M. Ligand-induced conformational changes in a SMALP-encapsulated GPCR. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183235. [PMID: 32126232 PMCID: PMC7156913 DOI: 10.1016/j.bbamem.2020.183235] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 02/25/2020] [Accepted: 02/26/2020] [Indexed: 12/27/2022]
Abstract
The adenosine 2A receptor (A2AR), a G-protein-coupled receptor (GPCR), was solubilised and purified encapsulated in styrene maleic acid lipid particles (SMALPs). The purified A2AR-SMALP was associated with phospholipids characteristic of the plasma membrane of Pichia pastoris, the host used for its expression, confirming that the A2AR-SMALP encapsulated native lipids. The fluorescence spectrum of the A2AR-SMALP showed a characteristic broad emission peak at 330 nm, produced by endogenous Trp residues. The inverse agonist ZM241385 caused 30% increase in fluorescence emission, unusually accompanied by a red-shift in the emission wavelength. The emission spectrum also showed sub-peaks at 321 nm, 335 nm and 350 nm, indicating that individual Trp inhabited different environments following ZM241385 addition. There was no effect of the agonist NECA on the A2AR-SMALP fluorescence spectrum. Substitution of two Trp residues by Tyr suggested that ZM241385 affected the environment and mobility of Trp2466.48 in TM6 and Trp2687.33 at the extracellular face of TM7, causing transition to a more hydrophobic environment. The fluorescent moiety IAEDANS was site-specifically introduced at the intracellular end of TM6 (residue 2316.33) to report on the dynamic cytoplasmic face of the A2AR. The inverse agonist ZM241385 caused a concentration-dependent increase in fluorescence emission as the IAEDANS moved to a more hydrophobic environment, consistent with closing the G-protein binding crevice. NECA generated only 30% of the effect of ZM241385. This study provides insight into the SMALP environment; encapsulation supported constitutive activity of the A2AR and ZM241385-induced conformational transitions but the agonist NECA generated only small effects. Conformational changes in the A2AR monitored in a nano-scale membrane disc (SMALP). Profile of phospholipids in A2AR-SMALP similar to the plasma membrane. A partially-active conformation of A2AR is supported in a SMALP. Inverse agonist induced dose-dependent conformational transitions in A2AR-SMALP. In contrast to inverse agonist, agonist induced only small conformational changes.
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Affiliation(s)
| | - Mohammed Jamshad
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Haydn A Little
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Yu-Pin Lin
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
| | - John Simms
- Life and Health Sciences, Aston University, Birmingham B4 7ET, UK
| | - Alpesh Thakker
- Life and Health Sciences, Aston University, Birmingham B4 7ET, UK
| | | | - Roslyn M Bill
- Life and Health Sciences, Aston University, Birmingham B4 7ET, UK
| | - Tim R Dafforn
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK.
| | - David R Poyner
- Life and Health Sciences, Aston University, Birmingham B4 7ET, UK.
| | - Mark Wheatley
- Centre for Sport, Exercise and Life Sciences, Alison Gingell Building, Faculty of Health and Life Sciences, Coventry University, Coventry CV1 2DS, UK; Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK.
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25
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Geisler R, Pedersen MC, Hannappel Y, Schweins R, Prévost S, Dattani R, Arleth L, Hellweg T. Aescin-Induced Conversion of Gel-Phase Lipid Membranes into Bicelle-like Lipid Nanoparticles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:16244-16255. [PMID: 31618036 DOI: 10.1021/acs.langmuir.9b02077] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Mixtures of the phospholipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and the saponin β-aescin spontaneously form monodisperse, bilayered discoidal micelles (also known as "bicelles" or "nanodisks") in aqueous solution. Such bicelles form below the melting temperature of DMPC when the phospholipids are in the rigid Lβ' state and are precursors of spontaneously formed vesicles. The aescin concentration must be far above the cmcaescin (≈0.3-0.4 mM). It was found that the shape and size of the bicelles are tunable by composition. High amounts of aescin decrease the size of the bicelles from diameters of ∼300 Å at 7 mol % to ∼120 Å at 30 mol % β-aescin. The structures are scrutinized by complementary small-angle X-ray and neutron scattering experiments. The scattering curves are subsequently analyzed by a model-independent (indirect Fourier transform analysis) and a model-based approach where bicelles are described as polydisperse bilayer disks encircled by a β-aescin rim. Moreover, the monomodal distribution and low polydispersity of the samples were confirmed by photon correlation spectroscopy. The discoidal structures were visualized by transmission electron microscopy.
