1
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Ayub H, Murray RJ, Kuyler GC, Napier-Khwaja F, Gunner J, Dafforn TR, Klumperman B, Poyner DR, Wheatley M. GPCRs in the round: SMA-like copolymers and SMALPs as a platform for investigating GPCRs. Arch Biochem Biophys 2024; 754:109946. [PMID: 38395122 DOI: 10.1016/j.abb.2024.109946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 01/21/2024] [Accepted: 02/20/2024] [Indexed: 02/25/2024]
Abstract
G-protein-coupled receptors (GPCRs) are the largest family of membrane proteins, regulate a plethora of physiological responses and are the therapeutic target for 30-40% of clinically-prescribed drugs. They are integral membrane proteins deeply embedded in the plasma membrane where they activate intracellular signalling via coupling to G-proteins and β-arrestin. GPCRs are in intimate association with the bilayer lipids and that lipid environment regulates the signalling functions of GPCRs. This complex lipid 'landscape' is both heterogeneous and dynamic. GPCR function is modulated by bulk membrane properties including membrane fluidity, microdomains, curvature, thickness and asymmetry but GPCRs are also regulated by specific lipid:GPCR binding, including cholesterol and anionic lipids. Understanding the molecular mechanisms whereby GPCR signalling is regulated by lipids is a very active area of research currently. A major advance in membrane protein research in recent years was the application of poly(styrene-co-maleic acid) (SMA) copolymers. These spontaneously generate SMA lipid particles (SMALPs) encapsulating membrane protein in a nano-scale disc of cell membrane, thereby removing the historical need for detergent and preserving lipid:GPCR interaction. The focus of this review is how GPCR-SMALPs are increasing our understanding of GPCR structure and function at the molecular level. Furthermore, an increasing number of 'second generation' SMA-like copolymers have been reported recently. These are reviewed from the context of increasing our understanding of GPCR molecular mechanisms. Moreover, their potential as a novel platform for downstream biophysical and structural analyses is assessed and looking ahead, the translational application of SMA-like copolymers to GPCR drug discovery programmes in the future is considered.
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Affiliation(s)
- Hoor Ayub
- Centre for Health and Life Sciences, Coventry University, Coventry, CV1 2DS, UK.
| | - Rebecca J Murray
- Centre for Health and Life Sciences, Coventry University, Coventry, CV1 2DS, UK; Department of Chemistry and Polymer Sciences, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Gestél C Kuyler
- Centre for Health and Life Sciences, Coventry University, Coventry, CV1 2DS, UK; Department of Chemistry and Polymer Sciences, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | | | - Joseph Gunner
- School of Life and Health Sciences, Aston University, Birmingham, B4 7ET, UK
| | - Tim R Dafforn
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Bert Klumperman
- Department of Chemistry and Polymer Sciences, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - David R Poyner
- School of Life and Health Sciences, Aston University, Birmingham, B4 7ET, UK
| | - Mark Wheatley
- Centre for Health and Life Sciences, Coventry University, Coventry, CV1 2DS, UK; Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
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2
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Jiang Y, Li Y, Fu X, Wu Y, Wang R, Zhao M, Mao C, Shi S. Interplay between G protein-coupled receptors and nanotechnology. Acta Biomater 2023; 169:1-18. [PMID: 37517621 DOI: 10.1016/j.actbio.2023.07.049] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 06/15/2023] [Accepted: 07/25/2023] [Indexed: 08/01/2023]
Abstract
G protein-coupled receptors (GPCRs), as the largest family of membrane receptors, actively modulate plasma membrane and endosomal signalling. Importantly, GPCRs are naturally nanosized, and spontaneously formed nanoaggregates of GPCRs (natural nano-GPCRs) may enhance GPCR-related signalling and functions. Although GPCRs are the molecular targets of the majority of marketed drugs, the poor pharmacokinetics and physicochemical properties of GPCR ligands greatly limit their clinical applicability. Nanotechnology, as versatile techniques, can encapsulate GPCR ligands to assemble synthetic nano-GPCRs to overcome their obstacles, robustly elevating drug efficacy and safety. Moreover, endosomal delivery of GPCR ligands by nanoparticles can precisely initiate sustained endosomal signal transduction, while nanotechnology has been widely utilized for isolation, diagnosis, and detection of GPCRs. In turn, due to overexpression of GPCRs on the surface of various types of cells, GPCR ligands can endow nanoparticles with active targeting capacity for specific cells via ligand-receptor binding and mediate receptor-dependent endocytosis of nanoparticles. This significantly enhances the potency of nanoparticle delivery systems. Therefore, emerging evidence has revealed the interplay between GPCRs and nanoparticles, although investigations into their relationship have been inadequate. This review aims to summarize the interaction between GPCRs and nanotechnology for understanding their mutual influences and utilizing their interplay for biomedical applications. It will provide a fundamental platform for developing powerful and safe GPCR-targeted drugs and nanoparticle systems. STATEMENT OF SIGNIFICANCE: GPCRs as molecular targets for the majority of marketed drugs are naturally nanosized, and even spontaneously form nano aggregations (nano-GPCRs). Nanotechnology has also been applied to construct synthetic nano-GPCRs or detect GPCRs, while endosomal delivery of GPCR ligands by nanoparticles can magnify endosomal signalling. Meanwhile, molecular engineering of nanoparticles with GPCRs or their ligands can modulate membrane binding and endocytosis, powerfully improving the efficacy of nanoparticle system. However, there are rare summaries on the interaction between GPCRs and nanoparticles. This review will not only provide a versatile platform for utilizing nanoparticles to modulate or detect GPCRs, but also facilitate better understanding of the designated value of GPCRs for molecular engineering of biomaterials with GPCRs in therapeutical application.
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Affiliation(s)
- Yuhong Jiang
- Sichuan Engineering Research Center for Biomimetic Synthesis of Natural Drugs, School of Life Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China.
| | - Yuke Li
- State Key Laboratory of Southwestern Chinese Medicine Resources, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Xiujuan Fu
- Sichuan Engineering Research Center for Biomimetic Synthesis of Natural Drugs, School of Life Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China
| | - Yue Wu
- Sichuan Engineering Research Center for Biomimetic Synthesis of Natural Drugs, School of Life Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China
| | - Rujing Wang
- State Key Laboratory of Southwestern Chinese Medicine Resources, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Mengnan Zhao
- State Key Laboratory of Southwestern Chinese Medicine Resources, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Canquan Mao
- Sichuan Engineering Research Center for Biomimetic Synthesis of Natural Drugs, School of Life Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China
| | - Sanjun Shi
- State Key Laboratory of Southwestern Chinese Medicine Resources, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China.
