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Aertgeerts K, Ho TT, Yan YG. Optimization of Recombinant GPCR Proteins for Biophysical and Structural Studies Using Virus-like Particles. Methods Mol Biol 2022; 2507:327-336. [PMID: 35773590 DOI: 10.1007/978-1-0716-2368-8_17] [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] [Indexed: 06/15/2023]
Abstract
Overexpression of biologically functional GPCRs and homogeneous purified protein solutions are required to enable structural studies and protein-based biophysical assay development. Iterative and time-consuming optimization cycles of protein engineering, expression, and purification are often needed to achieve the desired protein quantity and quality. Here, we describe the reconstitution of GPCRs in virus-like particles (VLPs) and their use in biophysical assays to characterize protein yield, stability, and small molecule ligand binding. This approach prevents the need for time-consuming detergent solubilization and protein purification during recombinant GPCR protein optimization.
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Affiliation(s)
| | - Thao T Ho
- Biology Department, Vertex Pharmaceuticals, San Diego, CA, USA
| | - Yingzhou G Yan
- Neuroscience TRC, Bristol Myers Squibb, San Diego, CA, USA
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2
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Waltenspühl Y, Ehrenmann J, Klenk C, Plückthun A. Engineering of Challenging G Protein-Coupled Receptors for Structure Determination and Biophysical Studies. Molecules 2021; 26:molecules26051465. [PMID: 33800379 PMCID: PMC7962830 DOI: 10.3390/molecules26051465] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/27/2021] [Accepted: 03/01/2021] [Indexed: 01/14/2023] Open
Abstract
Membrane proteins such as G protein-coupled receptors (GPCRs) exert fundamental biological functions and are involved in a multitude of physiological responses, making these receptors ideal drug targets. Drug discovery programs targeting GPCRs have been greatly facilitated by the emergence of high-resolution structures and the resulting opportunities to identify new chemical entities through structure-based drug design. To enable the determination of high-resolution structures of GPCRs, most receptors have to be engineered to overcome intrinsic hurdles such as their poor stability and low expression levels. In recent years, multiple engineering approaches have been developed to specifically address the technical difficulties of working with GPCRs, which are now beginning to make more challenging receptors accessible to detailed studies. Importantly, successfully engineered GPCRs are not only valuable in X-ray crystallography, but further enable biophysical studies with nuclear magnetic resonance spectroscopy, surface plasmon resonance, native mass spectrometry, and fluorescence anisotropy measurements, all of which are important for the detailed mechanistic understanding, which is the prerequisite for successful drug design. Here, we summarize engineering strategies based on directed evolution to reduce workload and enable biophysical experiments of particularly challenging GPCRs.
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3
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Development of a Novel SPR Assay to Study CXCR4-Ligand Interactions. BIOSENSORS-BASEL 2020; 10:bios10100150. [PMID: 33096938 PMCID: PMC7589327 DOI: 10.3390/bios10100150] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 10/15/2020] [Accepted: 10/21/2020] [Indexed: 01/16/2023]
Abstract
G protein-coupled receptors (GPCRs) are involved in a plethora of different diseases. Consequently, these proteins are considered as an important class of drug targets. Measuring detailed kinetic information on these types of proteins has been challenging. Surface plasmon resonance (SPR) can provide this information, however, the use of SPR on GPCRs remains a complex issue. Here, we report an SPR assay to investigate the interactions between the full-length chemokine receptor CXCR4 and nanobody-Fc (Nb-Fc) ligands. Nb-Fcs consist of two monovalent VHH domains fused with an Fc domain of a human IgG molecule. The CXCR4 protein used in this assay was produced with a C-terminal 10x-histidine tag and was immobilized on a nitrilotriacetic acid chip. In order to verify the sensitivity and effectiveness of this assay, the results were compared to data obtained from cellular assays as well as from another SPR assay using CXCR4 virus-like particles (VLPs). CXCR4 remained intact and stable for at least 12 h, and the kinetic results correlated well with both the cellular assays and the VLP SPR assay results. Apart from determining the binding kinetics of Nb-Fc with CXCR4, our results contributed to understanding CXCR4 interaction dynamics. In conclusion, this assay provides a viable experimental platform that has high potential to be expanded for studying other molecules as well as other histidine-tagged GPCRs.
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4
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Rico CA, Berchiche YA, Horioka M, Peeler JC, Lorenzen E, Tian H, Kazmi MA, Fürstenberg A, Gaertner H, Hartley O, Sakmar TP, Huber T. High-Affinity Binding of Chemokine Analogs that Display Ligand Bias at the HIV-1 Coreceptor CCR5. Biophys J 2019; 117:903-919. [PMID: 31421836 DOI: 10.1016/j.bpj.2019.07.043] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 07/01/2019] [Accepted: 07/22/2019] [Indexed: 11/30/2022] Open
Abstract
The chemokine receptor CCR5 is a drug target to prevent transmission of HIV/AIDS. We studied four analogs of the native chemokine regulated, on activation, normal T-cell-expressed, and secreted (RANTES) (CCL5) that have anti-HIV potencies of around 25 pM, which is more than four orders of magnitude higher than that of RANTES itself. It has been hypothesized that the ultrahigh potency of the analogs is due to their ability to bind populations of receptors not accessible to native chemokines. To test this hypothesis, we developed a homogeneous dual-color fluorescence cross-correlation spectroscopy assay for saturation- and competition-binding experiments. The fluorescence cross-correlation spectroscopy assay has the advantage that it does not rely on competition with radioactively labeled native chemokines used in conventional assays. We prepared site-specifically labeled fluorescent analogs using native chemical ligation of synthetic peptides, followed by bioorthogonal fluorescent labeling. We engineered a mammalian cell expression construct to provide fluorescently labeled CCR5, which was purified using a tandem immunoaffinity and size-exclusion chromatography approach to obtain monomeric fluorescent CCR5 in detergent solution. We found subnanomolar binding affinities for the two analogs 5P12-RANTES and 5P14-RANTES and about 20-fold reduced affinities for PSC-RANTES and 6P4-RANTES. Using homologous and heterologous competition experiments with unlabeled chemokine analogs, we conclude that the analogs all bind at the same binding site, whereas the native chemokines (RANTES and MIP-1α) fail to displace bound fluorescent analogs even at tens of micromolar concentrations. Our results can be rationalized with de novo structural models of the N-terminal tails of the synthetic chemokines that adopt a different binding mode as compared to the parent compound.
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Affiliation(s)
- Carlos A Rico
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, New York; Tri-Institutional PhD Program in Chemical Biology, The Rockefeller University, New York, New York
| | - Yamina A Berchiche
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, New York; B Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, US National Institutes of Health, Bethesda, Maryland
| | - Mizuho Horioka
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, New York; Tri-Institutional PhD Program in Chemical Biology, The Rockefeller University, New York, New York
| | - Jennifer C Peeler
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, New York; Deparment of Chemistry, Boston College, Chestnut Hill, Massachusetts
| | - Emily Lorenzen
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, New York
| | - He Tian
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, New York
| | - Manija A Kazmi
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, New York
| | - Alexandre Fürstenberg
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, New York; Department of Inorganic and Analytical Chemistry, Geneva, Switzerland
| | - Hubert Gaertner
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Oliver Hartley
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Thomas P Sakmar
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, New York
| | - Thomas Huber
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, New York.
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5
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Colin P, Zhou Z, Staropoli I, Garcia-Perez J, Gasser R, Armani-Tourret M, Benureau Y, Gonzalez N, Jin J, Connell BJ, Raymond S, Delobel P, Izopet J, Lortat-Jacob H, Alcami J, Arenzana-Seisdedos F, Brelot A, Lagane B. CCR5 structural plasticity shapes HIV-1 phenotypic properties. PLoS Pathog 2018; 14:e1007432. [PMID: 30521629 PMCID: PMC6283471 DOI: 10.1371/journal.ppat.1007432] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 10/24/2018] [Indexed: 01/20/2023] Open
Abstract
CCR5 plays immune functions and is the coreceptor for R5 HIV-1 strains. It exists in diverse conformations and oligomerization states. We interrogated the significance of the CCR5 structural diversity on HIV-1 infection. We show that envelope glycoproteins (gp120s) from different HIV-1 strains exhibit divergent binding levels to CCR5 on cell lines and primary cells, but not to CD4 or the CD4i monoclonal antibody E51. This owed to differential binding of the gp120s to different CCR5 populations, which exist in varying quantities at the cell surface and are differentially expressed between different cell types. Some, but not all, of these populations are antigenically distinct conformations of the coreceptor. The different binding levels of gp120s also correspond to differences in their capacity to bind CCR5 dimers/oligomers. Mutating the CCR5 dimerization interface changed conformation of the CCR5 homodimers and modulated differentially the binding of distinct gp120s. Env-pseudotyped viruses also use particular CCR5 conformations for entry, which may differ between different viruses and represent a subset of those binding gp120s. In particular, even if gp120s can bind both CCR5 monomers and oligomers, impairment of CCR5 oligomerization improved viral entry, suggesting that HIV-1 prefers monomers for entry. From a functional standpoint, we illustrate that the nature of the CCR5 molecules to which gp120/HIV-1 binds shapes sensitivity to inhibition by CCR5 ligands and cellular tropism. Differences exist in the CCR5 populations between T-cells and macrophages, and this is associated with differential capacity to bind gp120s and to support viral entry. In macrophages, CCR5 structural plasticity is critical for entry of blood-derived R5 isolates, which, in contrast to prototypical M-tropic strains from brain tissues, cannot benefit from enhanced affinity for CD4. Collectively, our results support a role for CCR5 heterogeneity in diversifying the phenotypic properties of HIV-1 isolates and provide new clues for development of CCR5-targeting drugs.
