1
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Levesque I, Juliano BR, Parson KF, Ruotolo BT. A Critical Evaluation of Detergent Exchange Methodologies for Membrane Protein Native Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:2662-2671. [PMID: 37956121 DOI: 10.1021/jasms.3c00230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Membrane proteins (MPs) play many critical roles in cellular physiology and constitute the majority of current pharmaceutical targets. However, MPs are comparatively understudied relative to soluble proteins due to the challenges associated with their solubilization in membrane mimetics. Native mass spectrometry (nMS) has emerged as a useful technique to probe the structures of MPs. Typically, nMS studies using MPs have employed detergent micelles to solubilize the MP. Oftentimes, the detergent micelle that the MP was purified in will be exchanged into another detergent prior to analysis by nMS. While methodologies for performing detergent exchange have been extensively described in prior reports, the effectiveness of these protocols remains understudied. Here, we present a critical analysis of detergent exchange efficacy using several model transmembrane proteins and a variety of commonly used detergents, evaluating the completeness of the exchange using a battery of existing protocols. Our data include results for octyl glucoside (OG), octaethylene glycol monododecyl ether (C12E8), and tetraethylene glycol monooctyl ether (C8E4), and these data demonstrate that existing protocols are insufficient and yield incomplete exchange for the proteins under the conditions probed here. In some cases, our data indicate that up to 99% of the measured detergent corresponds to the original pre-exchange detergent rather than the desired post-exchange detergent. We conclude by discussing the need for new detergent exchange methodologies alongside improved exchange yield expectations for studying the potential influence of detergents on MP structures.
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Affiliation(s)
- Iliana Levesque
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Brock R Juliano
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Kristine F Parson
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Brandon T Ruotolo
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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2
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Sawczyc H, Heit S, Watts A. A comparative characterisation of commercially available lipid-polymer nanoparticles formed from model membranes. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2023; 52:39-51. [PMID: 36786921 PMCID: PMC10039845 DOI: 10.1007/s00249-023-01632-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 01/30/2023] [Accepted: 02/01/2023] [Indexed: 02/15/2023]
Abstract
From the discovery of the first membrane-interacting polymer, styrene maleic-acid (SMA), there has been a rapid development of membrane solubilising polymers. These new polymers can solubilise membranes under a wide range of conditions and produce varied sizes of nanoparticles, yet there has been a lack of broad comparison between the common polymer types and solubilising conditions. Here, we present a comparative study on the three most common commercial polymers: SMA 3:1, SMA 2:1, and DIBMA. Additionally, this work presents, for the first time, a comparative characterisation of polymethacrylate copolymer (PMA). Absorbance and dynamic light scattering measurements were used to evaluate solubilisation across key buffer conditions in a simple, adaptable assay format that looked at pH, salinity, and divalent cation concentration. Lipid-polymer nanoparticles formed from SMA variants were found to be the most susceptible to buffer effects, with nanoparticles from either zwitterionic DMPC or POPC:POPG (3:1) bilayers only forming in low to moderate salinity (< 600 mM NaCl) and above pH 6. DIBMA-lipid nanoparticles could be formed above a pH of 5 and were stable in up to 4 M NaCl. Similarly, PMA-lipid nanoparticles were stable in all NaCl concentrations tested (up to 4 M) and a broad pH range (3-10). However, for both DIBMA and PMA nanoparticles there is a severe penalty observed for bilayer solubilisation in non-optimal conditions or when using a charged membrane. Additionally, lipid fluidity of the DMPC-polymer nanoparticles was analysed through cw-EPR, showing no cooperative gel-fluid transition as would be expected for native-like lipid membranes.
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Affiliation(s)
- Henry Sawczyc
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
| | - Sabine Heit
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Anthony Watts
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
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3
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Banerjee C, Liauw BWH, Vafabakhsh R. Visualizing the Conformational Dynamics of Membrane Receptors Using Single-Molecule FRET. J Vis Exp 2022:10.3791/64254. [PMID: 36062999 PMCID: PMC11287711 DOI: 10.3791/64254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/12/2023] Open
Abstract
The ability of cells to respond to external signals is essential for cellular development, growth, and survival. To respond to a signal from the environment, a cell must be able to recognize and process it. This task mainly relies on the function of membrane receptors, whose role is to convert signals into the biochemical language of the cell. G protein-coupled receptors (GPCRs) constitute the largest family of membrane receptor proteins in humans. Among GPCRs, metabotropic glutamate receptors (mGluRs) are a unique subclass that function as obligate dimers and possess a large extracellular domain that contains the ligand-binding site. Recent advances in structural studies of mGluRs have improved the understanding of their activation process. However, the propagation of large-scale conformational changes through mGluRs during activation and modulation is poorly understood. Single-molecule fluorescence resonance energy transfer (smFRET) is a powerful technique to visualize and quantify the structural dynamics of biomolecules at the single-protein level. To visualize the dynamic process of mGluR2 activation, fluorescent conformational sensors based on unnatural amino acid (UAA) incorporation were developed that allowed site-specific protein labeling without perturbation of the native structure of receptors. The protocol described here explains how to perform these experiments, including the novel UAA labeling approach, sample preparation, and smFRET data acquisition and analysis. These strategies are generalizable and can be extended to investigate the conformational dynamics of a variety of membrane proteins.
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Affiliation(s)
| | | | - Reza Vafabakhsh
- Department of Molecular Biosciences, Northwestern University;
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4
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Piper SJ, Johnson RM, Wootten D, Sexton PM. Membranes under the Magnetic Lens: A Dive into the Diverse World of Membrane Protein Structures Using Cryo-EM. Chem Rev 2022; 122:13989-14017. [PMID: 35849490 DOI: 10.1021/acs.chemrev.1c00837] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Membrane proteins are highly diverse in both structure and function and can, therefore, present different challenges for structure determination. They are biologically important for cells and organisms as gatekeepers for information and molecule transfer across membranes, but each class of membrane proteins can present unique obstacles to structure determination. Historically, many membrane protein structures have been investigated using highly engineered constructs or using larger fusion proteins to improve solubility and/or increase particle size. Other strategies included the deconstruction of the full-length protein to target smaller soluble domains. These manipulations were often required for crystal formation to support X-ray crystallography or to circumvent lower resolution due to high noise and dynamic motions of protein subdomains. However, recent revolutions in membrane protein biochemistry and cryo-electron microscopy now provide an opportunity to solve high resolution structures of both large, >1 megadalton (MDa), and small, <100 kDa (kDa), drug targets in near-native conditions, routinely reaching resolutions around or below 3 Å. This review provides insights into how the recent advances in membrane biology and biochemistry, as well as technical advances in cryo-electron microscopy, help us to solve structures of a large variety of membrane protein groups, from small receptors to large transporters and more complex machineries.
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Affiliation(s)
- Sarah J Piper
- Drug Discovery Biology theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia.,ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Rachel M Johnson
- Drug Discovery Biology theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia.,ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Denise Wootten
- Drug Discovery Biology theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia.,ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Patrick M Sexton
- Drug Discovery Biology theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia.,ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
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5
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Petit D, Fernández SG, Zoltowska KM, Enzlein T, Ryan NS, O'Connor A, Szaruga M, Hill E, Vandenberghe R, Fox NC, Chávez-Gutiérrez L. Aβ profiles generated by Alzheimer's disease causing PSEN1 variants determine the pathogenicity of the mutation and predict age at disease onset. Mol Psychiatry 2022; 27:2821-2832. [PMID: 35365805 PMCID: PMC9156411 DOI: 10.1038/s41380-022-01518-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 02/23/2022] [Accepted: 03/03/2022] [Indexed: 02/05/2023]
Abstract
Familial Alzheimer's disease (FAD), caused by mutations in Presenilin (PSEN1/2) and Amyloid Precursor Protein (APP) genes, is associated with an early age at onset (AAO) of symptoms. AAO is relatively consistent within families and between carriers of the same mutations, but differs markedly between individuals carrying different mutations. Gaining a mechanistic understanding of why certain mutations manifest several decades earlier than others is extremely important in elucidating the foundations of pathogenesis and AAO. Pathogenic mutations affect the protease (PSEN/γ-secretase) and the substrate (APP) that generate amyloid β (Aβ) peptides. Altered Aβ metabolism has long been associated with AD pathogenesis, with absolute or relative increases in Aβ42 levels most commonly implicated in the disease development. However, analyses addressing the relationships between these Aβ42 increments and AAO are inconsistent. Here, we investigated this central aspect of AD pathophysiology via comprehensive analysis of 25 FAD-linked Aβ profiles. Hypothesis- and data-driven approaches demonstrate linear correlations between mutation-driven alterations in Aβ profiles and AAO. In addition, our studies show that the Aβ (37 + 38 + 40) / (42 + 43) ratio offers predictive value in the assessment of 'unclear' PSEN1 variants. Of note, the analysis of PSEN1 variants presenting additionally with spastic paraparesis, indicates that a different mechanism underlies the aetiology of this distinct clinical phenotype. This study thus delivers valuable assays for fundamental, clinical and genetic research as well as supports therapeutic interventions aimed at shifting Aβ profiles towards shorter Aβ peptides.
