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Mamatkulov K, Zavatski S, Arynbek Y, Esawii HA, Burko A, Bandarenka H, Arzumanyan G. Conformational analysis of lipid membrane mimetics modified with A β42 peptide by Raman spectroscopy and computer simulations. J Biomol Struct Dyn 2024:1-14. [PMID: 38520152 DOI: 10.1080/07391102.2024.2330706] [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: 12/20/2023] [Accepted: 03/08/2024] [Indexed: 03/25/2024]
Abstract
Peptide-lipid interactions play an important role in maintaining the integrity and function of the cell membrane. Even slight changes in these interactions can induce the development of various diseases. Specifically, peptide misfolding and aggregation in the membrane is considered to be one of the triggers of Alzheimer's disease (AD), however its exact mechanism is still unclear. To this end, an increase of amyloid-beta (Aβ) peptide concentration in the human brain is widely accepted to gradually produce cytotoxic Aβ aggregates (plaques). These plaques initiate a sequence of pathogenic events ending up in observable symptoms of dementia. Understanding the mechanism of the Aβ interaction with cells is crucial for early detection and prevention of Alzheimer's disease. Hence, in this work, a comprehensive Raman analysis of the Aβ42 conformational dynamics in water and in liposomes and lipodiscs that mimic the membrane system is presented. The obtained results show that the secondary structure of Aβ42 in liposomes is dominated by the α-helix conformation, which remains stable over time. However, it comes as a surprise to reveal that the lipodisc environment induces the transformation of the Aβ42 secondary structure to a β-turn/random coil. Our Raman spectroscopy findings are supported with molecular dynamics (MD) and density functional theory (DFT) simulations, showing their good agreement.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Kahramon Mamatkulov
- Laboratory of Neutron Physics, Sector of Raman Spectroscopy, Joint Institute for Nuclear Research, Dubna, Russia
| | - Siarhei Zavatski
- Applied Plasmonics Laboratory, Belarusian State University of Informatics and Radioelectronics, Minsk, Belarus
| | - Yersultan Arynbek
- Laboratory of Neutron Physics, Sector of Raman Spectroscopy, Joint Institute for Nuclear Research, Dubna, Russia
- Faculty of Physics and Technology, al-Farabi, Kazakh National University, Almaty, Kazakhstan
| | - Heba A Esawii
- Laboratory of Neutron Physics, Sector of Raman Spectroscopy, Joint Institute for Nuclear Research, Dubna, Russia
- Biophysics Department, Faculty of Science, Cairo University, Egypt
| | - Aliaksandr Burko
- Applied Plasmonics Laboratory, Belarusian State University of Informatics and Radioelectronics, Minsk, Belarus
| | - Hanna Bandarenka
- Applied Plasmonics Laboratory, Belarusian State University of Informatics and Radioelectronics, Minsk, Belarus
| | - Grigory Arzumanyan
- Laboratory of Neutron Physics, Sector of Raman Spectroscopy, Joint Institute for Nuclear Research, Dubna, Russia
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Neville GM, Morrison KA, Shilliday ER, Doutch J, Dalgliesh R, Price GJ, Edler KJ. The effect of polymer end-group on the formation of styrene - maleic acid lipid particles (SMALPs). SOFT MATTER 2023; 19:8507-8518. [PMID: 37889133 DOI: 10.1039/d3sm01180a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2023]
Abstract
A series of block copolymers comprising styrene and maleic acid (SMA) has been prepared using RAFT polymerisation. RAFT often results in a large hydrophobic alkylthiocarbonylthio end group and this work examines its effect on the solution behaviour of the copolymers. SMA variants with, and without, this end group were synthesised and their behaviour compared with a commercially-available random copolymer of similar molecular weight. Dynamic light scattering and surface tension measurements found the RAFT-copolymers preferentially self-assembled into higher-order aggregates in aqueous solution. Small angle neutron scattering using deuterated styrene varients add support to the accepted model that these agreggates comprise a solvent-protected styrenic core with an acid-rich shell. Replacing the hydrophobic RAFT end group with a more hydrophilic nitrile caused differences in the resulting surface activity, attributed to the ability of the adjoining styrene homoblock to drive aggregation. Each of the copolymers formed SMALP nanodiscs with DMPC lipids, which were found to encapsulate a model membrane protein, gramicidin. However, end group variation affected solubilisition of DPPC, a lipid with a higher phase transition temperature. When using RAFT-copolymers terminated with a hydrophobic group, swelling of the bilayer and greater penetration of the homoblock into the nanodisc core occurred with increasing homoblock length. Conversely, commercial and nitrile-terminated RAFT-copolymers produced nanodisc sizes that stayed constant, instead indicating interaction at the edge of the lipid patch. The results highlight how even minor changes to the copolymer can modify the amphiphilic balance between regions, knowledge useful towards optimising copolymer structure to enhance and control nanodisc formation.
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Affiliation(s)
- George M Neville
- Centre for Sustainable Chemical Technologies, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Kerrie A Morrison
- Centre for Sustainable Chemical Technologies, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
- Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Ella R Shilliday
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - James Doutch
- ISIS Pulsed Neutron and Muon Source, Rutherford Appleton Laboratory, Didcot, OX11 0QX, UK
| | - Robert Dalgliesh
- ISIS Pulsed Neutron and Muon Source, Rutherford Appleton Laboratory, Didcot, OX11 0QX, UK
| | - Gareth J Price
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
- Department of Chemistry, Khalifa University, P.O. Box 127788, Abu Dhabi, United Arab Emirates
| | - Karen J Edler
- Centre for Sustainable Chemical Technologies, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
- Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
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3
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Workman CE, Bag P, Cawthon B, Ali FH, Brady NG, Bruce BD, Long BK. Alternatives to Styrene- and Diisobutylene-Based Copolymers for Membrane Protein Solubilization via Nanodisc Formation. Angew Chem Int Ed Engl 2023; 62:e202306572. [PMID: 37682083 PMCID: PMC10591821 DOI: 10.1002/anie.202306572] [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: 05/10/2023] [Revised: 09/05/2023] [Accepted: 09/08/2023] [Indexed: 09/09/2023]
Abstract
Styrene-maleic acid copolymers (SMAs), and related amphiphilic copolymers, are promising tools for isolating and studying integral membrane proteins in a native-like state. However, they do not exhibit this ability universally, as several reports have found that SMAs and related amphiphilic copolymers show little to no efficiency when extracting specific membrane proteins. Recently, it was discovered that esterified SMAs could enhance the selective extraction of trimeric Photosystem I from the thylakoid membranes of thermophilic cyanobacteria; however, these polymers are susceptible to saponification that can result from harsh preparation or storage conditions. To address this concern, we herein describe the development of α-olefin-maleic acid copolymers (αMAs) that can extract trimeric PSI from cyanobacterial membranes with the highest extraction efficiencies observed when using any amphiphilic copolymers, including diisobutylene-co-maleic acid (DIBMA) and functionalized SMA samples. Furthermore, we will show that αMAs facilitate the formation of photosystem I-containing nanodiscs that retain an annulus of native lipids and a native-like activity. We also highlight how αMAs provide an agile, tailorable synthetic platform that enables fine-tuning hydrophobicity, controllable molar mass, and consistent monomer incorporation while overcoming shortcomings of prior amphiphilic copolymers.
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Affiliation(s)
| | - Pushan Bag
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, USA
| | - Bridgie Cawthon
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, USA
| | - Fidaa H Ali
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, USA
| | - Nathan G Brady
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, USA
| | - Barry D Bruce
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, USA
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, USA
| | - Brian K Long
- Department of Chemistry, University of Tennessee, Knoxville, USA
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4
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Janata M, Gupta S, Čadová E, Angelisová P, Krishnarjuna B, Ramamoorthy A, Hořejší V, Raus V. Sulfonated polystyrenes: pH and Mg 2+-insensitive amphiphilic copolymers for detergent-free membrane protein isolation. Eur Polym J 2023; 198:112412. [PMID: 37780808 PMCID: PMC10538444 DOI: 10.1016/j.eurpolymj.2023.112412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Amphiphilic polymers are increasingly applied in the detergent-free isolation and functional studies of membrane proteins. However, the carboxylate group present in the structure of many popular variants, such as styrene-maleic acid (SMA) copolymers, brings limitations in terms of polymer sensitivity to precipitation at acidic pH or in the presence of divalent metal cations. Herein, we addressed this problem by replacing carboxylate with the more acidic sulfonate groups. To this end, we synthesized a library of amphiphilic poly[styrene-co-(sodium 4-styrene sulfonate)] copolymers (termed SSS), differing in their molecular weight and overall polarity. Using model cell membranes (Jurkat), we identified two copolymer compositions (SSS-L30 and SSS-L36) that solubilized membranes to an extent similar to SMA. Interestingly, the density gradient ultracentrifugation/SDS-PAGE/Western blotting analysis of cell lysates revealed a distribution of studied membrane proteins in the gradient fractions that was different than for SMA-solubilized membranes. Importantly, unlike SMA, the SSS copolymers remained soluble at low pH and in the presence of Mg2+ ions. Additionally, the solubilization of DMPC liposomes by the lead materials was studied by turbidimetry, DLS, SEC, and high-resolution NMR, revealing, for SSS-L36, the formation of stable particles (nanodiscs), facilitated by the direct hydrophobic interaction of the copolymer phenyls with lipid acyl chains.
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Affiliation(s)
- Miroslav Janata
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského nám. 2, 162 06 Prague 6, Czech Republic
| | - Sachin Gupta
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského nám. 2, 162 06 Prague 6, Czech Republic
| | - Eva Čadová
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského nám. 2, 162 06 Prague 6, Czech Republic
| | - Pavla Angelisová
- Institute of Molecular Genetics of the Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague 4, Czech Republic
| | - 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
| | - 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
| | - Václav Hořejší
- Institute of Molecular Genetics of the Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague 4, Czech Republic
| | - Vladimír Raus
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského nám. 2, 162 06 Prague 6, Czech Republic
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Scheyer MW, Campbell C, William PL, Hussain M, Begum A, Fonseca SE, Asare IK, Dabney P, Dabney-Smith C, Lorigan GA, Sahu ID. Electron paramagnetic resonance spectroscopic characterization of the human KCNE3 protein in lipodisq nanoparticles for structural dynamics of membrane proteins. Biophys Chem 2023; 301:107080. [PMID: 37531799 DOI: 10.1016/j.bpc.2023.107080] [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: 05/25/2023] [Revised: 07/07/2023] [Accepted: 07/24/2023] [Indexed: 08/04/2023]
Abstract
One of the major challenges in solubilization of membrane proteins is to find the optimal physiological environment for their biophysical studies. EPR spectroscopy is a powerful biophysical technique for studying the structural and dynamic properties of macromolecules. However, the challenges in the membrane protein sample preparation and flexible motion of the spin label limit the utilization of EPR spectroscopy to a majority of membrane protein systems in a physiological membrane-bound state. Recently, lipodisq nanoparticles or styrene-maleic acid copolymer-lipid nanoparticles (SMALPs) have emerged as a membrane mimetic system for investigating the structural studies of membrane proteins. However, its detail characterization for membrane protein studies is still poorly understood. Recently, we characterized the potassium channel membrane protein KCNQ1 voltage sensing domain (KCNQ1-VSD) and KCNE1 reconstituted into lipodisq nanoparticles using EPR spectroscopy. In this study, the potassium channel accessory protein KCNE3 containing flexible N- and C-termini was encapsulated into proteoliposomes and lipodisq nanoparticles and characterized for studying its structural and dynamic properties using nitroxide based site-directed spin labeling EPR spectroscopy. CW-EPR lineshape analysis data indicated an increase in spectral line broadenings with the addition of the styrene-maleic acid (SMA) polymer which approaches close to the rigid limit providing a homogeneous stabilization of the protein-lipid complex. Similarly, EPR DEER measurements indicated an enhanced quality of distance measurements with an increase in the phase memory time (Tm) values upon incorporation of the sample into lipodisq nanoparticles, when compared to proteoliposomes. These results agree with the solution NMR structural structure of the KCNE3 and EPR studies of other membrane proteins in lipodisq nanoparticles. This study along with our earlier studies will provide the reference characterization data that will provide benefit to the membrane protein researchers for studying structural dynamics of challenging membrane proteins.