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Affiliation(s)
| | - Martin Cramer Pedersen
- Niels Bohr Institute , University of Copenhagen , Universitetsparken 5 , 2100 Copenhagen , Denmark
| | | | - Ralf Schweins
- Institut Laue-Langevin , DS/LSS, 71 Avenue des Martyrs , 38042 Grenoble Cedex 9 , France
| | - Sylvain Prévost
- ESRF-The European Synchrotron , 71 Avenue des Martyrs , 38043 Grenoble Cedex 9 , France
| | - Rajeev Dattani
- ESRF-The European Synchrotron , 71 Avenue des Martyrs , 38043 Grenoble Cedex 9 , France
| | - Lise Arleth
- Niels Bohr Institute , University of Copenhagen , Universitetsparken 5 , 2100 Copenhagen , Denmark
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Swiecicki JM, Santana JT, Imperiali B. A Strategic Approach for Fluorescence Imaging of Membrane Proteins in a Native-like Environment. Cell Chem Biol 2019; 27:245-251.e3. [PMID: 31831268 DOI: 10.1016/j.chembiol.2019.11.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 09/22/2019] [Accepted: 11/14/2019] [Indexed: 01/06/2023]
Abstract
Biological membranes are complex barriers in which membrane proteins and thousands of lipidic species participate in structural and functional interactions. Developing a strategic approach that allows uniform labeling of membrane proteins while maintaining a lipidic environment that retains functional interactions is highly desirable for in vitro fluorescence studies. Herein, we focus on complementing current methods by integrating the powerful processes of unnatural amino acid mutagenesis, bioorthogonal labeling, and the detergent-free membrane protein solubilization based on the amphiphilic styrene-maleic acid (SMA) polymer. Importantly, the SMA polymer preserves a thermodynamically stable shell of phospholipids. The approach that we present is both rapid and generalizable providing a population of uniquely labeled membrane proteins in lipid nanoparticles for quantitative fluorescence-based studies.
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Affiliation(s)
- Jean-Marie Swiecicki
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Jordan Tyler Santana
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Barbara Imperiali
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
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27
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Domínguez Pardo J, van Walree C, Egmond M, Koorengevel M, Killian J. Nanodiscs bounded by styrene-maleic acid allow trans-cis isomerization of enclosed photoswitches of azobenzene labeled lipids. Chem Phys Lipids 2019; 220:1-5. [DOI: 10.1016/j.chemphyslip.2019.02.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 02/14/2019] [Accepted: 02/14/2019] [Indexed: 11/30/2022]
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Teo ACK, Lee SC, Pollock NL, Stroud Z, Hall S, Thakker A, Pitt AR, Dafforn TR, Spickett CM, Roper DI. Analysis of SMALP co-extracted phospholipids shows distinct membrane environments for three classes of bacterial membrane protein. Sci Rep 2019; 9:1813. [PMID: 30755655 PMCID: PMC6372662 DOI: 10.1038/s41598-018-37962-0] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 12/05/2018] [Indexed: 11/24/2022] Open
Abstract
Biological characterisation of membrane proteins lags behind that of soluble proteins. This reflects issues with the traditional use of detergents for extraction, as the surrounding lipids are generally lost, with adverse structural and functional consequences. In contrast, styrene maleic acid (SMA) copolymers offer a detergent-free method for biological membrane solubilisation to produce SMA-lipid particles (SMALPs) containing membrane proteins together with their surrounding lipid environment. We report the development of a reverse-phase LC-MS/MS method for bacterial phospholipids and the first comparison of the profiles of SMALP co-extracted phospholipids from three exemplar bacterial membrane proteins with different topographies: FtsA (associated membrane protein), ZipA (single transmembrane helix), and PgpB (integral membrane protein). The data showed that while SMA treatment per se did not preferentially extract specific phospholipids from the membrane, SMALP-extracted ZipA showed an enrichment in phosphatidylethanolamines and depletion in cardiolipins compared to the bulk membrane lipid. Comparison of the phospholipid profiles of the 3 SMALP-extracted proteins revealed distinct lipid compositions for each protein: ZipA and PgpB were similar, but in FtsA samples longer chain phosphatidylglycerols and phosphatidylethanolamines were more abundant. This method offers novel information on the phospholipid interactions of these membrane proteins.
