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Stoddart LA, Goulding J, Briddon SJ. Advances in the application of fluorescence correlation spectroscopy to study detergent purified and encapsulated membrane proteins. Int J Biochem Cell Biol 2022; 146:106210. [PMID: 35390493 DOI: 10.1016/j.biocel.2022.106210] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 03/30/2022] [Accepted: 04/01/2022] [Indexed: 11/25/2022]
Abstract
Fluorescence correlation spectroscopy (FCS) is a quantitative spectroscopy technique which could potentially increase throughput and sensitivity of screening for ligand, substrate and inhibitor binding to membrane proteins in solution. However, the purification of membrane proteins in their active forms is complex, as the lipid bilayer provides stability and its removal often causes the protein to become conformationally unstable. This has limited the application of biophysical techniques such as FCS to study the function of membrane proteins. The recent application of native extraction techniques such as styrene maleic acid lipid particles (SMALPs) has resolved this issue and FCS has emerged as a powerful option for studying proteins extracted in this way. This review will discuss the application of FCS to study purified membrane proteins in detergent micelles, nanodiscs and SMALPs and its potential to be used routinely in membrane protein drug discovery.
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Affiliation(s)
- Leigh A Stoddart
- Cell Signalling and Pharmacology Research Group, Division of Physiology Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, NG7 2UH, UK; Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, The Midlands, UK
| | - Joëlle Goulding
- Cell Signalling and Pharmacology Research Group, Division of Physiology Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, NG7 2UH, UK; Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, The Midlands, UK
| | - Stephen J Briddon
- Cell Signalling and Pharmacology Research Group, Division of Physiology Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, NG7 2UH, UK; Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, The Midlands, UK.
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2
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Scott MJ, Jowett A, Orecchia M, Ertl P, Ouro-Gnao L, Ticehurst J, Gower D, Yates J, Poulton K, Harris C, Mullin MJ, Smith KJ, Lewis AP, Barton N, Washburn ML, de Wildt R. Rapid identification of highly potent human anti-GPCR antagonist monoclonal antibodies. MAbs 2021; 12:1755069. [PMID: 32343620 PMCID: PMC7188403 DOI: 10.1080/19420862.2020.1755069] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Complex cellular targets such as G protein-coupled receptors (GPCRs), ion channels, and other multi-transmembrane proteins represent a significant challenge for therapeutic antibody discovery, primarily because of poor stability of the target protein upon extraction from cell membranes. To assess whether a limited set of membrane-bound antigen formats could be exploited to identify functional antibodies directed against such targets, we selected a GPCR of therapeutic relevance (CCR1) and identified target binders using an in vitro yeast-based antibody discovery platform (AdimabTM) to expedite hit identification. Initially, we compared two different biotinylated antigen formats overexpressing human CCR1 in a ‘scouting’ approach using a subset of the antibody library. Binders were isolated using streptavidin-coated beads, expressed as yeast supernatants, and screened using a high-throughput binding assay and flow cytometry on appropriate cell lines. The most suitable antigen was then selected to isolate target binders using the full library diversity. This approach identified a combined total of 183 mAbs with diverse heavy chain sequences. A subset of clones exhibited high potencies in primary cell chemotaxis assays, with IC50 values in the low nM/high pM range. To assess the feasibility of any further affinity enhancement, full-length hCCR1 protein was purified, complementary-determining region diversified libraries were constructed from a high and lower affinity mAb, and improved binders were isolated by fluorescence-activated cell sorting selections. A significant affinity enhancement was observed for the lower affinity parental mAb, but not the high affinity mAb. These data exemplify a methodology to generate potent human mAbs for challenging targets rapidly using whole cells as antigen and define a route to the identification of affinity-matured variants if required.
