1
|
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.
Collapse
|
2
|
Minimal nanodisc without exogenous lipids for stabilizing membrane proteins in detergent-free buffer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:852-860. [DOI: 10.1016/j.bbamem.2019.01.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 12/17/2018] [Accepted: 01/24/2019] [Indexed: 01/29/2023]
|
3
|
Ligand-induced conformational switch in an artificial bidomain protein scaffold. Sci Rep 2019; 9:1178. [PMID: 30718544 PMCID: PMC6362204 DOI: 10.1038/s41598-018-37256-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 11/28/2018] [Indexed: 11/15/2022] Open
Abstract
Artificial proteins binding any predefined “target” protein can now be efficiently generated using combinatorial libraries based on robust protein scaffolds. αRep is such a family of artificial proteins, based on an α-solenoid protein repeat scaffold. The low aggregation propensity of the specific “binders” generated from this library opens new protein engineering opportunities such as the creation of biosensors within multidomain constructions. Here, we have explored the properties of two new types of artificial bidomain proteins based on αRep structures. Their structural and functional properties are characterized in detail using biophysical methods. The results clearly show that both bidomain proteins adopt a closed bivalve shell-like conformation, in the ligand free form. However, the presence of ligands induces a conformational transition, and the proteins adopt an open form in which each domain can bind its cognate protein partner. The open/closed equilibria alter the affinities of each domain and induce new cooperative effects. The binding-induced relative domain motion was monitored by FRET. Crystal structures of the chimeric proteins indicate that the conformation of each constituting domain is conserved but that their mutual interactions explain the emergent properties of these artificial bidomain proteins. The ligand-induced structural transition observed in these bidomain proteins should be transferable to other αRep proteins with different specificity and could provide the basis of a new generic biosensor design.
Collapse
|
4
|
Inada M, Kinoshita M, Sumino A, Oiki S, Matsumori N. A concise method for quantitative analysis of interactions between lipids and membrane proteins. Anal Chim Acta 2019; 1059:103-112. [PMID: 30876624 DOI: 10.1016/j.aca.2019.01.042] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 01/17/2019] [Accepted: 01/18/2019] [Indexed: 01/31/2023]
Abstract
Although interactions between lipids and membrane proteins (MPs) have been considered crucially important for understanding the functions of lipids, lack of useful and convincing experimental methods has hampered the analysis of the interactions. Here, we developed a surface plasmon resonance (SPR)-based concise method for quantitative analysis of lipid-MP interactions, coating the sensor chip surface with self-assembled monolayer (SAM) with C6-chain. To develop this method, we used bacteriorhodopsin (bR) as an MP, and examined its interaction with various types of lipids. The merits of using C6-SAM-modified sensor chip are as follows: (1) alkyl-chains of SAM confer a better immobilization of MPs because of the efficient preconcentration due to hydrophobic contacts; (2) SAM provides immobilized MPs with a partial membranous environment, which is important for the stabilization of MPs; and (3) a thinner C6-SAM layer (1 nm) compared with MP size forces the MP to bulge outward from the SAM surface, allowing extraneously injected lipids to be accessible to the hydrophobic transmembrane regions. Actually, the amount of bR immobilized on C6-SAM is 10 times higher than that on a hydrophilic CM5 sensor chip, and AFM observations confirmed that bR molecules are exposed on the SAM surface. Of the lipids tested, S-TGA-1, a halobacterium-derived glycolipid, had the highest specificity to bR with a nanomolar dissociation constant. This is consistent with the reported co-crystal structure that indicates the formation of several intermolecular hydrogen bonds. Therefore, we not only reproduced the specific lipid-bR recognition, but also succeeded in its quantitative evaluation, demonstrating the validity and utility of this method.
Collapse
Affiliation(s)
- Masataka Inada
- Department of Chemistry, Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Masanao Kinoshita
- Department of Chemistry, Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Ayumi Sumino
- Department of Molecular Physiology and Biophysics, Faculty of Medical Sciences, University of Fukui, Fukui, 910-1193, Japan; High-speed AFM for Biological Application Unit, Institute for Frontier Science Initiative, Kanazawa University, Kanazawa, 920-1192, Japan; Bio-AFM Frontier Research Center, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Shigetoshi Oiki
- Department of Molecular Physiology and Biophysics, Faculty of Medical Sciences, University of Fukui, Fukui, 910-1193, Japan
| | - Nobuaki Matsumori
- Department of Chemistry, Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan.
| |
Collapse
|
5
|
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.