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Affiliation(s)
- Alvin C K Teo
- School of Life Sciences, Gibbet Hill Road, University of Warwick, Coventry, CV4 7AL, UK
| | - Sarah C Lee
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Naomi L Pollock
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Zoe Stroud
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Stephen Hall
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Alpesh Thakker
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK
| | - Andrew R Pitt
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK
| | - Timothy R Dafforn
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Corinne M Spickett
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK.
| | - David I Roper
- School of Life Sciences, Gibbet Hill Road, University of Warwick, Coventry, CV4 7AL, UK.
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30
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Role of Coulombic Repulsion in Collisional Lipid Transfer Among SMA(2:1)-Bounded Nanodiscs. J Membr Biol 2018; 251:443-451. [DOI: 10.1007/s00232-018-0024-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 02/24/2018] [Indexed: 01/13/2023]
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Parmar M, Rawson S, Scarff CA, Goldman A, Dafforn TR, Muench SP, Postis VLG. Using a SMALP platform to determine a sub-nm single particle cryo-EM membrane protein structure. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2018; 1860:378-383. [PMID: 28993151 PMCID: PMC5780298 DOI: 10.1016/j.bbamem.2017.10.005] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 10/02/2017] [Accepted: 10/04/2017] [Indexed: 01/10/2023]
Abstract
The field of membrane protein structural biology has been revolutionized over the last few years with a number of high profile structures being solved using cryo-EM including Piezo, Ryanodine receptor, TRPV1 and the Glutamate receptor. Further developments in the EM field hold the promise of even greater progress in terms of greater resolution, which for membrane proteins is still typically within the 4-7Å range. One advantage of a cryo-EM approach is the ability to study membrane proteins in more "native" like environments for example proteoliposomes, amphipols and nanodiscs. Recently, styrene maleic acid co-polymers (SMA) have been used to extract membrane proteins surrounded by native lipids (SMALPs) maintaining a more natural environment. We report here the structure of the Escherichia coli multidrug efflux transporter AcrB in a SMALP scaffold to sub-nm resolution, with the resulting map being consistent with high resolution crystal structures and other EM derived maps. However, both the C-terminal helix (TM12) and TM7 are poorly defined in the map. These helices are at the exterior of the helical bundle and form the greater interaction with the native lipids and SMA polymer and may represent a more dynamic region of the protein. This work shows the promise of using an SMA approach for single particle cryo-EM studies to provide sub-nm structures.
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Affiliation(s)
- Mayuriben Parmar
- Biomedicine Research Group, Faculty of Health and Social Sciences, Leeds Beckett University, LS1 3HE, UK; School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK
| | - Shaun Rawson
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK; Astbury Centre for Structural Molecular Biology, University of Leeds, LS2 9JT, UK
| | - Charlotte A Scarff
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK; Astbury Centre for Structural Molecular Biology, University of Leeds, LS2 9JT, UK
| | - Adrian Goldman
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK; Astbury Centre for Structural Molecular Biology, University of Leeds, LS2 9JT, UK; Department of Biosciences, Division of Biochemistry, University of Helsinki, Helsinki, Finland
| | - Timothy R Dafforn
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Stephen P Muench
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK; Astbury Centre for Structural Molecular Biology, University of Leeds, LS2 9JT, UK.
| | - Vincent L G Postis
- Biomedicine Research Group, Faculty of Health and Social Sciences, Leeds Beckett University, LS1 3HE, UK; School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK.
