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Zhu L, Chang Y, Li Y, Qiao M, Liu L. Biosensors Based on the Binding Events of Nitrilotriacetic Acid-Metal Complexes. BIOSENSORS 2023; 13:bios13050507. [PMID: 37232868 DOI: 10.3390/bios13050507] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 04/21/2023] [Accepted: 04/24/2023] [Indexed: 05/27/2023]
Abstract
Molecular immobilization and recognition are two key events for the development of biosensors. The general ways for the immobilization and recognition of biomolecules include covalent coupling reactions and non-covalent interactions of antigen-antibody, aptamer-target, glycan-lectin, avidin-biotin and boronic acid-diol. Tetradentate nitrilotriacetic acid (NTA) is one of the most common commercial ligands for chelating metal ions. The NTA-metal complexes show high and specific affinity toward hexahistidine tags. Such metal complexes have been widely utilized in protein separation and immobilization for diagnostic applications since most of commercialized proteins have been integrated with hexahistidine tags by synthetic or recombinant techniques. This review focused on the development of biosensors with NTA-metal complexes as the binding units, mainly including surface plasmon resonance, electrochemistry, fluorescence, colorimetry, surface-enhanced Raman scattering spectroscopy, chemiluminescence and so on.
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Affiliation(s)
- Lin Zhu
- College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang 455000, China
| | - Yong Chang
- College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang 455000, China
| | - Yingying Li
- College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang 455000, China
| | - Mingyi Qiao
- College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang 455000, China
| | - Lin Liu
- College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang 455000, China
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Marconnet A, Michon B, Prost B, Solgadi A, Le Bon C, Giusti F, Tribet C, Zoonens M. Influence of Hydrophobic Groups Attached to Amphipathic Polymers on the Solubilization of Membrane Proteins along with Their Lipids. Anal Chem 2022; 94:14151-14158. [PMID: 36200347 DOI: 10.1021/acs.analchem.2c01746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
One of the biggest challenges in membrane protein (MP) research is to secure physiologically relevant structural and functional information after extracting MPs from their native membrane. Amphipathic polymers represent attractive alternatives to detergents for stabilizing MPs in aqueous solutions. The predominant polymers used in MP biochemistry and biophysics are amphipols (APols), one class of which, styrene maleic acid (SMA) copolymers and their derivatives, has proven particularly efficient at MP extraction. In order to examine the relationship between the chemical structure of the polymers and their ability to extract MPs from membranes, we have developed two novel classes of APols bearing either cycloalkane or aryl (aromatic) rings, named CyclAPols and ArylAPols, respectively. The effect on solubilization of such parameters as the density of hydrophobic groups, the number of carbon atoms and their arrangement in the hydrophobic moieties, as well as the charge density of the polymers was evaluated. The membrane-solubilizing efficiency of the SMAs, CyclAPols, and ArylAPols was compared using as models (i) two MPs, BmrA and a GFP-fused version of LacY, overexpressed in the inner membrane of Escherichia coli, and (ii) bacteriorhodopsin, naturally expressed in the purple membrane of Halobacterium salinarum. This analysis shows that, as compared to SMAs, the novel APols feature an improved efficiency at extracting MPs while preserving native protein-lipid interactions.
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Affiliation(s)
- Anaïs Marconnet
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, CNRS, UMR 7099, Université Paris Cité, F-75005 Paris, France.,Fondation Edmond de Rothschild pour le développement de la recherche scientifique, Institut de Biologie Physico-Chimique, F-75005 Paris, France
| | - Baptiste Michon
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, CNRS, UMR 7099, Université Paris Cité, F-75005 Paris, France.,Fondation Edmond de Rothschild pour le développement de la recherche scientifique, Institut de Biologie Physico-Chimique, F-75005 Paris, France
| | - Bastien Prost
- UMS-IPSIT SAMM, Inserm, CNRS, Ingénierie et Plateformes au Service de l'Innovation Thérapeutique, Université Paris-Saclay, F-92296 Châtenay-Malabry, France
| | - Audrey Solgadi
- UMS-IPSIT SAMM, Inserm, CNRS, Ingénierie et Plateformes au Service de l'Innovation Thérapeutique, Université Paris-Saclay, F-92296 Châtenay-Malabry, France
| | - Christel Le Bon
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, CNRS, UMR 7099, Université Paris Cité, F-75005 Paris, France.,Fondation Edmond de Rothschild pour le développement de la recherche scientifique, Institut de Biologie Physico-Chimique, F-75005 Paris, France
| | - Fabrice Giusti
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, CNRS, UMR 7099, Université Paris Cité, F-75005 Paris, France.,Fondation Edmond de Rothschild pour le développement de la recherche scientifique, Institut de Biologie Physico-Chimique, F-75005 Paris, France
| | - Christophe Tribet
- P.A.S.T.E.U.R., Département de Chimie, École Normale Supérieure, PSL University, CNRS, Sorbonne Université, F-75005 Paris, France
| | - Manuela Zoonens
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, CNRS, UMR 7099, Université Paris Cité, F-75005 Paris, France.,Fondation Edmond de Rothschild pour le développement de la recherche scientifique, Institut de Biologie Physico-Chimique, F-75005 Paris, France
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Clénet D, Clavier L, Strobbe B, Le Bon C, Zoonens M, Saulnier A. Full-length G glycoprotein directly extracted from rabies virus with detergent and then stabilized by amphipols in liquid and freeze-dried forms. Biotechnol Bioeng 2021; 118:4317-4330. [PMID: 34297405 PMCID: PMC9291542 DOI: 10.1002/bit.27900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 06/22/2021] [Accepted: 07/09/2021] [Indexed: 11/11/2022]
Abstract
Pathogen surface antigens are at the forefront of the viral strategy when invading host organisms. These antigens, including membrane proteins (MPs), are broadly targeted by the host immune response. Obtaining these MPs in a soluble and stable form constitutes a real challenge, regardless of the application purposes (e.g. quantification/characterization assays, diagnosis, and preventive and curative strategies). A rapid process to obtain a native-like antigen by solubilization of a full-length MP directly from a pathogen is reported herein. Rabies virus (RABV) was used as a model for this demonstration and its full-length G glycoprotein (RABV-G) was stabilized with amphipathic polymers, named amphipols (APols). The stability of RABV-G trapped in APol A8-35 (RABV-G/A8-35) was evaluated under different stress conditions (temperature, agitation, and light exposure). RABV-G/A8-35 in liquid form exhibited higher unfolding temperature (+6°C) than in detergent and was demonstrated to be antigenically stable over 1 month at 5°C and 25°C. Kinetic modeling of antigenicity data predicted antigenic stability of RABV-G/A8-35 in a solution of up to 1 year at 5°C. The RABV-G/A8-35 complex formulated in an optimized buffer composition and subsequently freeze-dried displayed long-term stability for 2-years at 5, 25, and 37°C. This study reports for the first time that a natural full-length MP extracted from a virus, complexed to APols and subsequently freeze-dried, displayed long-term antigenic stability, without requiring storage under refrigerated conditions.