Collapse
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.
| |
Collapse
|
6
|
Chevrel A, Mesneau A, Sanchez D, Celma L, Quevillon-Cheruel S, Cavagnino A, Nessler S, Li de la Sierra-Gallay I, van Tilbeurgh H, Minard P, Valerio-Lepiniec M, Urvoas A. Alpha repeat proteins (αRep) as expression and crystallization helpers. J Struct Biol 2018; 201:88-99. [DOI: 10.1016/j.jsb.2017.08.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 07/28/2017] [Accepted: 08/14/2017] [Indexed: 12/30/2022]
|
7
|
Figueroa M, Sleutel M, Vandevenne M, Parvizi G, Attout S, Jacquin O, Vandenameele J, Fischer AW, Damblon C, Goormaghtigh E, Valerio-Lepiniec M, Urvoas A, Durand D, Pardon E, Steyaert J, Minard P, Maes D, Meiler J, Matagne A, Martial JA, Van de Weerdt C. The unexpected structure of the designed protein Octarellin V.1 forms a challenge for protein structure prediction tools. J Struct Biol 2016; 195:19-30. [PMID: 27181418 DOI: 10.1016/j.jsb.2016.05.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 04/19/2016] [Accepted: 05/12/2016] [Indexed: 12/26/2022]
Abstract
Despite impressive successes in protein design, designing a well-folded protein of more 100 amino acids de novo remains a formidable challenge. Exploiting the promising biophysical features of the artificial protein Octarellin V, we improved this protein by directed evolution, thus creating a more stable and soluble protein: Octarellin V.1. Next, we obtained crystals of Octarellin V.1 in complex with crystallization chaperons and determined the tertiary structure. The experimental structure of Octarellin V.1 differs from its in silico design: the (αβα) sandwich architecture bears some resemblance to a Rossman-like fold instead of the intended TIM-barrel fold. This surprising result gave us a unique and attractive opportunity to test the state of the art in protein structure prediction, using this artificial protein free of any natural selection. We tested 13 automated webservers for protein structure prediction and found none of them to predict the actual structure. More than 50% of them predicted a TIM-barrel fold, i.e. the structure we set out to design more than 10years ago. In addition, local software runs that are human operated can sample a structure similar to the experimental one but fail in selecting it, suggesting that the scoring and ranking functions should be improved. We propose that artificial proteins could be used as tools to test the accuracy of protein structure prediction algorithms, because their lack of evolutionary pressure and unique sequences features.
Collapse
Affiliation(s)
- Maximiliano Figueroa
- GIGA-Research, Molecular Biomimetics and Protein Engineering, University of Liège, Liège, Belgium.
| | - Mike Sleutel
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Marylene Vandevenne
- GIGA-Research, Molecular Biomimetics and Protein Engineering, University of Liège, Liège, Belgium
| | - Gregory Parvizi
- GIGA-Research, Molecular Biomimetics and Protein Engineering, University of Liège, Liège, Belgium
| | - Sophie Attout
- GIGA-Research, Molecular Biomimetics and Protein Engineering, University of Liège, Liège, Belgium
| | - Olivier Jacquin
- GIGA-Research, Molecular Biomimetics and Protein Engineering, University of Liège, Liège, Belgium
| | - Julie Vandenameele
- Laboratoire d'Enzymologie et Repliement des Protéines, Centre for Protein Engineering, University of Liège, Liège, Belgium
| | - Axel W Fischer
- Department of Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN, United States
| | | | - Erik Goormaghtigh
- Laboratory for the Structure and Function of Biological Membranes, Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles, Brussels, Belgium
| | - Marie Valerio-Lepiniec
- Institute for Integrative Biology of the Cell (I2BC), UMT 9198, CEA, CNRS, Université Paris-Sud, Orsay, France
| | - Agathe Urvoas
- Institute for Integrative Biology of the Cell (I2BC), UMT 9198, CEA, CNRS, Université Paris-Sud, Orsay, France
| | - Dominique Durand
- Institute for Integrative Biology of the Cell (I2BC), UMT 9198, CEA, CNRS, Université Paris-Sud, Orsay, France
| | - Els Pardon
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; Structural Biology Research Center, VIB, Pleinlaan 2, 1050 Brussels, Belgium
| | - Jan Steyaert
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; Structural Biology Research Center, VIB, Pleinlaan 2, 1050 Brussels, Belgium
| | - Philippe Minard
- Institute for Integrative Biology of the Cell (I2BC), UMT 9198, CEA, CNRS, Université Paris-Sud, Orsay, France
| | - Dominique Maes
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Jens Meiler
- Department of Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN, United States
| | - André Matagne
- Laboratoire d'Enzymologie et Repliement des Protéines, Centre for Protein Engineering, University of Liège, Liège, Belgium
| | - Joseph A Martial
- GIGA-Research, Molecular Biomimetics and Protein Engineering, University of Liège, Liège, Belgium
| | - Cécile Van de Weerdt
- GIGA-Research, Molecular Biomimetics and Protein Engineering, University of Liège, Liège, Belgium.