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3
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Farrelly MD, Zhai J, Tiong AYJ, van 't Hag L, Yu HH, Li J, Martin LL, Thang SH. Membrane interaction and selectivity of novel alternating cationic lipid-nanodisc assembling polymers. Biomater Sci 2023; 11:5955-5969. [PMID: 37477383 DOI: 10.1039/d3bm00477e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/22/2023]
Abstract
Synthetic polymer nanodiscs are self-assembled structures formed from amphipathic copolymers encapsulating membrane proteins and surrounding phospholipids into water soluble discs. These nanostructures have served as an analytical tool for the detergent free solubilisation and structural study of membrane proteins (MPs) in their native lipid environment. We established the polymer-lipid nanodisc forming ability of a novel class of amphipathic copolymer comprised of an alternating sequence of N-alkyl functionalised maleimide (AlkylM) of systematically varied hydrocarbon chain length, and cationic N-methyl-4-vinyl pyridinium iodide (MVP). Using a combination of physicochemical techniques, the solubilisation efficiency, size, structure and shape of DMPC lipid containing poly(MVP-co-AlkylM) nanodiscs were determined. Lipid solubilisation increased with AlkylM hydrocarbon chain length from methyl (MM), ethyl (EtM), n-propyl (PM), iso-butyl (IBM) through to n-butyl (BM) maleimide bearing polymers. More hydrophobic derivatives formed smaller sized nanodiscs and lipid ordering within poly(MVP-co-AlkylM) nanodiscs was affected by nanodisc size. In dye-release assays, shorter N-alkyl substituted polymers, particularly poly(MVP-co-EtM), exhibited low activities against eukaryotic mimetic POPC membrane and increased their liposome disruption as POPC : POPG membrane mixtures increased in their anionic POPG component, resembling the charge profile of bacterial membranes. These trends in membrane selectivity were transferred towards native cell systems in which gram-positive Staphylococcus aureus and gram-negative Acenobacter baumannii bacterial strains were relatively susceptible to disruption by hydrophobic n-butyl- and n-propyl-poly(MVP-co-AlkylM) derivatives compared to human red blood cells (HRBCs), with a more pronounced selectivity resulting from poly(MVP-co-PM). Such selective membrane interaction by less hydrophobic polymers provides a framework for polymer design towards applications including selective membrane component solubilisation, biosensing and antimicrobial development.
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Affiliation(s)
| | - Jiali Zhai
- School of Science, STEM College, RMIT University Melbourne, VIC 3000, Australia
| | - Alice Y J Tiong
- Department of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Leonie van 't Hag
- Department of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Heidi H Yu
- Infection Program and Department of Microbiology, Biomedicine Discovery Institute, Monash University Clayton, VIC 3800, Australia
| | - Jian Li
- Infection Program and Department of Microbiology, Biomedicine Discovery Institute, Monash University Clayton, VIC 3800, Australia
| | - Lisandra L Martin
- School of Chemistry, Monash University Clayton, VIC 3800, Australia.
| | - San H Thang
- School of Chemistry, Monash University Clayton, VIC 3800, Australia.
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4
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Pettersen JM, Yang Y, Robinson AS. Advances in nanodisc platforms for membrane protein purification. Trends Biotechnol 2023; 41:1041-1054. [PMID: 36935323 DOI: 10.1016/j.tibtech.2023.02.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/07/2023] [Accepted: 02/20/2023] [Indexed: 03/19/2023]
Abstract
Membrane scaffold protein nanodiscs (MSPNDs) are an invaluable tool for improving purified membrane protein (MP) stability and activity compared to traditional micellar methods, thus enabling an increase in high-resolution MP structures, particularly in concert with cryogenic electron microscopy (cryo-EM) approaches. In this review we highlight recent advances and breakthroughs in MSPND methodology and applications. We also introduce and discuss saposin-lipoprotein nanoparticles (salipros) and copolymer nanodiscs which have recently emerged as authentic MSPND alternatives. We compare the advantages and disadvantages of MSPNDs, salipros, and copolymer nanodisc technologies to highlight potential opportunities for using each platform for MP purification and characterization.
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Affiliation(s)
- John M Pettersen
- Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Yaxin Yang
- Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Anne S Robinson
- Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA.
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5
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Sawczyc H, Heit S, Watts A. A comparative characterisation of commercially available lipid-polymer nanoparticles formed from model membranes. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2023; 52:39-51. [PMID: 36786921 PMCID: PMC10039845 DOI: 10.1007/s00249-023-01632-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 01/30/2023] [Accepted: 02/01/2023] [Indexed: 02/15/2023]
Abstract
From the discovery of the first membrane-interacting polymer, styrene maleic-acid (SMA), there has been a rapid development of membrane solubilising polymers. These new polymers can solubilise membranes under a wide range of conditions and produce varied sizes of nanoparticles, yet there has been a lack of broad comparison between the common polymer types and solubilising conditions. Here, we present a comparative study on the three most common commercial polymers: SMA 3:1, SMA 2:1, and DIBMA. Additionally, this work presents, for the first time, a comparative characterisation of polymethacrylate copolymer (PMA). Absorbance and dynamic light scattering measurements were used to evaluate solubilisation across key buffer conditions in a simple, adaptable assay format that looked at pH, salinity, and divalent cation concentration. Lipid-polymer nanoparticles formed from SMA variants were found to be the most susceptible to buffer effects, with nanoparticles from either zwitterionic DMPC or POPC:POPG (3:1) bilayers only forming in low to moderate salinity (< 600 mM NaCl) and above pH 6. DIBMA-lipid nanoparticles could be formed above a pH of 5 and were stable in up to 4 M NaCl. Similarly, PMA-lipid nanoparticles were stable in all NaCl concentrations tested (up to 4 M) and a broad pH range (3-10). However, for both DIBMA and PMA nanoparticles there is a severe penalty observed for bilayer solubilisation in non-optimal conditions or when using a charged membrane. Additionally, lipid fluidity of the DMPC-polymer nanoparticles was analysed through cw-EPR, showing no cooperative gel-fluid transition as would be expected for native-like lipid membranes.