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Affiliation(s)
- Matthew W Scheyer
- Natural Science Division, Campbellsville University, Campbellsville, KY 42718, USA
| | - Conner Campbell
- Natural Science Division, Campbellsville University, Campbellsville, KY 42718, USA
| | - Patrick L William
- Natural Science Division, Campbellsville University, Campbellsville, KY 42718, USA
| | - Mustakim Hussain
- Natural Science Division, Campbellsville University, Campbellsville, KY 42718, USA
| | - Afsana Begum
- Natural Science Division, Campbellsville University, Campbellsville, KY 42718, USA
| | | | - Isaac K Asare
- Natural Science Division, Campbellsville University, Campbellsville, KY 42718, USA
| | - Peyton Dabney
- Natural Science Division, Campbellsville University, Campbellsville, KY 42718, USA
| | - Carole Dabney-Smith
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA
| | - Gary A Lorigan
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA
| | - Indra D Sahu
- Natural Science Division, Campbellsville University, Campbellsville, KY 42718, USA; Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA.
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Trinh TKH, Cabezas AJ, Joshi S, Catalano C, Siddique AB, Qiu W, Deshmukh S, des Georges A, Guo Y. pH-tunable membrane-active polymers, NCMNP2a- x, and their potential membrane protein applications. Chem Sci 2023; 14:7310-7326. [PMID: 37416719 PMCID: PMC10321531 DOI: 10.1039/d3sc01890c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 05/30/2023] [Indexed: 07/08/2023] Open
Abstract
Accurate 3D structures of membrane proteins are essential for comprehending their mechanisms of action and designing specific ligands to modulate their activities. However, these structures are still uncommon due to the involvement of detergents in the sample preparation. Recently, membrane-active polymers have emerged as an alternative to detergents, but their incompatibility with low pH and divalent cations has hindered their efficacy. Herein, we describe the design, synthesis, characterization, and application of a new class of pH-tunable membrane-active polymers, NCMNP2a-x. The results demonstrated that NCMNP2a-x could be used for high-resolution single-particle cryo-EM structural analysis of AcrB in various pH conditions and can effectively solubilize BcTSPO with the function preserved. Molecular dynamic simulation is consistent with experimental data that shed great insights into the working mechanism of this class of polymers. These results demonstrated that NCMNP2a-x might have broad applications in membrane protein research.
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Affiliation(s)
- Thi Kim Hoang Trinh
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University Richmond VA 23298 USA
- Institute for Structural Biology, Drug Discovery and Development, School of Pharmacy, Virginia Commonwealth University Richmond VA 23219 USA
| | - Andres Jorge Cabezas
- Structural Biology Initiative, CUNY Advanced Science Research Center, City University of New York New York New York 10017 USA
- PhD Program in Biochemistry, The Graduate Center of the City University of New York New York New York 10017 USA
| | - Soumil Joshi
- Department of Chemical Engineering, Virginia Tech Blacksburg VA2 4060 USA
| | - Claudio Catalano
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University Richmond VA 23298 USA
- Institute for Structural Biology, Drug Discovery and Development, School of Pharmacy, Virginia Commonwealth University Richmond VA 23219 USA
| | - Abu Bakkar Siddique
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University Richmond VA 23298 USA
- Institute for Structural Biology, Drug Discovery and Development, School of Pharmacy, Virginia Commonwealth University Richmond VA 23219 USA
| | - Weihua Qiu
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University Richmond VA 23298 USA
- Institute for Structural Biology, Drug Discovery and Development, School of Pharmacy, Virginia Commonwealth University Richmond VA 23219 USA
| | - Sanket Deshmukh
- Department of Chemical Engineering, Virginia Tech Blacksburg VA2 4060 USA
| | - Amedee des Georges
- Structural Biology Initiative, CUNY Advanced Science Research Center, City University of New York New York New York 10017 USA
- PhD Program in Biochemistry, The Graduate Center of the City University of New York New York New York 10017 USA
- Department of Chemistry & Biochemistry, City College of New York New York New York 10017 USA
| | - Youzhong Guo
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University Richmond VA 23298 USA
- Institute for Structural Biology, Drug Discovery and Development, School of Pharmacy, Virginia Commonwealth University Richmond VA 23219 USA
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7
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Role of membrane mimetics on biophysical EPR studies of membrane proteins. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184138. [PMID: 36764474 DOI: 10.1016/j.bbamem.2023.184138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 02/01/2023] [Accepted: 02/03/2023] [Indexed: 02/11/2023]
Abstract
Biological membranes are essential in providing the stability of membrane proteins in a functional state. Functionally stable homogeneous sample is required for biophysical electron paramagnetic resonance (EPR) studies of membrane proteins for obtaining pertinent structural dynamics of the protein. Significant progresses have been made for the optimization of the suitable membrane environments required for biophysical EPR measurements. However, no universal membrane mimetic system is available that can solubilize all membrane proteins suitable for biophysical EPR studies while maintaining the functional integrity. Great efforts are needed to optimize the sample condition to obtain better EPR data quality of membrane proteins that can provide meaningful information on structural dynamics. In this mini-review, we will discuss important aspects of membrane mimetics for biophysical EPR measurements and current progress with some of the recent examples.
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Kamilar E, Bariwal J, Zheng W, Ma H, Liang H. SMALPs Are Not Simply Nanodiscs: The Polymer-to-Lipid Ratios of Fractionated SMALPs Underline Their Heterogeneous Nature. Biomacromolecules 2023; 24:1819-1838. [PMID: 36947865 DOI: 10.1021/acs.biomac.3c00034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/24/2023]
Abstract
Amphipathic styrene-maleic acid (SMA) copolymers directly solubilize biomembranes into SMA-lipid particles, or SMALPs, that are often regarded as nanodiscs and hailed as a native membrane platform. The promising outlook of SMALPs inspires the discovery of many SMA-like copolymers that also solubilize biomembranes into putative nanodiscs, but a fundamental question remains on how much the SMALPs or SMALP analogues truly resemble the bilayer structure of nanodiscs. This unfortunate ambiguity undermines the utility of SMA or SMA-like copolymers in membrane biology because the structure and function of many membrane proteins depend critically on their surrounding matrices. Here, we report the structural heterogeneity of SMALPs revealed through fractionating SMALPs comprised of lipids and well-defined SMAs via size-exclusion chromatography followed by quantitative determination of the polymer-to-lipid (P/L) stoichiometric ratios in individual fractions. Through the lens of P/L stoichiometric ratios, different self-assembled polymer-lipid nanostructures are inferred, such as polymer-remodeled liposomes, polymer-encased nanodiscs, polymer-lipid mixed micelles, and lipid-doped polymer micellar aggregates. We attribute the structural heterogeneity of SMALPs to the microstructure variations amongst individual polymer chains that give rise to their polydisperse detergency. As an example, we demonstrate that SMAs with a similar S/MA ratio but different chain sizes participate preferentially in different polymer-lipid nanostructures. We further demonstrate that proteorhodopsin, a light-driven proton pump solubilized within the same SMALPs is distributed amongst different self-assembled nanostructures to display different photocycle kinetics. Our discovery challenges the native nanodisc notion of SMALPs or SMALP analogues and highlights the necessity to separate and identify the structurally dissimilar polymer-lipid particles in membrane biology studies.
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Affiliation(s)
- Elizabeth Kamilar
- Department of Cell Physiology & Molecular Biophysics, Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas 79430, United States
| | - Jitender Bariwal
- Department of Cell Physiology & Molecular Biophysics, Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas 79430, United States
| | - Wan Zheng
- Department of Cell Physiology & Molecular Biophysics, Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas 79430, United States
| | - Hairong Ma
- Department of Cell Physiology & Molecular Biophysics, Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas 79430, United States
| | - Hongjun Liang
- Department of Cell Physiology & Molecular Biophysics, Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas 79430, United States
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Cheng D, Zhao L, Guan G, Lai H, Luo J. Synthesis of SMA by RAFT polymerization and its dispersion of TiO 2 in aqueous solution. RSC Adv 2023; 13:7366-7371. [PMID: 36895768 PMCID: PMC9989742 DOI: 10.1039/d3ra00637a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 02/27/2023] [Indexed: 03/09/2023] Open
Abstract
Styrene-maleic anhydride copolymer (SMA) with controlled molecular weight (M n) and narrow dispersity was prepared by RAFT polymerization. The effect of reaction time on monomer conversion was investigated, and the conversion of monomer could achieve 99.1% after 24 h at the temperature of 55 °C. The synthesized SMA was characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) and size exclusion chromatography (SEC). The result demonstrated that the polymerization of SMA was well controlled and the dispersity (Đ) of SMA was lower than 1.20. Furthermore, SMA copolymers with narrow dispersity and well-regulated M n (denoted SMA1500, SMA3000, SMA5000, SMA8000, and SMA15800, respectively) were obtained by adjusting the molar ratio of monomer to the chain transfer agent. Moreover, the synthesized SMA was hydrolyzed in NaOH aqueous solution. Then the dispersion of TiO2 in aqueous solution by the hydrolyzed SMA and SZ40005 (the industrial product) were studied. The agglomerate size, the viscosity and the fluidity of TiO2 slurry were tested. The results show that the performance of dispersity for TiO2 in water by SMA prepared via RAFT was better than that of SZ40005. It was found that the viscosity of the TiO2 slurry dispersed by SMA5000 was the lowest among the SMA copolymers tested, and the viscosity value of the TiO2 slurry with a pigment loading of 75% was only 76.6 cp.
