title: Allosteric transitions of Torpedo acetylcholine receptor in lipids, detergent and amphipols: molecular interactions vs. physical constraints.
abstract: The binding of a fluorescent agonist to the acetycholine receptor from Torpedo electric organ has been studied by time-resolved spectroscopy in three different environments: in native membrane fragments, in the detergent CHAPS, and after complexation by amphipathic polymers ('amphipols'). Binding kinetics was similar in the membrane and in amphipols, demonstrating that the receptor can display unaltered allosteric transitions outside its natural lipid environment. In contrast, allosteric equilibria were strongly shifted towards the desensitized state in CHAPS. Therefore, the effect of CHAPS likely results from molecular interactions rather than from the loss of bulk physical properties of the membrane environment.
authors.affiliation: Unité de Neurobiologie Moléculaire, CNRS URA 2182, Institut Pasteur, 25 rue du Dr Roux, 75734 Paris, France.
authors.forename: Karen L
authors.initials: KL
authors.lastname: Martinez
authors.forename: Yann
authors.initials: Y
authors.lastname: Gohon
authors.forename: Pierre-Jean
authors.initials: PJ
authors.lastname: Corringer
authors.forename: Christophe
authors.initials: C
authors.lastname: Tribet
authors.forename: Fabienne
authors.initials: F
authors.lastname: Mérola
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Changeux
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Popot
mesh_terms: D000494:Allosteric Regulation; D000818:Animals; D001665:Binding Sites; D002793:Cholic Acids; D003902:Detergents; D004557:Electric Organ / Q000378:metabolism; D005456:Fluorescent Dyes; D066298:In Vitro Techniques; D008055:Lipids; D011487:Protein Conformation; D011978:Receptors, Nicotinic / Q000737:chemistry* / Q000378:metabolism*; D012995:Solubility; D013501:Surface-Active Agents; D014101:Torpedo / Q000378:metabolism*
chemical_list: D002793:Cholic Acids; D003902:Detergents; D005456:Fluorescent Dyes; D008055:Lipids; D011978:Receptors, Nicotinic; D013501:Surface-Active Agents; C028213:3-((3-cholamidopropyl)dimethylammonium)-1-propanesulfonate