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Affiliation(s)
- Philippe Colin
- Viral Pathogenesis Unit, Department of Virology, Institut Pasteur, Paris, France
- INSERM Unit U1108, Institut Pasteur, Paris, France
- Paris Diderot University, Sorbonne Paris Cité, Cellule Pasteur, Rue du Docteur Roux, Paris, France
| | - Zhicheng Zhou
- Viral Pathogenesis Unit, Department of Virology, Institut Pasteur, Paris, France
- INSERM Unit U1108, Institut Pasteur, Paris, France
| | - Isabelle Staropoli
- Viral Pathogenesis Unit, Department of Virology, Institut Pasteur, Paris, France
- INSERM Unit U1108, Institut Pasteur, Paris, France
| | | | - Romain Gasser
- Centre de Physiopathologie Toulouse-Purpan (CPTP), Université de Toulouse, CNRS, Inserm, UPS, Toulouse, France
| | - Marie Armani-Tourret
- Centre de Physiopathologie Toulouse-Purpan (CPTP), Université de Toulouse, CNRS, Inserm, UPS, Toulouse, France
| | - Yann Benureau
- Viral Pathogenesis Unit, Department of Virology, Institut Pasteur, Paris, France
- INSERM Unit U1108, Institut Pasteur, Paris, France
| | - Nuria Gonzalez
- AIDS Immunopathogenesis Unit, Instituto de Salud Carlos III, Madrid, Spain
| | - Jun Jin
- Viral Pathogenesis Unit, Department of Virology, Institut Pasteur, Paris, France
- INSERM Unit U1108, Institut Pasteur, Paris, France
| | - Bridgette J. Connell
- Grenoble Alpes University, CNRS, CEA, Institut de Biologie Structurale (IBS), Grenoble, France
| | - Stéphanie Raymond
- Centre de Physiopathologie Toulouse-Purpan (CPTP), Université de Toulouse, CNRS, Inserm, UPS, Toulouse, France
- CHU de Toulouse, Laboratoire de Virologie, Toulouse, France
| | - Pierre Delobel
- Centre de Physiopathologie Toulouse-Purpan (CPTP), Université de Toulouse, CNRS, Inserm, UPS, Toulouse, France
- CHU de Toulouse, Service des Maladies Infectieuses et Tropicales, Toulouse, France
| | - Jacques Izopet
- Centre de Physiopathologie Toulouse-Purpan (CPTP), Université de Toulouse, CNRS, Inserm, UPS, Toulouse, France
- CHU de Toulouse, Laboratoire de Virologie, Toulouse, France
| | - Hugues Lortat-Jacob
- Grenoble Alpes University, CNRS, CEA, Institut de Biologie Structurale (IBS), Grenoble, France
| | - Jose Alcami
- AIDS Immunopathogenesis Unit, Instituto de Salud Carlos III, Madrid, Spain
| | - Fernando Arenzana-Seisdedos
- Viral Pathogenesis Unit, Department of Virology, Institut Pasteur, Paris, France
- INSERM Unit U1108, Institut Pasteur, Paris, France
| | - Anne Brelot
- Viral Pathogenesis Unit, Department of Virology, Institut Pasteur, Paris, France
- INSERM Unit U1108, Institut Pasteur, Paris, France
| | - Bernard Lagane
- Viral Pathogenesis Unit, Department of Virology, Institut Pasteur, Paris, France
- INSERM Unit U1108, Institut Pasteur, Paris, France
- Centre de Physiopathologie Toulouse-Purpan (CPTP), Université de Toulouse, CNRS, Inserm, UPS, Toulouse, France
- * E-mail:
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6
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Zhang S, Tao F, Qing R, Tang H, Skuhersky M, Corin K, Tegler L, Wassie A, Wassie B, Kwon Y, Suter B, Entzian C, Schubert T, Yang G, Labahn J, Kubicek J, Maertens B. QTY code enables design of detergent-free chemokine receptors that retain ligand-binding activities. Proc Natl Acad Sci U S A 2018; 115:E8652-E8659. [PMID: 30154163 PMCID: PMC6140526 DOI: 10.1073/pnas.1811031115] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Structure and function studies of membrane proteins, particularly G protein-coupled receptors and multipass transmembrane proteins, require detergents. We have devised a simple tool, the QTY code (glutamine, threonine, and tyrosine), for designing hydrophobic domains to become water soluble without detergents. Here we report using the QTY code to systematically replace the hydrophobic amino acids leucine, valine, isoleucine, and phenylalanine in the seven transmembrane α-helices of CCR5, CXCR4, CCR10, and CXCR7. We show that QTY code-designed chemokine receptor variants retain their thermostabilities, α-helical structures, and ligand-binding activities in buffer and 50% human serum. CCR5QTY, CXCR4QTY, and CXCR7QTY also bind to HIV coat protein gp41-120. Despite substantial transmembrane domain changes, the detergent-free QTY variants maintain stable structures and retain their ligand-binding activities. We believe the QTY code will be useful for designing water-soluble variants of membrane proteins and other water-insoluble aggregated proteins.
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Affiliation(s)
- Shuguang Zhang
- Center for Bits and Atoms, Massachusetts Institute of Technology, Cambridge, MA 02139;
| | - Fei Tao
- Center for Bits and Atoms, Massachusetts Institute of Technology, Cambridge, MA 02139
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiaotong University, 200240 Shanghai, China
| | - Rui Qing
- Center for Bits and Atoms, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Hongzhi Tang
- Center for Bits and Atoms, Massachusetts Institute of Technology, Cambridge, MA 02139
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiaotong University, 200240 Shanghai, China
| | - Michael Skuhersky
- Center for Bits and Atoms, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Karolina Corin
- Center for Bits and Atoms, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Lotta Tegler
- Center for Bits and Atoms, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Asmamaw Wassie
- Center for Bits and Atoms, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Brook Wassie
- Center for Bits and Atoms, Massachusetts Institute of Technology, Cambridge, MA 02139
| | | | | | | | | | - Ge Yang
- Centre for Structural Systems Biology, Research Center Juelich, D-22607 Hamburg, Germany
| | - Jörg Labahn
- Centre for Structural Systems Biology, Research Center Juelich, D-22607 Hamburg, Germany
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7
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Yeh V, Lee TY, Chen CW, Kuo PC, Shiue J, Chu LK, Yu TY. Highly Efficient Transfer of 7TM Membrane Protein from Native Membrane to Covalently Circularized Nanodisc. Sci Rep 2018; 8:13501. [PMID: 30201976 PMCID: PMC6131177 DOI: 10.1038/s41598-018-31925-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 08/29/2018] [Indexed: 11/09/2022] Open
Abstract
Incorporating membrane proteins into membrane mimicking systems is an essential process for biophysical studies and structure determination. Monodisperse lipid nanodiscs have been found to be a suitable tool, as they provide a near-native lipid bilayer environment. Recently, a covalently circularized nanodisc (cND) assembled with a membrane scaffold protein (MSP) in circular form, instead of conventional linear form, has emerged. Covalently circularized nanodiscs have been shown to have improved stability, however the optimal strategies for the incorporation of membrane proteins, as well as the physicochemical properties of the membrane protein embedded in the cND, have not been studied. Bacteriorhodopsin (bR) is a seven-transmembrane helix (7TM) membrane protein, and it forms a two dimensional crystal consisting of trimeric bR on the purple membrane of halophilic archea. Here it is reported that the bR trimer in its active form can be directly incorporated into a cND from its native purple membrane. Furthermore, the assembly conditions of the native purple membrane nanodisc (PMND) were optimized to achieve homogeneity and high yield using a high sodium chloride concentration. Additionally, the native PMND was demonstrated to have the ability to assemble over a range of different pHs, suggesting flexibility in the preparation conditions. The native PMND was then found to not only preserve the trimeric structure of bR and most of the native lipids in the PM, but also maintained the photocycle function of bR. This suggests a promising potential for assembling a cND with a 7TM membrane protein, extracted directly from its native membrane environment, while preserving the protein conformation and lipid composition.
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Affiliation(s)
- Vivien Yeh
- Institute of Atomic and Molecular Sciences, Academia Sinica, 1, Sec. 4, Roosevelt Rd., Taipei, 10617, Taiwan.,Department of Chemistry, National Taiwan University, 1, Sec. 4, Roosevelt Rd., Taipei, 10617, Taiwan
| | - Tsung-Yen Lee
- Department of Chemistry, National Tsing Hua University, 101, Sec. 2, Kuang-Fu Rd., Hsinchu, 30013, Taiwan
| | - Chung-Wen Chen
- Institute of Atomic and Molecular Sciences, Academia Sinica, 1, Sec. 4, Roosevelt Rd., Taipei, 10617, Taiwan
| | - Pai-Chia Kuo
- Institute of Physics, Academia Sinica, No.128, Sec. 2, Academia Rd., Taipei, 11529, Taiwan
| | - Jessie Shiue
- Institute of Physics, Academia Sinica, No.128, Sec. 2, Academia Rd., Taipei, 11529, Taiwan
| | - Li-Kang Chu
- Department of Chemistry, National Tsing Hua University, 101, Sec. 2, Kuang-Fu Rd., Hsinchu, 30013, Taiwan.
| | - Tsyr-Yan Yu
- Institute of Atomic and Molecular Sciences, Academia Sinica, 1, Sec. 4, Roosevelt Rd., Taipei, 10617, Taiwan.
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8
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Surveying GPCR solubilisation conditions using surface plasmon resonance. Anal Biochem 2018; 556:23-34. [PMID: 29908863 DOI: 10.1016/j.ab.2018.06.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 05/08/2018] [Accepted: 06/13/2018] [Indexed: 11/22/2022]
Abstract
Biophysical screening techniques, such as surface plasmon resonance, enable detailed kinetic analysis of ligands binding to solubilised G-protein coupled receptors. The activity of a receptor solubilised out of the membrane is crucially dependent on the environment in which it is suspended. Finding the right conditions is challenging due to the number of variables to investigate in order to determine the optimum solubilisation buffer for any given receptor. In this study we used surface plasmon resonance technology to screen a variety of solubilisation conditions including buffers and detergents for two model receptors: CXCR4 and CCR5. We tested 950 different combinations of solubilisation conditions for both receptors. The activity of both receptors was monitored by using conformation dependent monoclonal antibodies and the binding of small molecule ligands. Despite both receptors belonging to the chemokine receptor family they show some differences in their preference for solubilisation conditions that provide the highest level of binding for both the conformation dependent antibodies and small molecules. The study described here is focused not only on finding the best solubilisation conditions for each receptor, but also on factors that determine the sensitivity of the assay for each receptor. We also suggest how these data about different buffers and detergents can be used as a guide for selecting solubilisation conditions for other membrane proteins.
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9
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Lee TH, Hirst DJ, Kulkarni K, Del Borgo MP, Aguilar MI. Exploring Molecular-Biomembrane Interactions with Surface Plasmon Resonance and Dual Polarization Interferometry Technology: Expanding the Spotlight onto Biomembrane Structure. Chem Rev 2018; 118:5392-5487. [PMID: 29793341 DOI: 10.1021/acs.chemrev.7b00729] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The molecular analysis of biomolecular-membrane interactions is central to understanding most cellular systems but has emerged as a complex technical challenge given the complexities of membrane structure and composition across all living cells. We present a review of the application of surface plasmon resonance and dual polarization interferometry-based biosensors to the study of biomembrane-based systems using both planar mono- or bilayers or liposomes. We first describe the optical principals and instrumentation of surface plasmon resonance, including both linear and extraordinary transmission modes and dual polarization interferometry. We then describe the wide range of model membrane systems that have been developed for deposition on the chips surfaces that include planar, polymer cushioned, tethered bilayers, and liposomes. This is followed by a description of the different chemical immobilization or physisorption techniques. The application of this broad range of engineered membrane surfaces to biomolecular-membrane interactions is then overviewed and how the information obtained using these techniques enhance our molecular understanding of membrane-mediated peptide and protein function. We first discuss experiments where SPR alone has been used to characterize membrane binding and describe how these studies yielded novel insight into the molecular events associated with membrane interactions and how they provided a significant impetus to more recent studies that focus on coincident membrane structure changes during binding of peptides and proteins. We then discuss the emerging limitations of not monitoring the effects on membrane structure and how SPR data can be combined with DPI to provide significant new information on how a membrane responds to the binding of peptides and proteins.