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Affiliation(s)
- Didier Clénet
- Bioprocess R&D DepartmentSanofi PasteurMarcy l'EtoileFrance
| | - Léna Clavier
- Bioprocess R&D DepartmentSanofi PasteurMarcy l'EtoileFrance
| | - Benoît Strobbe
- Bioprocess R&D DepartmentSanofi PasteurMarcy l'EtoileFrance
| | - Christel Le Bon
- Laboratoire de Biologie Physico‐Chimique des Protéines Membranaires, CNRS, Institut de Biologie Physico‐ChimiqueUniversité de ParisParisFrance
| | - Manuela Zoonens
- Laboratoire de Biologie Physico‐Chimique des Protéines Membranaires, CNRS, Institut de Biologie Physico‐ChimiqueUniversité de ParisParisFrance
| | - Aure Saulnier
- Bioprocess R&D DepartmentSanofi PasteurMarcy l'EtoileFrance
- Department of Analytical SciencesSanofi PasteurMarcy l'EtoileFrance
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Zhang CYC, Zhao SQ, Zhang SL, Luo LH, Liu DC, Ding WH, Fu DJ, Deng XD, Yin DC. Database Study on the Expression and Purification of Membrane Proteins. Protein Pept Lett 2021; 28:972-982. [PMID: 33858308 DOI: 10.2174/0929866528666210415120234] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 02/04/2021] [Accepted: 03/10/2021] [Indexed: 11/22/2022]
Abstract
Membrane proteins are crucial for biological processes, and many of them are important to drug targets. Understanding the three-dimensional structures of membrane proteins are essential to evaluate their bio function and drug design. High-purity membrane proteins are important for structural determination. Membrane proteins have low yields and are difficult to purify because they tend to aggregate. We summarized membrane protein expression systems, vectors, tags, and detergents, which have deposited in the Protein Data Bank (PDB) in recent four-and-a-half years. Escherichia coli is the most expression system for membrane proteins, and HEK293 cells are the most commonly cell lines for human membrane protein expression. The most frequently vectors are pFastBac1 for alpha-helical membrane proteins, pET28a for beta-barrel membrane proteins, and pTRC99a for monotopic membrane proteins. The most used tag for membrane proteins is the 6×His-tag. FLAG commonly used for alpha-helical membrane proteins, Strep and GST for beta-barrel and monotopic membrane proteins, respectively. The detergents and their concentrations used for alpha-helical, beta-barrel, and monotopic membrane proteins are different, and DDM is commonly used for membrane protein purification. It can guide the expression and purification of membrane proteins, thus contributing to their structure and bio function studying.
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Affiliation(s)
- Chen-Yan China Zhang
- Institute for Special Environmental Biophysics, Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an 710072, Shaanxi. China
| | - Shi-Qi Zhao
- Institute for Special Environmental Biophysics, Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an 710072, Shaanxi. China
| | - Shi-Long Zhang
- Institute for Special Environmental Biophysics, Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an 710072, Shaanxi. China
| | - Li-Heng Luo
- Institute for Special Environmental Biophysics, Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an 710072, Shaanxi. China
| | - Ding-Chang Liu
- Institute for Special Environmental Biophysics, Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an 710072, Shaanxi. China
| | - Wei-Hang Ding
- Institute for Special Environmental Biophysics, Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an 710072, Shaanxi. China
| | - Dong-Jie Fu
- Institute for Special Environmental Biophysics, Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an 710072, Shaanxi. China
| | - Xu-Dong Deng
- Institute for Special Environmental Biophysics, Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an 710072, Shaanxi. China
| | - Da-Chuan Yin
- Institute for Special Environmental Biophysics, Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an 710072, Shaanxi. China
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Amphipathic environments for determining the structure of membrane proteins by single-particle electron cryo-microscopy. Q Rev Biophys 2021; 54:e6. [PMID: 33785082 DOI: 10.1017/s0033583521000044] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Over the past decade, the structural biology of membrane proteins (MPs) has taken a new turn thanks to epoch-making technical progress in single-particle electron cryo-microscopy (cryo-EM) as well as to improvements in sample preparation. The present analysis provides an overview of the extent and modes of usage of the various types of surfactants for cryo-EM studies. Digitonin, dodecylmaltoside, protein-based nanodiscs, lauryl maltoside-neopentyl glycol, glyco-diosgenin, and amphipols (APols) are the most popular surfactants at the vitrification step. Surfactant exchange is frequently used between MP purification and grid preparation, requiring extensive optimization each time the study of a new MP is undertaken. The variety of both the surfactants and experimental approaches used over the past few years bears witness to the need to continue developing innovative surfactants and optimizing conditions for sample preparation. The possibilities offered by novel APols for EM applications are discussed.