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Affiliation(s)
- Henry Sawczyc
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
| | - Sabine Heit
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Anthony Watts
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
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6
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Piper SJ, Johnson RM, Wootten D, Sexton PM. Membranes under the Magnetic Lens: A Dive into the Diverse World of Membrane Protein Structures Using Cryo-EM. Chem Rev 2022; 122:13989-14017. [PMID: 35849490 PMCID: PMC9480104 DOI: 10.1021/acs.chemrev.1c00837] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Indexed: 11/29/2022]
Abstract
Membrane proteins are highly diverse in both structure and function and can, therefore, present different challenges for structure determination. They are biologically important for cells and organisms as gatekeepers for information and molecule transfer across membranes, but each class of membrane proteins can present unique obstacles to structure determination. Historically, many membrane protein structures have been investigated using highly engineered constructs or using larger fusion proteins to improve solubility and/or increase particle size. Other strategies included the deconstruction of the full-length protein to target smaller soluble domains. These manipulations were often required for crystal formation to support X-ray crystallography or to circumvent lower resolution due to high noise and dynamic motions of protein subdomains. However, recent revolutions in membrane protein biochemistry and cryo-electron microscopy now provide an opportunity to solve high resolution structures of both large, >1 megadalton (MDa), and small, <100 kDa (kDa), drug targets in near-native conditions, routinely reaching resolutions around or below 3 Å. This review provides insights into how the recent advances in membrane biology and biochemistry, as well as technical advances in cryo-electron microscopy, help us to solve structures of a large variety of membrane protein groups, from small receptors to large transporters and more complex machineries.
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Affiliation(s)
- Sarah J. Piper
- Drug
Discovery Biology theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
- ARC
Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute
of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Rachel M. Johnson
- Drug
Discovery Biology theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
- ARC
Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute
of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Denise Wootten
- Drug
Discovery Biology theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
- ARC
Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute
of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Patrick M. Sexton
- Drug
Discovery Biology theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
- ARC
Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute
of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
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7
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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: 17] [Impact Index Per Article: 8.5] [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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8
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The function of BK channels extracted and purified within SMALPs. Biochem J 2022; 479:1609-1619. [PMID: 35851603 PMCID: PMC9444072 DOI: 10.1042/bcj20210628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 06/27/2022] [Accepted: 07/19/2022] [Indexed: 11/17/2022]
Abstract
Human BK channels are large voltage and Ca2+-activated K+ channels, involved in several important functions within the body. The core channel is a tetramer of α subunits, and its function is modulated by the presence of β and γ accessory subunits. BK channels composed of α subunits, as well as BK channels composed of α and β1 subunits, were successfully solubilised from HEK cells with styrene maleic acid (SMA) polymer and purified by nickel affinity chromatography. Native SMA–PAGE analysis of the purified proteins showed the α subunits were extracted as a tetramer. In the presence of β1 subunits, they were co-extracted with the α subunits as a heteromeric complex. Purified SMA lipid particles (SMALPs) containing BK channel could be inserted into planar lipid bilayers (PLB) and single channel currents recorded, showing a high conductance (≈260 pS), as expected. The open probability was increased in the presence of co-purified β1 subunits. However, voltage-dependent gating of the channel was restricted. In conclusion, we have demonstrated that SMA can be used to effectively extract and purify large, complex, human ion channels, from low expressing sources. That these large channels can be incorporated into PLB from SMALPs and display voltage-dependent channel activity. However, the SMA appears to reduce the voltage dependent gating of the channels.
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9
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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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10
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An original approach to measure ligand/receptor binding affinity in non-purified samples. Sci Rep 2022; 12:5400. [PMID: 35354858 PMCID: PMC8967833 DOI: 10.1038/s41598-022-09217-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 03/10/2022] [Indexed: 11/30/2022] Open
Abstract
Several biochemical and biophysical methods are available to determine ligand binding affinities between a biological target and its ligands, most of which require purification, labelling or surface immobilisation. These measurements, however, remain challenging in regards to membrane proteins, as purification processes require their extraction from their native lipid environment, which may in turn impact receptor conformation and functionality. In this study, we have developed a novel experimental procedure using microscale thermophoresis (MST) directly from cell membrane fragments, to determine different ligand binding affinities to a membrane protein, the dopamine D2 receptor (D2R). In order to achieve this, two main challenges had to be overcome: determining the concentration of dopamine D2R in the crude sample; finding ways to minimize or account for non-specific binding of the ligand to cell fragments. Using MST, we were able to determine the D2R concentration in cell membrane fragments to approximately 36.8 ± 2.6 pmol/mg. Next, the doses-responses curves allowed for the determination of KD, to approximately 5.3 ± 1.7 nM, which is very close to the reported value. Important details of the experimental procedure have been detailed in this paper to allow the application of this novel method to various membrane proteins.
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11
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Morrison KA, Wood L, Edler KJ, Doutch J, Price GJ, Koumanov F, Whitley P. Membrane extraction with styrene-maleic acid copolymer results in insulin receptor autophosphorylation in the absence of ligand. Sci Rep 2022; 12:3532. [PMID: 35241773 PMCID: PMC8894449 DOI: 10.1038/s41598-022-07606-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 02/21/2022] [Indexed: 11/09/2022] Open
Abstract
Extraction of integral membrane proteins with poly(styrene-co-maleic acid) provides a promising alternative to detergent extraction. A major advantage of extraction using copolymers rather than detergent is the retention of the lipid bilayer around the proteins. Here we report the first functional investigation of the mammalian insulin receptor which was extracted from cell membranes using poly(styrene-co-maleic acid). We found that the copolymer efficiently extracted the insulin receptor from 3T3L1 fibroblast membranes. Surprisingly, activation of the insulin receptor and proximal downstream signalling was detected upon copolymer extraction even in the absence of insulin stimulation. Insulin receptor and IRS1 phosphorylations were above levels measured in the control extracts made with detergents. However, more distal signalling events in the insulin signalling cascade, such as the phosphorylation of Akt were not observed. Following copolymer extraction, in vitro addition of insulin had no further effect on insulin receptor or IRS1 phosphorylation. Therefore, under our experimental conditions, the insulin receptor is not functionally responsive to insulin. This study is the first to investigate receptor tyrosine kinases extracted from mammalian cells using a styrene-maleic acid copolymer and highlights the importance of thorough functional characterisation when using this method of protein extraction.