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Affiliation(s)
- Dieter Petit
- VIB-KU Leuven Center for Brain & Disease Research, Herestraat 49 box 602, 3000, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Herestraat 49 box 602, 3000, Leuven, Belgium
| | - Sara Gutiérrez Fernández
- VIB-KU Leuven Center for Brain & Disease Research, Herestraat 49 box 602, 3000, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Herestraat 49 box 602, 3000, Leuven, Belgium
| | - Katarzyna Marta Zoltowska
- VIB-KU Leuven Center for Brain & Disease Research, Herestraat 49 box 602, 3000, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Herestraat 49 box 602, 3000, Leuven, Belgium
| | - Thomas Enzlein
- VIB-KU Leuven Center for Brain & Disease Research, Herestraat 49 box 602, 3000, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Herestraat 49 box 602, 3000, Leuven, Belgium
- Center for Mass Spectrometry and Optical Spectroscopy (CeMOS), Mannheim University of Applied Sciences, Paul-Wittsack Str. 10, 68163, Mannheim, Germany
| | - Natalie S Ryan
- UK Dementia Research Institute at UCL, Queen Square, WC1N 3BG, London, UK
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, Queen Square, WC1N 3BG, London, UK
| | - Antoinette O'Connor
- UK Dementia Research Institute at UCL, Queen Square, WC1N 3BG, London, UK
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, Queen Square, WC1N 3BG, London, UK
| | - Maria Szaruga
- VIB-KU Leuven Center for Brain & Disease Research, Herestraat 49 box 602, 3000, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Herestraat 49 box 602, 3000, Leuven, Belgium
| | - Elizabeth Hill
- VIB-KU Leuven Center for Brain & Disease Research, Herestraat 49 box 602, 3000, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Herestraat 49 box 602, 3000, Leuven, Belgium
| | - Rik Vandenberghe
- Laboratory for Cognitive Neurology, Department of Neurosciences, KU Leuven, Herestraat 49 box 1027, 3000, Leuven, Belgium
- Neurology Department, University Hospitals Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Nick C Fox
- UK Dementia Research Institute at UCL, Queen Square, WC1N 3BG, London, UK
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, Queen Square, WC1N 3BG, London, UK
| | - Lucía Chávez-Gutiérrez
- VIB-KU Leuven Center for Brain & Disease Research, Herestraat 49 box 602, 3000, Leuven, Belgium.
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Herestraat 49 box 602, 3000, Leuven, Belgium.
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6
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Yeast-based directed-evolution for high-throughput structural stabilization of G protein-coupled receptors (GPCRs). Sci Rep 2022; 12:8657. [PMID: 35606532 PMCID: PMC9126886 DOI: 10.1038/s41598-022-12731-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 05/10/2022] [Indexed: 11/08/2022] Open
Abstract
The immense potential of G protein-coupled receptors (GPCRs) as targets for drug discovery is not fully realized due to the enormous difficulties associated with structure elucidation of these profoundly unstable membrane proteins. The existing methods of GPCR stability-engineering are cumbersome and low-throughput; in addition, the scope of GPCRs that could benefit from these techniques is limited. Here, we present a yeast-based screening platform for a single-step isolation of GRCR variants stable in the presence of short-chain detergents, a feature essential for their successful crystallization using vapor diffusion method. The yeast detergent-resistant cell wall presents a unique opportunity for compartmentalization, to physically link the receptor's phenotype to its encoding DNA, and thus enable discovery of stable GPCR variants with unprecedent efficiency. The scope of mutations identified by the method reveals a surprising amenability of the GPCR scaffold to stabilization, and suggests an intriguing possibility of amending the stability properties of GPCR by varying the structural status of the C-terminus.
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7
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Morrison KA, Heesom KJ, Edler KJ, Doutch J, Price GJ, Koumanov F, Whitley P. Development of Methodology to Investigate the Surface SMALPome of Mammalian Cells. Front Mol Biosci 2021; 8:780033. [PMID: 34869600 PMCID: PMC8637157 DOI: 10.3389/fmolb.2021.780033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 10/14/2021] [Indexed: 11/24/2022] Open
Abstract
Extraction of membrane proteins from biological membranes has traditionally involved detergents. In the past decade, a new technique has been developed, which uses styrene maleic acid (SMA) copolymers to extract membrane proteins into nanodiscs without the requirement of detergents. SMA nanodiscs are compatible with analytical techniques, such as small-angle scattering, NMR spectroscopy, and DLS, and are therefore an attractive medium for membrane protein characterization. While mass spectrometry has also been reported as a technique compatible with copolymer extraction, most studies have focused on lipidomics, which involves solvent extraction of lipids from nanodiscs prior to mass-spectrometry analysis. In this study, mass spectrometry proteomics was used to investigate whether there are qualitative or quantitative differences in the mammalian plasma membrane proteins extracted with SMA compared to a detergent control. For this, cell surface proteins of 3T3L1 fibroblasts were biotinylated and extracted using either SMA or detergent. Following affinity pull-down of biotinylated proteins with NeutrAvidin beads, samples were analyzed by nanoLC-MS. Here, we report for the first time, a global proteomics protocol for detection of a mammalian cell "SMALPome", membrane proteins incorporated into SMA nanodiscs. Removal of SMA from samples prior to processing of samples for mass spectrometry was a crucial step in the protocol. The reported surface SMALPome of 3T3L1 fibroblasts consists of 205 integral membrane proteins. It is apparent that the detergent extraction method used is, in general, quantitatively more efficient at extracting proteins from the plasma membrane than SMA extraction. However, samples prepared following detergent extraction contained a greater proportion of proteins that were considered to be "non-specific" than in samples prepared from SMA extracts. Tantalizingly, it was also observed that proteins detected uniquely or highly preferentially in pull-downs from SMA extracts were primarily multi-spanning membrane proteins. These observations hint at qualitative differences between SMA and detergent extraction that are worthy of further investigation.