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Affiliation(s)
- Deshu Cheng
- School of Resourses and Chemical Engineering, Sanming University Sanming 365004 China .,Sanming Institute of Fluorochemmical Industry Sanming 365004 China
| | - Lei Zhao
- College of Chemical Engineering, Fuzhou University Fuzhou 350108 China
| | - Guoxiang Guan
- College of Chemical Engineering, Fuzhou University Fuzhou 350108 China
| | - Huaidong Lai
- College of Environment and Safety Engineering, Fuzhou University Fuzhou 350108 China
| | - Juxiang Luo
- School of Resourses and Chemical Engineering, Sanming University Sanming 365004 China
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10
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Wang H, Ullah A. Synthesis and Evaluation of Thermoresponsive Renewable Lipid-Based Block Copolymers for Drug Delivery. Polymers (Basel) 2022; 14:polym14173436. [PMID: 36080511 PMCID: PMC9460350 DOI: 10.3390/polym14173436] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 08/18/2022] [Accepted: 08/21/2022] [Indexed: 11/16/2022] Open
Abstract
Polymeric micelle forming from self-assembly of amphiphilic macromolecules is one of the most potent drug delivery systems. Fatty acids, naturally occurring hydrophobic lipid components, can be considered as potential candidates for the fabrication of block copolymer micelles. However, examples of synthesis of responsive block copolymers using renewable fatty acids are scarce. Herein, we report the synthesis, characterization and testing of block copolymer micelles composed of a renewable fatty-acid-based hydrophobic block and thermoresponsive hydrophilic block for controlled drug delivery. The block copolymers of functionalized fatty acid and poly(N-isopropylacrylamide) (PNIPAM) were prepared via consecutive microwave-assisted reversible addition fragmentation chain transfer (RAFT) polymerization. The block copolymers with variable hydrophobic block length self-assembled in aqueous media and formed spherical nanoparticles of ~30 nm with low critical micelle concentration (CMC). To demonstrate the proof-of-concept, carbamazepine (CBZ) was used as a hydrophobic model drug to evaluate the performance of these micelles as nanocarriers. The in vitro drug release tests were carried out below (25 °C) and above (37 °C) the lower critical solution temperature (LCST) of the block copolymer. The drug release showed obvious temperature-triggered response and an accelerated drug release at 37 °C.
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11
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Janata M, Čadová E, Angelisová P, Charnavets T, Hořejší V, Raus V. Tailoring Butyl Methacrylate/Methacrylic Acid Copolymers for the Solubilization of Membrane Proteins: The Influence of Composition and Molecular Weight. Macromol Biosci 2022; 22:e2200284. [PMID: 35964154 DOI: 10.1002/mabi.202200284] [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: 07/11/2022] [Revised: 08/02/2022] [Indexed: 11/11/2022]
Abstract
Low-molecular weight (MW) amphiphilic copolymers have been recently introduced as a powerful tool for the detergent-free isolation of cell membrane proteins. Herein, we use a screening approach to identify a new copolymer type for this application. Via a two-step ATRP/acidolysis procedure, we prepare a 3×3 matrix of well-defined poly[(butyl methacrylate)-co-(methacrylic acid)] copolymers (denoted BMAA) differing in their MW and ratio of hydrophobic (BMA) and hydrophilic (MAA) units. Subsequently, using the biologically relevant model (T-cell line Jurkat), we identify two compositions of BMAA copolymers that solubilize cell membranes to an extent comparable to the industry standard, styrene-maleic acid copolymer (SMA), while avoiding the potentially problematic phenyl groups. Surprisingly, while only the lowest-MW variant of the BMA/MAA 2:1 composition is effective, all the copolymers of the BMA/MAA 1:1 composition are found to solubilize the model membranes, including the high-MW variant (MW of 14 000). Importantly, the density gradient ultracentrifugation/SDS PAGE/Western blotting experiments reveal that the BMA/MAA 1:1 copolymers disintegrate the Jurkat membranes differently than SMA, as demonstrated by the different distribution patterns of two tested membrane protein markers. This makes the BMAA copolymers a useful tool for studies on membrane microdomains differing in their composition and resistance to membrane-disintegrating polymers. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Miroslav Janata
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského nám. 2, Prague 6, 162 06, Czech Republic
| | - Eva Čadová
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského nám. 2, Prague 6, 162 06, Czech Republic
| | - Pavla Angelisová
- Institute of Molecular Genetics of the Czech Academy of Sciences, Vídeňská 1083, Prague 4, 142 20, Czech Republic
| | - Tatsiana Charnavets
- Institute of Molecular Genetics of the Czech Academy of Sciences, Vídeňská 1083, Prague 4, 142 20, Czech Republic.,T. Charnavets, Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Průmyslová 595, Vestec, CZ-25242, Czech Republic
| | - Václav Hořejší
- Institute of Molecular Genetics of the Czech Academy of Sciences, Vídeňská 1083, Prague 4, 142 20, Czech Republic
| | - Vladimír Raus
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského nám. 2, Prague 6, 162 06, Czech Republic
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12
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Krishnarjuna B, Ramamoorthy A. Detergent-Free Isolation of Membrane Proteins and Strategies to Study Them in a Near-Native Membrane Environment. Biomolecules 2022; 12:1076. [PMID: 36008970 PMCID: PMC9406181 DOI: 10.3390/biom12081076] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 07/31/2022] [Accepted: 08/02/2022] [Indexed: 02/06/2023] Open
Abstract
Atomic-resolution structural studies of membrane-associated proteins and peptides in a membrane environment are important to fully understand their biological function and the roles played by them in the pathology of many diseases. However, the complexity of the cell membrane has severely limited the application of commonly used biophysical and biochemical techniques. Recent advancements in NMR spectroscopy and cryoEM approaches and the development of novel membrane mimetics have overcome some of the major challenges in this area. For example, the development of a variety of lipid-nanodiscs has enabled stable reconstitution and structural and functional studies of membrane proteins. In particular, the ability of synthetic amphipathic polymers to isolate membrane proteins directly from the cell membrane, along with the associated membrane components such as lipids, without the use of a detergent, has opened new avenues to study the structure and function of membrane proteins using a variety of biophysical and biological approaches. This review article is focused on covering the various polymers and approaches developed and their applications for the functional reconstitution and structural investigation of membrane proteins. The unique advantages and limitations of the use of synthetic polymers are also discussed.
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Affiliation(s)
- Bankala Krishnarjuna
- Department of Chemistry and Biophysics, Biomedical Engineering, Macromolecular Science and Engineering, Michigan Neuroscience Institute, The University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Ayyalusamy Ramamoorthy
- Department of Chemistry and Biophysics, Biomedical Engineering, Macromolecular Science and Engineering, Michigan Neuroscience Institute, The University of Michigan, Ann Arbor, MI 48109-1055, USA
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13
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Zhu L, Zhao H, Wang Y, Yu C, Liu J, Li L, Li Z, Zhang J, Dai H, Wang J, Zhu L. Solubilization, purification, and ligand binding characterization of G protein-coupled receptor SMO in native membrane bilayer using styrene maleic acid copolymer. PeerJ 2022; 10:e13381. [PMID: 35529497 PMCID: PMC9074879 DOI: 10.7717/peerj.13381] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 04/13/2022] [Indexed: 01/13/2023] Open
Abstract
Smoothened (SMO) protein is a member of the G protein-coupled receptor (GPCR) family that is involved in the Hedgehog (Hh) signaling pathway. It is a putative target for treating various cancers, including medulloblastoma and basal cell carcinoma (BCC). Characterizing membrane proteins such as SMO in their native state is highly beneficial for the development of effective pharmaceutical drugs, as their structures and functions are retained to the highest extent in this state. Therefore, although SMO protein is conventionally solubilized in detergent micelles, incorporating the protein in a lipid-based membrane mimic is still required. In this study, we used styrene maleic acid (SMA) copolymer that directly extracted membrane protein and surrounding lipids as well as formed the so-called polymer nanodiscs, to solubilize and purify the SMO transmembrane domain encapsulated by SMA-nanodiscs. The obtained SMA-nanodiscs showed high homogeneity and maintained the physiological activity of SMO protein, thereby enabling the measurement of the dissociation constant (Kd) for SMO ligands SMO-ligands Shh Signaling Antagonist V (SANT-1) and Smoothened Agonist (SAG) using ligand-based solution nuclear magnetic resonance spectroscopy. This work paves the way for investigating the structure, function, and drug development of SMO proteins in a native-like lipid environment.
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Affiliation(s)
- Lina Zhu
- Institute of Physical Science and Information Technology, Anhui University, Hefei, China,High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Hongxin Zhao
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Yizhuo Wang
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China,University of Science and Technology of China, Hefei, China
| | - Chuandi Yu
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China,University of Science and Technology of China, Hefei, China
| | - Juanjuan Liu
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Ling Li
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China,University of Science and Technology of China, Hefei, China
| | - Zehua Li
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China,University of Science and Technology of China, Hefei, China
| | - Jin Zhang
- School of Basic Medical Sciences, Nanchang University, Nanchang, China
| | - Han Dai
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Junfeng Wang
- Institute of Physical Science and Information Technology, Anhui University, Hefei, China,High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China,University of Science and Technology of China, Hefei, China
| | - Lei Zhu
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
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14
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Neville GM, Edler KJ, Price GJ. Fluorescent styrene maleic acid copolymers to facilitate membrane protein studies in lipid nanodiscs. NANOSCALE 2022; 14:5689-5693. [PMID: 35315461 DOI: 10.1039/d1nr07230g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Fluorescently-labelled variants of poly(styrene-co-maleic acid), SMA, have been synthesised by RAFT copolymerisation. We show that low ratios of vinyl fluorophores, analogous to styrene, can be successfully incorporated during polymerisation without detriment to nanodisc formation upon interaction with lipids. These novel copolymers are capable of encapuslating lipids and the model membrane protein, gramicidin, and hence have the potential to be applied in fluorescence-based biological studies. To demonstrate this, energy transfer is used to probe polymer-protein interactions in nanodiscs. The copolymers may also be used to monitor nanodisc self assembly by exploiting aggregation-caused-quenching (ACQ).