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Affiliation(s)
- Tzong-Hsien Lee
- Department of Biochemistry and Molecular Biology and Biomedicine Discovery Institute , Monash University , Clayton , VIC 3800 , Australia
| | - Daniel J Hirst
- Department of Biochemistry and Molecular Biology and Biomedicine Discovery Institute , Monash University , Clayton , VIC 3800 , Australia
| | - Ketav Kulkarni
- Department of Biochemistry and Molecular Biology and Biomedicine Discovery Institute , Monash University , Clayton , VIC 3800 , Australia
| | - Mark P Del Borgo
- Department of Biochemistry and Molecular Biology and Biomedicine Discovery Institute , Monash University , Clayton , VIC 3800 , Australia
| | - Marie-Isabel Aguilar
- Department of Biochemistry and Molecular Biology and Biomedicine Discovery Institute , Monash University , Clayton , VIC 3800 , Australia
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10
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Drescher DG, Selvakumar D, Drescher MJ. Analysis of Protein Interactions by Surface Plasmon Resonance. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2017; 110:1-30. [PMID: 29412994 DOI: 10.1016/bs.apcsb.2017.07.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Surface plasmon resonance is an optical technique that is utilized for detecting molecular interactions, such as interactions that occur between proteins or other classes of molecules. Binding of a mobile molecule (analyte) to a molecule immobilized on a thin metal film (ligand) changes the refractive index of the film. The angle of extinction of light that is completely reflected after polarized light impinges upon the film, is altered and monitored as a change in detector position for a dip in reflected intensity (the surface plasmon resonance phenomenon). Because the method strictly detects mass, there is no need to label the interacting components, thus eliminating possible changes of their molecular properties. In this chapter, we review essential SPR methodology and present applications to basic science and human disease.
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Affiliation(s)
- Dennis G Drescher
- Wayne State University School of Medicine, Detroit, MI, United States.
| | | | - Marian J Drescher
- Wayne State University School of Medicine, Detroit, MI, United States
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11
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Huber S, Casagrande F, Hug MN, Wang L, Heine P, Kummer L, Plückthun A, Hennig M. SPR-based fragment screening with neurotensin receptor 1 generates novel small molecule ligands. PLoS One 2017; 12:e0175842. [PMID: 28510609 PMCID: PMC5433701 DOI: 10.1371/journal.pone.0175842] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 04/01/2017] [Indexed: 12/22/2022] Open
Abstract
The neurotensin receptor 1 represents an important drug target involved in various diseases of the central nervous system. So far, the full exploitation of potential therapeutic activities has been compromised by the lack of compounds with favorable physicochemical and pharmacokinetic properties which efficiently penetrate the blood-brain barrier. Recent progress in the generation of stabilized variants of solubilized neurotensin receptor 1 and its subsequent purification and successful structure determination presents a solid starting point to apply the approach of fragment-based screening to extend the chemical space of known neurotensin receptor 1 ligands. In this report, surface plasmon resonance was used as primary method to screen 6369 compounds. Thereby 44 hits were identified and confirmed in competition as well as dose-response experiments. Furthermore, 4 out of 8 selected hits were validated using nuclear magnetic resonance spectroscopy as orthogonal biophysical method. Computational analysis of the compound structures, taking the known crystal structure of the endogenous peptide agonist into consideration, gave insight into the potential fragment-binding location and interactions and inspires chemistry efforts for further exploration of the fragments.
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Affiliation(s)
- Sylwia Huber
- Roche Innovation Center Basel, Pharmaceutical Research and Early Development, Basel, Switzerland
- * E-mail: (SH); (MH)
| | - Fabio Casagrande
- Roche Innovation Center Basel, Pharmaceutical Research and Early Development, Basel, Switzerland
| | - Melanie N. Hug
- Roche Innovation Center Basel, Pharmaceutical Research and Early Development, Basel, Switzerland
| | - Lisha Wang
- Roche Innovation Center Basel, Pharmaceutical Research and Early Development, Basel, Switzerland
| | - Philipp Heine
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Lutz Kummer
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Andreas Plückthun
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Michael Hennig
- Roche Innovation Center Basel, Pharmaceutical Research and Early Development, Basel, Switzerland
- * E-mail: (SH); (MH)
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12
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Desplantes R, Lévêque C, Muller B, Lotierzo M, Ferracci G, Popoff M, Seagar M, Mamoun R, El Far O. Affinity biosensors using recombinant native membrane proteins displayed on exosomes: application to botulinum neurotoxin B receptor. Sci Rep 2017; 7:1032. [PMID: 28432329 PMCID: PMC5430821 DOI: 10.1038/s41598-017-01198-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 03/27/2017] [Indexed: 12/31/2022] Open
Abstract
The development of simple molecular assays with membrane protein receptors in a native conformation still represents a challenging task. Exosomes are extracellular vesicles which, due to their stability and small size, are suited for analysis in various assay formats. Here, we describe a novel approach to sort recombinant fully native and functional membrane proteins to exosomes using a targeting peptide. Specific binding of high affinity ligands to the potassium channel Kv1.2, the G-protein coupled receptor CXCR4, and the botulinum neurotoxin type B (BoNT/B) receptor, indicated their correct assembly and outside out orientation in exosomes. We then developed, using a label-free optical biosensor, a new method to determine the kinetic constants of BoNT/B holotoxin binding to its receptor synaptotagmin2/GT1b ganglioside (kon = 2.3 ×105 M−1.s−1, koff = 1.3 10−4 s−1), yielding an affinity constant (KD = 0.6 nM) similar to values determined from native tissue. In addition, the recombinant binding domain of BoNT/B, a potential vector for neuronal delivery, bound quasi-irreversibly to synaptotagmin 2/GT1b exosomes. Engineered exosomes provide thus a novel means to study membrane proteins for biotechnology and clinical applications.
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Affiliation(s)
- Richard Desplantes
- INSERM, UMR_S 1072, 13015, Marseille, France.,Aix-Marseille Université, 13015, Marseille, France
| | - Christian Lévêque
- INSERM, UMR_S 1072, 13015, Marseille, France.,Aix-Marseille Université, 13015, Marseille, France
| | - Benjamin Muller
- Ciloa, cc90 - Université Montpellier 2, Place E. Bataillon, 34095, Montpellier Cedex 5, France
| | - Manuela Lotierzo
- Ciloa, cc90 - Université Montpellier 2, Place E. Bataillon, 34095, Montpellier Cedex 5, France
| | - Géraldine Ferracci
- Aix-Marseille Université, 13015, Marseille, France.,CNRS, UMR 7286, Plate-Forme de Recherche en Neurosciences PFRN, 13015, Marseille, France
| | - Michel Popoff
- CNR Anaérobies et botulisme, Unité Bactéries anaérobies et toxines. Institut Pasteur, 28 rue du Dr Roux, 75724, Paris, Cedex 15, France
| | - Michael Seagar
- INSERM, UMR_S 1072, 13015, Marseille, France.,Aix-Marseille Université, 13015, Marseille, France
| | - Robert Mamoun
- Ciloa, cc90 - Université Montpellier 2, Place E. Bataillon, 34095, Montpellier Cedex 5, France
| | - Oussama El Far
- INSERM, UMR_S 1072, 13015, Marseille, France. .,Aix-Marseille Université, 13015, Marseille, France.
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13
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Renaud JP, Chung CW, Danielson UH, Egner U, Hennig M, Hubbard RE, Nar H. Biophysics in drug discovery: impact, challenges and opportunities. Nat Rev Drug Discov 2016; 15:679-98. [PMID: 27516170 DOI: 10.1038/nrd.2016.123] [Citation(s) in RCA: 209] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Over the past 25 years, biophysical technologies such as X-ray crystallography, nuclear magnetic resonance spectroscopy, surface plasmon resonance spectroscopy and isothermal titration calorimetry have become key components of drug discovery platforms in many pharmaceutical companies and academic laboratories. There have been great improvements in the speed, sensitivity and range of possible measurements, providing high-resolution mechanistic, kinetic, thermodynamic and structural information on compound-target interactions. This Review provides a framework to understand this evolution by describing the key biophysical methods, the information they can provide and the ways in which they can be applied at different stages of the drug discovery process. We also discuss the challenges for current technologies and future opportunities to use biophysical methods to solve drug discovery problems.
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Affiliation(s)
- Jean-Paul Renaud
- NovAliX, Boulevard Sébastien Brant, 67405 Illkirch Cedex, France.,Institut de Génétique et Biologie Moléculaire et Cellulaire, CNRS UMR7104/INSERM U964/Université de Strasbourg, 1 rue Laurent Fries - BP10142, 67404 Illkirch Cedex, France.,RiboStruct, 15 rue Neuve, 67540 Ostwald, France
| | - Chun-Wa Chung
- GlaxoSmithKline R&D, Gunnels Wood Road, Stevenage, SG1 2NY, UK
| | - U Helena Danielson
- Department of Chemistry - BMC and Science for Life Laboratory, Drug Discovery &Development Platform, Uppsala University, SE-751 05 Uppsala, Sweden.,Beactica AB, Uppsala Business Park, 754 50 Uppsala, Sweden
| | - Ursula Egner
- Bayer Pharma AG, Müllerstrasse 178, 13353 Berlin, Germany
| | - Michael Hennig
- Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070 Basel, Switzerland.,leadXpro AG, PARK INNOVAARE, CH-5234 Villigen, Switzerland
| | - Roderick E Hubbard
- University of York, Heslington, York, YO10 5DD, UK.,Vernalis (R&D), Granta Park, Cambridge, CB21 6GB, UK
| | - Herbert Nar
- Boehringer Ingelheim GmbH &Co. KG, Birkendorfer Strasse 65, 88400 Biberach, Germany
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14
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Benureau Y, Colin P, Staropoli I, Gonzalez N, Garcia-Perez J, Alcami J, Arenzana-Seisdedos F, Lagane B. Guidelines for cloning, expression, purification and functional characterization of primary HIV-1 envelope glycoproteins. J Virol Methods 2016; 236:184-195. [PMID: 27451265 DOI: 10.1016/j.jviromet.2016.07.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 07/13/2016] [Accepted: 07/19/2016] [Indexed: 12/14/2022]
Abstract
The trimeric HIV-1 envelope (Env) glycoproteins gp120 and gp41 mediate virus entry into target cells by engaging CD4 and the coreceptors CCR5 or CXCR4 at the cell surface and driving membrane fusion. Receptor/gp120 interactions regulate the virus life cycle, HIV infection transmission and pathogenesis. Env is also the target of neutralizing antibodies. Efforts have thus been made to produce soluble HIV-1 glycoproteins to develop vaccines and study the role and mechanisms of HIV/receptor interactions. However, production and purification of Env glycoproteins and their functional assessment has to cope with multiple obstacles. These include difficulties in amplifying and cloning env sequences and setting up receptor binding assays that are suitable for studies on large collections of glycoproteins, flexible enough to adapt to Env and receptor structural heterogeneities, and allow recapitulating the receptor binding properties of virion-associated Env trimers. Here we identify these difficulties and present protocols to produce primary gp120 and determination of their binding properties to receptors. The receptor binding assays confirmed that the produced glycoproteins are competent for binding CD4 and undergo proper CD4-induced conformational changes required for interaction with CCR5. These assays may help elucidate the role of gp120/receptor interactions in the pathophysiology of HIV infection and develop HIV-1 entry inhibitors.