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Affiliation(s)
- Kerrie A. Morrison
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
- Department of Chemistry, University of Bath, Bath, United Kingdom
- Centre for Sustainable Circular Technologies, University of Bath, Bath, United Kingdom
| | - Kate J. Heesom
- University of Bristol, Proteomics Facility, Bristol, United Kingdom
| | - Karen J. Edler
- Department of Chemistry, University of Bath, Bath, United Kingdom
| | - James Doutch
- Rutherford Appleton Laboratory, ISIS Pulsed Neutron and Muon Source, Harwell Oxford, United Kingdom
| | - Gareth J. Price
- Department of Chemistry, University of Bath, Bath, United Kingdom
- Department of Chemistry, Khalifa University, Abu Dhabi, United Arab Emirates
| | | | - Paul Whitley
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
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8
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Thermostability-based binding assays reveal complex interplay of cation, substrate and lipid binding in the bacterial DASS transporter, VcINDY. Biochem J 2021; 478:3847-3867. [PMID: 34643224 PMCID: PMC8652582 DOI: 10.1042/bcj20210061] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 10/08/2021] [Accepted: 10/13/2021] [Indexed: 12/04/2022]
Abstract
The divalent anion sodium symporter (DASS) family of transporters (SLC13 family in humans) are key regulators of metabolic homeostasis, disruption of which results in protection from diabetes and obesity, and inhibition of liver cancer cell proliferation. Thus, DASS transporter inhibitors are attractive targets in the treatment of chronic, age-related metabolic diseases. The characterisation of several DASS transporters has revealed variation in the substrate selectivity and flexibility in the coupling ion used to power transport. Here, using the model DASS co-transporter, VcINDY from Vibrio cholerae, we have examined the interplay of the three major interactions that occur during transport: the coupling ion, the substrate, and the lipid environment. Using a series of high-throughput thermostability-based interaction assays, we have shown that substrate binding is Na+-dependent; a requirement that is orchestrated through a combination of electrostatic attraction and Na+-induced priming of the binding site architecture. We have identified novel DASS ligands and revealed that ligand binding is dominated by the requirement of two carboxylate groups in the ligand that are precisely distanced to satisfy carboxylate interaction regions of the substrate-binding site. We have also identified a complex relationship between substrate and lipid interactions, which suggests a dynamic, regulatory role for lipids in VcINDY's transport cycle.
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9
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Majeed S, Ahmad AB, Sehar U, Georgieva ER. Lipid Membrane Mimetics in Functional and Structural Studies of Integral Membrane Proteins. MEMBRANES 2021; 11:685. [PMID: 34564502 PMCID: PMC8470526 DOI: 10.3390/membranes11090685] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/18/2021] [Accepted: 08/30/2021] [Indexed: 12/12/2022]
Abstract
Integral membrane proteins (IMPs) fulfill important physiological functions by providing cell-environment, cell-cell and virus-host communication; nutrients intake; export of toxic compounds out of cells; and more. However, some IMPs have obliterated functions due to polypeptide mutations, modifications in membrane properties and/or other environmental factors-resulting in damaged binding to ligands and the adoption of non-physiological conformations that prevent the protein from returning to its physiological state. Thus, elucidating IMPs' mechanisms of function and malfunction at the molecular level is important for enhancing our understanding of cell and organism physiology. This understanding also helps pharmaceutical developments for restoring or inhibiting protein activity. To this end, in vitro studies provide invaluable information about IMPs' structure and the relation between structural dynamics and function. Typically, these studies are conducted on transferred from native membranes to membrane-mimicking nano-platforms (membrane mimetics) purified IMPs. Here, we review the most widely used membrane mimetics in structural and functional studies of IMPs. These membrane mimetics are detergents, liposomes, bicelles, nanodiscs/Lipodisqs, amphipols, and lipidic cubic phases. We also discuss the protocols for IMPs reconstitution in membrane mimetics as well as the applicability of these membrane mimetic-IMP complexes in studies via a variety of biochemical, biophysical, and structural biology techniques.
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Affiliation(s)
- Saman Majeed
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
| | - Akram Bani Ahmad
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
| | - Ujala Sehar
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
| | - Elka R Georgieva
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
- Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Science Center, Lubbock, TX 79409, USA
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10
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Hoi KK, Bada Juarez JF, Judge PJ, Yen HY, Wu D, Vinals J, Taylor GF, Watts A, Robinson CV. Detergent-free Lipodisq Nanoparticles Facilitate High-Resolution Mass Spectrometry of Folded Integral Membrane Proteins. NANO LETTERS 2021; 21:2824-2831. [PMID: 33787280 PMCID: PMC8050825 DOI: 10.1021/acs.nanolett.0c04911] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 03/04/2021] [Indexed: 05/04/2023]
Abstract
Integral membrane proteins pose considerable challenges to mass spectrometry (MS) owing to the complexity and diversity of the components in their native environment. Here, we use native MS to study the post-translational maturation of bacteriorhodopsin (bR) and archaerhodopsin-3 (AR3), using both octyl-glucoside detergent micelles and lipid-based nanoparticles. A lower collision energy was required to obtain well-resolved spectra for proteins in styrene-maleic acid copolymer (SMA) Lipodisqs than in membrane scaffold protein (MSP) Nanodiscs. By comparing spectra of membrane proteins prepared using the different membrane mimetics, we found that SMA may favor selective solubilization of correctly folded proteins and better preserve native lipid interactions than other membrane mimetics. Our spectra reveal the correlation between the post-translation modifications (PTMs), lipid-interactions, and protein-folding states of bR, providing insights into the process of maturation of the photoreceptor proteins.
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Affiliation(s)
- Kin Kuan Hoi
- Department
of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Juan Francisco Bada Juarez
- Department
of Biochemistry, Biomembrane Structure Unit, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Peter J. Judge
- Department
of Biochemistry, Biomembrane Structure Unit, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Hsin-Yung Yen
- Department
of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
- OMass
Therapeutics, The Schrödinger
Building, Oxford Science Park, Oxford OX4
4GE, United Kingdom
| | - Di Wu
- Department
of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Javier Vinals
- Department
of Biochemistry, Biomembrane Structure Unit, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Garrick F. Taylor
- Department
of Biochemistry, Biomembrane Structure Unit, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Anthony Watts
- Department
of Biochemistry, Biomembrane Structure Unit, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Carol V. Robinson
- Department
of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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11
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Errasti-Murugarren E, Bartoccioni P, Palacín M. Membrane Protein Stabilization Strategies for Structural and Functional Studies. MEMBRANES 2021; 11:membranes11020155. [PMID: 33671740 PMCID: PMC7926488 DOI: 10.3390/membranes11020155] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 02/15/2021] [Accepted: 02/18/2021] [Indexed: 02/07/2023]
Abstract
Accounting for nearly two-thirds of known druggable targets, membrane proteins are highly relevant for cell physiology and pharmacology. In this regard, the structural determination of pharmacologically relevant targets would facilitate the intelligent design of new drugs. The structural biology of membrane proteins is a field experiencing significant growth as a result of the development of new strategies for structure determination. However, membrane protein preparation for structural studies continues to be a limiting step in many cases due to the inherent instability of these molecules in non-native membrane environments. This review describes the approaches that have been developed to improve membrane protein stability. Membrane protein mutagenesis, detergent selection, lipid membrane mimics, antibodies, and ligands are described in this review as approaches to facilitate the production of purified and stable membrane proteins of interest for structural and functional studies.
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Affiliation(s)
- Ekaitz Errasti-Murugarren
- Laboratory of Amino acid Transporters and Disease, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac 10, 08028 Barcelona, Spain;
- CIBERER (Centro Español en Red de Biomedicina de Enfermedades Raras), 28029 Barcelona, Spain
- Correspondence: (E.E.-M.); (M.P.)
| | - Paola Bartoccioni
- Laboratory of Amino acid Transporters and Disease, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac 10, 08028 Barcelona, Spain;
- CIBERER (Centro Español en Red de Biomedicina de Enfermedades Raras), 28029 Barcelona, Spain
| | - Manuel Palacín
- Laboratory of Amino acid Transporters and Disease, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac 10, 08028 Barcelona, Spain;
- CIBERER (Centro Español en Red de Biomedicina de Enfermedades Raras), 28029 Barcelona, Spain
- Department of Biochemistry and Molecular Biomedicine, Universitat de Barcelona, 08028 Barcelona, Spain
- Correspondence: (E.E.-M.); (M.P.)