| |
Collapse
|
8
|
Daury L, Orange F, Taveau JC, Verchère A, Monlezun L, Gounou C, Marreddy RKR, Picard M, Broutin I, Pos KM, Lambert O. Tripartite assembly of RND multidrug efflux pumps. Nat Commun 2016; 7:10731. [PMID: 26867482 PMCID: PMC4754349 DOI: 10.1038/ncomms10731] [Citation(s) in RCA: 123] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 01/15/2016] [Indexed: 12/18/2022] Open
Abstract
Tripartite multidrug efflux systems of Gram-negative bacteria are composed of an inner membrane transporter, an outer membrane channel and a periplasmic adaptor protein. They are assumed to form ducts inside the periplasm facilitating drug exit across the outer membrane. Here we present the reconstitution of native Pseudomonas aeruginosa MexAB–OprM and Escherichia coli AcrAB–TolC tripartite Resistance Nodulation and cell Division (RND) efflux systems in a lipid nanodisc system. Single-particle analysis by electron microscopy reveals the inner and outer membrane protein components linked together via the periplasmic adaptor protein. This intrinsic ability of the native components to self-assemble also leads to the formation of a stable interspecies AcrA–MexB–TolC complex suggesting a common mechanism of tripartite assembly. Projection structures of all three complexes emphasize the role of the periplasmic adaptor protein as part of the exit duct with no physical interaction between the inner and outer membrane components. Tripartite efflux systems consist of inner membrane, outer membrane and periplasmic components. Here, Daury et al. reconstitute native versions of RND transporters in nanodiscs and present projection structures emphasizing the role of the periplasmic adaptor in linking the inner and outer membrane proteins.
Collapse
Affiliation(s)
- Laetitia Daury
- Université de Bordeaux, CBMN UMR 5248, Bordeaux INP, IECB, Pessac F-33600, France.,CNRS, CBMN UMR 5248, Pessac F-33600, France
| | - François Orange
- Université de Bordeaux, CBMN UMR 5248, Bordeaux INP, IECB, Pessac F-33600, France.,CNRS, CBMN UMR 5248, Pessac F-33600, France
| | - Jean-Christophe Taveau
- Université de Bordeaux, CBMN UMR 5248, Bordeaux INP, IECB, Pessac F-33600, France.,CNRS, CBMN UMR 5248, Pessac F-33600, France
| | - Alice Verchère
- Laboratoire de Cristallographie et RMN Biologiques, UMR 8015, CNRS, Université Paris Descartes, Faculté de Pharmacie, 4 Avenue de l'Observatoire, Paris 75006, France
| | - Laura Monlezun
- Laboratoire de Cristallographie et RMN Biologiques, UMR 8015, CNRS, Université Paris Descartes, Faculté de Pharmacie, 4 Avenue de l'Observatoire, Paris 75006, France
| | - Céline Gounou
- Université de Bordeaux, CBMN UMR 5248, Bordeaux INP, IECB, Pessac F-33600, France.,CNRS, CBMN UMR 5248, Pessac F-33600, France
| | - Ravi K R Marreddy
- Institute of Biochemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany
| | - Martin Picard
- Laboratoire de Cristallographie et RMN Biologiques, UMR 8015, CNRS, Université Paris Descartes, Faculté de Pharmacie, 4 Avenue de l'Observatoire, Paris 75006, France
| | - Isabelle Broutin
- Laboratoire de Cristallographie et RMN Biologiques, UMR 8015, CNRS, Université Paris Descartes, Faculté de Pharmacie, 4 Avenue de l'Observatoire, Paris 75006, France
| | - Klaas M Pos
- Institute of Biochemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany
| | - Olivier Lambert
- Université de Bordeaux, CBMN UMR 5248, Bordeaux INP, IECB, Pessac F-33600, France.,CNRS, CBMN UMR 5248, Pessac F-33600, France
| |
Collapse
|
9
|
Giusti F, Kessler P, Hansen RW, Della Pia EA, Le Bon C, Mourier G, Popot JL, Martinez KL, Zoonens M. Synthesis of a Polyhistidine-bearing Amphipol and its Use for Immobilizing Membrane Proteins. Biomacromolecules 2015; 16:3751-61. [DOI: 10.1021/acs.biomac.5b01010] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Fabrice Giusti
- Laboratoire de
Biologie Physico-Chimique des Protéines Membranaires, UMR 7099,
CNRS/Université Paris 7, Institut de Biologie Physico-Chimique