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Affiliation(s)
- Yann Benureau
- INSERM U1108, Institut Pasteur, 75015 Paris, France; Viral Pathogenesis Unit, Department of Virology, Institut Pasteur, 75015 Paris, France.
| | - Philippe Colin
- INSERM U1108, Institut Pasteur, 75015 Paris, France; Viral Pathogenesis Unit, Department of Virology, Institut Pasteur, 75015 Paris, France.
| | - Isabelle Staropoli
- INSERM U1108, Institut Pasteur, 75015 Paris, France; Viral Pathogenesis Unit, Department of Virology, Institut Pasteur, 75015 Paris, France.
| | - Nuria Gonzalez
- AIDS Immunopathogenesis Unit, Instituto de Salud Carlos III, 28220, Majadahonda, Madrid, Spain.
| | - Javier Garcia-Perez
- AIDS Immunopathogenesis Unit, Instituto de Salud Carlos III, 28220, Majadahonda, Madrid, Spain.
| | - Jose Alcami
- AIDS Immunopathogenesis Unit, Instituto de Salud Carlos III, 28220, Majadahonda, Madrid, Spain.
| | - Fernando Arenzana-Seisdedos
- INSERM U1108, Institut Pasteur, 75015 Paris, France; Viral Pathogenesis Unit, Department of Virology, Institut Pasteur, 75015 Paris, France.
| | - Bernard Lagane
- INSERM U1108, Institut Pasteur, 75015 Paris, France; Viral Pathogenesis Unit, Department of Virology, Institut Pasteur, 75015 Paris, France.
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15
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Tian H, Fürstenberg A, Huber T. Labeling and Single-Molecule Methods To Monitor G Protein-Coupled Receptor Dynamics. Chem Rev 2016; 117:186-245. [DOI: 10.1021/acs.chemrev.6b00084] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- He Tian
- Laboratory of Chemical Biology
and Signal Transduction, The Rockefeller University, 1230 York
Avenue, New York, New York 10065, United States
| | - Alexandre Fürstenberg
- Laboratory of Chemical Biology
and Signal Transduction, The Rockefeller University, 1230 York
Avenue, New York, New York 10065, United States
| | - Thomas Huber
- Laboratory of Chemical Biology
and Signal Transduction, The Rockefeller University, 1230 York
Avenue, New York, New York 10065, United States
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16
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Abstract
Plasmonic imaging is crucial for understanding cellular behaviours for biological sciences, where is used to image and track organelles in cells, such as DNA and virus molecules. Due to the fast dynamics of the intra-cellular processes, it is essential to keep the cells under their native states (i.e. label-free), establishing plasmonic imaging as one of the most powerful tools for studying biological samples. In this article, a theoretical model is presented that accurately predicts the properties of a plasmonic image, paving the route towards the characterization of an imaged nano-object. It is shown that natural modes are not only excited, but actually dominate the intensity and shape of the observed plasmonic image. Hence, the proposed model explains the dynamics forming the plasmonic image and can be used to extract spectroscopy information from current plasmonic imaging techniques.
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17
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Rodríguez-Frade JM, Martínez-Muñoz L, Villares R, Cascio G, Lucas P, Gomariz RP, Mellado M. Chemokine Detection Using Receptors Immobilized on an SPR Sensor Surface. Methods Enzymol 2015; 570:1-18. [PMID: 26921939 DOI: 10.1016/bs.mie.2015.09.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Chemokines and their receptors take part in many physiological and pathological processes, and their dysregulated expression is linked to chronic inflammatory and autoimmune diseases, immunodeficiencies, and cancer. The chemokine receptors, members of the G protein-coupled receptor family, are integral membrane proteins, with seven-transmembrane domains that bind the chemokines and transmit signals through GTP-binding proteins. Many assays used to study the structure, conformation, or activation mechanism of these receptors are based on ligand-binding measurement, as are techniques to detect new agonists and antagonists that modulate chemokine function. Such methods require labeling of the chemokine and/or its receptor, which can alter their binding characteristics. Surface plasmon resonance (SPR) is a powerful technique for analysis of the interaction between immobilized receptors and ligands in solution, in real time, and without labeling. SPR measurements nonetheless require expression and purification steps that can alter the conformation, stability, and function of the chemokine and/or the chemokine receptor. In this review, we focus on distinct methods to immobilize chemokine receptors on the surface of an optical biosensor. We expose the advantages and disadvantages of different protocols used and describe in detail the method to retain viral particles as receptor carriers that can be used for SPR determinations.
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Affiliation(s)
| | - Laura Martínez-Muñoz
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB/CSIC), Madrid, Spain
| | - Ricardo Villares
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB/CSIC), Madrid, Spain
| | - Graciela Cascio
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB/CSIC), Madrid, Spain
| | - Pilar Lucas
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB/CSIC), Madrid, Spain
| | - Rosa P Gomariz
- Department of Cell Biology, Universidad Complutense de Madrid, Madrid, Spain
| | - Mario Mellado
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB/CSIC), Madrid, Spain.
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18
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Real-time monitoring of binding events on a thermostabilized human A2A receptor embedded in a lipid bilayer by surface plasmon resonance. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:1224-33. [PMID: 25725488 DOI: 10.1016/j.bbamem.2015.02.014] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 01/19/2015] [Accepted: 02/13/2015] [Indexed: 12/12/2022]
Abstract
Membrane proteins (MPs) are prevalent drug discovery targets involved in many cell processes. Despite their high potential as drug targets, the study of MPs has been hindered by limitations in expression, purification and stabilization in order to acquire thermodynamic and kinetic parameters of small molecules binding. These bottlenecks are grounded on the mandatory use of detergents to isolate and extract MPs from the cell plasma membrane and the coexistence of multiple conformations, which reflects biochemical versatility and intrinsic instability of MPs. In this work ,we set out to define a new strategy to enable surface plasmon resonance (SPR) measurements on a thermostabilized and truncated version of the human adenosine (A2A) G-protein-coupled receptor (GPCR) inserted in a lipid bilayer nanodisc in a label- and detergent-free manner by using a combination of affinity tags and GFP-based fluorescence techniques. We were able to detect and characterize small molecules binding kinetics on a GPCR fully embedded in a lipid environment. By providing a comparison between different binding assays in membranes, nanodiscs and detergent micelles, we show that nanodiscs can be used for small molecule binding studies by SPR to enhance the MP stability and to trigger a more native-like behaviour when compared to kinetics on A2A receptors isolated in detergent. This work provides thus a new methodology in drug discovery to characterize the binding kinetics of small molecule ligands for MPs targets in a lipid environment.
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19
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Aristotelous T, Hopkins AL, Navratilova I. Surface Plasmon Resonance Analysis of Seven-Transmembrane Receptors. Methods Enzymol 2015; 556:499-525. [DOI: 10.1016/bs.mie.2015.01.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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20
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Martínez-Muñoz L, Barroso R, Paredes AG, Mellado M, Rodríguez-Frade JM. Methods to immobilize GPCR on the surface of SPR sensors. Methods Mol Biol 2015; 1272:173-188. [PMID: 25563184 DOI: 10.1007/978-1-4939-2336-6_12] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The G protein-coupled receptors (GPCRs) form one of the largest membrane receptor families. The nature of the ligands that interact with these receptors is highly diverse; they include light, peptides and hormones, neurotransmitters, and small molecular weight compounds. The GPCRs are involved in a wide variety of physiological processes and thus hold considerable therapeutic potential.GPCR function is usually determined in cell-based assays, whose complexity nonetheless limits their use. The use of alternative, cell-free assays is hampered by the difficulties in purifying these seven-transmembrane domain receptors without altering their functional properties. Several methods have been proposed to immobilize GPCR on biosensor surfaces which use antibodies or avidin-/biotin-based capture procedures, alone or with reconstitution of the GPCR physiological microenvironment. Here we propose a method for GPCR immobilization in their native membrane microenvironment that requires no manipulation of the target receptor and maintains the many conformations GPCR can adopt in the cell membrane.
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Affiliation(s)
- Laura Martínez-Muñoz
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB/CSIC), Darwin 3, Campus de Cantoblanco, Madrid, 28049, Spain
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21
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Chu R, Reczek D, Brondyk W. Capture-stabilize approach for membrane protein SPR assays. Sci Rep 2014; 4:7360. [PMID: 25484112 PMCID: PMC5154539 DOI: 10.1038/srep07360] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 11/19/2014] [Indexed: 02/01/2023] Open
Abstract
Measuring the binding kinetics of antibodies to intact membrane proteins by surface plasmon resonance has been challenging largely because of the inherent difficulties in capturing membrane proteins on chip surfaces while retaining their native conformation. Here we describe a method in which His-tagged CXCR5, a GPCR, was purified and captured on a Biacore chip surface via the affinity tag. The captured receptor protein was then stabilized on the chip surface by limited cross-linking. The resulting chip surface retained ligand binding activity and was used for monoclonal antibody kinetics assays by a standard Biacore kinetics assay method with a simple low pH regeneration step. We demonstrate the advantages of this whole receptor assay when compared to available peptide-based binding assays. We further extended the application of the capture-stabilize approach to virus-like particles and demonstrated its utility analyzing antibodies against CD52, a GPI-anchored protein, in its native membrane environment. The results are the first demonstration of chemically stabilized chip surfaces for membrane protein SPR assays.
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Affiliation(s)
- Ruiyin Chu
- Genzyme Corporation, 49 New York Avenue, Framingham, MA 01701, USA
| | - David Reczek
- Genzyme Corporation, 49 New York Avenue, Framingham, MA 01701, USA
| | - William Brondyk
- Genzyme Corporation, 49 New York Avenue, Framingham, MA 01701, USA
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22
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Angiogenic growth factors interactome and drug discovery: The contribution of surface plasmon resonance. Cytokine Growth Factor Rev 2014; 26:293-310. [PMID: 25465594 DOI: 10.1016/j.cytogfr.2014.11.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 11/10/2014] [Accepted: 11/11/2014] [Indexed: 11/21/2022]
Abstract
Angiogenesis is implicated in several pathological conditions, including cancer, and in regenerative processes, including the formation of collateral blood vessels after stroke. Physiological angiogenesis is the outcome of a fine balance between the action of angiogenic growth factors (AGFs) and anti-angiogenic molecules, while pathological angiogenesis occurs when this balance is pushed toward AGFs. AGFs interact with multiple endothelial cell (EC) surface receptors inducing cell proliferation, migration and proteases upregulation. On the contrary, free or extracellular matrix-associated molecules inhibit angiogenesis by sequestering AGFs (thus hampering EC stimulation) or by interacting with specific EC receptors inducing apoptosis or decreasing responsiveness to AGFs. Thus, angiogenesis results from an intricate network of interactions among pro- and anti-angiogenic molecules, EC receptors and various modulators. All these interactions represent targets for the development of pro- or anti-angiogenic therapies. These aims call for suitable technologies to study the countless interactions occurring during neovascularization. Surface plasmon resonance (SPR) is a label-free optical technique to study biomolecular interactions in real time. It has become the golden standard technology for interaction analysis in biomedical research, including angiogenesis. From a survey of the literature it emerges that SPR has already contributed substantially to the better understanding of the neovascularization process, laying the basis for the decoding of the angiogenesis "interactome" and the identification of "hub molecules" that may represent preferential targets for an efficacious modulation of angiogenesis. Here, the still unexploited full potential of SPR is enlightened, pointing to improvements in its use for a deeper understanding of the mechanisms of neovascularization and the identification of novel anti-angiogenic drugs.