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12
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Affiliation(s)
- James E. Keener
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Guozhi Zhang
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Michael T. Marty
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
- Bio5 Institute, University of Arizona, Tucson, AZ 85721, USA
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13
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Lavington S, Watts A. Lipid nanoparticle technologies for the study of G protein-coupled receptors in lipid environments. Biophys Rev 2020; 12:10.1007/s12551-020-00775-5. [PMID: 33215301 PMCID: PMC7755959 DOI: 10.1007/s12551-020-00775-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 11/06/2020] [Indexed: 12/12/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are a large family of integral membrane proteins which conduct a wide range of biological roles and represent significant drug targets. Most biophysical and structural studies of GPCRs have been conducted on detergent-solubilised receptors, and it is clear that detergents can have detrimental effects on GPCR function. Simultaneously, there is increasing appreciation of roles for specific lipids in modulation of GPCR function. Lipid nanoparticles such as nanodiscs and styrene maleic acid lipid particles (SMALPs) offer opportunities to study integral membrane proteins in lipid environments, in a form that is soluble and amenable to structural and biophysical experiments. Here, we review the application of lipid nanoparticle technologies to the study of GPCRs, assessing the relative merits and limitations of each system. We highlight how these technologies can provide superior platforms to detergents for structural and biophysical studies of GPCRs and inform on roles for protein-lipid interactions in GPCR function.
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Affiliation(s)
- Steven Lavington
- Biochemistry Department, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Anthony Watts
- Biochemistry Department, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
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14
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Reis RI, Moraes I. Probing Membrane Protein Assembly into Nanodiscs by In Situ Dynamic Light Scattering: A 2A Receptor as a Case Study. BIOLOGY 2020; 9:biology9110400. [PMID: 33202740 PMCID: PMC7696381 DOI: 10.3390/biology9110400] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 11/02/2020] [Accepted: 11/12/2020] [Indexed: 12/20/2022]
Abstract
Simple Summary Located within the biological cell membranes, integral membrane proteins are responsible for a large variety of vital cellular processes. In humans, nearly a quarter of the genome codes integral membrane proteins, therefore malfunction of these proteins is associated with a variety of symptoms and diseases such as obesity, cancer and Parkinson’s disease. Clearly, knowledge of membrane proteins behaviour, in both structural and functional terms, is important not only in medicine but also in the design of better drugs with improved pharmaceutical properties. Nevertheless, much still remains unknown about these proteins, mainly because of the technical challenges associated with their production and stability in vitro once removed from their native lipidic environment. Recently, several membrane mimetic systems have been developed including nanodisc lipid particles. Nanodiscs are self-assembled lipidic structures that “trap” membrane proteins into a disc shaped phospholipid bilayer that is stabilised by a belt made of a protein know as membrane scaffold protein (MSP). Membrane proteins assembled into lipidic nanodiscs can maintain their structural and functional integrity and are compatible with most biophysical methods. Here we demonstrate the use of in situ dynamic light scattering as a high-throughput screening tool to assess the best conditions for nanodisc assembly and protein incorporation. Abstract Membrane proteins play a crucial role in cell physiology by participating in a variety of essential processes such as transport, signal transduction and cell communication. Hence, understanding their structure–function relationship is vital for the improvement of therapeutic treatments. Over the last decade, based on the development of detergents, amphipoles and styrene maleic-acid lipid particles (SMALPs), remarkable accomplishments have been made in the field of membrane protein structural biology. Nevertheless, there are still many drawbacks associated with protein–detergent complexes, depending on the protein in study or experimental application. Recently, newly developed membrane mimetic systems have become very popular for allowing a structural and functional characterisation of membrane proteins in vitro. The nanodisc technology is one such valuable tool, which provides a more native-like membrane environment than detergent micelles or liposomes. In addition, it is also compatible with many biophysical and biochemical methods. Here we describe the use of in situ dynamic light scattering to accurately and rapidly probe membrane proteins’ reconstitution into nanodiscs. The adenosine type 2A receptor (A2AR) was used as a case study.
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Affiliation(s)
- Rosana I. Reis
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK;
- Research Complex at Harwell Rutherford, Appleton Laboratory, Harwell, Oxford, Didcot OX11 0FA, UK
| | - Isabel Moraes
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK;
- Research Complex at Harwell Rutherford, Appleton Laboratory, Harwell, Oxford, Didcot OX11 0FA, UK
- Correspondence:
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15
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Jones AJY, Gabriel F, Tandale A, Nietlispach D. Structure and Dynamics of GPCRs in Lipid Membranes: Physical Principles and Experimental Approaches. Molecules 2020; 25:E4729. [PMID: 33076366 PMCID: PMC7587580 DOI: 10.3390/molecules25204729] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/11/2020] [Accepted: 10/12/2020] [Indexed: 02/06/2023] Open
Abstract
Over the past decade, the vast amount of information generated through structural and biophysical studies of GPCRs has provided unprecedented mechanistic insight into the complex signalling behaviour of these receptors. With this recent information surge, it has also become increasingly apparent that in order to reproduce the various effects that lipids and membranes exert on the biological function for these allosteric receptors, in vitro studies of GPCRs need to be conducted under conditions that adequately approximate the native lipid bilayer environment. In the first part of this review, we assess some of the more general effects that a membrane environment exerts on lipid bilayer-embedded proteins such as GPCRs. This is then followed by the consideration of more specific effects, including stoichiometric interactions with specific lipid subtypes. In the final section, we survey a range of different membrane mimetics that are currently used for in vitro studies, with a focus on NMR applications.
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Affiliation(s)
| | | | | | - Daniel Nietlispach
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK; (A.J.Y.J.); (F.G.); (A.T.)
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16
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Wu X, Kuang N, Chen L, Fan Y, Fu F, Li J, Zhang J. Synthesis and property of alkyl dioxyethyl α- D-xyloside. J Mol Liq 2020; 315:113770. [PMID: 32834260 PMCID: PMC7342039 DOI: 10.1016/j.molliq.2020.113770] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 07/01/2020] [Accepted: 07/06/2020] [Indexed: 11/21/2022]
Abstract
Due to the inherent defects of the long alkyl chain in the related hydrophilicity and water solubility, alkyl α-D-xylosides (7) had hardly the practical application as sugar-based surfactants and should be reconstructed to obtain alkyl dioxyethyl α-D-xylosides (5) with dioxyethylene fragment (-(OCH2CH2)2-)) as the hydrophilic spacer to increase the related TPSA value. With D-xylose as the raw material, 1,2-cis alkyl dioxyethyl α-D-xylosides (5a-5f, n = 6-12) were stereoselectively synthesized. Their physicochemical properties including water solubility, surface tension, foamability, emulsification, thermotropic liquid crystal, and hygroscopicity had been investigated. Their water solubility was found to decrease gradually whereas their calculated HLB numbers were 14.72 → 11.67 (n = 6 → 12) with increasing alkyl chain length (n). Dodecyl dioxyethyl α-D-xyloside (5f) had not water solubility because the HLB number was low. Furthermore, their CMC values decreased with increasing the alkyl chain length, and the CMC value of decyl dioxyethyl α-D-xyloside (5e) was as low as 9.21 × 10-5 mol·L-1. Octyl dioxyethyl α-D-xyloside (5c) had the lowest surface tension (27.25 mN·m-1) at the CMC. Both of nonyl and decyl dioxyethyl α-D-xylosides (5d & 5e) possessed good foaming power and foam stability. Decyl dioxyethyl α-D-xyloside (5e) had the strongest emulsifying property either in the toluene/water system or in the octane/water system. Nonyl dioxyethyl α-D-xylosides (5d) had the most stylish SA texture. Hexyl dioxyethyl α-D-xyloside (5a) possessed the strongest hygroscopicity. Therefore, the alkyl dioxyethyl α-D-xylosides as a class of novel sugar-based surfactants will be widely considered as promising candidates for various practical applications.