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Affiliation(s)
- Kerrie A Morrison
- Department of Biology and Biochemistry, University of Bath, Bath, UK.,Department of Chemistry, University of Bath, Bath, UK.,Centre for Sustainable Circular Technologies, University of Bath, Bath, UK
| | - Laura Wood
- Department of Biology and Biochemistry, University of Bath, Bath, UK.,Department for Health, Centre for Nutrition, Exercise and Metabolism, University of Bath, Bath, UK
| | - Karen J Edler
- Department of Chemistry, University of Bath, Bath, UK
| | - James Doutch
- ISIS Pulsed Neutron and Muon Source, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, OX11 0QX, UK
| | - Gareth J Price
- Department of Chemistry, University of Bath, Bath, UK.,Department of Chemistry, Khalifa University, Abu Dhabi, UAE
| | - Francoise Koumanov
- Department for Health, Centre for Nutrition, Exercise and Metabolism, University of Bath, Bath, UK.
| | - Paul Whitley
- Department of Biology and Biochemistry, University of Bath, Bath, UK.
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12
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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 (BASEL, SWITZERLAND) 2022; 12:361. [PMID: 35159706 PMCID: PMC8838559 DOI: 10.3390/nano12030361] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [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
| | - 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.)
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13
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Broadbent L, Depping P, Lodé A, Vaitsopoulou A, Hardy D, Ayub H, Mitchell-White J, Kerr ID, Goddard AD, Bill RM, Rothnie AJ. Detergent-Free Membrane Protein Purification Using SMA Polymer. Methods Mol Biol 2022; 2507:389-404. [PMID: 35773594 DOI: 10.1007/978-1-0716-2368-8_21] [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] [Indexed: 06/15/2023]
Abstract
One of the big challenges for the study of structure and function of membrane proteins is the need to extract them from the membrane. Traditionally this was achieved using detergents which disrupt the membrane and form a micelle around the protein, but this can cause issues with protein function and/or stability. In 2009 an alternative approach was reported, using styrene maleic acid (SMA) copolymer to extract small discs of lipid bilayer encapsulated by the polymer and termed SMALPs (SMA lipid particles). Since then this approach has been shown to work for a range of different proteins from many different expression systems. It allows the extraction and purification of a target protein while maintaining a lipid bilayer environment. Recently this has led to several new high-resolution structures and novel insights to function. As with any method there are some limitations and issues to be aware of. Here we describe a standard protocol for preparation of the polymer and its use for membrane protein purification, and also include details of typical challenges that may be encountered and possible ways to address those.
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Affiliation(s)
- Luke Broadbent
- College of Health & Life Sciences, Aston University, Birmingham, UK
| | - Peer Depping
- College of Health & Life Sciences, Aston University, Birmingham, UK
| | - Alexis Lodé
- College of Health & Life Sciences, Aston University, Birmingham, UK
| | | | - David Hardy
- College of Health & Life Sciences, Aston University, Birmingham, UK
- School of Biosciences, University of Birmingham, Birmingham, UK
| | - Hoor Ayub
- College of Health & Life Sciences, Aston University, Birmingham, UK
- Faculty of Health & Life Sciences, Coventry University, Coventry, UK
| | - James Mitchell-White
- School of Life Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, UK
| | - Ian D Kerr
- School of Life Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, UK
| | - Alan D Goddard
- College of Health & Life Sciences, Aston University, Birmingham, UK
| | - Roslyn M Bill
- College of Health & Life Sciences, Aston University, Birmingham, UK
| | - Alice J Rothnie
- College of Health & Life Sciences, Aston University, Birmingham, UK.
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14
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Harwood CR, Sykes DA, Hoare BL, Heydenreich FM, Uddin R, Poyner DR, Briddon SJ, Veprintsev DB. Functional solubilization of the β 2-adrenoceptor using diisobutylene maleic acid. iScience 2021; 24:103362. [PMID: 34825145 PMCID: PMC8605084 DOI: 10.1016/j.isci.2021.103362] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 07/16/2021] [Accepted: 10/25/2021] [Indexed: 12/16/2022] Open
Abstract
The β2-adrenoceptor (β2AR) is a well-established target in asthma and a prototypical G protein-coupled receptor for biophysical studies. Solubilization of membrane proteins has classically involved the use of detergents. However, the detergent environment differs from the native membrane environment and often destabilizes membrane proteins. Use of amphiphilic copolymers is a promising strategy to solubilize membrane proteins within their native lipid environment in the complete absence of detergents. Here we show the isolation of the β2AR in the polymer diisobutylene maleic acid (DIBMA). We demonstrate that β2AR remains functional in the DIBMA lipid particle and shows improved thermal stability compared with the n-dodecyl-β-D-maltopyranoside detergent-solubilized β2AR. This unique method of extracting β2AR offers significant advantages over previous methods routinely employed such as the introduction of thermostabilizing mutations and the use of detergents, particularly for functional biophysical studies.