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Mao J, Qiu L, Ge L, Zhou J, Ji Q, Yang Y, Long M, Wang D, Teng L, Chen J. Overcoming multidrug resistance by intracellular drug release and inhibiting p-glycoprotein efflux in breast cancer. Biomed Pharmacother 2021; 134:111108. [PMID: 33341670 DOI: 10.1016/j.biopha.2020.111108] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 12/04/2020] [Accepted: 12/06/2020] [Indexed: 12/20/2022] Open
Abstract
Doxorubicin (DOX) is limited to use in clinical practice because of poor targeting, serious side effects and multidrug resistance (MDR). Vitamin E and its derivatives are currently considered as hydrophobic material that can reverse tumor MDR by suppressing the action of p-glycoprotein (p-gp). Therefore, reduction-sensitive amphiphilic heparosan polysaccharide-cystamine-vitamin E succinate (KSV) copolymers were designed to reverse breast cancer MDR cells. The spherical micelles (DOX/KSV) micelles which had suitable particle size presented redox-sensitive release character. Simultaneously, DOX-loaded reduction insensitive heparosan-adipic dihydrazide-vitamin E succinate (KV) micellar system was designed as a control. DOX/KSV and DOX/KV micelles had the higher capability to overcome tumor MDR than that free DOX. However, DOX/KSV had the highest amount of cellular uptake which might be caused by the synergistic intracellular drug release and inhibition of p-gp expression. The mechanism experiments revealed that DOX/KSV could be fast disassembled to release DOX after internalization into tumor cells. Moreover, DOX/KSV produced more ROS than free DOX and DOX/KV resulting in enhanced anticancer effect. In vivo tumor-bearing mice study suggested that DOX/KSV micelles could efficiently enhance antitumor effect by overcoming tumor MDR and reduce toxicity of DOX. The DOX/KSV micelles could synergistically increase the therapeutic effect of chemotherapeutic drug on tumor MDR cells.
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Affiliation(s)
- Jing Mao
- School of Pharmaceutical Sciences, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Lipeng Qiu
- School of Pharmaceutical Sciences, Jiangnan University, Wuxi, 214122, Jiangsu, China; Sunhover Industry Group Company Limited, Linyi, 276000, Shandong, China
| | - Lu Ge
- School of Pharmaceutical Sciences, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Juan Zhou
- School of Pharmaceutical Sciences, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Qian Ji
- School of Pharmaceutical Sciences, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Yang Yang
- School of Pharmaceutical Sciences, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Miaomiao Long
- Department of Pharmacy, Wuxi Higher Health Vocational Technology School, Wuxi, 214028, Jiangsu, China.
| | - Danhui Wang
- Wuxi School of Medicine, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Liping Teng
- Wuxi School of Medicine, Jiangnan University, Wuxi, 214122, Jiangsu, China.
| | - Jinghua Chen
- School of Pharmaceutical Sciences, Jiangnan University, Wuxi, 214122, Jiangsu, China
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Biotinylated non-ionic amphipols for GPCR ligands screening. Methods 2020; 180:69-78. [PMID: 32505829 DOI: 10.1016/j.ymeth.2020.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 05/29/2020] [Accepted: 06/01/2020] [Indexed: 12/18/2022] Open
Abstract
We present herein the synthesis of biotin-functionalized polymers (BNAPols) that have been developed for the fixation of membrane proteins (MPs) onto surfaces. BNAPols were synthesized by free-radical polymerization of a tris(hydroxymethyl)acrylamidomethane (THAM)-derived amphiphilic monomer in the presence of a thiol-based transfer agent with an azido group. Then a Huisgen-cycloaddition reaction was performed with Biotin-(PEG)8-alkyne that resulted in formation of the biotinylated polymers. The designed structure of BNAPols was confirmed by NMR spectroscopy, and a HABA/avidin assay was used for estimating the percentage of biotin grafted on the polymer end chain. The colloidal characterization of these biotin-functionalized polymers was done using both dynamic light scattering (DLS) and small angle X-ray scattering (SAXS) techniques. BNAPols were used to stabilize a model G protein-coupled receptor (GPCR), the human Growth Hormone Secretagogue Receptor (GHSR), out of its membrane environment. Subsequent immobilization of the BNAPols:GHSR complex onto a streptavidin-coated surface allowed screening of ligands based on their ability to bind the immobilized receptor. This opens the way to the use of biotinylated NAPols to immobilize functional, unmodified, membrane proteins, providing original sensor devices for multiple applications including innovative ligand screening assays.