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32
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Swainsbury DJK, Proctor MS, Hitchcock A, Cartron ML, Qian P, Martin EC, Jackson PJ, Madsen J, Armes SP, Hunter CN. Probing the local lipid environment of the Rhodobacter sphaeroides cytochrome bc 1 and Synechocystis sp. PCC 6803 cytochrome b 6f complexes with styrene maleic acid. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1859:215-225. [PMID: 29291373 PMCID: PMC5805856 DOI: 10.1016/j.bbabio.2017.12.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 12/21/2017] [Accepted: 12/28/2017] [Indexed: 01/21/2023]
Abstract
Intracytoplasmic vesicles (chromatophores) in the photosynthetic bacterium Rhodobacter sphaeroides represent a minimal structural and functional unit for absorbing photons and utilising their energy for the generation of ATP. The cytochrome bc1 complex (cytbc1) is one of the four major components of the chromatophore alongside the reaction centre-light harvesting 1-PufX core complex (RC-LH1-PufX), the light-harvesting 2 complex (LH2), and ATP synthase. Although the membrane organisation of these complexes is known, their local lipid environments have not been investigated. Here we utilise poly(styrene-alt-maleic acid) (SMA) co-polymers as a tool to simultaneously determine the local lipid environments of the RC-LH1-PufX, LH2 and cytbc1 complexes. SMA has previously been reported to effectively solubilise complexes in lipid-rich membrane regions whilst leaving lipid-poor ordered protein arrays intact. Here we show that SMA solubilises cytbc1 complexes with an efficiency of nearly 70%, whereas solubilisation of RC-LH1-PufX and LH2 was only 10% and 22% respectively. This high susceptibility of cytbc1 to SMA solubilisation is consistent with this complex residing in a locally lipid-rich region. SMA solubilised cytbc1 complexes retain their native dimeric structure and co-purify with 56 ± 6 phospholipids from the chromatophore membrane. We extended this approach to the model cyanobacterium Synechocystis sp. PCC 6803, and show that the cytochrome b6f complex (cytb6f) and Photosystem II (PSII) complexes are susceptible to SMA solubilisation, suggesting they also reside in lipid-rich environments. Thus, lipid-rich membrane regions could be a general requirement for cytbc1/cytb6f complexes, providing a favourable local solvent to promote rapid quinol/quinone binding and release at the Q0 and Qi sites. SMA preferentially solubilises cytbc1 from chromatophore membranes. Solubilised cytbc1 SMALPs contain dimeric complexes co-purified with 56 lipids. SMA-resistant fractions contain RC-LH1-PufX and LH2 rich membrane patches. The Rba. sphaeroides cytbc1 complex is likely to reside in a lipid-rich environment. Similar results for Synechocystis suggest cytbc1/b6f may be universally lipid-rich.
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Affiliation(s)
- David J K Swainsbury
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, United Kingdom
| | - Matthew S Proctor
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, United Kingdom
| | - Andrew Hitchcock
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, United Kingdom
| | - Michaël L Cartron
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, United Kingdom
| | - Pu Qian
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, United Kingdom
| | - Elizabeth C Martin
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, United Kingdom
| | - Philip J Jackson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, United Kingdom; ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield S1 3JD, United Kingdom
| | - Jeppe Madsen
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, United Kingdom
| | - Steven P Armes
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, United Kingdom
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, United Kingdom.
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Hall SCL, Tognoloni C, Price GJ, Klumperman B, Edler KJ, Dafforn TR, Arnold T. Influence of Poly(styrene-co-maleic acid) Copolymer Structure on the Properties and Self-Assembly of SMALP Nanodiscs. Biomacromolecules 2017; 19:761-772. [DOI: 10.1021/acs.biomac.7b01539] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Stephen C. L. Hall
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 ODE, United Kingdom
| | - Cecilia Tognoloni
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
- ISIS Neutron and Muon Source, Science and Technology Facilities Council Rutherford Appleton Laboratory, Harwell, Didcot OX11 0QX, United Kingdom
| | - Gareth J. Price
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Bert Klumperman
- Department of Chemistry and Polymer Science, Division of Polymer Science, Stellenbosch University, De Beers Street, Stellenbosch 7600, South Africa
| | - Karen J. Edler
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Tim R. Dafforn
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Thomas Arnold
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 ODE, United Kingdom
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Pollock NL, Lee SC, Patel JH, Gulamhussein AA, Rothnie AJ. Structure and function of membrane proteins encapsulated in a polymer-bound lipid bilayer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:809-817. [PMID: 28865797 DOI: 10.1016/j.bbamem.2017.08.012] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 08/18/2017] [Accepted: 08/21/2017] [Indexed: 12/14/2022]
Abstract
New technologies for the purification of stable membrane proteins have emerged in recent years, in particular methods that allow the preparation of membrane proteins with their native lipid environment. Here, we look at the progress achieved with the use of styrene-maleic acid copolymers (SMA) which are able to insert into biological membranes forming nanoparticles containing membrane proteins and lipids. This technology can be applied to membrane proteins from any host source, and, uniquely, allows purification without the protein ever being removed from a lipid bilayer. Not only do these SMA lipid particles (SMALPs) stabilise membrane proteins, allowing structural and functional studies, but they also offer opportunities to understand the local lipid environment of the host membrane. With any new or different method, questions inevitably arise about the integrity of the protein purified: does it retain its activity; its native structure; and ability to perform its function? How do membrane proteins within SMALPS perform in existing assays and lend themselves to analysis by established methods? We outline here recent work on the structure and function of membrane proteins that have been encapsulated like this in a polymer-bound lipid bilayer, and the potential for the future with this approach. This article is part of a Special Issue entitled: Beyond the Structure-Function Horizon of Membrane Proteins edited by Ute Hellmich, Rupak Doshi and Benjamin McIlwain.