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23
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Adamson RJ, Watts A. Kinetics of the early events of GPCR signalling. FEBS Lett 2014; 588:4701-7. [PMID: 25447525 PMCID: PMC4266533 DOI: 10.1016/j.febslet.2014.10.043] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 10/10/2014] [Accepted: 10/27/2014] [Indexed: 11/28/2022]
Abstract
Little is known of the kinetics of interactions between GPCRs and their signalling partners. NTS1 binds Gαi1 and Gαs with affinities of 15 ± 6 nM and 31 ± 18 nM (SE), respectively. This SPR assay may be applicable to multiple partners in the signalling cascade. We provide the first direct evidence for GPCR-G protein coupling in nanodiscs.
Neurotensin receptor type 1 (NTS1) is a G protein-coupled receptor (GPCR) that affects cellular responses by initiating a cascade of interactions through G proteins. The kinetic details for these interactions are not well-known. Here, NTS1-nanodisc-Gαs and Gαi1 interactions were studied. The binding affinities of Gαi1 and Gαs to NTS1 were directly measured by surface plasmon resonance (SPR) and determined to be 15 ± 6 nM and 31 ± 18 nM, respectively. This SPR configuration permits the kinetics of early events in signalling pathways to be explored and can be used to initiate descriptions of the GPCR interactome.
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Affiliation(s)
- Roslin J Adamson
- Biomembrane Structure Unit, Biochemistry Department, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Anthony Watts
- Biomembrane Structure Unit, Biochemistry Department, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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24
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Conformational antibody binding to a native, cell-free expressed GPCR in block copolymer membranes. PLoS One 2014; 9:e110847. [PMID: 25329156 PMCID: PMC4203850 DOI: 10.1371/journal.pone.0110847] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 09/19/2014] [Indexed: 11/19/2022] Open
Abstract
G-protein coupled receptors (GPCRs) play a key role in physiological processes and are attractive drug targets. Their biophysical characterization is, however, highly challenging because of their innate instability outside a stabilizing membrane and the difficulty of finding a suitable expression system. We here show the cell-free expression of a GPCR, CXCR4, and its direct embedding in diblock copolymer membranes. The polymer-stabilized CXCR4 is readily immobilized onto biosensor chips for label-free binding analysis. Kinetic characterization using a conformationally sensitive antibody shows the receptor to exist in the correctly folded conformation, showing binding behaviour that is commensurate with heterologously expressed CXCR4.
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25
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Shepherd CA, Hopkins AL, Navratilova I. Fragment screening by SPR and advanced application to GPCRs. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 116:113-23. [PMID: 25301577 DOI: 10.1016/j.pbiomolbio.2014.09.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 09/25/2014] [Indexed: 12/31/2022]
Abstract
Surface plasmon resonance (SPR) is one of the primary biophysical methods for the screening of low molecular weight 'fragment' libraries, due to its low protein consumption and 'label-free' methodology. SPR biosensor interaction analysis is employed to both screen and confirm the binding of compounds in fragment screening experiments, as it provides accurate information on the affinity and kinetics of molecular interactions. The most advanced application of the use of SPR for fragment screening is against membrane protein drug targets, such G-protein coupled receptors (GPCRs). Biophysical GPCR assays using SPR have been validated with pharmacological measurements approximate to cell-based methods, yet provide the advantage of biophysical methods in their ability to measure the weak affinities of low molecular weight fragments. A number of SPR fragment screens against GPCRs have now been disclosed in the literature. SPR fragment screening is proving versatile to screen both thermostabilised GPCRs and solubilised wild type receptors. In this chapter, we discuss the state-of-the-art in GPCR fragment screening by SPR and the technical considerations in performing such experiments.
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Affiliation(s)
- Claire A Shepherd
- Division of Biological Chemistry and Drug Discovery, College of Life Science, University of Dundee, Dow Street, Dundee DD1 5EH, United Kingdom
| | - Andrew L Hopkins
- Division of Biological Chemistry and Drug Discovery, College of Life Science, University of Dundee, Dow Street, Dundee DD1 5EH, United Kingdom.
| | - Iva Navratilova
- Division of Biological Chemistry and Drug Discovery, College of Life Science, University of Dundee, Dow Street, Dundee DD1 5EH, United Kingdom
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26
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Wittenberg NJ, Wootla B, Jordan LR, Denic A, Warrington AE, Oh SH, Rodriguez M. Applications of SPR for the characterization of molecules important in the pathogenesis and treatment of neurodegenerative diseases. Expert Rev Neurother 2014; 14:449-63. [PMID: 24625008 PMCID: PMC3989105 DOI: 10.1586/14737175.2014.896199] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Characterization of binding kinetics and affinity between a potential drug and its receptor are key steps in the development of new drugs. Among the techniques available to determine binding affinities, surface plasmon resonance has emerged as the gold standard because it can measure binding and dissociation rates in real-time in a label-free fashion. Surface plasmon resonance is now finding applications in the characterization of molecules for treatment of neurodegenerative diseases, characterization of molecules associated with pathogenesis of neurodegenerative diseases and detection of neurodegenerative disease biomarkers. In addition it has been used in the characterization of a new class of natural autoantibodies that have therapeutic potential in a number of neurologic diseases. In this review we will introduce surface plasmon resonance and describe some applications of the technique that pertain to neurodegenerative disorders and their treatment.
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Affiliation(s)
- Nathan J. Wittenberg
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN USA
| | - Bharath Wootla
- Department of Neurology, Mayo Clinic College of Medicine, Rochester, MN USA
| | - Luke R. Jordan
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN USA
| | - Aleksandar Denic
- Department of Neurology, Mayo Clinic College of Medicine, Rochester, MN USA
| | | | - Sang-Hyun Oh
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN USA
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN USA
| | - Moses Rodriguez
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN USA
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN USA
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27
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Wiktor M, Hartley O, Grzesiek S. Characterization of structure, dynamics, and detergent interactions of the anti-HIV chemokine variant 5P12-RANTES. Biophys J 2013; 105:2586-97. [PMID: 24314089 PMCID: PMC3853082 DOI: 10.1016/j.bpj.2013.10.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 10/14/2013] [Accepted: 10/28/2013] [Indexed: 10/26/2022] Open
Abstract
RANTES (CCL5) is a chemokine that recruits immune cells to inflammatory sites by interacting with the G-protein coupled receptor CCR5, which is also the primary coreceptor used together with CD4 by HIV to enter and infect target cells. Ligands of CCR5, including chemokines and chemokine analogs, are capable of blocking HIV entry, and studies of their structures and interactions with CCR5 will be key to understanding and optimizing HIV inhibition. The RANTES derivative 5P12-RANTES is a highly potent HIV entry inhibitor that is being developed as a topical HIV prevention agent (microbicide). We have characterized the structure and dynamics of 5P12-RANTES by solution NMR. With the exception of the nine flexible N-terminal residues, 5P12-RANTES has the same structure as wild-type RANTES but unlike the wild-type, does not dimerize via its N-terminus. To prepare the ground for interaction studies with detergent-solubilized CCR5, we have also investigated the interaction of RANTES and 5P12-RANTES with various commonly used detergents. Both RANTES variants are stable in Cymal-5, DHPC, Anzergent-3-12, dodecyltrimethylammonium chloride, and a DDM/CHAPS/CHS mixture. Fos-Cholines, dodecyldimethylglycine, and sodium dodecyl-sulfate denature both RANTES variants at low pH, whereas at neutral pH the stability is considerably higher. The onset of Fos-Choline-12-induced denaturation and the denatured state were characterized by circular dichroism and NMR. The detergent interaction starts below the critical micelle concentration at a well-defined mixed hydrophobic/positive surface region of the chemokine, which overlaps with the dimer interface. An increase of Fos-Choline-12 concentration above the critical micelle concentration causes a transition to a denatured state with a high α-helical content.
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Affiliation(s)
- Maciej Wiktor
- Focal Area Structural Biology and Biophysics, Biozentrum, University of Basel, Basel, Switzerland
| | - Oliver Hartley
- Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Stephan Grzesiek
- Focal Area Structural Biology and Biophysics, Biozentrum, University of Basel, Basel, Switzerland
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Tenascin-C is an innate broad-spectrum, HIV-1-neutralizing protein in breast milk. Proc Natl Acad Sci U S A 2013; 110:18220-5. [PMID: 24145401 DOI: 10.1073/pnas.1307336110] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Achieving an AIDS-free generation will require elimination of postnatal transmission of HIV-1 while maintaining the nutritional and immunologic benefits of breastfeeding for infants in developing regions. Maternal/infant antiretroviral prophylaxis can reduce postnatal HIV-1 transmission, yet toxicities and the development of drug-resistant viral strains may limit the effectiveness of this strategy. Interestingly, in the absence of antiretroviral prophylaxis, greater than 90% of infants exposed to HIV-1 via breastfeeding remain uninfected, despite daily mucosal exposure to the virus for up to 2 y. Moreover, milk of uninfected women inherently neutralizes HIV-1 and prevents virus transmission in animal models, yet the factor(s) responsible for this anti-HIV activity is not well-defined. In this report, we identify a primary HIV-1-neutralizing protein in breast milk, Tenascin-C (TNC). TNC is an extracellular matrix protein important in fetal development and wound healing, yet its antimicrobial properties have not previously been established. Purified TNC captured and neutralized multiclade chronic and transmitted/founder HIV-1 variants, and depletion of TNC abolished the HIV-1-neutralizing activity of milk. TNC bound the HIV-1 Envelope protein at a site that is induced upon engagement of its primary receptor, CD4, and is blocked by V3 loop- (19B and F39F) and chemokine coreceptor binding site-directed (17B) monoclonal antibodies. Our results demonstrate the ability of an innate mucosal host protein found in milk to neutralize HIV-1 via binding to the chemokine coreceptor site, potentially explaining why the majority of HIV-1-exposed breastfed infants are protected against mucosal HIV-1 transmission.