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Tifrea DF, Pal S, le Bon C, Cocco MJ, Zoonens M, de la Maza LM. Improved protection against Chlamydia muridarum using the native major outer membrane protein trapped in Resiquimod-carrying amphipols and effects in protection with addition of a Th1 (CpG-1826) and a Th2 (Montanide ISA 720) adjuvant. Vaccine 2020; 38:4412-4422. [PMID: 32386746 DOI: 10.1016/j.vaccine.2020.04.065] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 03/17/2020] [Accepted: 04/26/2020] [Indexed: 01/15/2023]
Abstract
A new vaccine formulated with the Chlamydia muridarum native major outer membrane protein (nMOMP) and amphipols was assessed in an intranasal (i.n.) challenge mouse model. nMOMP was trapped either in amphipol A8-35 (nMOMP/A8-35) or in A8-35 conjugated with Resiquimod (nMOMP/Resiq-A8-35), a TLR7/8 agonist added as adjuvant. The effects of free Resiquimod and/or additional adjuvants, Montanide ISA 720 (TLR independent) and CpG-1826 (TLR9 agonist), were also evaluated. Immunization with nMOMP/A8-35 alone administered i.n. was used as negative adjuvant-control group, whereas immunizations with C. muridarum elementary bodies (EBs) and MEM buffer, administered i.n., were used as positive and negative controls, respectively. Vaccinated mice were challenged i.n. with C. muridarum and changes in body weight, lungs weight and recovery of Chlamydia from the lungs were evaluated. All the experimental groups showed protection when compared with the negative control group. Resiquimod alone produced weak humoral and cellular immune responses, but both Montanide and CpG-1826 showed significant increases in both responses. The addition of CpG-1826 alone switched immune responses to be Th1-biased. The most robust protection was elicited in mice immunized with the three adjuvants and conjugated Resiquimod. Increased protection induced by the Resiquimod covalently linked to A8-35, in the presence of Montanide and CpG-1826 was established based on a set of parameters: (1) the ability of the antibodies to neutralize C. muridarum; (2) the increased proliferation of T-cells in vitro accompanied by higher production of IFN-γ, IL-6 and IL-17; (3) the decreased body weight loss over the 10 days after challenge; and (4) the number of IFUs recovered from the lungs at day 10 post challenge. In conclusion, a vaccine formulated with the C. muridarum nMOMP bound to amphipols conjugated with Resiquimod enhances protective immune responses that can be further improved by the addition of Montanide and CpG-1826.
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Affiliation(s)
- Delia F Tifrea
- Department of Pathology and Laboratory Medicine, Medical Sciences I, Room D440, University of California, Irvine, Irvine, CA 92697-4800, USA
| | - Sukumar Pal
- Department of Pathology and Laboratory Medicine, Medical Sciences I, Room D440, University of California, Irvine, Irvine, CA 92697-4800, USA
| | - Christel le Bon
- Université de Paris, Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, CNRS, UMR 7099, F-75005 Paris, France; Institut de Biologie Physico-Chimique, Fondation Edmond de Rothschild pour le développement de la recherche scientifique, F-75005 Paris, France
| | - Melanie J Cocco
- Department of Molecular Biology and Biochemistry, Department of Pharmaceutical Sciences, 1218 Natural Sciences, University of California, Irvine, Irvine, CA 92697-3900, USA
| | - Manuela Zoonens
- Université de Paris, Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, CNRS, UMR 7099, F-75005 Paris, France; Institut de Biologie Physico-Chimique, Fondation Edmond de Rothschild pour le développement de la recherche scientifique, F-75005 Paris, France.
| | - Luis M de la Maza
- Department of Pathology and Laboratory Medicine, Medical Sciences I, Room D440, University of California, Irvine, Irvine, CA 92697-4800, USA.
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Perry TN, Souabni H, Rapisarda C, Fronzes R, Giusti F, Popot JL, Zoonens M, Gubellini F. BAmSA: Visualising transmembrane regions in protein complexes using biotinylated amphipols and electron microscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:466-477. [DOI: 10.1016/j.bbamem.2018.11.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 11/06/2018] [Accepted: 11/08/2018] [Indexed: 12/30/2022]
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Tifrea DF, Pal S, Le Bon C, Giusti F, Popot JL, Cocco MJ, Zoonens M, de la Maza LM. Co-delivery of amphipol-conjugated adjuvant with antigen, and adjuvant combinations, enhance immune protection elicited by a membrane protein-based vaccine against a mucosal challenge with Chlamydia. Vaccine 2018; 36:6640-6649. [PMID: 30293763 DOI: 10.1016/j.vaccine.2018.09.055] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 08/28/2018] [Accepted: 09/23/2018] [Indexed: 01/24/2023]
Abstract
INTRODUCTION Chlamydial infections are spread worldwide and a vaccine is needed to control this pathogen. The goals of this study were to determine if the delivery of an adjuvant associated to the antigen, via a derivatized amphipol, and adjuvant combinations improve vaccine protection. METHODS A novel approach, trapping the Chlamydia muridarum (Cm) native MOMP (nMOMP) with amphipols (A8-35), bearing a covalently conjugated peptide (EP67), was used. Adjuvants incorporated were: EP67 either conjugated to A8-35, which was used to trap nMOMP (nMOMP/EP67-A8-35), or free as a control, added to nMOMP/A8-35 complexes (nMOMP/A8-35+EP67); Montanide ISA 720 to enhance humoral responses, and CpG-1826 to elicit robust cell-mediated immunity (CMI). BALB/c mice were immunized by mucosal and systemic routes. Intranasal immunization with live Cm was used as positive control and three negative controls were included. Mice were challenged intranasally with Cm and changes in body weight, lungs weight and number of Cm-inclusion forming units (IFU) recovered from the lungs were evaluated to establish protection. To assess local responses levels of IFN- γ and Cm-specific IgA were determined in lungs' supernatants. RESULTS Structural assays demonstrated that nMOMP secondary structure and thermal stability were maintained when A8-35 was covalently modified. Mice vaccinated with nMOMP/EP67-A8-35 were better protected than animals immunized with nMOMP/A8-35+EP67. Addition of Montanide enhanced Th2 responses and improved protection. Including CpG-1826 further broadened, intensified and switched to Th1-biased immune responses. With delivery of nMOMP and the three adjuvants, as determined by changes in body weight, lungs weight and number of IFU recovered from lungs, protection at 10 days post-challenge was equivalent to that induced by immunization with live Cm. CONCLUSIONS Covalent association of EP67 to A8-35, used to keep nMOMP water-soluble, improves protection over that conferred by free EP67. Adjuvant combinations including EP67+Montanide+CpG-1826, by broadening and intensifying cellular and humoral immune responses, further enhanced protection.