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Affiliation(s)
| | - Karen J Edler
- Department of Chemistry, University of Bath, Bath, BA2 7AY, UK
| | - Gareth J Price
- Department of Chemistry, University of Bath, Bath, BA2 7AY, UK
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15
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Formation of styrene maleic acid lipid nanoparticles (SMALPs) using SMA thin film on a substrate. Anal Biochem 2022; 647:114692. [DOI: 10.1016/j.ab.2022.114692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 04/13/2022] [Accepted: 04/15/2022] [Indexed: 11/21/2022]
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16
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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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17
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Migliore N, Van Kooten T, Ruggeri G, Picchioni F, Raffa P. Synthesis and solution properties of poly(p,α dimethylstyrene-co-maleic anhydride): The use of a monomer potentially obtained from renewable sources as a substitute of styrene in amphiphilic copolymers. REACT FUNCT POLYM 2022. [DOI: 10.1016/j.reactfunctpolym.2022.105204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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18
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Jeong C, Franklin R, Edler KJ, Vanommeslaeghe K, Krueger S, Curtis JE. Styrene-Maleic Acid Copolymer Nanodiscs to Determine the Shape of Membrane Proteins. J Phys Chem B 2022; 126:1034-1044. [PMID: 35089036 DOI: 10.1021/acs.jpcb.1c05050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Lipid nanodiscs can be used to solubilize functional membrane proteins (MPs) in nativelike environments. Thus, they are promising reagents that have been proven useful to characterize MPs. Both protein and non-protein molecular belts have shown promise to maintain the structural integrity of MPs in lipid nanodiscs. Small-angle neutron scattering (SANS) can be used to determine low-resolution structures of proteins in solution, which can be enhanced through the use of contrast variation methods. We present theoretical contrast variation SANS results for protein and styrene-maleic acid copolymer (SMA) belt 1,2-dimyristoyl-sn-glycero-3-phosphorylcholine (DMPC) nanodiscs with and without additional bound or transmembrane proteins. The predicted scattering properties are derived from atomistic molecular dynamics simulations to account for conformational fluctuations, and we determine deuterium-labeling conditions such that SANS intensity profiles only include contributions from the scattering of the MP of interest. We propose strategies to tune the neutron scattering length densities (SLDs) of the SMA and DMPC using selective deuterium labeling such that the SLD of the nanodisc becomes homogeneous and its scattering can essentially be eliminated in solvents containing an appropriate amount of D2O. These finely tuned labeled polymer-based nanodiscs are expected to be useful to extract the size and molecular shape information of MPs using SANS-based contrast variation experiments, and they can be used with MPs of any molecular weight.
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Affiliation(s)
- Cheol Jeong
- NIST Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, Mail Stop 6102, Gaithersburg, Maryland 20899, United States.,Department of Chemistry, The University of Tennessee, Knoxville, Tennessee 37996-1600, United States
| | - Ryan Franklin
- NIST Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, Mail Stop 6102, Gaithersburg, Maryland 20899, United States
| | - Karen J Edler
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, U.K
| | - Kenno Vanommeslaeghe
- Department of Analytical Chemistry, Applied Chemometrics and Molecular Modelling─FABI, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium
| | - Susan Krueger
- NIST Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, Mail Stop 6102, Gaithersburg, Maryland 20899, United States
| | - Joseph E Curtis
- NIST Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, Mail Stop 6102, Gaithersburg, Maryland 20899, United States
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19
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Orekhov PS, Bozdaganyan ME, Voskoboynikova N, Mulkidjanian AY, Karlova MG, Yudenko A, Remeeva A, Ryzhykau YL, Gushchin I, Gordeliy VI, Sokolova OS, Steinhoff HJ, Kirpichnikov MP, Shaitan KV. Mechanisms of Formation, Structure, and Dynamics of Lipoprotein Discs Stabilized by Amphiphilic Copolymers: A Comprehensive Review. NANOMATERIALS 2022; 12:nano12030361. [PMID: 35159706 PMCID: PMC8838559 DOI: 10.3390/nano12030361] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 01/15/2022] [Accepted: 01/20/2022] [Indexed: 12/16/2022]
Abstract
Amphiphilic copolymers consisting of alternating hydrophilic and hydrophobic units account for a major recent methodical breakthrough in the investigations of membrane proteins. Styrene–maleic acid (SMA), diisobutylene–maleic acid (DIBMA), and related copolymers have been shown to extract membrane proteins directly from lipid membranes without the need for classical detergents. Within the particular experimental setup, they form disc-shaped nanoparticles with a narrow size distribution, which serve as a suitable platform for diverse kinds of spectroscopy and other biophysical techniques that require relatively small, homogeneous, water-soluble particles of separate membrane proteins in their native lipid environment. In recent years, copolymer-encased nanolipoparticles have been proven as suitable protein carriers for various structural biology applications, including cryo-electron microscopy (cryo-EM), small-angle scattering, and conventional and single-molecule X-ray diffraction experiments. Here, we review the current understanding of how such nanolipoparticles are formed and organized at the molecular level with an emphasis on their chemical diversity and factors affecting their size and solubilization efficiency.
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Affiliation(s)
- Philipp S. Orekhov
- Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (M.E.B.); (M.G.K.); (O.S.S.); (M.P.K.)
- Faculty of Biology, Shenzhen MSU-BIT University, Shenzhen 518172, China
- Institute of Personalized Medicine, Sechenov University, 119146 Moscow, Russia
- Correspondence: (P.S.O.); (K.V.S.)
| | - Marine E. Bozdaganyan
- Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (M.E.B.); (M.G.K.); (O.S.S.); (M.P.K.)
- Faculty of Biology, Shenzhen MSU-BIT University, Shenzhen 518172, China
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Natalia Voskoboynikova
- Department of Physics, University of Osnabrück, Barbarastrasse 7, 49076 Osnabrück, Germany; (N.V.); (A.Y.M.); (H.-J.S.)
| | - Armen Y. Mulkidjanian
- Department of Physics, University of Osnabrück, Barbarastrasse 7, 49076 Osnabrück, Germany; (N.V.); (A.Y.M.); (H.-J.S.)
- Faculty of Bioengineering and Bioinformatics and Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Maria G. Karlova
- Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (M.E.B.); (M.G.K.); (O.S.S.); (M.P.K.)
| | - Anna Yudenko
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia; (A.Y.); (A.R.); (Y.L.R.); (I.G.); (V.I.G.)
| | - Alina Remeeva
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia; (A.Y.); (A.R.); (Y.L.R.); (I.G.); (V.I.G.)
| | - Yury L. Ryzhykau
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia; (A.Y.); (A.R.); (Y.L.R.); (I.G.); (V.I.G.)
| | - Ivan Gushchin
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia; (A.Y.); (A.R.); (Y.L.R.); (I.G.); (V.I.G.)
| | - Valentin I. Gordeliy
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia; (A.Y.); (A.R.); (Y.L.R.); (I.G.); (V.I.G.)
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, 52428 Jülich, Germany
- Institut de Biologie Structurale J.-P. Ebel, Université Grenoble Alpes-CEA-CNRS, 38000 Grenoble, France
- JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, 52428 Jülich, Germany
| | - Olga S. Sokolova
- Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (M.E.B.); (M.G.K.); (O.S.S.); (M.P.K.)
- Faculty of Biology, Shenzhen MSU-BIT University, Shenzhen 518172, China
| | - Heinz-Jürgen Steinhoff
- Department of Physics, University of Osnabrück, Barbarastrasse 7, 49076 Osnabrück, Germany; (N.V.); (A.Y.M.); (H.-J.S.)
| | - Mikhail P. Kirpichnikov
- Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (M.E.B.); (M.G.K.); (O.S.S.); (M.P.K.)
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Konstantin V. Shaitan
- Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (M.E.B.); (M.G.K.); (O.S.S.); (M.P.K.)
- Correspondence: (P.S.O.); (K.V.S.)
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20
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Morrison KA, Doekhie A, Neville GM, Price GJ, Whitley P, Doutch J, Edler KJ. Ab initio reconstruction of small angle scattering data for membrane proteins in copolymer nanodiscs. BBA ADVANCES 2022; 2:100033. [PMID: 37082608 PMCID: PMC10074903 DOI: 10.1016/j.bbadva.2021.100033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background Small angle scattering techniques are beginning to be more widely utilised for structural analysis of biological systems. However, applying these techniques to study membrane proteins still remains problematic, due to sample preparation requirements and analysis of the resulting data. The development of styrene-maleic acid co-polymers (SMA) to extract membrane proteins into nanodiscs for further study provides a suitable environment for structural analysis. Methods We use small angle neutron scattering (SANS) with three different contrasts to determine structural information for two different polymer nanodisc-incorporated proteins, Outer membrane protein F (OmpF) and gramicidin. Ab initio modelling was applied to generate protein/lipid structures from the SANS data. Other complementary structural methodologies, such as DLS, CD and TEM were compared alongside this data with known protein crystal structures. Results A single-phase model was constructed for gramicidin-containing nanodiscs, which showed dimer formation in the centre of the nanodisc. For OmpF-nanodiscs we were able to construct a multi-phase model, providing structural information on the protein/lipid and polymer components of the sample. Conclusions Polymer-nanodiscs can provide a suitable platform to investigate certain membrane proteins using SANS, alongside other structural methodologies. However, differences between the published crystal structure and OmpF-nanodiscs were observed, suggesting the nanodisc structure could be altering the folding of the protein. General significance Small angle scattering techniques can provide structural information on the protein and polymer nanodisc without requiring crystallisation of the protein. Additional complementary techniques, such as ab initio modelling, can generate alternative models both the protein and nanodisc system.
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Affiliation(s)
- Kerrie A. Morrison
- Department of Chemistry, University of Bath, Bath, UK
- Department of Biology and Biochemistry, University of Bath, Bath, UK
- Centre for Sustainable and Circular Technologies, University of Bath, Bath, UK
| | - Aswin Doekhie
- Department of Chemistry, University of Bath, Bath, UK
| | - George M. Neville
- Department of Chemistry, University of Bath, Bath, UK
- Centre for Sustainable and Circular Technologies, University of Bath, Bath, UK
| | - Gareth J. Price
- Department of Chemistry, University of Bath, Bath, UK
- Department of Chemistry, Khalifa University, Abu Dhabi, UAE
| | - Paul Whitley
- Department of Biology and Biochemistry, University of Bath, Bath, UK
| | - James Doutch
- ISIS Pulsed Neutron and Muon Source, Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX. UK
- Corresponding authors.
| | - Karen J. Edler
- Department of Chemistry, University of Bath, Bath, UK
- Corresponding authors.
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21
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Burridge KM, Rahman MS, De Alwis Watuthanthrige N, Gordon E, Shah MZ, Chandrarathne BM, Lorigan GA, Page RC, Konkolewicz D. Network polymers incorporating lipid-bilayer disrupting polymers: towards antiviral functionality. Polym Chem 2022. [DOI: 10.1039/d2py00602b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Polymer based solid-state materials capable of disrupting lipid-bilayers are developed. The materials are mechanically robust and capable of outperforming a 10% small-molecule surfactant and modify filter materials.