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Affiliation(s)
- Xiubing Wu
- College of Chemistry, Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, Xiangtan University, Xiangtan City, 411105, Hunan, People's Republic of China
| | - Na Kuang
- College of Chemistry, Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, Xiangtan University, Xiangtan City, 411105, Hunan, People's Republic of China
| | - Langqiu Chen
- College of Chemistry, Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, Xiangtan University, Xiangtan City, 411105, Hunan, People's Republic of China
| | - Yulin Fan
- College of Chemistry, Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, Xiangtan University, Xiangtan City, 411105, Hunan, People's Republic of China
| | - Fang Fu
- College of Chemistry, Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, Xiangtan University, Xiangtan City, 411105, Hunan, People's Republic of China
| | - Jiping Li
- College of Chemistry, Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, Xiangtan University, Xiangtan City, 411105, Hunan, People's Republic of China
| | - Jing Zhang
- College of Chemistry, Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, Xiangtan University, Xiangtan City, 411105, Hunan, People's Republic of China
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17
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Lee S, Ghosh S, Jana S, Robertson N, Tate CG, Vaidehi N. How Do Branched Detergents Stabilize GPCRs in Micelles? Biochemistry 2020; 59:2125-2134. [PMID: 32437610 PMCID: PMC7302508 DOI: 10.1021/acs.biochem.0c00183] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
![]()
The
structural and functional properties of G protein-coupled receptors
(GPCRs) are often studied in a detergent micellar environment, but
many GPCRs tend to denature or aggregate in short alkyl chain detergents.
In our previous work [Lee, S., et al. (2016) J. Am. Chem.
Soc.138, 15425–15433], we showed
that GPCRs in alkyl glucosides were highly dynamic, resulting in the
penetration of detergent molecules between transmembrane α-helices,
which is the initial step in receptor denaturation. Although this
was not observed for GPCRs in dodecyl maltoside (DDM, also known as
lauryl maltoside), even this detergent is not mild enough to preserve
the integrity of many GPCRs during purification. Lauryl maltose neopentylglycol
(LMNG) detergents have been found to have significant advantages for
purifying GPCRs in a native state as they impart more stability to
the receptor than DDM. To gain insights into how they stabilize GPCRs,
we used atomistic molecular dynamics simulations of wild type adenosine
A2A receptor (WT-A2AR), thermostabilized A2AR (tA2AR), and wild type β2-adrenoceptor
(β2AR) in a variety of detergents (LMNG, DMNG, OGNG,
and DDM). Analysis of molecular dynamics simulations of tA2AR in LMNG, DMNG, and OGNG showed that this series of detergents exhibited
behavior very similar to that of an analogous series of detergents
DDM, DM, and OG in our previous study. However, there was a striking
difference upon comparison of the behavior of LMNG to that of DDM.
LMNG showed considerably less motion than DDM, which resulted in the
enhanced density of the aliphatic chains around the hydrophobic regions
of the receptor and considerably more hydrogen bond formation between
the head groups. This contributed to enhanced interaction energies
between both detergent molecules and between the receptor and detergent,
explaining the enhanced stability of GPCRs purified in this detergent.
Branched detergents occlude between transmembrane helices and reduce
their flexibility. Our results provide a rational foundation to develop
detergent variants for stabilizing membrane proteins.
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Affiliation(s)
- Sangbae Lee
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, 1500 East Duarte Road, Duarte, California 91010, United States
| | - Soumadwip Ghosh
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, 1500 East Duarte Road, Duarte, California 91010, United States
| | - Suvamay Jana
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, 1500 East Duarte Road, Duarte, California 91010, United States
| | - Nathan Robertson
- Heptares Therapeutics Ltd., BioPark, Broadwater Road, Welwyn Garden City, AL7 3AX, U.K
| | - Christopher G Tate
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, U.K
| | - Nagarajan Vaidehi
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, 1500 East Duarte Road, Duarte, California 91010, United States
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18
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Urner LH, Liko I, Yen HY, Hoi KK, Bolla JR, Gault J, Almeida FG, Schweder MP, Shutin D, Ehrmann S, Haag R, Robinson CV, Pagel K. Modular detergents tailor the purification and structural analysis of membrane proteins including G-protein coupled receptors. Nat Commun 2020; 11:564. [PMID: 31992701 PMCID: PMC6987200 DOI: 10.1038/s41467-020-14424-8] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 12/19/2019] [Indexed: 01/29/2023] Open
Abstract
Detergents enable the purification of membrane proteins and are indispensable reagents in structural biology. Even though a large variety of detergents have been developed in the last century, the challenge remains to identify guidelines that allow fine-tuning of detergents for individual applications in membrane protein research. Addressing this challenge, here we introduce the family of oligoglycerol detergents (OGDs). Native mass spectrometry (MS) reveals that the modular OGD architecture offers the ability to control protein purification and to preserve interactions with native membrane lipids during purification. In addition to a broad range of bacterial membrane proteins, OGDs also enable the purification and analysis of a functional G-protein coupled receptor (GPCR). Moreover, given the modular design of these detergents, we anticipate fine-tuning of their properties for specific applications in structural biology. Seen from a broader perspective, this represents a significant advance for the investigation of membrane proteins and their interactions with lipids. Detergents are indispensable reagents in membrane protein structural biology. Here, L. H. Urner and co-workers introduce oligoglycerol detergents (OGDs) and use native mass spectrometry to show how interactions of membrane proteins with native membrane lipids can be preserved during purification.
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Affiliation(s)
- Leonhard H Urner
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, 14195, Berlin, Germany.,Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK
| | - Idlir Liko
- Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK.,OMass Therapeutics, The Schrödinger Building, Heatley Road, The Oxford Science Park, Oxford, OX4 4GE, UK
| | - Hsin-Yung Yen
- Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK.,OMass Therapeutics, The Schrödinger Building, Heatley Road, The Oxford Science Park, Oxford, OX4 4GE, UK
| | - Kin-Kuan Hoi
- Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK
| | - Jani Reddy Bolla
- Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK
| | - Joseph Gault
- Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK
| | - Fernando Gonçalves Almeida
- OMass Therapeutics, The Schrödinger Building, Heatley Road, The Oxford Science Park, Oxford, OX4 4GE, UK
| | - Marc-Philip Schweder
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, 14195, Berlin, Germany
| | - Denis Shutin
- Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK
| | - Svenja Ehrmann
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, 14195, Berlin, Germany
| | - Rainer Haag
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, 14195, Berlin, Germany.
| | - Carol V Robinson
- Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK.
| | - Kevin Pagel
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, 14195, Berlin, Germany. .,Department of Molecular Physics, Fritz Haber Institute of the Max Planck Society, 14195, Berlin, Germany.
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19
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Bada Juarez JF, Muñoz-García JC, Inácio Dos Reis R, Henry A, McMillan D, Kriek M, Wood M, Vandenplas C, Sands Z, Castro L, Taylor R, Watts A. Detergent-free extraction of a functional low-expressing GPCR from a human cell line. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1862:183152. [PMID: 31843475 DOI: 10.1016/j.bbamem.2019.183152] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 11/21/2019] [Accepted: 12/05/2019] [Indexed: 01/02/2023]
Abstract
Dopamine receptors (DRs) are class A G-Protein Coupled Receptors (GPCRs) prevalent in the central nervous system (CNS). These receptors mediate physiological functions ranging from voluntary movement and reward recognition to hormonal regulation and hypertension. Drugs targeting dopaminergic neurotransmission have been employed to treat several neurological and psychiatric disorders, including Parkinson's disease, schizophrenia, Huntington's disease, attention deficit hyperactivity disorder (ADHD), and Tourette's syndrome. In vivo, incorporation of GPCRs into lipid membranes is known to be key to their biological function and, by inference, maintenance of their tertiary structure. A further significant challenge in the structural and biochemical characterization of human DRs is their low levels of expression in mammalian cells. Thus, the purification and enrichment of DRs whilst retaining their structural integrity and function is highly desirable for biophysical studies. A promising new approach is the use of styrene-maleic acid (SMA) copolymer to solubilize GPCRs directly in their native environment, to produce polymer-assembled Lipodisqs (LQs). We have developed a novel methodology to yield detergent-free D1-containing Lipodisqs directly from HEK293f cells expressing wild-type human dopamine receptor 1 (D1). We demonstrate that D1 in the Lipodisq retains activity comparable to that in the native environment and report, for the first time, the affinity constant for the interaction of the peptide neurotransmitter neurotensin (NT) with D1, in the native state.