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Affiliation(s)
- Martin J Scott
- Department of Biopharm Discovery, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - Amanda Jowett
- Department of Biopharm Discovery, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - Martin Orecchia
- Department of Biopharm Discovery, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - Peter Ertl
- Department of Biopharm Discovery, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - Larissa Ouro-Gnao
- Department of Biopharm Discovery, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - Julia Ticehurst
- Department of Biopharm Discovery, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - David Gower
- Department of Biopharm Discovery, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - John Yates
- Department of Biopharm Discovery, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - Katie Poulton
- Department of Biopharm Discovery, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - Carol Harris
- Department of Protein & Cellular Sciences, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - Michael J Mullin
- Department of Protein & Cellular Sciences, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - Kathrine J Smith
- Department of Protein & Cellular Sciences, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - Alan P Lewis
- Department of Data & Computational Sciences, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - Nick Barton
- Department of Data & Computational Sciences, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - Michael L Washburn
- Experimental Medicine Unit, Glaxo Smith Kline Research & Development, Collegeville, PA, USA
| | - Ruud de Wildt
- Department of Biopharm Discovery, Glaxo Smith Kline Research & Development, Hertfordshire, UK
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3
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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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4
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Generating therapeutic monoclonal antibodies to complex multi-spanning membrane targets: Overcoming the antigen challenge and enabling discovery strategies. Methods 2020; 180:111-126. [PMID: 32422249 DOI: 10.1016/j.ymeth.2020.05.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 04/21/2020] [Accepted: 05/13/2020] [Indexed: 12/17/2022] Open
Abstract
Complex integral membrane proteins, which are embedded in the cell surface lipid bilayer by multiple transmembrane spanning helices, encompass families of proteins which are important target classes for drug discovery. These protein families include G protein-coupled receptors, ion channels and transporters. Although these proteins have typically been targeted by small molecule drugs and peptides, the high specificity of monoclonal antibodies offers a significant opportunity to selectively modulate these target proteins. However, it remains the case that isolation of antibodies with desired pharmacological function(s) has proven difficult due to technical challenges in preparing membrane protein antigens suitable to support antibody drug discovery. In this review recent progress in defining strategies for generation of membrane protein antigens is outlined. We also highlight antibody isolation strategies which have generated antibodies which bind the membrane protein and modulate the protein function.
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Juárez-Jiménez J, Gupta AA, Karunanithy G, Mey ASJS, Georgiou C, Ioannidis H, De Simone A, Barlow PN, Hulme AN, Walkinshaw MD, Baldwin AJ, Michel J. Dynamic design: manipulation of millisecond timescale motions on the energy landscape of cyclophilin A. Chem Sci 2020; 11:2670-2680. [PMID: 34084326 PMCID: PMC8157532 DOI: 10.1039/c9sc04696h] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 01/14/2020] [Indexed: 12/21/2022] Open
Abstract
Proteins need to interconvert between many conformations in order to function, many of which are formed transiently, and sparsely populated. Particularly when the lifetimes of these states approach the millisecond timescale, identifying the relevant structures and the mechanism by which they interconvert remains a tremendous challenge. Here we introduce a novel combination of accelerated MD (aMD) simulations and Markov state modelling (MSM) to explore these 'excited' conformational states. Applying this to the highly dynamic protein CypA, a protein involved in immune response and associated with HIV infection, we identify five principally populated conformational states and the atomistic mechanism by which they interconvert. A rational design strategy predicted that the mutant D66A should stabilise the minor conformations and substantially alter the dynamics, whereas the similar mutant H70A should leave the landscape broadly unchanged. These predictions are confirmed using CPMG and R1ρ solution state NMR measurements. By efficiently exploring functionally relevant, but sparsely populated conformations with millisecond lifetimes in silico, our aMD/MSM method has tremendous promise for the design of dynamic protein free energy landscapes for both protein engineering and drug discovery.