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Affiliation(s)
- Kevin M. Burridge
- Department of Chemistry and Biochemistry, Miami University, 651 E High St, Oxford, OH 45056, USA
| | - Monica S. Rahman
- Department of Chemistry and Biochemistry, Miami University, 651 E High St, Oxford, OH 45056, USA
| | | | - Emma Gordon
- Department of Chemistry and Biochemistry, Miami University, 651 E High St, Oxford, OH 45056, USA
| | - Muhammad Zeeshan Shah
- Department of Chemistry and Biochemistry, Miami University, 651 E High St, Oxford, OH 45056, USA
| | | | - Gary A. Lorigan
- Department of Chemistry and Biochemistry, Miami University, 651 E High St, Oxford, OH 45056, USA
| | - Richard C. Page
- Department of Chemistry and Biochemistry, Miami University, 651 E High St, Oxford, OH 45056, USA
| | - Dominik Konkolewicz
- Department of Chemistry and Biochemistry, Miami University, 651 E High St, Oxford, OH 45056, USA
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22
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Morrison KA, Heesom KJ, Edler KJ, Doutch J, Price GJ, Koumanov F, Whitley P. Development of Methodology to Investigate the Surface SMALPome of Mammalian Cells. Front Mol Biosci 2021; 8:780033. [PMID: 34869600 PMCID: PMC8637157 DOI: 10.3389/fmolb.2021.780033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 10/14/2021] [Indexed: 11/24/2022] Open
Abstract
Extraction of membrane proteins from biological membranes has traditionally involved detergents. In the past decade, a new technique has been developed, which uses styrene maleic acid (SMA) copolymers to extract membrane proteins into nanodiscs without the requirement of detergents. SMA nanodiscs are compatible with analytical techniques, such as small-angle scattering, NMR spectroscopy, and DLS, and are therefore an attractive medium for membrane protein characterization. While mass spectrometry has also been reported as a technique compatible with copolymer extraction, most studies have focused on lipidomics, which involves solvent extraction of lipids from nanodiscs prior to mass-spectrometry analysis. In this study, mass spectrometry proteomics was used to investigate whether there are qualitative or quantitative differences in the mammalian plasma membrane proteins extracted with SMA compared to a detergent control. For this, cell surface proteins of 3T3L1 fibroblasts were biotinylated and extracted using either SMA or detergent. Following affinity pull-down of biotinylated proteins with NeutrAvidin beads, samples were analyzed by nanoLC-MS. Here, we report for the first time, a global proteomics protocol for detection of a mammalian cell "SMALPome", membrane proteins incorporated into SMA nanodiscs. Removal of SMA from samples prior to processing of samples for mass spectrometry was a crucial step in the protocol. The reported surface SMALPome of 3T3L1 fibroblasts consists of 205 integral membrane proteins. It is apparent that the detergent extraction method used is, in general, quantitatively more efficient at extracting proteins from the plasma membrane than SMA extraction. However, samples prepared following detergent extraction contained a greater proportion of proteins that were considered to be "non-specific" than in samples prepared from SMA extracts. Tantalizingly, it was also observed that proteins detected uniquely or highly preferentially in pull-downs from SMA extracts were primarily multi-spanning membrane proteins. These observations hint at qualitative differences between SMA and detergent extraction that are worthy of further investigation.
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Affiliation(s)
- Kerrie A. Morrison
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
- Department of Chemistry, University of Bath, Bath, United Kingdom
- Centre for Sustainable Circular Technologies, University of Bath, Bath, United Kingdom
| | - Kate J. Heesom
- University of Bristol, Proteomics Facility, Bristol, United Kingdom
| | - Karen J. Edler
- Department of Chemistry, University of Bath, Bath, United Kingdom
| | - James Doutch
- Rutherford Appleton Laboratory, ISIS Pulsed Neutron and Muon Source, Harwell Oxford, United Kingdom
| | - Gareth J. Price
- Department of Chemistry, University of Bath, Bath, United Kingdom
- Department of Chemistry, Khalifa University, Abu Dhabi, United Arab Emirates
| | | | - Paul Whitley
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
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23
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Biophysical characterisation of SMALPs. Biochem Soc Trans 2021; 49:2037-2050. [PMID: 34643233 DOI: 10.1042/bst20201088] [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: 08/02/2021] [Revised: 09/22/2021] [Accepted: 09/23/2021] [Indexed: 11/17/2022]
Abstract
Membrane proteins such as receptors, ion channels and transport proteins are important drug targets. The structure-based study of membrane proteins is challenging, especially when the target protein contains both soluble and insoluble domains. Most membrane proteins are insoluble in aqueous solvent and embedded in the plasma membrane lipid bilayer, which significantly complicates biophysical studies. Poly(styrene-co-maleic acid) (SMA) and other polymer derivatives are increasingly common solubilisation agents, used to isolate membrane proteins stabilised in their native lipid environment in the total absence of detergent. Since the initial report of SMA-mediated solubilisation, and the formation of SMA lipid particles (SMALPs), this technique can directly isolate therapeutic targets from biological membranes, including G-protein coupled receptors (GPCRs). SMA now allows biophysical and structural analyses of membrane proteins in solution that was not previously possible. Here, we critically review several existing biophysical techniques compatible with SMALPs, with a focus on hydrodynamic analysis, microcalorimetric analysis and optical spectroscopic techniques.
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24
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Cuthbert J, Wanasinghe SV, Matyjaszewski K, Konkolewicz D. Are RAFT and ATRP Universally Interchangeable Polymerization Methods in Network Formation? Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c01587] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Julia Cuthbert
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Ave., Pittsburgh, Pennsylvania 15213, United States
| | - Shiwanka V. Wanasinghe
- Department of Chemistry and Biochemistry, Miami University, 651 E. High St., Oxford, Ohio 45056, United States
| | - Krzysztof Matyjaszewski
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Ave., Pittsburgh, Pennsylvania 15213, United States
| | - Dominik Konkolewicz
- Department of Chemistry and Biochemistry, Miami University, 651 E. High St., Oxford, Ohio 45056, United States
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25
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Farrelly MD, Martin LL, Thang SH. Polymer Nanodiscs and Their Bioanalytical Potential. Chemistry 2021; 27:12922-12939. [PMID: 34180107 DOI: 10.1002/chem.202101572] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Indexed: 12/21/2022]
Abstract
Membrane proteins (MPs) play a pivotal role in cellular function and are therefore predominant pharmaceutical targets. Although detailed understanding of MP structure and mechanistic activity is invaluable for rational drug design, challenges are associated with the purification and study of MPs. This review delves into the historical developments that became the prelude to currently available membrane mimetic technologies before shining a spotlight on polymer nanodiscs. These are soluble nanosized particles capable of encompassing MPs embedded in a phospholipid ring. The expanding range of reported amphipathic polymer nanodisc materials is presented and discussed in terms of their tolerance to different solution conditions and their nanodisc properties. Finally, the analytical scope of polymer nanodiscs is considered in both the demonstration of basic nanodisc parameters as well as in the elucidation of structures, lipid-protein interactions, and the functional mechanisms of reconstituted membrane proteins. The final emphasis is given to the unique benefits and applications demonstrated for native nanodiscs accessed through a detergent free process.
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Affiliation(s)
| | - Lisandra L Martin
- School of Chemistry, Monash University, Clayton, 3800, Vic, Australia
| | - San H Thang
- School of Chemistry, Monash University, Clayton, 3800, Vic, Australia
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26
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Bjørnestad V, Orwick-Rydmark M, Lund R. Understanding the Structural Pathways for Lipid Nanodisc Formation: How Styrene Maleic Acid Copolymers Induce Membrane Fracture and Disc Formation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:6178-6188. [PMID: 33979520 PMCID: PMC8280715 DOI: 10.1021/acs.langmuir.1c00304] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 04/28/2021] [Indexed: 06/12/2023]
Abstract
Lipid nanodiscs formed by mixtures of styrene maleic acid (SMA) copolymers and lipid membranes are important tools for studying membrane proteins in many biotechnological applications. However, molecular interactions leading up to their formation are not well understood. Here, we elucidate the nanodisc formation pathways for SMA/lipid vesicle mixtures using small-angle X-ray scattering (SAXS) that allows detailed in situ nanostructural information. SMA copolymer that is initially aggregated in solution inserts its styrene units into the lipid bilayer hydrocarbon region, leading to fractures in the membrane. The initial copolymer-lipid interactions observed in the vesicles are also present in the formed discs, with excess copolymer distributed along the normal of the bilayer. The size and SMA distribution in the resulting discs strongly depend on the temperature, lipid/copolymer ratio, and lipid type. We find that the solubilization limit increases for membranes above the melting point, suggesting that defects in gel-like lipid membranes play a significant role in membrane fracturing and nanodisc formation. These findings provide unique insights into the formation of nanodiscs as well as into the microscopic mechanism of solubilization, which plays an important role in many applications and products ranging from household goods to biotechnology and medicine.
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Affiliation(s)
| | | | - Reidar Lund
- Department
of Chemistry, University of Oslo, Sem Sælandsvei 26, 0371 Oslo, Norway
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27
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Probing Structural Dynamics of Membrane Proteins Using Electron Paramagnetic Resonance Spectroscopic Techniques. BIOPHYSICA 2021. [DOI: 10.3390/biophysica1020009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Membrane proteins are essential for the survival of living organisms. They are involved in important biological functions including transportation of ions and molecules across the cell membrane and triggering the signaling pathways. They are targets of more than half of the modern medical drugs. Despite their biological significance, information about the structural dynamics of membrane proteins is lagging when compared to that of globular proteins. The major challenges with these systems are low expression yields and lack of appropriate solubilizing medium required for biophysical techniques. Electron paramagnetic resonance (EPR) spectroscopy coupled with site directed spin labeling (SDSL) is a rapidly growing powerful biophysical technique that can be used to obtain pertinent structural and dynamic information on membrane proteins. In this brief review, we will focus on the overview of the widely used EPR approaches and their emerging applications to answer structural and conformational dynamics related questions on important membrane protein systems.
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28
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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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29
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Lipid Dynamics in Diisobutylene-Maleic Acid (DIBMA) Lipid Particles in Presence of Sensory Rhodopsin II. Int J Mol Sci 2021; 22:ijms22052548. [PMID: 33806280 PMCID: PMC7961963 DOI: 10.3390/ijms22052548] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 02/25/2021] [Accepted: 02/26/2021] [Indexed: 01/01/2023] Open
Abstract
Amphiphilic diisobutylene/maleic acid (DIBMA) copolymers extract lipid-encased membrane proteins from lipid bilayers in a detergent-free manner, yielding nanosized, discoidal DIBMA lipid particles (DIBMALPs). Depending on the DIBMA/lipid ratio, the size of DIBMALPs can be broadly varied which makes them suitable for the incorporation of proteins of different sizes. Here, we examine the influence of the DIBMALP sizes and the presence of protein on the dynamics of encased lipids. As shown by a set of biophysical methods, the stability of DIBMALPs remains unaffected at different DIBMA/lipid ratios. Coarse-grained molecular dynamics simulations confirm the formation of viable DIBMALPs with an overall size of up to 35 nm. Electron paramagnetic resonance spectroscopy of nitroxides located at the 5th, 12th or 16th carbon atom positions in phosphatidylcholine-based spin labels reveals that the dynamics of enclosed lipids are not altered by the DIBMALP size. The presence of the membrane protein sensory rhodopsin II from Natronomonas pharaonis (NpSRII) results in a slight increase in the lipid dynamics compared to empty DIBMALPs. The light-induced photocycle shows full functionality of DIBMALPs-embedded NpSRII and a significant effect of the protein-to-lipid ratio during preparation on the NpSRII dynamics. This study indicates a possible expansion of the applicability of the DIBMALP technology on studies of membrane protein–protein interaction and oligomerization in a constraining environment.