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Affiliation(s)
- Delia F Tifrea
- Department of Pathology and Laboratory Medicine, Medical Sciences I, Room D440, University of California, Irvine, Irvine, CA 92697-4800, USA
| | - Sukumar Pal
- Department of Pathology and Laboratory Medicine, Medical Sciences I, Room D440, University of California, Irvine, Irvine, CA 92697-4800, USA
| | - Christel Le Bon
- C.N.R.S./Université Paris-7 UMR 7099, Institut de Biologie Physico-Chimique, 13, rue Pierre-et-Marie-Curie, F-75005 Paris, France
| | - Fabrice Giusti
- C.N.R.S./Université Paris-7 UMR 7099, Institut de Biologie Physico-Chimique, 13, rue Pierre-et-Marie-Curie, F-75005 Paris, France
| | - Jean-Luc Popot
- C.N.R.S./Université Paris-7 UMR 7099, Institut de Biologie Physico-Chimique, 13, rue Pierre-et-Marie-Curie, F-75005 Paris, France
| | - Melanie J Cocco
- Department of Molecular Biology and Biochemistry, Department of Pharmaceutical Sciences, 1218 Natural Sciences, University of California, Irvine, Irvine, CA 92697-3900, USA
| | - Manuela Zoonens
- C.N.R.S./Université Paris-7 UMR 7099, Institut de Biologie Physico-Chimique, 13, rue Pierre-et-Marie-Curie, F-75005 Paris, France.
| | - Luis M de la Maza
- Department of Pathology and Laboratory Medicine, Medical Sciences I, Room D440, University of California, Irvine, Irvine, CA 92697-4800, USA.
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Schmidt V, Sturgis JN. Modifying Styrene-maleic Acid Co-polymer for Studying Lipid Nanodiscs by Direct Fluorescent Labeling. Bio Protoc 2018; 8:e2969. [PMID: 34395773 DOI: 10.21769/bioprotoc.2969] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 07/27/2018] [Accepted: 08/01/2018] [Indexed: 11/02/2022] Open
Abstract
This protocol was developed to functionalize styrene maleic acid (SMA) by direct fluorescent labeling in an easy way, accessible to biochemistry laboratories. This novel method is based on the coupling of carboxylic acids to primary amines using a carbodiimide, a reaction commonly used for protein chemistry. The procedure uses the hydrolyzed styrene-maleic acid copolymer and occurs entirely in aqueous solution with mild conditions compatible with many biomolecules.
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Affiliation(s)
- Victoria Schmidt
- LISM UMR 7255, CNRS and Aix-Marseille University, Marseille cedex 09, France
| | - James N Sturgis
- LISM UMR 7255, CNRS and Aix-Marseille University, Marseille cedex 09, France
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Serra-Batiste M, Tolchard J, Giusti F, Zoonens M, Carulla N. Stabilization of a Membrane-Associated Amyloid-β Oligomer for Its Validation in Alzheimer's Disease. Front Mol Biosci 2018; 5:38. [PMID: 29725595 PMCID: PMC5917194 DOI: 10.3389/fmolb.2018.00038] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 03/28/2018] [Indexed: 11/13/2022] Open
Abstract
We have recently reported on the preparation of a membrane-associated β-barrel Pore-Forming Aβ42 Oligomer (βPFOAβ42). It corresponds to a stable and homogeneous Aβ42 oligomer that inserts into lipid bilayers as a well-defined pore and adopts a specific structure with characteristics of a β-barrel arrangement. As a follow-up of this work, we aim to establish βPFOAβ42's relevance in Alzheimer's disease (AD). However, βPFOAβ42 is formed under dodecyl phosphocholine (DPC) micelle conditions-intended to mimic the hydrophobic environment of membranes-which are dynamic. Consequently, dilution of the βPFOAβ42/DPC complex in a detergent-free buffer leads to dispersion of the DPC molecules from the oligomer surface, leaving the oligomer without the hydrophobic micelle belt that stabilizes it. Since dilution is required for any biological test, transfer of βPFOAβ42 from DPC micelles into another hydrophobic biomimetic membrane environment, that remains associated with βPFOAβ42 even under high dilution conditions, is a requisite for the validation of βPFOAβ42 in AD. Here we describe conditions for exchanging DPC micelles with amphipols (APols), which are amphipathic polymers designed to stabilize membrane proteins in aqueous solutions. APols bind in an irreversible but non-covalent manner to the hydrophobic surface of membrane proteins preserving their structure even under extreme dilution conditions. We tested three types of APols with distinct physical-chemical properties and found that the βPFOAβ42/DPC complex can only be trapped in non-ionic APols (NAPols). The characterization of the resulting βPFOAβ42/NAPol complex by biochemical tools and structural biology techniques allowed us to establish that the oligomer structure is maintained even under high dilution. Based on these findings, this work constitutes a first step towards the in vivo validation of βPFOAβ42 in AD.