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29
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Aristotelous T, Ahn S, Shukla AK, Gawron S, Sassano MF, Kahsai AW, Wingler LM, Zhu X, Tripathi-Shukla P, Huang XP, Riley J, Besnard J, Read KD, Roth BL, Gilbert IH, Hopkins AL, Lefkowitz RJ, Navratilova I. Discovery of β2 Adrenergic Receptor Ligands Using Biosensor Fragment Screening of Tagged Wild-Type Receptor. ACS Med Chem Lett 2013; 4:1005-1010. [PMID: 24454993 PMCID: PMC3892729 DOI: 10.1021/ml400312j] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 09/03/2013] [Indexed: 01/09/2023] Open
Abstract
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G-protein coupled receptors (GPCRs)
are the primary target class
of currently marketed drugs, accounting for about a quarter of all
drug targets of approved medicines. However, almost all the screening
efforts for novel ligand discovery rely exclusively on cellular systems
overexpressing the receptors. An alternative ligand discovery strategy
is a fragment-based drug discovery, where low molecular weight compounds,
known as fragments, are screened as initial starting points for optimization.
However, the screening of fragment libraries usually employs biophysical
screening methods, and as such, it has not been routinely applied
to membrane proteins. We present here a surface plasmon resonance
biosensor approach that enables, cell-free, label-free, fragment screening
that directly measures fragment interactions with wild-type GPCRs.
We exemplify the method by the discovery of novel, selective, high
affinity antagonists of human β2 adrenoceptor.
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Affiliation(s)
- Tonia Aristotelous
- Division
of Biological Chemistry and Drug Discovery, College of
Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, United Kingdom
| | - Seungkirl Ahn
- Department
of Medicine, Duke University Medical Center, Durham, North Carolina 27710, United States
| | - Arun K. Shukla
- Department
of Medicine, Duke University Medical Center, Durham, North Carolina 27710, United States
| | - Sylwia Gawron
- Division
of Biological Chemistry and Drug Discovery, College of
Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, United Kingdom
| | - Maria F. Sassano
- NIMH Psychoactive
Drug Screening Program, Department of Pharmacology, The University of North Carolina Chapel Hill School of Medicine, Chapel Hill, North Carolina 27759, United States
| | - Alem W. Kahsai
- Department
of Medicine, Duke University Medical Center, Durham, North Carolina 27710, United States
| | - Laura M. Wingler
- Department
of Medicine, Duke University Medical Center, Durham, North Carolina 27710, United States
| | - Xiao Zhu
- Department
of Medicine, Duke University Medical Center, Durham, North Carolina 27710, United States
| | - Prachi Tripathi-Shukla
- Department
of Medicine, Duke University Medical Center, Durham, North Carolina 27710, United States
| | - Xi-Ping Huang
- NIMH Psychoactive
Drug Screening Program, Department of Pharmacology, The University of North Carolina Chapel Hill School of Medicine, Chapel Hill, North Carolina 27759, United States
| | - Jennifer Riley
- Division
of Biological Chemistry and Drug Discovery, College of
Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, United Kingdom
| | - Jérémy Besnard
- Division
of Biological Chemistry and Drug Discovery, College of
Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, United Kingdom
| | - Kevin D. Read
- Division
of Biological Chemistry and Drug Discovery, College of
Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, United Kingdom
| | - Bryan L. Roth
- NIMH Psychoactive
Drug Screening Program, Department of Pharmacology, The University of North Carolina Chapel Hill School of Medicine, Chapel Hill, North Carolina 27759, United States
- Department
of Pharmacology and Division of Chemical Biology and Medicinal Chemistry, The University of North Carolina Chapel Hill School of Medicine, Chapel Hill, North Carolina 27759, United States
| | - Ian H. Gilbert
- Division
of Biological Chemistry and Drug Discovery, College of
Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, United Kingdom
| | - Andrew L. Hopkins
- Division
of Biological Chemistry and Drug Discovery, College of
Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, United Kingdom
| | - Robert J. Lefkowitz
- Department
of Medicine, Duke University Medical Center, Durham, North Carolina 27710, United States
- Howard Hughes
Medical Institute, Duke University Medical Center, Durham, North Carolina 27710, United States
- Department
of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, United States
| | - Iva Navratilova
- Division
of Biological Chemistry and Drug Discovery, College of
Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, United Kingdom
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Rusnati M, Chiodelli P, Bugatti A, Urbinati C. Bridging the past and the future of virology: surface plasmon resonance as a powerful tool to investigate virus/host interactions. Crit Rev Microbiol 2013; 41:238-60. [PMID: 24059853 DOI: 10.3109/1040841x.2013.826177] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Despite decades of antiviral drug research and development, viruses still remain a top global healthcare problem. Compared to eukaryotic cells, viruses are composed by a limited numbers of proteins that, nevertheless, set up multiple interactions with cellular components, allowing the virus to take control of the infected cell. Each virus/host interaction can be considered as a therapeutical target for new antiviral drugs but, unfortunately, the systematic study of a so huge number of interactions is time-consuming and expensive, calling for models overcoming these drawbacks. Surface plasmon resonance (SPR) is a label-free optical technique to study biomolecular interactions in real time by detecting reflected light from a prism-gold film interface. Launched 20 years ago, SPR has become a nearly irreplaceable technology for the study of biomolecular interactions. Accordingly, SPR is increasingly used in the field of virology, spanning from the study of biological interactions to the identification of putative antiviral drugs. From the literature available, SPR emerges as an ideal link between conventional biological experimentation and system biology studies functional to the identification of highly connected viral or host proteins that act as nodal points in virus life cycle and thus considerable as therapeutical targets for the development of innovative antiviral strategies.
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Affiliation(s)
- Marco Rusnati
- Department of Molecular and Translational Medicine, University of Brescia , Brescia , Italy
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31
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Expression, surface immobilization, and characterization of functional recombinant cannabinoid receptor CB2. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:2045-56. [PMID: 23777860 DOI: 10.1016/j.bbapap.2013.06.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 06/05/2013] [Accepted: 06/07/2013] [Indexed: 11/23/2022]
Abstract
Human peripheral cannabinoid receptor CB2, a G protein-coupled receptor (GPCR) involved in regulation of immune response has become an important target for pharmaceutical drug development. Structural and functional studies on CB2 may benefit from immobilization of the purified and functional receptor onto a suitable surface at a controlled density and, preferably in a uniform orientation. The goal of this project was to develop a generic strategy for preparation of functional recombinant CB2 and immobilization at solid interfaces. Expression of CB2 as a fusion with Rho-tag (peptide composed of the last nine amino acids of rhodopsin) in E. coli was evaluated in terms of protein levels, accessibility of the tag, and activity of the receptor. The structural integrity of CB2 was tested by ligand binding to the receptor solubilized in detergent micelles, captured on tag-specific monoclonal 1D4 antibody-coated resin. Highly pure and functional CB2 was obtained by sequential chromatography on a 1D4- and Ni-NTA-resin and its affinity to the 1D4 antibody characterized by surface plasmon resonance (SPR). Either the purified receptor or fusion CB2 from the crude cell extract was captured onto a 1D4-coated CM4 chip (Biacore) in a quantitative fashion at uniform orientation as demonstrated by the SPR signal. Furthermore, the accessibility of the extracellular surface of immobilized CB2 and the affinity of interaction with a novel monoclonal antibody NAA-1 was studied by SPR. In summary, we present an integral strategy for purification, surface immobilization, ligand- and antibody binding studies of functional cannabinoid receptor CB2.
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Surface plasmon resonance spectroscopy for characterisation of membrane protein-ligand interactions and its potential for drug discovery. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:43-55. [PMID: 23665295 DOI: 10.1016/j.bbamem.2013.04.028] [Citation(s) in RCA: 257] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 04/25/2013] [Accepted: 04/29/2013] [Indexed: 11/22/2022]
Abstract
Surface plasmon resonance (SPR) spectroscopy is a rapidly developing technique for the study of ligand binding interactions with membrane proteins, which are the major molecular targets for validated drugs and for current and foreseeable drug discovery. SPR is label-free and capable of measuring real-time quantitative binding affinities and kinetics for membrane proteins interacting with ligand molecules using relatively small quantities of materials and has potential to be medium-throughput. The conventional SPR technique requires one binding component to be immobilised on a sensor chip whilst the other binding component in solution is flowed over the sensor surface; a binding interaction is detected using an optical method that measures small changes in refractive index at the sensor surface. This review first describes the basic SPR experiment and the challenges that have to be considered for performing SPR experiments that measure membrane protein-ligand binding interactions, most importantly having the membrane protein in a lipid or detergent environment that retains its native structure and activity. It then describes a wide-range of membrane protein systems for which ligand binding interactions have been characterised using SPR, including the major drug targets G protein-coupled receptors, and how challenges have been overcome for achieving this. Finally it describes some recent advances in SPR-based technology and future potential of the technique to screen ligand binding in the discovery of drugs. This article is part of a Special Issue entitled: Structural and biophysical characterisation of membrane protein-ligand binding.
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Vega B, Calle A, Sánchez A, Lechuga LM, Ortiz AM, Armelles G, Rodríguez-Frade JM, Mellado M. Real-time detection of the chemokine CXCL12 in urine samples by surface plasmon resonance. Talanta 2013; 109:209-15. [PMID: 23618162 DOI: 10.1016/j.talanta.2013.02.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Revised: 01/30/2013] [Accepted: 02/05/2013] [Indexed: 11/25/2022]
Abstract
Surface plasmon resonance (SPR)-based biosensors are established tools for measuring biomolecular interactions between unlabeled analytes in real time, and are thus an ideal method to evaluate G protein-coupled receptor (GPCR) binding interactions. Using as a vehicle lentiviral particles bearing the chemokine receptor CXCR4 in its native plasma membrane context, SPR analysis can be performed using the particles as specific receptors to monitor the CXCR4 interaction with its ligand, CXCL12. The method shows linear correlation in the 5-40 nM range, with low intra- and inter-assay variation, a relative standard deviation <10%, chip-to-chip variation <12%, with stability of the sensor response for more than 150 measurements in the same chip over a four-week period. Our objective was to develop a method for rapid detection and quantification of analytes such as CXCL12 in biological samples, with no need for pretreatment. As a proof of concept, we tested for CXCL12 in urine samples from rheumatoid arthritis patients, who have elevated levels of this chemokine in plasma and synovial fluid. The biosensor method allowed sensitive, reproducible CXCL12 detection in the physiological range, suggesting its value for the diagnosis of autoimmune disorders.
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Affiliation(s)
- Beatriz Vega
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB/CSIC), Campus de Cantoblanco, Madrid, Spain
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34
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Goncalves J, Eilers M, South K, Opefi CA, Laissue P, Reeves PJ, Smith SO. Magic angle spinning nuclear magnetic resonance spectroscopy of G protein-coupled receptors. Methods Enzymol 2013; 522:365-89. [PMID: 23374193 DOI: 10.1016/b978-0-12-407865-9.00017-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
G protein-coupled receptors (GPCRs) represent the largest family of membrane receptors and mediate a diversity of cellular processes. These receptors have a common seven-transmembrane helix structure, yet have evolved to respond to literally thousands of different ligands. In this chapter, we describe the use of magic angle spinning solid-state NMR spectroscopy for characterizing the structure and dynamics of GPCRs. Solid-state NMR spectroscopy is well suited for structural measurements in both detergent micelles and membrane bilayer environments. We first outline the methods for large-scale production of stable, functional receptors containing (13)C- and (15)N-labeled amino acids. The expression methods make use of eukaryotic HEK293S cell lines that produce correctly folded, fully functional receptors. We subsequently describe the basic methods used for magic angle spinning solid-state NMR measurements of chemical shifts and dipolar couplings, which reveal detailed information on GPCR structure and dynamics.