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A Three-Dimensional Model of the Yeast Transmembrane Sensor Wsc1 Obtained by SMA-Based Detergent-Free Purification and Transmission Electron Microscopy. J Fungi (Basel) 2021; 7:jof7020118. [PMID: 33562593 PMCID: PMC7915640 DOI: 10.3390/jof7020118] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 01/29/2021] [Accepted: 02/01/2021] [Indexed: 12/31/2022] Open
Abstract
The cell wall sensor Wsc1 belongs to a small family of transmembrane proteins, which are crucial to sustain cell integrity in yeast and other fungi. Wsc1 acts as a mechanosensor of the cell wall integrity (CWI) signal transduction pathway which responds to external stresses. Here we report on the purification of Wsc1 by its trapping in water-soluble polymer-stabilized lipid nanoparticles, obtained with an amphipathic styrene-maleic acid (SMA) copolymer. The latter was employed to transfer tagged sensors from their native yeast membranes into SMA/lipid particles (SMALPs), which allows their purification in a functional state, i.e., avoiding denaturation. The SMALPs composition was characterized by fluorescence correlation spectroscopy, followed by two-dimensional image acquisition from single particle transmission electron microscopy to build a three-dimensional model of the sensor. The latter confirms that Wsc1 consists of a large extracellular domain connected to a smaller intracellular part by a single transmembrane domain, which is embedded within the hydrophobic moiety of the lipid bilayer. The successful extraction of a sensor from the yeast plasma membrane by a detergent-free procedure into a native-like membrane environment provides new prospects for in vitro structural and functional studies of yeast plasma proteins which are likely to be applicable to other fungi, including plant and human pathogens.
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31
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Sharma P, Plant M, Lam SK, Chen Q. Kinetic analysis of antibody binding to integral membrane proteins stabilized in SMALPs. BBA ADVANCES 2021; 1:100022. [PMID: 37082021 PMCID: PMC10074945 DOI: 10.1016/j.bbadva.2021.100022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The fundamental importance of membrane protein (MP) targets in central biological and cellular events has driven a marked increase in the use of membrane mimetics for exploring these proteins as therapeutic targets. The main challenge associated with biophysical analysis of membrane protein is the need for detergent extraction from the bilayer environment, which in many cases causes the proteins to become insoluble, unstable or display altered structure or activity. Recent technological advances have tried to limit the exposure of purified membrane protein to detergents. One such method involves the amphipathic co-polymer of styrene and maleic acid (SMA), which can release lipids and integral membrane proteins into water soluble native particles (or vesicles) termed SMALPs (Styrene Maleic Acid Lipid Particles). In this study, assay conditions that leverage SMA for membrane protein stabilization were developed to perform kinetic analysis of antibody binding to integral membrane protein and complexes in SMALPs in both purified and complex mixture settings using multiple biosensor platforms. To develop a robust and flexible platform using SMALPs technology, we optimized various SPR assay formats to analyze SMALPs produced with cell membrane pellets as well as whole cell lysates from the cell lines overexpressing membrane protein of interest. Here we emphasize the extraction of model membrane proteins of diverse architecture and function from native environments to encapsulate with SMALPs. Given the importance of selected membrane targets in central biological events and therapeutic relevance, MP-specific or tag-specific antibodies were used as a proof-of-principal to validate the SMALPs platform for ligand binding studies to support drug discovery or tool generation processes. MP-SMALPs that retain specific binding capability in multiple assay formats and biosensors, such as waveguide interferometry and surface plasmon resonance, would be a versatile platform for a wide range of downstream applications.
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Affiliation(s)
- Pooja Sharma
- Discovery Attribute Sciences, Amgen Research, Amgen Inc., Thousand Oaks, CA, 91320
- Corresponding author.
| | - Matthew Plant
- Discovery Attribute Sciences, Amgen Research, Amgen Inc., Cambridge, MA, 02141
| | - Sheung Kwan Lam
- Biologics, Amgen Research, Amgen Inc., South San Francisco, CA 94080
| | - Qing Chen
- Discovery Attribute Sciences, Amgen Research, Amgen Inc., Thousand Oaks, CA, 91320
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32
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Synthesis of novel superdisintegrants for pharmaceutical tableting based on functionalized nanocellulose hydrogels. Int J Biol Macromol 2020; 167:667-675. [PMID: 33249148 DOI: 10.1016/j.ijbiomac.2020.11.173] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 11/16/2020] [Accepted: 11/24/2020] [Indexed: 12/28/2022]
Abstract
Superdisintegrants have an important function in Fast dissolving tablets (FDT). It's believed that an increase in surface to the mass (size reduction) can enhance their performance. Due to the obligation of pharmaceutical excipients being in GRAS (generally recognized as safe) list, we've devoted our research to modify one of the routinely used and important natural polymer, cellulose, as superdisintegrant. Nanocrystalline cellulose (NCC) was extracted from microcrystalline cellulose (MCC) via the sulfuric acid hydrolysis process. NCC derivatives have been synthesized by Itaconic acid/Hydroxyethyl methacrylate (IA/HEMA) via maleic anhydride (MA) to acquire unique swellability properties in to achieve superabsorbent cellulose-based nano hydrogel with the cross-linking system. The disintegration performance of prepared tablets was compared with tablets composed of sodium starch glycolate (SSG) and MCC as positive and negative controls. The results show that the disintegration time of tablets formulated with synthesized modified NCC (m-NCC) decreased dramatically compared to other disintegrants. The dissolution analysis showed suitable condition for complete drug release in a shorter time. The in vitro cytotoxic experiments proved the biocompatibility of newly synthesized superdisintegrant. The dissolution Analysis findings suggest that our developed novel superdisintegrant paves the way for the formulation of fast dissolving tablets containing rapidly acting medicines such as zolpidem.
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33
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de Jonge PA, Smit Sibinga DJC, Boright OA, Costa AR, Nobrega FL, Brouns SJJ, Dutilh BE. Development of Styrene Maleic Acid Lipid Particles as a Tool for Studies of Phage-Host Interactions. J Virol 2020; 94:e01559-20. [PMID: 32938760 PMCID: PMC7654272 DOI: 10.1128/jvi.01559-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 09/08/2020] [Indexed: 01/08/2023] Open
Abstract
The infection of a bacterium by a phage starts with attachment to a receptor molecule on the host cell surface by the phage. Since receptor-phage interactions are crucial to successful infections, they are major determinants of phage host range and, by extension, of the broader effects that phages have on bacterial communities. Many receptor molecules, particularly membrane proteins, are difficult to isolate because their stability is supported by their native membrane environments. Styrene maleic acid lipid particles (SMALPs), a recent advance in membrane protein studies, are the result of membrane solubilizations by styrene maleic acid (SMA) copolymer chains. SMALPs thereby allow for isolation of membrane proteins while maintaining their native environment. Here, we explore SMALPs as a tool to isolate and study phage-receptor interactions. We show that SMALPs produced from taxonomically distant bacterial membranes allow for receptor-specific decrease of viable phage counts of several model phages that span the three largest phage families. After characterizing the effects of incubation time and SMALP concentration on the activity of three distinct phages, we present evidence that the interaction between two model phages and SMALPs is specific to bacterial species and the phage receptor molecule. These interactions additionally lead to DNA ejection by nearly all particles at high phage titers. We conclude that SMALPs are a potentially highly useful tool for phage-host interaction studies.IMPORTANCE Bacteriophages (viruses that infect bacteria or phages) impact every microbial community. All phage infections start with the binding of the viral particle to a specific receptor molecule on the host cell surface. Due to its importance in phage infections, this first step is of interest to many phage-related research and applications. However, many phage receptors are difficult to isolate. Styrene maleic acid lipid particles (SMALPs) are a recently developed approach to isolate membrane proteins in their native environment. In this study, we explore SMALPs as a tool to study phage-receptor interactions. We find that different phage species bind to SMALPs, while maintaining specificity to their receptor. We then characterize the time and concentration dependence of phage-SMALP interactions and furthermore show that they lead to genome ejection by the phage. The results presented here show that SMALPs are a useful tool for future studies of phage-receptor interactions.
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Affiliation(s)
- Patrick A de Jonge
- Theoretical Biology and Bioinformatics, Science4Life, Utrecht University, Utrecht, The Netherlands
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Dieuwke J C Smit Sibinga
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Oliver A Boright
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Ana Rita Costa
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Franklin L Nobrega
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Stan J J Brouns
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Bas E Dutilh
- Theoretical Biology and Bioinformatics, Science4Life, Utrecht University, Utrecht, The Netherlands
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Esmaili M, Brown CJ, Shaykhutdinov R, Acevedo-Morantes C, Wang YL, Wille H, Gandour RD, Turner SR, Overduin M. Homogeneous nanodiscs of native membranes formed by stilbene-maleic-acid copolymers. NANOSCALE 2020; 12:16705-16709. [PMID: 32780785 DOI: 10.1039/d0nr03435e] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Methylstilbene-alt-maleic acid copolymers spontaneously convert biological membranes into bilayer discs with ∼20 nm diameters. This readily functionalizable class of copolymers has the compositional homogeneity, hydrophobicity, dynamics, and charge that may help to achieve optimal structural resolution, membrane dissolution, stability, and broad utility.
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Affiliation(s)
- Mansoore Esmaili
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada.
| | - Chanelle J Brown
- Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA 24061, USA.
| | - Rustem Shaykhutdinov
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada.
| | - Claudia Acevedo-Morantes
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB T6G 2M8, Canada
| | - Yong Liang Wang
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB T6G 2M8, Canada
| | - Holger Wille
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB T6G 2M8, Canada
| | - Richard D Gandour
- Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA 24061, USA.
| | - S Richard Turner
- Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA 24061, USA.
| | - Michael Overduin
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada.
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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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36
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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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Sahu ID, Dixit G, Reynolds WD, Kaplevatsky R, Harding BD, Jaycox CK, McCarrick RM, Lorigan GA. Characterization of the Human KCNQ1 Voltage Sensing Domain (VSD) in Lipodisq Nanoparticles for Electron Paramagnetic Resonance (EPR) Spectroscopic Studies of Membrane Proteins. J Phys Chem B 2020; 124:2331-2342. [PMID: 32130007 DOI: 10.1021/acs.jpcb.9b11506] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Membrane proteins are responsible for conducting essential biological functions that are necessary for the survival of living organisms. In spite of their physiological importance, limited structural information is currently available as a result of challenges in applying biophysical techniques for studying these protein systems. Electron paramagnetic resonance (EPR) spectroscopy is a very powerful technique to study the structural and dynamic properties of membrane proteins. However, the application of EPR spectroscopy to membrane proteins in a native membrane-bound state is extremely challenging due to the complexity observed in inhomogeneity sample preparation and the dynamic motion of the spin label. Detergent micelles are very popular membrane mimetics for membrane proteins due to their smaller size and homogeneity, providing high-resolution structure analysis by solution NMR spectroscopy. However, it is important to test whether the protein structure in a micelle environment is the same as that of its membrane-bound state. Lipodisq nanoparticles or styrene-maleic acid copolymer-lipid nanoparticles (SMALPs) have been introduced as a potentially good membrane-mimetic system for structural studies of membrane proteins. Recently, we reported on the EPR characterization of the KCNE1 membrane protein having a single transmembrane incorporated into lipodisq nanoparticles. In this work, lipodisq nanoparticles were used as a membrane mimic system for probing the structural and dynamic properties of the more complicated membrane protein system human KCNQ1 voltage sensing domain (Q1-VSD) having four transmembrane helices using site-directed spin-labeling EPR spectroscopy. Characterization of spin-labeled Q1-VSD incorporated into lipodisq nanoparticles was carried out using CW-EPR spectral line shape analysis and pulsed EPR double-electron electron resonance (DEER) measurements. The CW-EPR spectra indicate an increase in spectral line broadening with the addition of the styrene-maleic acid (SMA) polymer which approaches close to the rigid limit providing a homogeneous stabilization of the protein-lipid complex. Similarly, EPR DEER measurements indicated a superior quality of distance measurement with an increase in the phase memory time (Tm) values upon incorporation of the sample into lipodisq nanoparticles when compared to proteoliposomes. These results are consistent with the solution NMR structural studies on the Q1-VSD. This study will be beneficial for researchers working on investigating the structural and dynamic properties of more complicated membrane protein systems using lipodisq nanoparticles.