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Affiliation(s)
- Naomi L Pollock
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Sarah C Lee
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Jaimin H Patel
- School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK
| | | | - Alice J Rothnie
- School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK.
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Cuevas Arenas R, Danielczak B, Martel A, Porcar L, Breyton C, Ebel C, Keller S. Fast Collisional Lipid Transfer Among Polymer-Bounded Nanodiscs. Sci Rep 2017; 7:45875. [PMID: 28378790 PMCID: PMC5381093 DOI: 10.1038/srep45875] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 03/03/2017] [Indexed: 01/08/2023] Open
Abstract
Some styrene/maleic acid (SMA) copolymers solubilise membrane lipids and proteins to form polymer-bounded nanodiscs termed SMA/lipid particles (SMALPs). Although SMALPs preserve a lipid-bilayer core, they appear to be more dynamic than other membrane mimics. We used time-resolved Förster resonance energy transfer and small-angle neutron scattering to determine the kinetics and the mechanisms of phospholipid transfer among SMALPs. In contrast with vesicles or protein-bounded nanodiscs, SMALPs exchange lipids not only by monomer diffusion but also by fast collisional transfer. Under typical experimental conditions, lipid exchange occurs within seconds in the case of SMALPs but takes minutes to days in the other bilayer particles. The diffusional and second-order collisional exchange rate constants for SMALPs at 30 °C are kdif = 0.287 s-1 and kcol = 222 M-1s-1, respectively. Together with the fast kinetics, the observed invariability of the rate constants with probe hydrophobicity and the moderate activation enthalpy of ~70 kJ mol-1 imply that lipids exchange through a "hydrocarbon continuum" enabled by the flexible nature of the SMA belt surrounding the lipid-bilayer core. Owing to their fast lipid-exchange kinetics, SMALPs represent highly dynamic equilibrium rather than kinetically trapped membrane mimics, which has important implications for studying protein/lipid interactions in polymer-bounded nanodiscs.
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Affiliation(s)
- Rodrigo Cuevas Arenas
- Molecular Biophysics, University of Kaiserslautern, Erwin-Schrödinger-Str. 13, 67663 Kaiserslautern, Germany
| | - Bartholomäus Danielczak
- Molecular Biophysics, University of Kaiserslautern, Erwin-Schrödinger-Str. 13, 67663 Kaiserslautern, Germany
| | - Anne Martel
- Institut Max von Laue Paul Langevin, Grenoble, 38042, France
| | - Lionel Porcar
- Institut Max von Laue Paul Langevin, Grenoble, 38042, France
| | - Cécile Breyton
- Institut de Biologie Structurale (IBS), Univ. Grenoble Alpes, CEA, CNRS, Grenoble, 38044, France
| | - Christine Ebel
- Institut de Biologie Structurale (IBS), Univ. Grenoble Alpes, CEA, CNRS, Grenoble, 38044, France
| | - Sandro Keller
- Molecular Biophysics, University of Kaiserslautern, Erwin-Schrödinger-Str. 13, 67663 Kaiserslautern, Germany
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36
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Crystallogenesis of Membrane Proteins Mediated by Polymer-Bounded Lipid Nanodiscs. Structure 2017; 25:384-392. [DOI: 10.1016/j.str.2016.12.004] [Citation(s) in RCA: 114] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 09/20/2016] [Accepted: 12/12/2016] [Indexed: 11/20/2022]
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