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Affiliation(s)
- Jordi Juárez-Jiménez
- EaStCHEM School of Chemistry, University of Edinburgh David Brewster Road Edinburgh EH9 3FJ UK
| | - Arun A Gupta
- EaStCHEM School of Chemistry, University of Edinburgh David Brewster Road Edinburgh EH9 3FJ UK
| | - Gogulan Karunanithy
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford South Parks Road Oxford OX1 3QZ UK
| | - Antonia S J S Mey
- EaStCHEM School of Chemistry, University of Edinburgh David Brewster Road Edinburgh EH9 3FJ UK
| | - Charis Georgiou
- EaStCHEM School of Chemistry, University of Edinburgh David Brewster Road Edinburgh EH9 3FJ UK
| | - Harris Ioannidis
- EaStCHEM School of Chemistry, University of Edinburgh David Brewster Road Edinburgh EH9 3FJ UK
| | - Alessio De Simone
- EaStCHEM School of Chemistry, University of Edinburgh David Brewster Road Edinburgh EH9 3FJ UK
| | - Paul N Barlow
- EaStCHEM School of Chemistry, University of Edinburgh David Brewster Road Edinburgh EH9 3FJ UK
| | - Alison N Hulme
- EaStCHEM School of Chemistry, University of Edinburgh David Brewster Road Edinburgh EH9 3FJ UK
| | - Malcolm D Walkinshaw
- School of Biological Sciences Michael Swann Building, Max Born Crescent Edinburgh EH9 3BF UK
| | - Andrew J Baldwin
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford South Parks Road Oxford OX1 3QZ UK
| | - Julien Michel
- EaStCHEM School of Chemistry, University of Edinburgh David Brewster Road Edinburgh EH9 3FJ UK
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Therapeutic Monoclonal Antibodies to Complex Membrane Protein Targets: Antigen Generation and Antibody Discovery Strategies. BioDrugs 2019; 32:339-355. [PMID: 29934752 DOI: 10.1007/s40259-018-0289-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Cell surface membrane proteins comprise a wide array of structurally and functionally diverse proteins involved in a variety of important physiological and homeostatic processes. Complex integral membrane proteins, which are embedded in the lipid bilayer by multiple transmembrane-spanning helices, are represented by families of proteins that are important target classes for drug discovery. Such protein families include G-protein-coupled receptors, ion channels and transporters. Although these targets have typically been the domain of small-molecule drugs, the exquisite specificity of monoclonal antibodies offers a significant opportunity to selectively modulate these target proteins. Nevertheless, the isolation of antibodies with desired pharmacological functions has proved difficult because of technical challenges in preparing membrane protein antigens for antibody drug discovery. In this review, we describe recent progress in defining strategies for the generation of membrane protein antigens. We also describe antibody-isolation strategies that identify antibodies that bind the membrane protein and modulate protein function.
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7
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Fragment-based drug discovery and its application to challenging drug targets. Essays Biochem 2017; 61:475-484. [PMID: 29118094 DOI: 10.1042/ebc20170029] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 09/26/2017] [Accepted: 09/27/2017] [Indexed: 11/17/2022]
Abstract
Fragment-based drug discovery (FBDD) is a technique for identifying low molecular weight chemical starting points for drug discovery. Since its inception 20 years ago, FBDD has grown in popularity to the point where it is now an established technique in industry and academia. The approach involves the biophysical screening of proteins against collections of low molecular weight compounds (fragments). Although fragments bind to proteins with relatively low affinity, they form efficient, high quality binding interactions with the protein architecture as they have to overcome a significant entropy barrier to bind. Of the biophysical methods available for fragment screening, X-ray protein crystallography is one of the most sensitive and least prone to false positives. It also provides detailed structural information of the protein-fragment complex at the atomic level. Fragment-based screening using X-ray crystallography is therefore an efficient method for identifying binding hotspots on proteins, which can then be exploited by chemists and biologists for the discovery of new drugs. The use of FBDD is illustrated here with a recently published case study of a drug discovery programme targeting the challenging protein-protein interaction Kelch-like ECH-associated protein 1:nuclear factor erythroid 2-related factor 2.