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Affiliation(s)
- Indra D Sahu
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States.,Natural Science Division, Campbellsville University, Campbellsville, Kentucky 42718, United States
| | - Gunjan Dixit
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Warren D Reynolds
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Ryan Kaplevatsky
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Benjamin D Harding
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Colleen K Jaycox
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Robert M McCarrick
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Gary A Lorigan
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
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Burridge KM, Harding BD, Sahu ID, Kearns MM, Stowe RB, Dolan MT, Edelmann RE, Dabney-Smith C, Page RC, Konkolewicz D, Lorigan GA. Simple Derivatization of RAFT-Synthesized Styrene-Maleic Anhydride Copolymers for Lipid Disk Formulations. Biomacromolecules 2020; 21:1274-1284. [PMID: 31961664 DOI: 10.1021/acs.biomac.0c00041] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Styrene-maleic acid copolymers have received significant attention because of their ability to interact with lipid bilayers and form styrene-maleic acid copolymer lipid nanoparticles (SMALPs). However, these SMALPs are limited in their chemical diversity, with only phenyl and carboxylic acid functional groups, resulting in limitations because of sensitivity to low pH and high concentrations of divalent metals. To address this limitation, various nucleophiles were reacted with the anhydride unit of well-defined styrene-maleic anhydride copolymers in order to assess the potential for a new lipid disk nanoparticle-forming species. These styrene-maleic anhydride copolymer derivatives (SMADs) can form styrene-maleic acid derivative lipid nanoparticles (SMADLPs) when they interact with lipid molecules. Polymers were synthesized, purified, characterized by Fourier-transform infrared spectroscopy, gel permeation chromatography, and nuclear magnetic resonance and then used to make disk-like SMADLPs, whose sizes were measured by dynamic light scattering (DLS). The SMADs form lipid nanoparticles, observable by DLS and transmission electron microscopy, and were used to reconstitute a spin-labeled transmembrane protein, KCNE1. The polymer method reported here is facile and scalable and results in functional and robust polymers capable of forming lipid nanodisks that are stable against a wide pH range and 100 mM magnesium.
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Affiliation(s)
- Kevin M Burridge
- Department of Chemistry and Biochemistry, Miami University of Oxford Ohio, Oxford, Ohio 45056, United States
| | - Benjamin D Harding
- Department of Chemistry and Biochemistry, Miami University of Oxford Ohio, Oxford, Ohio 45056, United States
| | - Indra D Sahu
- Department of Chemistry and Biochemistry, Miami University of Oxford Ohio, Oxford, Ohio 45056, United States.,Natural Science Division, Campbellsville University, Campbellsville, KY 42718, United States
| | - Madison M Kearns
- Department of Chemistry and Biochemistry, Miami University of Oxford Ohio, Oxford, Ohio 45056, United States
| | - Rebecca B Stowe
- Department of Chemistry and Biochemistry, Miami University of Oxford Ohio, Oxford, Ohio 45056, United States
| | - Madison T Dolan
- Department of Chemistry and Biochemistry, Miami University of Oxford Ohio, Oxford, Ohio 45056, United States
| | - Richard E Edelmann
- Center for Advanced Microscopy & Imaging, Miami University, Oxford, Ohio 45056, United States
| | - Carole Dabney-Smith
- Department of Chemistry and Biochemistry, Miami University of Oxford Ohio, Oxford, Ohio 45056, United States
| | - Richard C Page
- Department of Chemistry and Biochemistry, Miami University of Oxford Ohio, Oxford, Ohio 45056, United States
| | - Dominik Konkolewicz
- Department of Chemistry and Biochemistry, Miami University of Oxford Ohio, Oxford, Ohio 45056, United States
| | - Gary A Lorigan
- Department of Chemistry and Biochemistry, Miami University of Oxford Ohio, Oxford, Ohio 45056, United States
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39
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Colbasevici A, Voskoboynikova N, Orekhov PS, Bozdaganyan ME, Karlova MG, Sokolova OS, Klare JP, Mulkidjanian AY, Shaitan KV, Steinhoff HJ. Lipid dynamics in nanoparticles formed by maleic acid-containing copolymers: EPR spectroscopy and molecular dynamics simulations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183207. [PMID: 31987867 DOI: 10.1016/j.bbamem.2020.183207] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 01/22/2020] [Accepted: 01/23/2020] [Indexed: 12/11/2022]
Abstract
Amphiphilic maleic acid-containing copolymers account for a recent methodical breakthrough in the study of membrane proteins. Their application enables a detergent-free extraction of membrane proteins from lipid bilayers, yielding stable water-soluble, discoidal lipid bilayer particles with incorporated proteins, which are wrapped with copolymers. Although many studies confirm the potential of this approach for membrane protein research, the interactions between the maleic acid-containing copolymers and extracted lipids, as well as possible effects of the copolymers on lipid-embedded proteins deserve further scrutinization. Here, we combine electron paramagnetic resonance spectroscopy and coarse-grain molecular dynamics simulations to compare the distribution and dynamics of lipids in lipid particles of phospholipid bilayers encased either by an aliphatic diisobutylene/maleic acid copolymer (DIBMALPs) or by an aromatic styrene/maleic acid copolymer (SMALPs). Nitroxides located at the 5th, 12th or 16th carbon atom positions in phosphatidylcholine-based spin labels experience restrictions of their reorientational motion depending on the type of encasing copolymer. The dynamics of the lipids was less constrained in DIBMALPs than in SMALPs with the affinity of spin labeled lipids to the polymeric rim being more pronounced in SMALPs.
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Affiliation(s)
| | | | - Philipp S Orekhov
- Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia; Sechenov University, Moscow 119146, Russia; Department of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Marine E Bozdaganyan
- Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia; Department of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Moscow 119991, Russia
| | - Maria G Karlova
- Department of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Olga S Sokolova
- Department of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Johann P Klare
- Department of Physics, Osnabrueck University, 49069 Osnabrueck, Germany
| | - Armen Y Mulkidjanian
- Department of Physics, Osnabrueck University, 49069 Osnabrueck, Germany; A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia; Department of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Konstantin V Shaitan
- Department of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Moscow 119991, Russia
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40
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Styrene maleic-acid lipid particles (SMALPs) into detergent or amphipols: An exchange protocol for membrane protein characterisation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183192. [PMID: 31945320 PMCID: PMC7086155 DOI: 10.1016/j.bbamem.2020.183192] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 12/06/2019] [Accepted: 01/10/2020] [Indexed: 12/24/2022]
Abstract
Membrane proteins are traditionally extracted and purified in detergent for biochemical and structural characterisation. This process is often costly and laborious, and the stripping away of potentially stabilising lipids from the membrane protein of interest can have detrimental effects on protein integrity. Recently, styrene-maleic acid (SMA) co-polymers have offered a solution to this problem by extracting membrane proteins directly from their native membrane, while retaining their naturally associated lipids in the form of stable SMA lipid particles (SMALPs). However, the inherent nature and heterogeneity of the polymer renders their use challenging for some downstream applications – particularly mass spectrometry (MS). While advances in cryo-electron microscopy (cryo-EM) have enhanced our understanding of membrane protein:lipid interactions in both SMALPs and detergent, the resolution obtained with this technique is often insufficient to accurately identify closely associated lipids within the transmembrane annulus. Native-MS has the power to fill this knowledge gap, but the SMA polymer itself remains largely incompatible with this technique. To increase sample homogeneity and allow characterisation of membrane protein:lipid complexes by native-MS, we have developed a novel SMA-exchange method; whereby the membrane protein of interest is first solubilised and purified in SMA, then transferred into amphipols or detergents. This allows the membrane protein and endogenously associated lipids extracted by SMA co-polymer to be identified and examined by MS, thereby complementing results obtained by cryo-EM and creating a better understanding of how the lipid bilayer directly affects membrane protein structure and function. First reported exchange protocol for transferring membrane proteins solubilised in SMALPs, into detergent or amphipols. Purification of protein:lipid complexes without detergent for mass spectrometry and subsequent lipid identification. Cost effective membrane protein purification requiring only minimal amounts of detergents in the exchange process.
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41
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Hardin NZ, Kocman V, Di Mauro GM, Ravula T, Ramamoorthy A. Metal‐Chelated Polymer Nanodiscs for NMR Studies. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201910118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Nathaniel Z. Hardin
- Biophysics Program and Department of ChemistryUniversity of Michigan Ann Arbor MI 48109-1055 USA
| | - Vojč Kocman
- Biophysics Program and Department of ChemistryUniversity of Michigan Ann Arbor MI 48109-1055 USA
| | - Giacomo M. Di Mauro
- Biophysics Program and Department of ChemistryUniversity of Michigan Ann Arbor MI 48109-1055 USA
| | - Thirupathi Ravula
- Biophysics Program and Department of ChemistryUniversity of Michigan Ann Arbor MI 48109-1055 USA
| | - Ayyalusamy Ramamoorthy
- Biophysics Program and Department of ChemistryUniversity of Michigan Ann Arbor MI 48109-1055 USA
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Hardin NZ, Kocman V, Di Mauro GM, Ravula T, Ramamoorthy A. Metal-Chelated Polymer Nanodiscs for NMR Studies. Angew Chem Int Ed Engl 2019; 58:17246-17250. [PMID: 31529579 PMCID: PMC6861636 DOI: 10.1002/anie.201910118] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 09/11/2019] [Indexed: 01/20/2023]
Abstract
Paramagnetic relaxation enhancement (PRE) is commonly used to speed up spin lattice relaxation time (T1 ) for rapid data acquisition in NMR structural studies. Consequently, there is significant interest in novel paramagnetic labels for enhanced NMR studies on biomolecules. Herein, we report the synthesis and characterization of a modified poly(styrene-co-maleic acid) polymer which forms nanodiscs while showing the ability to chelate metal ions. Cu2+ -chelated nanodiscs are demonstrated to reduce the T1 of protons for both polymer and lipid-nanodisc components. The chelated nanodiscs also decrease the proton T1 values for a water-soluble DNA G-quadruplex. These results suggest that polymer nanodiscs functionalized with paramagnetic tags can be used to speed-up data acquisition from lipid bilayer samples and also to provide structural information from water-soluble biomolecules.