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Affiliation(s)
| | - Juan C Muñoz-García
- Biochemistry Department, Oxford University, South Parks Road, Oxford OX1 3QU, UK; School of Pharmacy, University of East Anglia, Norwich NR4 7TJ, UK
| | | | | | | | - Marco Kriek
- UCB Celltech, 216 Bath Road, Slough SL1 3WE, UK
| | - Martyn Wood
- UCB BioPharma SPRL, Braine-l'Alleud, Belgium
| | | | - Zara Sands
- UCB Celltech, 216 Bath Road, Slough SL1 3WE, UK
| | - Luis Castro
- UCB Celltech, 216 Bath Road, Slough SL1 3WE, UK
| | | | - Anthony Watts
- Biochemistry Department, Oxford University, South Parks Road, Oxford OX1 3QU, UK.
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20
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Das M, Du Y, Mortensen JS, Ramos M, Ghani L, Lee HJ, Bae HE, Byrne B, Guan L, Loland CJ, Kobilka BK, Chae PS. Trehalose-cored amphiphiles for membrane protein stabilization: importance of the detergent micelle size in GPCR stability. Org Biomol Chem 2019; 17:3249-3257. [PMID: 30843907 DOI: 10.1039/c8ob03153c] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Despite their importance in biology and medicinal chemistry, structural and functional studies of membrane proteins present major challenges. To study diverse membrane proteins, it is crucial to have the correct detergent to efficiently extract and stabilize the proteins from the native membranes for biochemical/biophysical downstream analyses. But many membrane proteins, particularly eukaryotic ones, are recalcitrant to stabilization and/or crystallization with currently available detergents and thus there are major efforts to develop novel detergents with enhanced properties. Here, a novel class of trehalose-cored amphiphiles are introduced, with multiple alkyl chains and carbohydrates projecting from the trehalose core unit are introduced. A few members displayed enhanced protein stabilization behavior compared to the benchmark conventional detergent, n-dodecyl-β-d-maltoside (DDM), for multiple tested membrane proteins: (i) a bacterial leucine transporter (LeuT), (ii) the R. capsulatus photosynthetic superassembly, and (iii) the human β2 adrenergic receptor (β2AR). Due to synthetic convenience and their favourable behaviors for a range of membrane proteins, these agents have potential for membrane protein research. In addition, the detergent property-efficacy relationship discussed here will guide future design of novel detergents.
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Affiliation(s)
- Manabendra Das
- Department of Bionanotechnology, Hanyang University, Ansan, 155-88, Korea.
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21
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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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22
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Kwan TOC, Reis R, Siligardi G, Hussain R, Cheruvara H, Moraes I. Selection of Biophysical Methods for Characterisation of Membrane Proteins. Int J Mol Sci 2019; 20:E2605. [PMID: 31137900 PMCID: PMC6566885 DOI: 10.3390/ijms20102605] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 05/22/2019] [Accepted: 05/24/2019] [Indexed: 02/01/2023] Open
Abstract
Over the years, there have been many developments and advances in the field of integral membrane protein research. As important pharmaceutical targets, it is paramount to understand the mechanisms of action that govern their structure-function relationships. However, the study of integral membrane proteins is still incredibly challenging, mostly due to their low expression and instability once extracted from the native biological membrane. Nevertheless, milligrams of pure, stable, and functional protein are always required for biochemical and structural studies. Many modern biophysical tools are available today that provide critical information regarding to the characterisation and behaviour of integral membrane proteins in solution. These biophysical approaches play an important role in both basic research and in early-stage drug discovery processes. In this review, it is not our objective to present a comprehensive list of all existing biophysical methods, but a selection of the most useful and easily applied to basic integral membrane protein research.
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Affiliation(s)
- Tristan O C Kwan
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK.
- Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot OX11 0FA, UK.
| | - Rosana Reis
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK.
- Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot OX11 0FA, UK.
| | - Giuliano Siligardi
- Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, UK.
| | - Rohanah Hussain
- Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, UK.
| | - Harish Cheruvara
- Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot OX11 0FA, UK.
- Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, UK.
| | - Isabel Moraes
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK.
- Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot OX11 0FA, UK.
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23
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Bada Juarez JF, Harper AJ, Judge PJ, Tonge SR, Watts A. From polymer chemistry to structural biology: The development of SMA and related amphipathic polymers for membrane protein extraction and solubilisation. Chem Phys Lipids 2019; 221:167-175. [PMID: 30940445 DOI: 10.1016/j.chemphyslip.2019.03.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 03/15/2019] [Accepted: 03/15/2019] [Indexed: 12/13/2022]
Abstract
Nanoparticles assembled with poly(styrene-maleic acid) copolymers, identified in the literature as Lipodisq, SMALPs or Native Nanodisc, are routinely used as membrane mimetics to stabilise protein structures in their native conformation. To date, transmembrane proteins of varying complexity (up to 8 beta strands or 48 alpha helices) and of a range of molecular weights (from 27 kDa up to 500 kDa) have been incorporated into this particle system for structural and functional studies. SMA and related amphipathic polymers have become versatile components of the biochemist's tool kit for the stabilisation, extraction and structural characterization of membrane proteins by techniques including cryo-EM and X-ray crystallography. Lipodisq formation does not require the use of conventional detergents and thus avoids their associated detrimental consequences. Here the development of this technology, from its fundamental concept and design to the diverse range of experimental methodologies to which it can now be applied, will be reviewed.
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Affiliation(s)
| | - Andrew J Harper
- Malvern Cosmeceutics Ltd, Malvern Hills Science Park, Geraldine Road, Malvern, WR14 3SZ, UK
| | - Peter J Judge
- Biochemistry Department, Oxford University, South Parks Road, Oxford, OX1 3QU, UK
| | - Stephen R Tonge
- Malvern Cosmeceutics Ltd, Malvern Hills Science Park, Geraldine Road, Malvern, WR14 3SZ, UK
| | - Anthony Watts
- Biochemistry Department, Oxford University, South Parks Road, Oxford, OX1 3QU, UK.
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Breyton C, Javed W, Vermot A, Arnaud CA, Hajjar C, Dupuy J, Petit-Hartlein I, Le Roy A, Martel A, Thépaut M, Orelle C, Jault JM, Fieschi F, Porcar L, Ebel C. Assemblies of lauryl maltose neopentyl glycol (LMNG) and LMNG-solubilized membrane proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:939-957. [PMID: 30776334 DOI: 10.1016/j.bbamem.2019.02.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 02/08/2019] [Accepted: 02/08/2019] [Indexed: 12/11/2022]
Abstract
Laurylmaltose neopentylglycol (LMNG) bears two linked hydrophobic chains of equal length and two hydrophilic maltoside groups. It arouses a strong interest in the field of membrane protein biochemistry, since it was shown to efficiently solubilize and stabilize membrane proteins often better than the commonly used dodecylmaltopyranoside (DDM), and to allow structure determination of some challenging membrane proteins. However, LMNG was described to form large micelles, which could be unfavorable for structural purposes. We thus investigated its auto-assemblies and the association state of different membrane proteins solubilized in LMNG by analytical ultracentrifugation, size exclusion chromatography coupled to light scattering, centrifugation on sucrose gradient and/or small angle scattering. At high concentrations (in the mM range), LMNG forms long rods, and it stabilized the membrane proteins investigated herein, i.e. a bacterial multidrug transporter, BmrA; a prokaryotic analogous of the eukaryotic NADPH oxidases, SpNOX; an E. coli outer membrane transporter, FhuA; and the halobacterial bacteriorhodopsin, bR. BmrA, in the Apo and the vanadate-inhibited forms showed reduced kinetics of limited proteolysis in LMNG compared to DDM. Both SpNOX and BmrA display an increased specific activity in LMNG compared to DDM. The four proteins form LMNG complexes with their usual quaternary structure and with usual amount of bound detergent. No heterogeneous complexes related to the large micelle size of LMNG alone were observed. In conditions where LMNG forms assemblies of large size, FhuA crystals diffracting to 4.0 Å were obtained by vapor diffusion. LMNG large micelle size thus does not preclude membrane protein homogeneity and crystallization.