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Affiliation(s)
- Montserrat Serra-Batiste
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute Science and Technology (BIST), Barcelona, Spain
| | - James Tolchard
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute Science and Technology (BIST), Barcelona, Spain.,CBMN (UMR 5248), Centre National de la Recherche Scientifique - IPB, Institut Européen de Chimie et Biologie, University of Bordeaux, Pessac, France
| | - Fabrice Giusti
- Laboratoire de Physico-Chimie Moléculaire des Protéines Membranaires (UMR 7099), Université Paris-7 - Centre National de la Recherche Scientifique, Institut de Biologie Physico-Chimique, Paris, France
| | - Manuela Zoonens
- Laboratoire de Physico-Chimie Moléculaire des Protéines Membranaires (UMR 7099), Université Paris-7 - Centre National de la Recherche Scientifique, Institut de Biologie Physico-Chimique, Paris, France
| | - Natàlia Carulla
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute Science and Technology (BIST), Barcelona, Spain.,CBMN (UMR 5248), Centre National de la Recherche Scientifique - IPB, Institut Européen de Chimie et Biologie, University of Bordeaux, Pessac, France
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Le Bon C, Marconnet A, Masscheleyn S, Popot JL, Zoonens M. Folding and stabilizing membrane proteins in amphipol A8-35. Methods 2018; 147:95-105. [PMID: 29678587 DOI: 10.1016/j.ymeth.2018.04.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 04/06/2018] [Accepted: 04/13/2018] [Indexed: 01/07/2023] Open
Abstract
Membrane proteins (MPs) are important pharmacological targets because of their involvement in many essential cellular processes whose dysfunction can lead to a large variety of diseases. A detailed knowledge of the structure of MPs and the molecular mechanisms of their activity is essential to the design of new therapeutic agents. However, studying MPs in vitro is challenging, because it generally implies their overexpression under a functional form, followed by their extraction from membranes and purification. Targeting an overexpressed MP to a membrane is often toxic and expression yields tend to be limited. One alternative is the formation of inclusion bodies (IBs) in the cytosol of the cell, from which MPs need then to be folded to their native conformation before structural and functional analysis can be contemplated. Folding MPs targeted to IBs is a difficult task. Specially designed amphipathic polymers called 'amphipols' (APols), which have been initially developed with the view of improving the stability of MPs in aqueous solutions compared to detergents, can be used to fold both α-helical and β-barrel MPs. APols represent an interesting novel amphipathic medium, in which high folding yields can be achieved. In this review, the properties of APol A8-35 and of the complexes they form with MPs are summarized. An overview of the most important studies reported so far using A8-35 to fold MPs is presented. Finally, from a practical point of view, a detailed description of the folding and trapping methods is given.
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Affiliation(s)
- Christel Le Bon
- CNRS/Université Paris-7 UMR 7099, Institut de Biologie Physico-Chimique, 13, rue Pierre-et-Marie-Curie, F-75005 Paris, France
| | - Anaïs Marconnet
- CNRS/Université Paris-7 UMR 7099, Institut de Biologie Physico-Chimique, 13, rue Pierre-et-Marie-Curie, F-75005 Paris, France
| | - Sandrine Masscheleyn
- CNRS/Université Paris-7 UMR 7099, Institut de Biologie Physico-Chimique, 13, rue Pierre-et-Marie-Curie, F-75005 Paris, France
| | - Jean-Luc Popot
- CNRS/Université Paris-7 UMR 7099, Institut de Biologie Physico-Chimique, 13, rue Pierre-et-Marie-Curie, F-75005 Paris, France
| | - Manuela Zoonens
- CNRS/Université Paris-7 UMR 7099, Institut de Biologie Physico-Chimique, 13, rue Pierre-et-Marie-Curie, F-75005 Paris, France.
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Schmidt V, Sturgis JN. Modifying styrene-maleic acid co-polymer for studying lipid nanodiscs. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:777-783. [PMID: 29273333 DOI: 10.1016/j.bbamem.2017.12.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 12/12/2017] [Accepted: 12/14/2017] [Indexed: 01/09/2023]
Abstract
Recently, styrene-maleic acid copolymer lipid nanodiscs have become an increasingly popular tool for the study of membrane proteins. In the work we report here, we have developed a novel method for the efficient preparation of labeled nanodiscs, under chemically mild conditions, by modification of the hydrolyzed styrene-maleic acid copolymer. This protocol is designed to be easily accessible to biochemistry laboratories. We use this procedure to prepare various fluorescent nanodiscs labeled with different fluorophores. By studying the development of Förster resonance energy transfer, we demonstrate the rapid exchange of co-polymer between nanodiscs. This demonstration, in conjunction of previous work, indicates that the lipid nanodiscs prepared using this polymer are very dynamic structures with rapid exchange of the different components.
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Affiliation(s)
- Victoria Schmidt
- LISM UMR 7255, CNRS and Aix-Marseille University, 31 Chemin Joseph Aiguier, Marseille cedex 20 13402, France
| | - James N Sturgis
- LISM UMR 7255, CNRS and Aix-Marseille University, 31 Chemin Joseph Aiguier, Marseille cedex 20 13402, France.
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Zeng K, Li Q, Wang J, Yin G, Zhang Y, Xiao C, Fan T, Zhao X, Zheng X. One-step methodology for the direct covalent capture of GPCRs from complex matrices onto solid surfaces based on the bioorthogonal reaction between haloalkane dehalogenase and chloroalkanes. Chem Sci 2017; 9:446-456. [PMID: 29629116 PMCID: PMC5868316 DOI: 10.1039/c7sc03887a] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 10/18/2017] [Indexed: 12/29/2022] Open
Abstract
An approach is established for the specific immobilization of GPCRs from cell lysates that circumvents labor intensive purification procedures and minimize loss of activity.
