title: Pore conformations and gating mechanism of a Cys-loop receptor.
abstract: Neurons regulate the propagation of chemoelectric signals throughout the nervous system by opening and closing ion channels, a process known as gating. Here, histidine-based metal-binding sites were engineered along the intrinsic pore of a chimeric Cys-loop receptor to probe state-dependent Zn(2+)-channel interactions. Patterns of Zn(2+) ion binding within the pore reveal that, in the closed state, the five pore-lining segments adopt an oblique orientation relative to the axis of ion conduction and constrict into a physical gate at their intracellular end. The interactions of Zn(2+) with the open state indicate that the five pore-lining segments should rigidly tilt to enable the movement of their intracellular ends away from the axis of ion conduction, so as to open the constriction (i.e., the gate). Alignment of the functional results with the 3D structure of an acetylcholine receptor allowed us to generate structural models accounting for the closed and open pore conformations and for a gating mechanism of a Cys-loop receptor.
authors.affiliation: Récepteurs et Cognition, Unité de Recherche Associée 2182 Centre National de la Recherche Scientifique, Institut Pasteur, 25 Rue du Docteur Roux, 75724 Paris Cedex 15, France. yopaas@netvision.net.il
authors.forename: Yoav
authors.initials: Y
authors.lastname: Paas
authors.forename: Gilad
authors.initials: G
authors.lastname: Gibor
authors.forename: Regis
authors.initials: R
authors.lastname: Grailhe
authors.forename: Nathalie
authors.initials: N
authors.lastname: Savatier-Duclert
authors.forename: Virginie
authors.initials: V
authors.lastname: Dufresne
authors.forename: Morten
authors.initials: M
authors.lastname: Sunesen
authors.forename: Lia Prado
authors.initials: LP
authors.lastname: de Carvalho
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Changeux
authors.forename: Bernard
authors.initials: B
authors.lastname: Attali
mesh_terms: D000818:Animals; D002460:Cell Line; D002463:Cell Membrane Permeability; D004594:Electrophysiology; D006801:Humans; D015640:Ion Channel Gating; D007473:Ion Channels / Q000737:chemistry* / Q000502:physiology*; D009474:Neurons / Q000737:chemistry; D009865:Oocytes; D016062:Porosity; D011487:Protein Conformation; D015202:Protein Engineering; D011950:Receptors, Cholinergic / Q000737:chemistry; D011993:Recombinant Fusion Proteins; D014981:Xenopus; D015032:Zinc / Q000378:metabolism
chemical_list: D007473:Ion Channels; D011950:Receptors, Cholinergic; D011993:Recombinant Fusion Proteins; D015032:Zinc