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Affiliation(s)
- Clare R Harwood
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands NG7 2UH, UK.,Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK
| | - David A Sykes
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands NG7 2UH, UK.,Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK
| | - Bradley L Hoare
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands NG7 2UH, UK.,Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK
| | - Franziska M Heydenreich
- Laboratory of Biomolecular Research, Paul Scherrer Institute, PSI, 5232 Villigen, Switzerland.,Department of Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - Romez Uddin
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands NG7 2UH, UK.,School of Life and Health Sciences, Aston University, Birmingham B47ET, UK
| | - David R Poyner
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands NG7 2UH, UK.,School of Life and Health Sciences, Aston University, Birmingham B47ET, UK
| | - Stephen J Briddon
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands NG7 2UH, UK.,Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK
| | - D B Veprintsev
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands NG7 2UH, UK.,Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK
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15
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Hou Y, Lu J, Wei D, Lv Y, He H, Wang C, He L. Establishment of substance P modified affinity chromatography for specific detection and enrichment of Mas-related G protein-coupled receptor X2. J Chromatogr A 2021; 1659:462633. [PMID: 34710807 DOI: 10.1016/j.chroma.2021.462633] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 10/14/2021] [Accepted: 10/16/2021] [Indexed: 01/02/2023]
Abstract
Mas-related G protein-coupled receptor X2 (MrgX2) has been identified to be critical in drug-induced pseudo-allergic reactions and allergic diseases. Herein, an affinity high-performance liquid chromatography was established for the specific detection and enrichment of MrgX2. Substance P was used as an affinity ligand and immobilized on a glutaraldehyde-modified amino silica gel. The successful grafting of substance P was characterized by infrared spectroscopy, elemental analysis, X-ray photoelectron spectroscopy, thermogravimetric analysis, and nitrogen adsorption and desorption analyzes. The prepared materials were then used as the stationary phase to investigate the retention behavior of MrgX2 recombinant protein on the affinity column. The results obtained with the analytical techniques show the specificity and selectivity of the MrgX2 recombinant protein on the affinity column. The repeatability and reproducibility for the analysis of MrgX2 on the NH2-Silico@GD@SP column show relative standard deviation (RSD) values lower than the acceptance criteria of 2 and 5% of retention time, and RSD of peak areas < 7%. The RSD value of the results obtained for the control of the activity of the prepared columns respond to the acceptance criteria of 5% and proves that the NH2-Silico@GD@SP column are stable until 48 h. The suitability of the NH2-Silico@GD@SP column offline SEC system has been tested by using MrgX2 as positive control. The results of this experiment indicate that the offline system may be used to analyze the retention fraction. MrgX2 extracted from human mast cells LAD2 was also verified. An obvious retention can be observed and the natural MrgX2 was concentrated 114.6 times compared with the original complex components by using the affinity column. These results may provide a new approach for the specific detection and enrichment of G-protein-coupled receptors.
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Affiliation(s)
- Yajing Hou
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China
| | - Jiayu Lu
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China
| | - Di Wei
- Xi'an Gaoxin Hospital Affiliated to Northwest University, Xi'an, Shaanxi 710075, China
| | - Yuexin Lv
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China
| | - Huaizhen He
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China
| | - Cheng Wang
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China; Pazhou Lab, Guangzhou 510330, China.
| | - Langchong He
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China; Pazhou Lab, Guangzhou 510330, China
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16
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Hawkins OP, Jahromi CPT, Gulamhussein AA, Nestorow S, Bahra T, Shelton C, Owusu-Mensah QK, Mohiddin N, O'Rourke H, Ajmal M, Byrnes K, Khan M, Nahar NN, Lim A, Harris C, Healy H, Hasan SW, Ahmed A, Evans L, Vaitsopoulou A, Akram A, Williams C, Binding J, Thandi RK, Joby A, Guest A, Tariq MZ, Rasool F, Cavanagh L, Kang S, Asparuhov B, Jestin A, Dafforn TR, Simms J, Bill RM, Goddard AD, Rothnie AJ. Membrane protein extraction and purification using partially-esterified SMA polymers. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2021; 1863:183758. [PMID: 34480878 PMCID: PMC8484863 DOI: 10.1016/j.bbamem.2021.183758] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 08/16/2021] [Accepted: 08/24/2021] [Indexed: 12/15/2022]
Abstract
Styrene maleic acid (SMA) polymers have proven to be very successful for the extraction of membrane proteins, forming SMA lipid particles (SMALPs), which maintain a lipid bilayer around the membrane protein. SMALP-encapsulated membrane proteins can be used for functional and structural studies. The SMALP approach allows retention of important protein-annular lipid interactions, exerts lateral pressure, and offers greater stability than traditional detergent solubilisation. However, SMA polymer does have some limitations, including a sensitivity to divalent cations and low pH, an absorbance spectrum that overlaps with many proteins, and possible restrictions on protein conformational change. Various modified polymers have been developed to try to overcome these challenges, but no clear solution has been found. A series of partially-esterified variants of SMA (SMA 2625, SMA 1440 and SMA 17352) has previously been shown to be highly effective for solubilisation of plant and cyanobacterial thylakoid membranes. It was hypothesised that the partial esterification of maleic acid groups would increase tolerance to divalent cations. Therefore, these partially-esterified polymers were tested for the solubilisation of lipids and membrane proteins, and their tolerance to magnesium ions. It was found that all partially esterified polymers were capable of solubilising and purifying a range of membrane proteins, but the yield of protein was lower with SMA 1440, and the degree of purity was lower for both SMA 1440 and SMA 17352. SMA 2625 performed comparably to SMA 2000. SMA 1440 also showed an increased sensitivity to divalent cations. Thus, it appears the interactions between SMA and divalent cations are more complex than proposed and require further investigation.
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Affiliation(s)
- Olivia P Hawkins
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | | | - Aiman A Gulamhussein
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Stephanie Nestorow
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Taranpreet Bahra
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Christian Shelton
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Quincy K Owusu-Mensah
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Naadiya Mohiddin
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Hannah O'Rourke
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Mariam Ajmal
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Kara Byrnes
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Madiha Khan
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Nila N Nahar
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Arcella Lim
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Cassandra Harris
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Hannah Healy
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Syeda W Hasan
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Asma Ahmed
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Lora Evans
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Afroditi Vaitsopoulou
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Aneel Akram
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Chris Williams
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Johanna Binding
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Rumandeep K Thandi
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Aswathy Joby
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Ashley Guest
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Mohammad Z Tariq
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Farah Rasool
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Luke Cavanagh
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Simran Kang
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Biser Asparuhov
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Aleksandr Jestin
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Timothy R Dafforn
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - John Simms
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Roslyn M Bill
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Alan D Goddard
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Alice J Rothnie
- College of Health & Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK.
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17
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Birch J, Quigley A. The high-throughput production of membrane proteins. Emerg Top Life Sci 2021; 5:655-663. [PMID: 34623416 PMCID: PMC8726054 DOI: 10.1042/etls20210196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 09/11/2021] [Accepted: 09/24/2021] [Indexed: 11/17/2022]
Abstract
Membrane proteins, found at the junctions between the outside world and the inner workings of the cell, play important roles in human disease and are used as biosensors. More than half of all therapeutics directly affect membrane protein function while nanopores enable DNA sequencing. The structural and functional characterisation of membrane proteins is therefore crucial. However, low levels of naturally abundant protein and the hydrophobic nature of membrane proteins makes production difficult. To maximise success, high-throughput strategies were developed that rely upon simple screens to identify successful constructs and rapidly exclude those unlikely to work. Parameters that affect production such as expression host, membrane protein origin, expression vector, fusion-tags, encapsulation reagent and solvent composition are screened in parallel. In this way, constructs with divergent requirements can be produced for a variety of structural applications. As structural techniques advance, sample requirements will change. Single-particle cryo-electron microscopy requires less protein than crystallography and as cryo-electron tomography and time-resolved serial crystallography are developed new sample production requirements will evolve. Here we discuss different methods used for the high-throughput production of membrane proteins for structural biology.
