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Pore conformations and gating mechanism of a Cys-loop receptor

Authors
  • Yoav Paas
  • Gilad Gibor
  • Regis Grailhe
  • Nathalie Savatier-Duclert
  • Virginie Dufresne
  • Morten Sunesen
  • Lia Prado de Carvalho
  • Jean-Pierre Changeux
  • Bernard Attali
Publisher
National Academy of Sciences
Publication Date
Oct 24, 2005
Source
PMC
Keywords
Disciplines
  • Engineering
License
Unknown

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 Zn2+-channel interactions. Patterns of Zn2+ 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 Zn2+ 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.

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