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Affiliation(s)
- Cécile Breyton
- Univ. Grenoble Alpes, CNRS, CEA, Institute for Structural Biology (IBS), 38000 Grenoble, France
| | - Waqas Javed
- Univ. Grenoble Alpes, CNRS, CEA, Institute for Structural Biology (IBS), 38000 Grenoble, France; University of Lyon, CNRS, UMR5086, Molecular Microbiology and Structural Biochemistry, IBCP, Lyon 69367, France
| | - Annelise Vermot
- Univ. Grenoble Alpes, CNRS, CEA, Institute for Structural Biology (IBS), 38000 Grenoble, France
| | - Charles-Adrien Arnaud
- Univ. Grenoble Alpes, CNRS, CEA, Institute for Structural Biology (IBS), 38000 Grenoble, France
| | - Christine Hajjar
- Univ. Grenoble Alpes, CNRS, CEA, Institute for Structural Biology (IBS), 38000 Grenoble, France
| | - Jérôme Dupuy
- Univ. Grenoble Alpes, CNRS, CEA, Institute for Structural Biology (IBS), 38000 Grenoble, France
| | - Isabelle Petit-Hartlein
- Univ. Grenoble Alpes, CNRS, CEA, Institute for Structural Biology (IBS), 38000 Grenoble, France
| | - Aline Le Roy
- Univ. Grenoble Alpes, CNRS, CEA, Institute for Structural Biology (IBS), 38000 Grenoble, France
| | - Anne Martel
- Institut Max Von Laue Paul Langevin, 38042 Grenoble, France
| | - Michel Thépaut
- Univ. Grenoble Alpes, CNRS, CEA, Institute for Structural Biology (IBS), 38000 Grenoble, France
| | - Cédric Orelle
- University of Lyon, CNRS, UMR5086, Molecular Microbiology and Structural Biochemistry, IBCP, Lyon 69367, France
| | - Jean-Michel Jault
- University of Lyon, CNRS, UMR5086, Molecular Microbiology and Structural Biochemistry, IBCP, Lyon 69367, France
| | - Franck Fieschi
- Univ. Grenoble Alpes, CNRS, CEA, Institute for Structural Biology (IBS), 38000 Grenoble, France
| | - Lionel Porcar
- Institut Max Von Laue Paul Langevin, 38042 Grenoble, France
| | - Christine Ebel
- Univ. Grenoble Alpes, CNRS, CEA, Institute for Structural Biology (IBS), 38000 Grenoble, France.
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25
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Ghosh S, Bierig T, Lee S, Jana S, Löhle A, Schnapp G, Tautermann CS, Vaidehi N. Engineering Salt Bridge Networks between Transmembrane Helices Confers Thermostability in G-Protein-Coupled Receptors. J Chem Theory Comput 2018; 14:6574-6585. [PMID: 30359017 DOI: 10.1021/acs.jctc.8b00602] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Introduction of specific point mutations has been an effective strategy in enhancing the thermostability of G-protein-coupled receptors (GPCRs). Our previous work showed that a specific residue position on transmembrane helix 6 (TM6) in class A GPCRs consistently yields thermostable mutants. The crystal structure of human chemokine receptor CCR5 also showed increased thermostability upon mutation of two positions, A233D6.33 and K303E7.59. With the goal of testing the transferability of these two thermostabilizing mutations in other chemokine receptors, we tested the mutations A237D6.33 and R307E7.59 in human CCR3 for thermostability and aggregation properties in detergent solution. Interestingly, the double mutant exhibited a 6-10-fold decrease in the aggregation propensity of the wild-type protein. This is in stark contrast to the two single mutants whose aggregation properties resemble the wild type (WT). Moreover, unlike in CCR5, the two single mutants separately showed no increase in thermostability compared to the wild-type CCR3, while the double-mutant A237D6.33/R307E7.59 confers an increase of 2.6 °C in the melting temperature compared to the WT. Extensive all-atom molecular dynamics (MD) simulations in detergent micelles show that a salt bridge network between transmembrane helices TM3, TM6, and TM7 that is absent in the two single mutants confers stability in the double mutant. The free energy surface of the double mutant shows conformational homogeneity compared to the single mutants. An annular n-dodecyl maltoside detergent layer packs tighter to the hydrophobic surface of the double-mutant CCR3 compared to the single mutants providing additional stability. The purification of other C-C chemokine receptors lacking such stabilizing residues may benefit from the incorporation of these two point mutations.
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Affiliation(s)
- Soumadwip Ghosh
- Department of Molecular Imaging and Therapy , Beckman Research Institute of the City of Hope , 1500 East Duarte Road , Duarte , California 91010 , United States
| | - Tobias Bierig
- Department of Medicinal Chemistry , Boehringer Ingelheim Pharma GmbH & Company KG , Birkendorfer Strasse 65 , D-88397 Biberach an der Riss , Germany
| | | | | | | | - Gisela Schnapp
- Department of Medicinal Chemistry , Boehringer Ingelheim Pharma GmbH & Company KG , Birkendorfer Strasse 65 , D-88397 Biberach an der Riss , Germany
| | - Christofer S Tautermann
- Department of Medicinal Chemistry , Boehringer Ingelheim Pharma GmbH & Company KG , Birkendorfer Strasse 65 , D-88397 Biberach an der Riss , Germany
| | - Nagarajan Vaidehi
- Department of Molecular Imaging and Therapy , Beckman Research Institute of the City of Hope , 1500 East Duarte Road , Duarte , California 91010 , United States
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26
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Nji E, Chatzikyriakidou Y, Landreh M, Drew D. An engineered thermal-shift screen reveals specific lipid preferences of eukaryotic and prokaryotic membrane proteins. Nat Commun 2018; 9:4253. [PMID: 30315156 PMCID: PMC6185904 DOI: 10.1038/s41467-018-06702-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Accepted: 09/19/2018] [Indexed: 12/11/2022] Open
Abstract
Membrane bilayers are made up of a myriad of different lipids that regulate the functional activity, stability, and oligomerization of many membrane proteins. Despite their importance, screening the structural and functional impact of lipid–protein interactions to identify specific lipid requirements remains a major challenge. Here, we use the FSEC-TS assay to show cardiolipin-dependent stabilization of the dimeric sodium/proton antiporter NhaA, demonstrating its ability to detect specific protein-lipid interactions. Based on the principle of FSEC-TS, we then engineer a simple thermal-shift assay (GFP-TS), which facilitates the high-throughput screening of lipid- and ligand- interactions with membrane proteins. By comparing the thermostability of medically relevant eukaryotic membrane proteins and a selection of bacterial counterparts, we reveal that eukaryotic proteins appear to have evolved to be more dependent to the presence of specific lipids. Membrane bilayers are made up of a myriad of different lipids that affect membrane proteins, but identifying those specific lipid requirements remains a challenge. Here authors present an engineered thermal-shift screen which reveals specific lipid preferences of eukaryotic and prokaryotic membrane proteins.
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Affiliation(s)
- Emmanuel Nji
- Centre for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91, Stockholm, Sweden
| | - Yurie Chatzikyriakidou
- Centre for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91, Stockholm, Sweden
| | - Michael Landreh
- SciLifeLab and Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-171 65, Stockholm, Sweden
| | - David Drew
- Centre for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91, Stockholm, Sweden.