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Affiliation(s)
- James Birch
- Membrane Protein Laboratory, Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, U.K
- Research Complex at Harwell (RCaH), Harwell Science and Innovation Campus, Didcot OX11 0FA, U.K
| | - Andrew Quigley
- Membrane Protein Laboratory, Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, U.K
- Research Complex at Harwell (RCaH), Harwell Science and Innovation Campus, Didcot OX11 0FA, U.K
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18
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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: 13] [Impact Index Per Article: 4.3] [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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19
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Sander CL, Sears AE, Pinto AF, Choi EH, Kahremany S, Gao F, Salom D, Jin H, Pardon E, Suh S, Dong Z, Steyaert J, Saghatelian A, Skowronska-Krawczyk D, Kiser PD, Palczewski K. Nano-scale resolution of native retinal rod disk membranes reveals differences in lipid composition. J Cell Biol 2021; 220:e202101063. [PMID: 34132745 PMCID: PMC8240855 DOI: 10.1083/jcb.202101063] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 04/26/2021] [Accepted: 05/18/2021] [Indexed: 02/07/2023] Open
Abstract
Photoreceptors rely on distinct membrane compartments to support their specialized function. Unlike protein localization, identification of critical differences in membrane content has not yet been expanded to lipids, due to the difficulty of isolating domain-specific samples. We have overcome this by using SMA to coimmunopurify membrane proteins and their native lipids from two regions of photoreceptor ROS disks. Each sample's copurified lipids were subjected to untargeted lipidomic and fatty acid analysis. Extensive differences between center (rhodopsin) and rim (ABCA4 and PRPH2/ROM1) samples included a lower PC to PE ratio and increased LC- and VLC-PUFAs in the center relative to the rim region, which was enriched in shorter, saturated FAs. The comparatively few differences between the two rim samples likely reflect specific protein-lipid interactions. High-resolution profiling of the ROS disk lipid composition gives new insights into how intricate membrane structure and protein activity are balanced within the ROS, and provides a model for future studies of other complex cellular structures.
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Affiliation(s)
- Christopher L. Sander
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
| | - Avery E. Sears
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
| | - Antonio F.M. Pinto
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA
| | - Elliot H. Choi
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
| | - Shirin Kahremany
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
| | - Fangyuan Gao
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
| | - David Salom
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
| | - Hui Jin
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH
| | - Els Pardon
- Vlaams Instituut voor Biotechnologie–Vrije Universiteit Brussel Center for Structural Biology, Vlaams Instituut voor Biotechnologie, Brussels, Belgium
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Susie Suh
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
| | - Zhiqian Dong
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
| | - Jan Steyaert
- Vlaams Instituut voor Biotechnologie–Vrije Universiteit Brussel Center for Structural Biology, Vlaams Instituut voor Biotechnologie, Brussels, Belgium
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Alan Saghatelian
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA
| | - Dorota Skowronska-Krawczyk
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA
| | - Philip D. Kiser
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA
- Research Service, VA Long Beach Healthcare System, Long Beach, CA
| | - Krzysztof Palczewski
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA
- Department of Chemistry, University of California, Irvine, Irvine, CA
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20
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Overduin M, Trieber C, Prosser RS, Picard LP, Sheff JG. Structures and Dynamics of Native-State Transmembrane Protein Targets and Bound Lipids. MEMBRANES 2021; 11:451. [PMID: 34204456 PMCID: PMC8235241 DOI: 10.3390/membranes11060451] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 06/08/2021] [Accepted: 06/15/2021] [Indexed: 02/06/2023]
Abstract
Membrane proteins work within asymmetric bilayers of lipid molecules that are critical for their biological structures, dynamics and interactions. These properties are lost when detergents dislodge lipids, ligands and subunits, but are maintained in native nanodiscs formed using styrene maleic acid (SMA) and diisobutylene maleic acid (DIBMA) copolymers. These amphipathic polymers allow extraction of multicomponent complexes of post-translationally modified membrane-bound proteins directly from organ homogenates or membranes from diverse types of cells and organelles. Here, we review the structures and mechanisms of transmembrane targets and their interactions with lipids including phosphoinositides (PIs), as resolved using nanodisc systems and methods including cryo-electron microscopy (cryo-EM) and X-ray diffraction (XRD). We focus on therapeutic targets including several G protein-coupled receptors (GPCRs), as well as ion channels and transporters that are driving the development of next-generation native nanodiscs. The design of new synthetic polymers and complementary biophysical tools bodes well for the future of drug discovery and structural biology of native membrane:protein assemblies (memteins).
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Affiliation(s)
- Michael Overduin
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada;
| | - Catharine Trieber
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada;
| | - R. Scott Prosser
- Department of Chemistry, University of Toronto, UTM, Mississauga, ON L5L 1C6, Canada; (R.S.P.); (L.-P.P.)
| | - Louis-Philippe Picard
- Department of Chemistry, University of Toronto, UTM, Mississauga, ON L5L 1C6, Canada; (R.S.P.); (L.-P.P.)
| | - Joey G. Sheff
- Human Health Therapeutics Research Centre, National Research Council Canada, Ottawa, ON K1A 0R6, Canada;
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21
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Biological insights from SMA-extracted proteins. Biochem Soc Trans 2021; 49:1349-1359. [PMID: 34110372 PMCID: PMC8286838 DOI: 10.1042/bst20201067] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 05/12/2021] [Accepted: 05/17/2021] [Indexed: 02/08/2023]
Abstract
In the twelve years since styrene maleic acid (SMA) was first used to extract and purify a membrane protein within a native lipid bilayer, this technological breakthrough has provided insight into the structural and functional details of protein–lipid interactions. Most recently, advances in cryo-EM have demonstrated that SMA-extracted membrane proteins are a rich-source of structural data. For example, it has been possible to resolve the details of annular lipids and protein–protein interactions within complexes, the nature of lipids within central cavities and binding pockets, regions involved in stabilising multimers, details of terminal residues that would otherwise remain unresolved and the identification of physiologically relevant states. Functionally, SMA extraction has allowed the analysis of membrane proteins that are unstable in detergents, the characterization of an ultrafast component in the kinetics of electron transfer that was not possible in detergent-solubilised samples and quantitative, real-time measurement of binding assays with low concentrations of purified protein. While the use of SMA comes with limitations such as its sensitivity to low pH and divalent cations, its major advantage is maintenance of a protein's lipid bilayer. This has enabled researchers to view and assay proteins in an environment close to their native ones, leading to new structural and mechanistic insights.