Protein immobilization techniques play an important role in the development of assays for disease diagnosis and drug discovery. However, many of these approaches are not applicable to transmembrane proteins. G protein-coupled receptors (GPCRs) are the largest protein superfamily encoded by the human genome and are targeted by a quarter of all prescription drugs. GPCRs are highly dynamic and sensitive to changes in the ambient environment, and current immobilization methodologies are not suitable for GPCRs. We used haloalkane dehalogenase (Halo) as an immobilization tag fused to the β2-adrenoceptor (β2-AR), angiotensin II type 1 (AT1) and angiotensin II type 2 (AT2) receptors. The engineered Halo-tag covalently binds to a specific substrate chloroalkane through Asp 106 in the catalytic pocket. The Halo-tagged GPCRs were expressed in Escherichia coli at a suitable yield. Accordingly, we loaded cell lysate containing Halo-tagged GPCRs onto a macroporous silica gel coated with chloroalkane. Morphological characterization indicated a homogeneous monolayer of immobilized Halo-tagged GPCRs on the silica gel surface. The immobilized receptors proved to be surrounded by specific bound phospholipids including PG C18:1/C18:1. We observed a radio-ligand binding ability and ligand-induced conformational changes in the immobilized GPCRs, suggesting the preservation of bioactivity. This method is a one-step approach for the specific immobilization of GPCRs from cell lysates and validates that immobilized receptors retain canonical ligand binding capacity. Our immobilization strategy circumvents labor-intensive purification procedures and minimizes loss of activity. The immobilized receptors can be applied to high-throughput drug and interaction partner screening for GPCRs.
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Affiliation(s)
- Kaizhu Zeng
- Key Laboratory of Resource Biology and Biotechnology in Western China , Ministry of Education , College of Life Sciences , Northwest University , Xi'an 710069 , China . ; ; Tel: +86 029 88302686
| | - Qian Li
- Key Laboratory of Resource Biology and Biotechnology in Western China , Ministry of Education , College of Life Sciences , Northwest University , Xi'an 710069 , China . ; ; Tel: +86 029 88302686
| | - Jing Wang
- Key Laboratory of Resource Biology and Biotechnology in Western China , Ministry of Education , College of Life Sciences , Northwest University , Xi'an 710069 , China . ; ; Tel: +86 029 88302686
| | - Guowei Yin
- Department of Biochemistry and Biophysics , University of North Carolina at Chapel Hill , NC , USA
| | - Yajun Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China , Ministry of Education , College of Life Sciences , Northwest University , Xi'an 710069 , China . ; ; Tel: +86 029 88302686
| | - Chaoni Xiao
- Key Laboratory of Resource Biology and Biotechnology in Western China , Ministry of Education , College of Life Sciences , Northwest University , Xi'an 710069 , China . ; ; Tel: +86 029 88302686
| | - Taiping Fan
- Key Laboratory of Resource Biology and Biotechnology in Western China , Ministry of Education , College of Life Sciences , Northwest University , Xi'an 710069 , China . ; ; Tel: +86 029 88302686.,Department of Pharmacology , University of Cambridge , Cambridge CB2 1PD , UK
| | - Xinfeng Zhao
- Key Laboratory of Resource Biology and Biotechnology in Western China , Ministry of Education , College of Life Sciences , Northwest University , Xi'an 710069 , China . ; ; Tel: +86 029 88302686
| | - Xiaohui Zheng
- Key Laboratory of Resource Biology and Biotechnology in Western China , Ministry of Education , College of Life Sciences , Northwest University , Xi'an 710069 , China . ; ; Tel: +86 029 88302686
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Hu Z, Ho JC, Nallani M. Synthetic (polymer) biology (membrane): functionalization of polymer scaffolds for membrane proteins. Curr Opin Biotechnol 2017; 46:51-56. [DOI: 10.1016/j.copbio.2016.10.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 10/24/2016] [Indexed: 12/13/2022]
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Qiu L, Zhu M, Huang Y, Gong K, Chen J. Mechanisms of cellular uptake with hyaluronic acid—octadecylamine micelles as drug delivery nanocarriers. RSC Adv 2016. [DOI: 10.1039/c5ra27532f] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
DOX/HM23, based on appropriate DS and proper particle size, presented enhanced anticancer activity and efficient internalization to achieve the highest intracellular drug concentration.