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Soave M, Cseke G, Hutchings CJ, Brown AJH, Woolard J, Hill SJ. A monoclonal antibody raised against a thermo-stabilised β 1-adrenoceptor interacts with extracellular loop 2 and acts as a negative allosteric modulator of a sub-set of β 1-adrenoceptors expressed in stable cell lines. Biochem Pharmacol 2017; 147:38-54. [PMID: 29102678 PMCID: PMC5770334 DOI: 10.1016/j.bcp.2017.10.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Accepted: 10/31/2017] [Indexed: 11/30/2022]
Abstract
Recent interest has focused on antibodies that can discriminate between different receptor conformations. Here we have characterised the effect of a monoclonal antibody (mAb3), raised against a purified thermo-stabilised turkey β1-adrenoceptor (β1AR-m23 StaR), on β1-ARs expressed in CHO-K1 or HEK 293 cells. Immunohistochemical and radioligand-binding studies demonstrated that mAb3 was able to bind to ECL2 of the tβ1-AR, but not its human homologue. Specific binding of mAb3 to tβ1-AR was inhibited by a peptide based on the turkey, but not the human, ECL2 sequence. Studies with [3H]-CGP 12177 demonstrated that mAb3 prevented the binding of orthosteric ligands to a subset (circa 40%) of turkey β1-receptors expressed in both CHO K1 and HEK 293 cells. MAb3 significantly reduced the maximum specific binding capacity of [3H]-CGP-12177 without influencing its binding affinity. Substitution of ECL2 of tβ1-AR with its human equivalent, or mutation of residues D186S, P187D, Q188E prevented the inhibition of [3H]-CGP 12177 binding by mAb3. MAb3 also elicited a negative allosteric effect on agonist-stimulated cAMP responses. The identity of the subset of turkey β1-adrenoceptors influenced by mAb3 remains to be established but mAb3 should become an important tool to investigate the nature of β1-AR conformational states and oligomeric complexes.
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Affiliation(s)
- Mark Soave
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK; Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Gabriella Cseke
- Heptares Therapeutics Ltd., Bio Park, Welwyn Garden City AL7 3AX, UK
| | | | | | - Jeanette Woolard
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK; Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK.
| | - Stephen J Hill
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK; Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK.
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9
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Hu T, Sprague ER, Fodor M, Stams T, Clark KL, Cowan-Jacob SW. The impact of structural biology in medicine illustrated with four case studies. J Mol Med (Berl) 2017; 96:9-19. [PMID: 28669027 DOI: 10.1007/s00109-017-1565-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 06/12/2017] [Accepted: 06/15/2017] [Indexed: 12/18/2022]
Abstract
The contributions of structural biology to drug discovery have expanded over the last 20 years from structure-based ligand optimization to a broad range of clinically relevant topics including the understanding of disease, target discovery, screening for new types of ligands, discovery of new modes of action, addressing clinical challenges such as side effects or resistance, and providing data to support drug registration. This expansion of scope is due to breakthroughs in the technology, which allow structural information to be obtained rapidly and for more complex molecular systems, but also due to the combination of different technologies such as X-ray, NMR, and other biophysical methods, which allows one to get a more complete molecular understanding of disease and ways to treat it. In this review, we provide examples of the types of impact molecular structure information can have in the clinic for both low molecular weight and biologic drug discovery and describe several case studies from our own work to illustrate some of these contributions.
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Affiliation(s)
- Tiancen Hu
- Novartis Institutes for Biomedical Research, Cambridge, MA, 02139, USA
| | | | - Michelle Fodor
- Novartis Institutes for Biomedical Research, Cambridge, MA, 02139, USA
| | - Travis Stams
- Novartis Institutes for Biomedical Research, Cambridge, MA, 02139, USA
| | - Kirk L Clark
- Novartis Institutes for Biomedical Research, Cambridge, MA, 02139, USA
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Novel protein kinase targets in vascular smooth muscle therapeutics. Curr Opin Pharmacol 2017; 33:12-16. [PMID: 28388507 DOI: 10.1016/j.coph.2017.03.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 03/08/2017] [Indexed: 01/22/2023]
Abstract
Many signaling factors have been identified over the years that serve as mechanistic foundations for the pathogenesis and/or maintenance of cardiovascular disease (CVD). Of these, cyclic nucleotide-driven protein kinases in vascular smooth muscle (VSM) are of essential importance. Comprised primarily of cyclic AMP-dependent and cyclic GMP-dependent protein kinases, these ubiquitous signaling molecules have capacity to operate through numerous downstream effectors including vasodilator-stimulated phosphoprotein (VASP) to control aberrant VSM growth elemental to CVD. As more information is gathered regarding genetic, biochemical, molecular and cellular makeup of CVD including VSM cyclic nucleotide-dependent protein kinases and VASP, advances will be made in precision medicine by identifying more precise therapeutic targets to enhance clinical decision making.
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