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22
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Phạm TTT, Rainey JK. On-cell nuclear magnetic resonance spectroscopy to probe cell surface interactions. Biochem Cell Biol 2021; 99:683-692. [PMID: 33945753 DOI: 10.1139/bcb-2021-0052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nuclear magnetic resonance (NMR) spectroscopy allows determination of atomic-level information about intermolecular interactions, molecular structure, and molecular dynamics in the cellular environment. This may be broadly divided into studies focused on obtaining detailed molecular information in the intracellular context ("in-cell") or those focused on characterizing molecules or events at the cell surface ("on-cell"). In this review, we outline some key NMR techniques applied for on-cell NMR studies through both solution-state and solid-state NMR and survey studies that have used these techniques to uncover key information. We particularly focus on application of on-cell NMR spectroscopy to characterize ligand interactions with cell surface membrane proteins such as G-protein coupled receptors (GPCRs), receptor tyrosine kinases, etc. These techniques allow for quantification of binding affinities, competitive binding assays, delineation of portions of ligands involved in binding, ligand bound-state conformational determination, evaluation of receptor structuring and dynamics, and inference of distance constraints characteristic of the ligand-receptor bound state. Excitingly, it is possible to avoid the barriers of production and purification of membrane proteins while obtaining directly physiologically-relevant information through on-cell NMR. We also provide a briefer survey of the applicability of on-cell NMR approaches to other classes of cell surface molecule.
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Affiliation(s)
- Trần Thanh Tâm Phạm
- Dalhousie University, 3688, Department of Biochemistry & Molecular Biology, Halifax, Nova Scotia, Canada;
| | - Jan K Rainey
- Dalhousie University, 3688, Department of Biochemistry & Molecular Biology, Halifax, Canada;
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23
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Guo R, Sumner J, Qian S. Structure of Diisobutylene Maleic Acid Copolymer (DIBMA) and Its Lipid Particle as a “Stealth” Membrane-Mimetic for Membrane Protein Research. ACS APPLIED BIO MATERIALS 2021; 4:4760-4768. [DOI: 10.1021/acsabm.0c01626] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Rong Guo
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Grinnell College, Grinnell, Iowa 50112, United States
| | - Jacob Sumner
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Shuo Qian
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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24
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Lavington S, Watts A. Lipid nanoparticle technologies for the study of G protein-coupled receptors in lipid environments. Biophys Rev 2020; 12:10.1007/s12551-020-00775-5. [PMID: 33215301 PMCID: PMC7755959 DOI: 10.1007/s12551-020-00775-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 11/06/2020] [Indexed: 12/12/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are a large family of integral membrane proteins which conduct a wide range of biological roles and represent significant drug targets. Most biophysical and structural studies of GPCRs have been conducted on detergent-solubilised receptors, and it is clear that detergents can have detrimental effects on GPCR function. Simultaneously, there is increasing appreciation of roles for specific lipids in modulation of GPCR function. Lipid nanoparticles such as nanodiscs and styrene maleic acid lipid particles (SMALPs) offer opportunities to study integral membrane proteins in lipid environments, in a form that is soluble and amenable to structural and biophysical experiments. Here, we review the application of lipid nanoparticle technologies to the study of GPCRs, assessing the relative merits and limitations of each system. We highlight how these technologies can provide superior platforms to detergents for structural and biophysical studies of GPCRs and inform on roles for protein-lipid interactions in GPCR function.
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Affiliation(s)
- Steven Lavington
- Biochemistry Department, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Anthony Watts
- Biochemistry Department, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
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25
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Birch J, Cheruvara H, Gamage N, Harrison PJ, Lithgo R, Quigley A. Changes in Membrane Protein Structural Biology. BIOLOGY 2020; 9:E401. [PMID: 33207666 PMCID: PMC7696871 DOI: 10.3390/biology9110401] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 11/11/2020] [Accepted: 11/12/2020] [Indexed: 12/21/2022]
Abstract
Membrane proteins are essential components of many biochemical processes and are important pharmaceutical targets. Membrane protein structural biology provides the molecular rationale for these biochemical process as well as being a highly useful tool for drug discovery. Unfortunately, membrane protein structural biology is a difficult area of study due to low protein yields and high levels of instability especially when membrane proteins are removed from their native environments. Despite this instability, membrane protein structural biology has made great leaps over the last fifteen years. Today, the landscape is almost unrecognisable. The numbers of available atomic resolution structures have increased 10-fold though advances in crystallography and more recently by cryo-electron microscopy. These advances in structural biology were achieved through the efforts of many researchers around the world as well as initiatives such as the Membrane Protein Laboratory (MPL) at Diamond Light Source. The MPL has helped, provided access to and contributed to advances in protein production, sample preparation and data collection. Together, these advances have enabled higher resolution structures, from less material, at a greater rate, from a more diverse range of membrane protein targets. Despite this success, significant challenges remain. Here, we review the progress made and highlight current and future challenges that will be overcome.
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Affiliation(s)
- James Birch
- Membrane Protein Laboratory, Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (J.B.); (H.C.); (N.G.); (P.J.H.); (R.L.)
- Research Complex at Harwell (RCaH), Harwell Science and Innovation Campus, Didcot OX11 0FA, UK
| | - Harish Cheruvara
- Membrane Protein Laboratory, Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (J.B.); (H.C.); (N.G.); (P.J.H.); (R.L.)