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Affiliation(s)
- Joseph Goncalves
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, USA
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35
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Knepp AM, Sakmar TP, Huber T. Homogeneous time-resolved fluorescence assay to probe folded G protein-coupled receptors. Methods Enzymol 2013; 522:169-89. [PMID: 23374186 DOI: 10.1016/b978-0-12-407865-9.00010-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
Continued advances in G protein-coupled receptor (GPCR) structural biology and biochemistry depend in part on strategies to stabilize these polytopic membrane proteins in purified systems. New methods to measure properly folded GPCRs are needed to facilitate the identification of suitable conditions and ensure sample quality. Most GPCRs do not contain an intrinsic reporter on their functionality, so probes must be introduced. Here, we describe a fluorescence-based approach to quantitatively measure the chemokine receptor CCR5 with labeled antibodies. The assay is exceptionally sensitive and high-throughput. We detail procedures to label antibodies, characterize the system, and process data. We also describe several useful applications, including optimization of incorporation into nanoscale apolipoprotein bound bilayers (NABBs or nanodiscs), measurement of receptor stability, and competition binding assays.
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Affiliation(s)
- Adam M Knepp
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, New York, USA
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36
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Wiktor M, Morin S, Sass HJ, Kebbel F, Grzesiek S. Biophysical and structural investigation of bacterially expressed and engineered CCR5, a G protein-coupled receptor. JOURNAL OF BIOMOLECULAR NMR 2013; 55:79-95. [PMID: 23229639 DOI: 10.1007/s10858-012-9688-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 11/22/2012] [Indexed: 06/01/2023]
Abstract
The chemokine receptor CCR5 belongs to the class of G protein-coupled receptors. Besides its role in leukocyte trafficking, it is also the major HIV-1 coreceptor and hence a target for HIV-1 entry inhibitors. Here, we report Escherichia coli expression and a broad range of biophysical studies on E. coli-produced CCR5. After systematic screening and optimization, we obtained 10 mg of purified, detergent-solubilized, folded CCR5 from 1L culture in a triply isotope-labeled ((2)H/(15)N/(13)C) minimal medium. Thus the material is suitable for NMR spectroscopic studies. The expected α-helical secondary structure content is confirmed by circular dichroism spectroscopy. The solubilized CCR5 is monodisperse and homogeneous as judged by transmission electron microscopy. Interactions of CCR5 with its ligands, RANTES and MIP-1β were assessed by surface plasmon resonance yielding K(D) values in the nanomolar range. Using size exclusion chromatography, stable monomeric CCR5 could be isolated. We show that cysteine residues affect both the yield and oligomer distribution of CCR5. HSQC spectra suggest that the transmembrane domains of CCR5 are in equilibrium between several conformations. In addition we present a model of CCR5 based on the crystal structure of CXCR4 as a starting point for protein engineering.
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Affiliation(s)
- Maciej Wiktor
- Focal Area Structural Biology and Biophysics, Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
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37
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Hausammann GJ, Heitkamp T, Matile H, Gsell B, Thoma R, Schmid G, Frasson D, Sievers M, Hennig M, Grütter MG. Generation of an antibody toolbox to characterize hERG. Biochem Biophys Res Commun 2012; 431:70-5. [PMID: 23277102 DOI: 10.1016/j.bbrc.2012.12.089] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 12/20/2012] [Indexed: 11/28/2022]
Abstract
The human ether-a-go-go related gene (hERG) potassium channel plays a major role in the repolarization of the cardiac action potential. Inhibition of the hERG function by mutations or a wide variety of pharmaceutical compounds cause long QT syndrome and lead to potentially lethal arrhythmias. For detailed insights into the structural and biochemical background of hERG function and drug binding, the purification of recombinant protein is essential. Because the hERG channel is a challenging protein to purify, fast and easy techniques to evaluate different expression, solubilization and purification conditions are of primary importance. Here, we describe the generation of a set of 12 monoclonal antibodies against hERG. Beside their suitability in western blot, immunoprecipitation and immunostaining, these antibodies were used to establish a sandwich ELISA for the detection and relative quantification of hERG in different expression systems. Furthermore, a Fab fragment was used in fluorescence size exclusion chromatography to determine the oligomeric state of hERG after solubilization. These new tools can be used for a fast and efficient screening of expression, solubilization and purification conditions.
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Affiliation(s)
- Georg J Hausammann
- Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland
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38
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Alonzo F, Kozhaya L, Rawlings SA, Reyes-Robles T, DuMont AL, Myszka DG, Landau NR, Unutmaz D, Torres VJ. CCR5 is a receptor for Staphylococcus aureus leukotoxin ED. Nature 2012; 493:51-5. [PMID: 23235831 PMCID: PMC3536884 DOI: 10.1038/nature11724] [Citation(s) in RCA: 224] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 10/26/2012] [Indexed: 12/14/2022]
Abstract
Pore-forming toxins are critical virulence factors for many bacterial pathogens and are central to Staphylococcus aureus-mediated killing of host cells. S. aureus encodes pore-forming bi-component leukotoxins that are toxic towards neutrophils, but also specifically target other immune cells. Despite decades since the first description of staphylococcal leukocidal activity, the host factors responsible for the selectivity of leukotoxins towards different immune cells remain unknown. Here we identify the human immunodeficiency virus (HIV) co-receptor CCR5 as a cellular determinant required for cytotoxic targeting of subsets of myeloid cells and T lymphocytes by the S. aureus leukotoxin ED (LukED). We further demonstrate that LukED-dependent cell killing is blocked by CCR5 receptor antagonists, including the HIV drug maraviroc. Remarkably, CCR5-deficient mice are largely resistant to lethal S. aureus infection, highlighting the importance of CCR5 targeting in S. aureus pathogenesis. Thus, depletion of CCR5(+) leukocytes by LukED suggests a new immune evasion mechanism of S. aureus that can be therapeutically targeted.
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Affiliation(s)
- Francis Alonzo
- Department of Microbiology, New York University School of Medicine, New York, New York 10016, USA
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39
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Seeger C, Christopeit T, Fuchs K, Grote K, Sieghart W, Danielson UH. Histaminergic pharmacology of homo-oligomeric β3 γ-aminobutyric acid type A receptors characterized by surface plasmon resonance biosensor technology. Biochem Pharmacol 2012; 84:341-51. [DOI: 10.1016/j.bcp.2012.04.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Revised: 04/01/2012] [Accepted: 04/09/2012] [Indexed: 12/12/2022]
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40
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Salon JA, Lodowski DT, Palczewski K. The significance of G protein-coupled receptor crystallography for drug discovery. Pharmacol Rev 2012; 63:901-37. [PMID: 21969326 DOI: 10.1124/pr.110.003350] [Citation(s) in RCA: 160] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Crucial as molecular sensors for many vital physiological processes, seven-transmembrane domain G protein-coupled receptors (GPCRs) comprise the largest family of proteins targeted by drug discovery. Together with structures of the prototypical GPCR rhodopsin, solved structures of other liganded GPCRs promise to provide insights into the structural basis of the superfamily's biochemical functions and assist in the development of new therapeutic modalities and drugs. One of the greatest technical and theoretical challenges to elucidating and exploiting structure-function relationships in these systems is the emerging concept of GPCR conformational flexibility and its cause-effect relationship for receptor-receptor and receptor-effector interactions. Such conformational changes can be subtle and triggered by relatively small binding energy effects, leading to full or partial efficacy in the activation or inactivation of the receptor system at large. Pharmacological dogma generally dictates that these changes manifest themselves through kinetic modulation of the receptor's G protein partners. Atomic resolution information derived from increasingly available receptor structures provides an entrée to the understanding of these events and practically applying it to drug design. Supported by structure-activity relationship information arising from empirical screening, a unified structural model of GPCR activation/inactivation promises to both accelerate drug discovery in this field and improve our fundamental understanding of structure-based drug design in general. This review discusses fundamental problems that persist in drug design and GPCR structural determination.
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Affiliation(s)
- John A Salon
- Department of Molecular Structure, Amgen Incorporated, Thousand Oaks, California, USA
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41
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Structure of the Acid-sensing ion channel 1 in complex with the gating modifier Psalmotoxin 1. Nat Commun 2012; 3:936. [DOI: 10.1038/ncomms1917] [Citation(s) in RCA: 141] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Accepted: 05/18/2012] [Indexed: 01/13/2023] Open
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Connell BJ, Baleux F, Coic YM, Clayette P, Bonnaffé D, Lortat-Jacob H. A synthetic heparan sulfate-mimetic peptide conjugated to a mini CD4 displays very high anti- HIV-1 activity independently of coreceptor usage. ACTA ACUST UNITED AC 2012; 19:131-9. [PMID: 22284360 DOI: 10.1016/j.chembiol.2011.12.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 11/30/2011] [Accepted: 12/12/2011] [Indexed: 12/01/2022]
Abstract
The HIV-1 envelope gp120, which features both the virus receptor (CD4) and coreceptor (CCR5/CXCR4) binding sites, offers multiple sites for therapeutic intervention. However, the latter becomes exposed, thus vulnerable to inhibition, only transiently when the virus has already bound cellular CD4. To pierce this defense mechanism, we engineered a series of heparan sulfate mimicking tridecapeptides and showed that one of them target the gp120 coreceptor binding site with μM affinity. Covalently linked to a CD4-mimetic that binds to gp120 and renders the coreceptor binding domain available to be targeted, the conjugated tridecapeptide now displays nanomolar affinity for its target. Using solubilized coreceptors captured on top of sensorchip we show that it inhibits gp120 binding to both CCR5 and CXCR4 and in peripheral blood mononuclear cells broadly inhibits HIV-1 replication with an IC(50) of 1 nM.
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Affiliation(s)
- Bridgette Janine Connell
- CEA, CNRS, Université Joseph Fourier - Grenoble 1, Institut de Biologie Structurale Jean-Pierre Ebel, UMR 5075, 38000 Grenoble, France
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Van den Bergh R, Morin S, Sass HJ, Grzesiek S, Vekemans M, Florence E, Tran HTT, Imiru RG, Heyndrickx L, Vanham G, De Baetselier P, Raes G. Monocytes contribute to differential immune pressure on R5 versus X4 HIV through the adipocytokine visfatin/NAMPT. PLoS One 2012; 7:e35074. [PMID: 22493731 PMCID: PMC3320877 DOI: 10.1371/journal.pone.0035074] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Accepted: 03/13/2012] [Indexed: 11/19/2022] Open
Abstract
Background The immune system exerts a diversifying selection pressure on HIV through cellular, humoral and innate mechanisms. This pressure drives viral evolution throughout infection. A better understanding of the natural immune pressure on the virus during infection is warranted, given the clinical interest in eliciting and sustaining an immune response to HIV which can help to control the infection. We undertook to evaluate the potential of the novel HIV-induced, monocyte-derived factor visfatin to modulate viral infection, as part of the innate immune pressure on viral populations. Results We show that visfatin is capable of selectively inhibiting infection by R5 HIV strains in macrophages and resting PBMC in vitro, while at the same time remaining indifferent to or even favouring infection by X4 strains. Furthermore, visfatin exerts a direct effect on the relative fitness of R5 versus X4 infections in a viral competition setup. Direct interaction of visfatin with the CCR5 receptor is proposed as a putative mechanism for this differential effect. Possible in vivo relevance of visfatin induction is illustrated by its association with the dominance of CXCR4-using HIV in the plasma. Conclusions As an innate factor produced by monocytes, visfatin is capable of inhibiting infections by R5 but not X4 strains, reflecting a potential selective pressure against R5 viruses.