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Affiliation(s)
- Nathaniel Z Hardin
- Biophysics Program and Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109-1055, USA
| | - Vojč Kocman
- Biophysics Program and Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109-1055, USA
| | - Giacomo M Di Mauro
- Biophysics Program and Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109-1055, USA
| | - Thirupathi Ravula
- Biophysics Program and Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109-1055, USA
| | - Ayyalusamy Ramamoorthy
- Biophysics Program and Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109-1055, USA
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43
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Overduin M, Esmaili M. Structures and Interactions of Transmembrane Targets in Native Nanodiscs. SLAS DISCOVERY 2019; 24:943-952. [PMID: 31242812 DOI: 10.1177/2472555219857691] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Transmembrane proteins function within a continuous layer of biologically relevant lipid molecules that stabilizes their structures and modulates their activities. Structures and interactions of biological membrane-protein complexes or "memteins" can now be elucidated using native nanodiscs made by poly(styrene co-maleic anhydride) derivatives. These linear polymers contain a series of hydrophobic and polar subunits that gently fragment membranes into water-soluble discs with diameters of 5-50 nm known as styrene maleic acid lipid particles (SMALPs). High-resolution structures of memteins that include endogenous lipid ligands and posttranslational modifications can be resolved without resorting to synthetic detergents or artificial lipids. The resulting ex situ structures better recapitulate the in vivo situation and can be visualized by methods including cryo-electron microscopy (cryoEM), electron paramagnetic resonance (EPR), mass spectrometry (MS), nuclear magnetic resonance (NMR) spectroscopy, small angle x-ray scattering (SAXS), and x-ray diffraction (XRD). Recent progress including 3D structures of biological bilayers illustrates how polymers and native nanodiscs expose previously inaccessible membrane assemblies at atomic resolution and suggest ways in which the SMALP system could be exploited for drug discovery.
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Affiliation(s)
- Michael Overduin
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
| | - Mansoore Esmaili
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
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44
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Single-particle cryo-EM studies of transmembrane proteins in SMA copolymer nanodiscs. Chem Phys Lipids 2019; 221:114-119. [PMID: 30940443 DOI: 10.1016/j.chemphyslip.2019.03.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 03/14/2019] [Accepted: 03/14/2019] [Indexed: 11/21/2022]
Abstract
Styrene-maleic acid (SMA) copolymers can extract membrane proteins from native membranes along with lipids as nanodiscs. Preparation with SMA is fast, cost-effective, and captures the native protein-lipid interactions. On the other hand, cryo-EM has become increasingly successful and efficient for structural determinations of membrane proteins, with biochemical sample preparation often the bottleneck. Three recent cryo-EM studies on the efflux transporter AcrB and the alternative complex III: cyt c oxidase supercomplex have demonstrated the potential of SMA nanodisc samples to yield high-resolution structure information of membrane proteins.
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45
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Ravula T, Hardin NZ, Ramamoorthy A. Polymer nanodiscs: Advantages and limitations. Chem Phys Lipids 2019; 219:45-49. [PMID: 30707909 PMCID: PMC6497063 DOI: 10.1016/j.chemphyslip.2019.01.010] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 01/25/2019] [Accepted: 01/28/2019] [Indexed: 11/29/2022]
Abstract
There is considerable interest in the development of membrane mimetics to study the structure, dynamics and function of membrane proteins. Polymer nanodiscs have been useful as a membrane mimetic by not only providing a native-like membrane environment, but also have the ability to extract the desired membrane protein directly from the cell membrane. In spite of such great potential, polymer nanodiscs have their disadvantages including lack of size control and instability at low pH and with divalent metals. In this review, we discuss how these limitations have been overcome by simple modifications of synthetic polymers commonly used to form nanodiscs. Recently, size control has been achieved using an ethanolamine functionalization of a low molecular weight polymer. This size control enabled the use of polymer-based lipid-nanodiscs in solution NMR and macro-nanodiscs in solid-state NMR applications. The introduction of quaternary ammonium functional groups has been shown to improve the stability in the presence of low pH and divalent metal ions, forming highly monodispersed nanodiscs. The polymer charge has been shown to play a significant role on the reconstitution of membrane proteins due to the high charge density on the nanodisc's belt. These recent developments have expanded the applications of polymer nanodiscs to study the membrane proteins using wide variety of techniques including NMR, Cryo-EM and other biophysical techniques.
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Affiliation(s)
- Thirupathi Ravula
- Biophysics Program, The University of Michigan, Ann Arbor, MI 48109-1055, USA; Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Nathaniel Z Hardin
- Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Ayyalusamy Ramamoorthy
- Biophysics Program, The University of Michigan, Ann Arbor, MI 48109-1055, USA; Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109-1055, USA; Biomedical Engineering, The University of Michigan, Ann Arbor, MI 48109-1055, USA; Macromolecular Science and Engineering, The University of Michigan, Ann Arbor, MI 48109-1055, USA.
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46
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Bali AP, Sahu ID, Craig AF, Clark EE, Burridge KM, Dolan MT, Dabney-Smith C, Konkolewicz D, Lorigan GA. Structural characterization of styrene-maleic acid copolymer-lipid nanoparticles (SMALPs) using EPR spectroscopy. Chem Phys Lipids 2019; 220:6-13. [PMID: 30796886 DOI: 10.1016/j.chemphyslip.2019.02.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 01/29/2019] [Accepted: 02/18/2019] [Indexed: 12/31/2022]
Abstract
Spectroscopic studies of membrane proteins (MPs) are challenging due to difficulties in preparing homogenous and functional lipid membrane mimetic systems into which membrane proteins can properly fold and function. It has recently been shown that styrene-maleic acid (SMA) copolymers act as a macromolecular surfactant and therefore facilitate the formation of disk-shaped lipid bilayer nanoparticles (styrene-maleic acid copolymer-lipid nanoparticles (SMALPs)) that retain structural characteristics of native lipid membranes. We have previously reported controlled synthesis of SMA block copolymers using reversible addition-fragmentation chain transfer (RAFT) polymerization, and that alteration of the weight ratio of styrene to maleic acid affects nanoparticle size. RAFT-synthesis offers superior control over SMA polymer architecture compared to conventional radical polymerization techniques used for commercially available SMA. However, the interactions between the lipid bilayer and the solubilized RAFT-synthesized SMA polymer are currently not fully understood. In this study, EPR spectroscopy was used to detect the perturbation on the acyl chain upon introduction of the RAFT-synthesized SMA polymer by attaching PC-based nitroxide spin labels to the 5th, 12th, and 16th positions along the acyl chain of the lipid bilayer. EPR spectra showed high rigidity at the 12th position compared to the other two regions, displaying similar qualities to commercially available polymers synthesized via conventional methods. In addition, central EPR linewidths and correlation time data were obtained that are consistent with previous findings.
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Affiliation(s)
- Avnika P Bali
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH, 45056, USA
| | - Indra D Sahu
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH, 45056, USA
| | - Andrew F Craig
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH, 45056, USA
| | - Emily E Clark
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH, 45056, USA
| | - Kevin M Burridge
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH, 45056, USA
| | - Madison T Dolan
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH, 45056, USA
| | - Carole Dabney-Smith
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH, 45056, USA
| | - Dominik Konkolewicz
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH, 45056, USA.
| | - Gary A Lorigan
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH, 45056, USA.
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48
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Zhang B, Ke J, Vakil JR, Cummings SC, Digby ZA, Sparks JL, Ye Z, Zanjani MB, Konkolewicz D. Dual-dynamic interpenetrated networks tuned through macromolecular architecture. Polym Chem 2019. [DOI: 10.1039/c9py01387c] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Controlled polymerization is used to make well defined polymers that are assembled into dynamic interpenetrated network materials. Self-healing, toughness and stress relaxation are imparted into the material through the dynamic linkages.
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Affiliation(s)
- Borui Zhang
- Department of Chemistry and Biochemistry
- Miami University
- Oxford
- USA
| | - Jun Ke
- Department of Chemistry and Biochemistry
- Miami University
- Oxford
- USA
| | - Jafer R. Vakil
- Department of Chemistry and Biochemistry
- Miami University
- Oxford
- USA
| | - Sean C. Cummings
- Department of Chemistry and Biochemistry
- Miami University
- Oxford
- USA
| | - Zachary A. Digby
- Department of Chemistry and Biochemistry
- Miami University
- Oxford
- USA
| | - Jessica L. Sparks
- Department of Chemical
- Paper and Biomedical Engineering
- Miami University
- Oxford
- USA
| | - Zhijiang Ye
- Department of Mechanical and Manufacturing Engineering
- Miami University
- Oxford
- USA
| | - Mehdi B. Zanjani
- Department of Mechanical and Manufacturing Engineering
- Miami University
- Oxford
- USA
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49
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Overduin M, Esmaili M. Memtein: The fundamental unit of membrane-protein structure and function. Chem Phys Lipids 2019; 218:73-84. [DOI: 10.1016/j.chemphyslip.2018.11.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Revised: 11/24/2018] [Accepted: 11/28/2018] [Indexed: 12/14/2022]
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50
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Systematic Characterization of DMPC/DHPC Self-Assemblies and Their Phase Behaviors in Aqueous Solution. COLLOIDS AND INTERFACES 2018. [DOI: 10.3390/colloids2040073] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Self-assemblies composed of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) form several kinds of structures, such as vesicle, micelle, and bicelle. Their morphological properties have been studied widely, but their interfacial membrane properties have not been adequately investigated. Herein, we report a systematic characterization of DMPC/DHPC assemblies at 20 °C. To investigate the phase behavior, optical density OD500, size (by dynamic light scattering), membrane fluidity 1/PDPH (using 1,6-diphenyl-1,3,5-hexatriene), and membrane polarity GP340 (using 6-dodecanoyl-N,N-dimethyl-2-naphthylamine) were measured as a function of molar ratio of DHPC (XDHPC). Based on structural properties (OD500 and size), large and small assemblies were categorized into Region (i) (XDHPC < 0.4) and Region (ii) (XDHPC ≥ 0.4), respectively. The DMPC/DHPC assemblies with 0.33 ≤ XDHPC ≤ 0.67 (Region (ii-1)) showed gel-phase-like interfacial membrane properties, whereas DHPC-rich assemblies (XDHPC ≥ 0.77) showed disordered membrane properties (Region (ii-2)). Considering the structural and interfacial membrane properties, the DMPC/DHPC assemblies in Regions (i), (ii-1), and (ii-2) can be determined to be vesicle, bicelle, and micelle, respectively.
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