(FRC 550), 13 rue Pierre et Marie Curie, F−75005 Paris, France
| | - Pascal Kessler
- CEA, Institut
de Biologie et de Technologies de Saclay, Service d’Ingénierie
Moléculaire des Protéines, 91191 Gif-sur-Yvette, France
| | - Randi Westh Hansen
- Department of Chemistry & Nano-Science Center, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | - Eduardo A. Della Pia
- Department of Chemistry & Nano-Science Center, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | - Christel Le Bon
- Laboratoire de
Biologie Physico-Chimique des Protéines Membranaires, UMR 7099,
CNRS/Université Paris 7, Institut de Biologie Physico-Chimique
(FRC 550), 13 rue Pierre et Marie Curie, F−75005 Paris, France
| | - Gilles Mourier
- CEA, Institut
de Biologie et de Technologies de Saclay, Service d’Ingénierie
Moléculaire des Protéines, 91191 Gif-sur-Yvette, France
| | - Jean-Luc Popot
- Laboratoire de
Biologie Physico-Chimique des Protéines Membranaires, UMR 7099,
CNRS/Université Paris 7, Institut de Biologie Physico-Chimique
(FRC 550), 13 rue Pierre et Marie Curie, F−75005 Paris, France
| | - Karen L. Martinez
- Department of Chemistry & Nano-Science Center, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | - Manuela Zoonens
- Laboratoire de
Biologie Physico-Chimique des Protéines Membranaires, UMR 7099,
CNRS/Université Paris 7, Institut de Biologie Physico-Chimique
(FRC 550), 13 rue Pierre et Marie Curie, F−75005 Paris, France
| |
Collapse
|
10
|
The αRep artificial repeat protein scaffold: a new tool for crystallization and live cell applications. Biochem Soc Trans 2015; 43:819-24. [DOI: 10.1042/bst20150075] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We have designed a new family of artificial proteins, named αRep, based on HEAT (acronym for Huntingtin, elongation factor 3 (EF3), protein pphosphatase 2A (PP2A), yeast kinase Tor1) repeat proteins containing an α-helical repeated motif. The sequence of the repeated motifs, first identified in a thermostable archae protein was optimized using a consensus design strategy and used for the construction of a library of artificial proteins. All proteins from this library share the same general fold but differ both in the number of repeats and in five highly randomized amino acid positions within each repeat. The randomized side chains altogether provide a hypervariable surface on αRep variants. Sequences from this library are efficiently expressed as soluble, folded and very stable proteins. αRep binders with high affinity for various protein targets were selected by phage display. Low micromolar to nanomolar dissociation constants between partners were measured and the structures of several complexes (specific αRep/protein target) were solved by X-ray crystallography. Using GFP as a model target, it was demonstrated that αReps can be used as bait in pull-down experiments. αReps can be expressed in eukaryotic cells and specifically interact with their target addressed to different cell compartments.
Collapse
|
11
|
Folding and stability of integral membrane proteins in amphipols. Arch Biochem Biophys 2014; 564:327-43. [PMID: 25449655 DOI: 10.1016/j.abb.2014.10.013] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 10/11/2014] [Accepted: 10/22/2014] [Indexed: 11/23/2022]
Abstract
Amphipols (APols) are a family of amphipathic polymers designed to keep transmembrane proteins (TMPs) soluble in aqueous solutions in the absence of detergent. APols have proven remarkably efficient at (i) stabilizing TMPs, as compared to detergent solutions, and (ii) folding them from a denatured state to a native, functional one. The underlying physical-chemical mechanisms are discussed.
Collapse
|
12
|
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.
Collapse
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
| | | | | |
Collapse
|
13
|
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.
Collapse
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
| |
Collapse
|
14
|
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]
|