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27
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Suzuki N, Takamuku Y, Asakawa T, Inai M, Hino T, Iwata S, Kan T, Murata T. An efficient screening method for purifying and crystallizing membrane proteins using modified clear-native PAGE. Anal Biochem 2018; 548:7-14. [DOI: 10.1016/j.ab.2018.02.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 01/01/2018] [Accepted: 02/08/2018] [Indexed: 10/18/2022]
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28
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Veith K, Martinez Molledo M, Almeida Hernandez Y, Josts I, Nitsche J, Löw C, Tidow H. Lipid-like Peptides can Stabilize Integral Membrane Proteins for Biophysical and Structural Studies. Chembiochem 2017; 18:1735-1742. [PMID: 28603929 PMCID: PMC5601290 DOI: 10.1002/cbic.201700235] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Indexed: 12/30/2022]
Abstract
A crucial bottleneck in membrane protein structural biology is the difficulty in identifying a detergent that can maintain the stability and functionality of integral membrane proteins (IMPs). Detergents are poor membrane mimics, and their common use in membrane protein crystallography may be one reason for the challenges in obtaining high-resolution crystal structures of many IMP families. Lipid-like peptides (LLPs) have detergent-like properties and have been proposed as alternatives for the solubilization of G protein-coupled receptors and other membrane proteins. Here, we systematically analyzed the stabilizing effect of LLPs on integral membrane proteins of different families. We found that LLPs could significantly stabilize detergent-solubilized IMPs in vitro. This stabilizing effect depended on the chemical nature of the LLP and the intrinsic stability of a particular IMP in the detergent. Our results suggest that screening a subset of LLPs is sufficient to stabilize a particular IMP, which can have a substantial impact on the crystallization and quality of the crystal.
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Affiliation(s)
- Katharina Veith
- The Hamburg Centre for Ultrafast ImagingDepartment of ChemistryInstitute for Biochemistry and Molecular BiologyUniversity of HamburgMartin-Luther-King-Platz 620146HamburgGermany
| | - Maria Martinez Molledo
- Centre for Structural Systems Biology (CSSB)DESY and European Molecular Biology Laboratory HamburgNotkestrasse 8522607HamburgGermany
| | - Yasser Almeida Hernandez
- The Hamburg Centre for Ultrafast ImagingDepartment of ChemistryInstitute for Biochemistry and Molecular BiologyUniversity of HamburgMartin-Luther-King-Platz 620146HamburgGermany
| | - Inokentijs Josts
- The Hamburg Centre for Ultrafast ImagingDepartment of ChemistryInstitute for Biochemistry and Molecular BiologyUniversity of HamburgMartin-Luther-King-Platz 620146HamburgGermany
| | - Julius Nitsche
- The Hamburg Centre for Ultrafast ImagingDepartment of ChemistryInstitute for Biochemistry and Molecular BiologyUniversity of HamburgMartin-Luther-King-Platz 620146HamburgGermany
| | - Christian Löw
- Centre for Structural Systems Biology (CSSB)DESY and European Molecular Biology Laboratory HamburgNotkestrasse 8522607HamburgGermany
- Department of Medical Biochemistry and BiophysicsKarolinska InstitutetScheeles väg 217177StockholmSweden
| | - Henning Tidow
- The Hamburg Centre for Ultrafast ImagingDepartment of ChemistryInstitute for Biochemistry and Molecular BiologyUniversity of HamburgMartin-Luther-King-Platz 620146HamburgGermany
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29
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Tian H, Sakmar TP, Huber T. The Energetics of Chromophore Binding in the Visual Photoreceptor Rhodopsin. Biophys J 2017; 113:60-72. [PMID: 28700926 DOI: 10.1016/j.bpj.2017.05.036] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 05/04/2017] [Accepted: 05/25/2017] [Indexed: 01/06/2023] Open
Abstract
The visual photoreceptor rhodopsin is a prototypical G-protein-coupled receptor (GPCR) that stabilizes its inverse agonist ligand, 11-cis-retinal (11CR), by a covalent, protonated Schiff base linkage. In the visual dark adaptation, the fundamental molecular event after photobleaching of rhodopsin is the recombination reaction between its apoprotein opsin and 11CR. Here we present a detailed analysis of the kinetics and thermodynamics of this reaction, also known as the "regeneration reaction". We compared the regeneration of purified rhodopsin reconstituted into phospholipid/detergent bicelles with rhodopsin reconstituted into detergent micelles. We found that the lipid bilayer of bicelles stabilized the chromophore-free opsin over the long timescale required for the regeneration experiments, and also facilitated the ligand reuptake binding reaction. We utilized genetic code expansion and site-specific bioorthogonal labeling of rhodopsin with Alexa488 to enable, to our knowledge, a novel fluorescence resonance energy transfer-based measurement of the binding kinetics between opsin and 11CR. Based on these results, we report a complete energy diagram for the regeneration reaction of rhodopsin. We show that the dissociation reaction of rhodopsin to 11CR and opsin has a 25-pM equilibrium dissociation constant, which corresponds to only 0.3 kcal/mol stabilization compared to the noncovalent, tightly bound antagonist-GPCR complex of iodopindolol and β-adrenergic receptor. However, 11CR dissociates four orders-of-magnitude slower than iodopindolol, which corresponds to a 6-kcal/mol higher dissociation free energy barrier. We further used isothermal titration calorimetry to show that ligand binding in rhodopsin is enthalpy driven with -22 kcal/mol, which is 12 kcal/mol more stable than the antagonist-GPCR complex. Our data provide insights into the ligand-receptor binding reaction for rhodopsin in particular, and for GPCRs more broadly.
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Affiliation(s)
- He Tian
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, New York
| | - Thomas P Sakmar
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, New York; Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Huddinge, Sweden.
| | - Thomas Huber
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, New York.
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30
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Strege A, Carpenter B, Edwards PC, Tate CG. Strategy for the Thermostabilization of an Agonist-Bound GPCR Coupled to a G Protein. Methods Enzymol 2017; 594:243-264. [PMID: 28779842 DOI: 10.1016/bs.mie.2017.05.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Structure determination of G protein-coupled receptors (GPCRs) in the inactive state bound to high-affinity antagonists has been very successful through the implementation of a number of protein engineering and crystallization strategies. However, the structure determination of GPCRs in their fully active state coupled to a G protein is still very challenging. Recently, mini-G proteins were developed, which recapitulate the coupling of a full heterotrimeric G protein to a GPCR despite being less than one-third of the size. This allowed the structure determination of the agonist-bound adenosine A2A receptor (A2AR) coupled to mini-Gs. Although this is extremely encouraging, A2AR is very stable compared with many other GPCRs, particularly when an agonist is bound. In contrast, the agonist-bound conformation of the human corticotropin-releasing factor receptor is considerably less stable, impeding the formation of good quality crystals for structure determination. We have therefore developed a novel strategy for the thermostabilization of a GPCR-mini-G protein complex. In this chapter, we will describe the theoretical and practical principles of the thermostability assay for stabilizing this complex, discuss its strengths and weaknesses, and show some typical results from the thermostabilization process.
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Affiliation(s)
- Annette Strege
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Byron Carpenter
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
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31
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Grisshammer R. New approaches towards the understanding of integral membrane proteins: A structural perspective on G protein-coupled receptors. Protein Sci 2017; 26:1493-1504. [PMID: 28547763 DOI: 10.1002/pro.3200] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 05/12/2017] [Accepted: 05/15/2017] [Indexed: 01/12/2023]
Abstract
Three-dimensional structure determination of integral membrane proteins has advanced in unprecedented detail our understanding of mechanistic events of how ion channels, transporters, receptors, and enzymes function. This exciting progress required a tremendous amount of methods development, as exemplified here with G protein-coupled receptors (GPCRs): Optimizing the production of GPCRs in recombinant hosts; increasing the probability of crystal formation using high-affinity ligands, nanobodies, and minimal G proteins for co-crystallization, thus stabilizing receptors into one conformation; using the T4 lysozyme technology and other fusion partners to promote crystal contacts; advancing crystallization methods including the development of novel detergents, and miniaturization and automation of the lipidic cubic phase crystallization method; the concept of conformational thermostabilization of GPCRs; and developing microfocus X-ray synchrotron technologies to analyze small GPCR crystals. However, despite immense progress to explain how GPCRs function, many receptors pose intractable hurdles to structure determination at this time. Three emerging methods, serial femtosecond crystallography, micro electron diffraction, and single particle electron cryo-microscopy, hold promise to overcome current limitations in structural membrane biology.
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Affiliation(s)
- Reinhard Grisshammer
- Department of Health and Human Services, Membrane Protein Structure Function Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Rockville, Maryland, 20852
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