- Research Complex at Harwell (RCaH), Harwell Science and Innovation Campus, Didcot OX11 0FA, UK
| | - Nadisha Gamage
- Membrane Protein Laboratory, Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (J.B.); (H.C.); (N.G.); (P.J.H.); (R.L.)
- Research Complex at Harwell (RCaH), Harwell Science and Innovation Campus, Didcot OX11 0FA, UK
| | - Peter J. Harrison
- Membrane Protein Laboratory, Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (J.B.); (H.C.); (N.G.); (P.J.H.); (R.L.)
- Research Complex at Harwell (RCaH), Harwell Science and Innovation Campus, Didcot OX11 0FA, UK
| | - Ryan Lithgo
- Membrane Protein Laboratory, Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (J.B.); (H.C.); (N.G.); (P.J.H.); (R.L.)
- Research Complex at Harwell (RCaH), Harwell Science and Innovation Campus, Didcot OX11 0FA, UK
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, Leicestershire, UK
| | - Andrew Quigley
- Membrane Protein Laboratory, Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (J.B.); (H.C.); (N.G.); (P.J.H.); (R.L.)
- Research Complex at Harwell (RCaH), Harwell Science and Innovation Campus, Didcot OX11 0FA, UK
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26
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Lemieux MJ, Overduin M. Structure and function of proteins in membranes and nanodiscs. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1863:183445. [PMID: 32841614 PMCID: PMC7443088 DOI: 10.1016/j.bbamem.2020.183445] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The field of membrane structural biology represents a fast-moving field with exciting developments including native nanodiscs that allow preparation of complexes of post-translationally modified proteins bound to biological lipids. This has led to conceptual advances including biological membrane:protein assemblies or “memteins” as the fundamental functional units of biological membranes. Tools including cryo-electron microscopy and X-ray crystallography are maturing such that it is becoming increasingly feasible to solve structures of large, multicomponent complexes, while complementary methods including nuclear magnetic resonance spectroscopy yield unique insights into interactions and dynamics. Challenges remain, including elucidating exactly how lipids and ligands are recognized at atomic resolution and transduce signals across asymmetric bilayers. In this special volume some of the latest thinking and methods are gathered through the analysis of a range of transmembrane targets. Ongoing work on areas including polymer design, protein labelling and microfluidic technologies will ensure continued progress on improving resolution and throughput, providing deeper understanding of this most important group of targets.
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Affiliation(s)
- M Joanne Lemieux
- Department of Biochemistry, Membrane Protein Disease Research Group, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Michael Overduin
- Department of Biochemistry, Membrane Protein Disease Research Group, University of Alberta, Edmonton, AB T6G 2H7, Canada.
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27
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Hothersall JD, Jones AY, Dafforn TR, Perrior T, Chapman KL. Releasing the technical 'shackles' on GPCR drug discovery: opportunities enabled by detergent-free polymer lipid particle (PoLiPa) purification. Drug Discov Today 2020; 25:S1359-6446(20)30337-8. [PMID: 32835806 DOI: 10.1016/j.drudis.2020.08.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 07/04/2020] [Accepted: 08/13/2020] [Indexed: 12/19/2022]
Abstract
G-protein-coupled receptor (GPCR) drug research is presently hindered by the technical challenges associated with generating purified receptors. Consequently, the application of critical modern discovery technologies has been limited, and the vast untapped opportunity for new GPCR-directed medicines is not being realised. A simple but transformative solution is to purify receptors without removing them from their native phospholipid environment by using polymer lipid particle (PoLiPa) technology, with reagents such as styrene-maleic acid co-polymer (SMA). Compared with contemporary detergent-based and stabilising mutagenesis methods, the PoLiPa approach is simple and generic and, therefore, offers huge advantages, with the potential to revolutionise GPCR research by facilitating the availability of the purified receptors that are required for structural biology, biophysical, and panning technologies.
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Affiliation(s)
- J Daniel Hothersall
- Domainex Ltd, Chesterford Research Park, Little Chesterford, Saffron Walden, CB10 1XL, UK.
| | - Andrew Y Jones
- Domainex Ltd, Chesterford Research Park, Little Chesterford, Saffron Walden, CB10 1XL, UK
| | - Tim R Dafforn
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Trevor Perrior
- Domainex Ltd, Chesterford Research Park, Little Chesterford, Saffron Walden, CB10 1XL, UK
| | - Kathryn L Chapman
- Domainex Ltd, Chesterford Research Park, Little Chesterford, Saffron Walden, CB10 1XL, UK
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28
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Lavington S, Watts A. Detergent-free solubilisation & purification of a G protein coupled receptor using a polymethacrylate polymer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1863:183441. [PMID: 32810489 DOI: 10.1016/j.bbamem.2020.183441] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 08/04/2020] [Accepted: 08/04/2020] [Indexed: 12/28/2022]
Abstract
G protein coupled receptors (GPCRs) function as guanine nucleotide exchange factors (GEFs) at heterotrimeric G proteins, and conduct this role embedded in a lipid bilayer. Detergents are widely used to solubilise GPCRs for structural and biophysical analysis, but are poor mimics of the lipid bilayer and may be deleterious to protein function. Amphipathic polymers have emerged as promising alternatives to detergents, which maintain a lipid environment around a membrane protein during purification. Of these polymers, the polymethacrylate (PMA) polymers have potential advantages over the most popular styrene maleic acid (SMA) polymer, but to date have not been applied to purification of membrane proteins. Here we use a class A GPCR, neurotensin receptor 1 (NTSR1), to explore detergent-free purification using PMA. By using an NTSR1-eGFP fusion protein expressed in Sf9 cells, a range of solubilisation conditions were screened, demonstrating the importance of solubilisation temperature, pH, NaCl concentration and the relative amounts of polymer and membrane sample. PMA-solubilised NTSR1 displayed compatibility with standard purification protocols and millimolar divalent cation concentrations. Moreover, the receptor in PMA discs showed stimulation of both Gq and Gi1 heterotrimers to an extent that was greater than that for the detergent-solubilised receptor. PMA therefore represents a viable alternative to SMA for membrane protein purification and has a potentially broad utility in studying GPCRs and other membrane proteins.
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Affiliation(s)
- Steven Lavington
- Department of Biochemistry, Oxford University, South Parks Road, OX1 3QU, UK
| | - Anthony Watts
- Department of Biochemistry, Oxford University, South Parks Road, OX1 3QU, UK.
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