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44
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Emerging role of surface plasmon resonance in fragment-based drug discovery. Future Med Chem 2012; 3:1809-20. [PMID: 22004086 DOI: 10.4155/fmc.11.128] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Surface plasmon resonance (SPR) offers a method of biophysical fragment screening that is fast, efficient, cost effective and accurate. SPR is increasingly being adopted as a secondary assay to validate fragment hits. Recently, technical advances have resulted in the emergence of SPR as a primary screening methodology for fragment-based drug discovery. Moreover, SPR biosensor assays can be developed for a wide range of proteins, including membrane proteins, such as G-protein-coupled receptors. In this review, we discuss the advantages and limitations of SPR fragment screening including experimental consideration of reducing false positive and false negative rates to a minimum. We discuss how ligand efficiency can be used both as a method to eliminate false positives and to understand which fragments in a library may be a source of false negatives.
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Navratilova I, Macdonald G, Robinson C, Hughes S, Mathias J, Phillips C, Cook A. Biosensor-Based Approach to the Identification of Protein Kinase Ligands with Dual-Site Modes of Action. ACTA ACUST UNITED AC 2011; 17:183-93. [DOI: 10.1177/1087057111422746] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The authors have used a surface plasmon resonance (SPR)–based biosensor approach to identify and characterize compounds with a unique binding mode to protein kinases. Biacore was used to characterize hits from an enzymatic high-throughput screen of the Tec family tyrosine kinase, IL2-inducible T cell kinase (ITK). Complex binding kinetics was observed for some compounds, which led to identification of compounds that bound simultaneously at both the adenosine triphosphate (ATP) binding site and a second, allosteric site on ITK. The presence of the second binding site was confirmed by X-ray crystallography. The second site is located in the N-terminal lobe of the protein kinase catalytic domain, adjacent to but distinct from the ATP site. To enable rapid optimization of binding properties, a competition-based Biacore assay has been developed to successfully identify second site noncompetitive binders that have been confirmed by X-ray crystallographic studies. The authors have found that SPR technology is a key method for rapid identification of compounds with dual-site modes of action.
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Affiliation(s)
- Iva Navratilova
- Structural Biology and Biophysics, Pfizer Global Research and Development, Sandwich, Kent, UK
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee, UK
| | - Graeme Macdonald
- Structural Biology and Biophysics, Pfizer Global Research and Development, Sandwich, Kent, UK
| | - Colin Robinson
- Structural Biology and Biophysics, Pfizer Global Research and Development, Sandwich, Kent, UK
| | - Samantha Hughes
- Lead Discovery Chemistry, Pfizer Global Research and Development, Sandwich, Kent, UK
| | - John Mathias
- Lead Discovery Chemistry, Pfizer Global Research and Development, Sandwich, Kent, UK
| | - Chris Phillips
- Structural Biology and Biophysics, Pfizer Global Research and Development, Sandwich, Kent, UK
| | - Andrew Cook
- Lead Discovery Chemistry, Pfizer Global Research and Development, Sandwich, Kent, UK
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Hötzel I, Chiang V, Diao J, Pantua H, Maun HR, Kapadia SB. Efficient production of antibodies against a mammalian integral membrane protein by phage display. Protein Eng Des Sel 2011; 24:679-89. [PMID: 21810920 DOI: 10.1093/protein/gzr039] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The application of phage display technology to mammalian proteins with multiple transmembrane regions has had limited success due to the difficulty in generating these proteins in sufficient amounts and purity. We report here a method that can be easily and generally applied to sorting of phage display libraries with multispan protein targets solubilized in detergent. A key feature of this approach is the production of biotinylated multispan proteins in virions of a baculovirus vector that allows library panning without prior purification of the target protein. We obtained Fab fragments from a naïve synthetic antibody phage library that, when engineered into full-length immunoglobulin (Ig)G, specifically bind cells expressing claudin-1, a protein with four transmembrane regions that is used as an entry co-receptor by the hepatitis C virus (HCV). Affinity-matured variants of one of these antibodies efficiently inhibited HCV infection. The use of baculovirus particles as a source of mammalian multispan protein facilitates the application of phage display to this difficult class of proteins.
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Affiliation(s)
- Isidro Hötzel
- Departments of Antibody Engineering, Genentech, 1 DNA Way, South San Francisco, CA 94080, USA.
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Navratilova I, Besnard J, Hopkins AL. Screening for GPCR Ligands Using Surface Plasmon Resonance. ACS Med Chem Lett 2011; 2:549-554. [PMID: 21765967 PMCID: PMC3137231 DOI: 10.1021/ml2000017] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2011] [Accepted: 05/16/2011] [Indexed: 11/30/2022] Open
Abstract
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G-protein coupled receptors (GPCRs) are a class of drug targets of primary importance. However, receptor assays are based on measurement of either ligand displacement or downstream functional responses, rather than direct observation of ligand binding. Issues of allosteric modulation, probe dependence, and functional selectivity create challenges in selecting suitable assays formats. Therefore, a method that directly measures GPCR–ligand interactions, independent of binding site, probe, and signaling pathway would be a useful primary and orthogonal screening method. We have developed a GPCR biosensor assay protocol that offers the opportunity for high-throughput label-free screening that directly measures GPCR–ligand interactions. The biosensor-based direct screening method identifies the interaction of both orthosteric and allosteric ligands with solubilized, native GPCRs, in a label-free and cell-free environment, thus overcoming the limitations of indirect and displacement assay methods. We exemplify the method by the discovery of novel ligands for the chemokine receptor, CCR5, that are ligand efficient fragments.
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Affiliation(s)
- Iva Navratilova
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee, DD1 5EH, United Kingdom
| | - Jérémy Besnard
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee, DD1 5EH, United Kingdom
| | - Andrew L. Hopkins
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee, DD1 5EH, United Kingdom
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48
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Vega B, Muñoz LM, Holgado BL, Lucas P, Rodríguez-Frade JM, Calle A, Rodríguez-Fernández JL, Lechuga LM, Rodríguez JF, Gutiérrez-Gallego R, Mellado M. Technical advance: Surface plasmon resonance-based analysis of CXCL12 binding using immobilized lentiviral particles. J Leukoc Biol 2011; 90:399-408. [PMID: 21593136 DOI: 10.1189/jlb.1010565] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Use of SPR-based biosensors is an established method for measuring molecular interactions. Their application to the study of GPCRs is nonetheless limited to detergent-solubilized receptors that can then be reconstituted into a lipid environment. Using the chemokine receptor CXCR4 and its specific ligand CXCL12, we outline here a highly reproducible biosensor method based on receptor presentation on the surface of lentiviral particles; the approach is simple and does not require the use of antibodies to achieve correct receptor orientation on the sensorchip surface. We measured the kinetic parameters of CXCR4/CXCL12 binding in a single step and in real time and evaluated the effect of GAG presentation of chemokines on this interaction. The data indicate that at low concentrations, soluble heparin modulates CXCR4/CXCL12 interaction and at high concentrations, abrogates binding. These observations suggest that in addition to their known role in modulating local chemokine availability, GAG affect the receptor/ligand interaction, although their influence on affinity parameters is very limited. The method will also be useful for quantifying these biomarkers in biological fluids and for the development of high-throughput screening for their antagonists.
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Affiliation(s)
- Beatriz Vega
- Department of Immunology and Oncology, Centro Nacional de Biotecnología/Consejo Superior de Investigaciones Cientificas, Campus de Cantoblanco, Madrid, Spain
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He M, Bakken T, Kassimova A, Boshoff C, Philpott N, Cannon ML. Focal adhesion kinase is required for KSHV vGPCR signaling. Mol Carcinog 2011; 51:339-51. [PMID: 21538577 DOI: 10.1002/mc.20790] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 03/21/2011] [Accepted: 04/06/2011] [Indexed: 01/01/2023]
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiologic agent of Kaposi's sarcoma, an angiogenic and inflammatory endothelial cell (EC) tumor that is common in areas of high KSHV prevalence. KSHV encodes a pro-angiogenic viral chemokine receptor (vGPCR) that promotes EC growth in vitro and KS-like tumors in mouse models. vGPCR is therefore considered a viral oncogene that plays a crucial role in the pathobiology of KS. In this study, we show that focal adhesion kinase (FAK) becomes activated upon vGPCR expression in primary ECs and that FAK is required for vGPCR-mediated activation of ERK1/2, NFκB, AP-1, and vGPCR-induced migration and inhibition of anoikis. FAK is crucial to cell motility and tumor invasiveness and is a potential therapeutic target in various malignancies. Our data show that via vGPCR, KSHV has evolved a way to constitutively activate FAK signaling.
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Affiliation(s)
- Meilan He
- The Department of Medicine, The University of Minnesota, Minneapolis, Minnesota; The Center for Infectious Diseases and Microbiology Translational Research, The University of Minnesota, Minneapolis, Minnesota
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Knepp AM, Grunbeck A, Banerjee S, Sakmar TP, Huber T. Direct measurement of thermal stability of expressed CCR5 and stabilization by small molecule ligands. Biochemistry 2011; 50:502-11. [PMID: 21155586 PMCID: PMC3038255 DOI: 10.1021/bi101059w] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The inherent instability of heptahelical G protein-coupled receptors (GPCRs) during purification and reconstitution is a primary impediment to biophysical studies and to obtaining high-resolution crystal structures. New approaches to stabilizing receptors during purification and screening reconstitution procedures are needed. Here we report the development of a novel homogeneous time-resolved fluorescence assay (HTRF) to quantify properly folded CC-chemokine receptor 5 (CCR5). The assay permits high-throughput thermal stability measurements of femtomole quantities of CCR5 in detergent and in engineered nanoscale apolipoprotein-bound bilayer (NABB) particles. We show that recombinantly expressed CCR5 can be incorporated into NABB particles in high yield, resulting in greater thermal stability compared with that of CCR5 in a detergent solution. We also demonstrate that binding of CCR5 to the HIV-1 cellular entry inhibitors maraviroc, AD101, CMPD 167, and vicriviroc dramatically increases receptor stability. The HTRF assay technology reported here is applicable to other membrane proteins and could greatly facilitate structural studies of GPCRs.
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Affiliation(s)
- Adam M Knepp
- Laboratory of Molecular Biology and Biochemistry, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
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