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Affiliation(s)
- Lipeng Qiu
- School of Pharmaceutical Sciences
- Jiangnan University
- Wuxi 214122
- PR China
| | - Mengqin Zhu
- School of Pharmaceutical Sciences
- Jiangnan University
- Wuxi 214122
- PR China
| | - Yan Huang
- School of Pharmaceutical Sciences
- Jiangnan University
- Wuxi 214122
- PR China
| | - Kai Gong
- School of Pharmaceutical Sciences
- Jiangnan University
- Wuxi 214122
- PR China
| | - Jinghua Chen
- School of Pharmaceutical Sciences
- Jiangnan University
- Wuxi 214122
- PR China
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Le Bon C, Popot JL, Giusti F. Labeling and functionalizing amphipols for biological applications. J Membr Biol 2014; 247:797-814. [PMID: 24696186 PMCID: PMC4185061 DOI: 10.1007/s00232-014-9655-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 03/07/2014] [Indexed: 12/19/2022]
Abstract
Amphipols (APols) are short amphipathic polymers developed as an alternative to detergents for handling membrane proteins (MPs) in aqueous solution. MPs are, as a rule, much more stable following trapping with APols than they are in detergent solutions. The best-characterized APol to date, called A8-35, is a mixture of short-chain sodium polyacrylates randomly derivatized with octylamine and isopropylamine. Its solution properties have been studied in detail, and it has been used extensively for biochemical and biophysical studies of MPs. One of the attractive characteristics of APols is that it is relatively easy to label them, isotopically or otherwise, without affecting their physical-chemical properties. Furthermore, several variously modified APols can be mixed, achieving multiple functionalization of MP/APol complexes in the easiest possible manner. Labeled or tagged APols are being used to study the solution properties of APols, their miscibility, their biodistribution upon injection into living organisms, their association with MPs and the composition, structure and dynamics of MP/APol complexes, examining the exchange of surfactants at the surface of MPs, labeling MPs to follow their distribution in fractionation experiments or to immobilize them, increasing the contrast between APols and solvent or MPs in biophysical experiments, improving NMR spectra, etc. Labeling or functionalization of APols can take various courses, each of which has its specific constraints and advantages regarding both synthesis and purification. The present review offers an overview of the various derivatives of A8-35 and its congeners that have been developed in our laboratory and discusses the pros and cons of various synthetic routes.
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Affiliation(s)
- Christel Le Bon
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, UMR 7099, Institut de Biologie Physico-Chimique (FRC 550), CNRS/Université Paris 7, 13 rue Pierre et Marie Curie, 75005, Paris, France
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Abstract
Amphipols (APols) are short amphipathic polymers that can substitute for detergents at the transmembrane surface of membrane proteins (MPs) and, thereby, keep them soluble in detergent free aqueous solutions. APol-trapped MPs are, as a rule, more stable biochemically than their detergent-solubilized counterparts. APols have proven useful to produce MPs, most noticeably by assisting their folding from the denatured state obtained after solubilizing MP inclusion bodies in either SDS or urea. They facilitate the handling in aqueous solution of fragile MPs for the purpose of proteomics, structural and functional studies, and therapeutics. Because APols can be chemically labeled or functionalized, and they form very stable complexes with MPs, they can also be used to functionalize those indirectly, which opens onto many novel applications. Following a brief recall of the properties of APols and MP/APol complexes, an update is provided of recent progress in these various fields.
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Affiliation(s)
- Manuela Zoonens
- Laboratoire de Physico-Chimie Moléculaire des Protéines Membranaires, UMR 7099, Institut de Biologie Physico-Chimique (FRC 550), Centre National de la Recherche Scientifique/Université Paris-7, 13, rue Pierre-et-Marie-Curie, 75005 Paris, France
| | - Jean-Luc Popot
- Laboratoire de Physico-Chimie Moléculaire des Protéines Membranaires, UMR 7099, Institut de Biologie Physico-Chimique (FRC 550), Centre National de la Recherche Scientifique/Université Paris-7, 13, rue Pierre-et-Marie-Curie, 75005 Paris, France
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Functionalized Amphipols: A Versatile Toolbox Suitable for Applications of Membrane Proteins in Synthetic Biology. J Membr Biol 2014; 247:815-26. [DOI: 10.1007/s00232-014-9663-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 03/27/2014] [Indexed: 10/25/2022]
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Giusti F, Rieger J, Catoire LJ, Qian S, Calabrese AN, Watkinson TG, Casiraghi M, Radford SE, Ashcroft AE, Popot JL. Synthesis, characterization and applications of a perdeuterated amphipol. J Membr Biol 2014; 247:909-24. [PMID: 24652511 DOI: 10.1007/s00232-014-9656-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 03/07/2014] [Indexed: 12/13/2022]
Abstract
Amphipols are short amphipathic polymers that can substitute for detergents at the hydrophobic surface of membrane proteins (MPs), keeping them soluble in the absence of detergents while stabilizing them. The most widely used amphipol, known as A8-35, is comprised of a polyacrylic acid (PAA) main chain grafted with octylamine and isopropylamine. Among its many applications, A8-35 has proven particularly useful for solution-state NMR studies of MPs, for which it can be desirable to eliminate signals originating from the protons of the surfactant. In the present work, we describe the synthesis and properties of perdeuterated A8-35 (perDAPol). Perdeuterated PAA was obtained by radical polymerization of deuterated acrylic acid. It was subsequently grafted with deuterated amines, yielding perDAPol. The number-average molar mass of hydrogenated and perDAPol, ~4 and ~5 kDa, respectively, was deduced from that of their PAA precursors, determined by size exclusion chromatography in tetrahydrofuran following permethylation. Electrospray ionization-ion mobility spectrometry-mass spectrometry measurements show the molar mass and distribution of the two APols to be very similar. Upon neutron scattering, the contrast match point of perDAPol is found to be ~120% D2O. In (1)H-(1)H nuclear overhauser effect NMR spectra, its contribution is reduced to ~6% of that of hydrogenated A8-35, making it suitable for extended uses in NMR spectroscopy. PerDAPol ought to also be of use for inelastic neutron scattering studies of the dynamics of APol-trapped MPs, as well as small-angle neutron scattering and analytical ultracentrifugation.
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Affiliation(s)
- Fabrice Giusti
- Laboratoire de Physico-Chimie Moléculaire des Membranes Biologiques, UMR 7099, Institut de Biologie Physico-Chimique (FRC 550), Centre National de la Recherche Scientifique and Université Paris-7, 13 rue Pierre et Marie Curie, 75005, Paris, France
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