Referenced in: none

Automatically associated channels: Kir2.3

Title: Multi-Site Binding Of A General Anesthetic To The Prokaryotic Pentameric Ligand-Gated Ion Channel ELIC.

Authors: Radovan Spurny, Bert Billen, Rebecca J Howard, Marijke Brams, Sarah Debaveye, Kerry L Price, David A Weston, Sergei V Strelkov, Jan Tytgat, Sonia Bertrand, Daniel Bertrand, Sarah C R Lummis, Chris Ulens

Journal, date & volume: J. Biol. Chem., 2013 Jan 30 , ,

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/23364792

Abstract
Pentameric ligand-gated ion channels (pLGICs), such as nicotinic acetylcholine, glycine, γ-aminobutyric acid GABA(A/C) receptors, and the Gloeobacter violaceus ligand-gated ion channel (GLIC), are receptors that contain multiple allosteric binding sites for a variety of therapeutics, including general anesthetics. Here, we report the x-ray crystal structure of the Erwinia chrysanthemi ligand-gated ion channel (ELIC) in complex with a derivative of chloroform, which reveals important features of anesthetic recognition, involving multiple binding at three different sites. One site is located in the channel pore and equates with a noncompetitive inhibitor site found in many pLGICs. A second transmembrane site is novel and is located in the lower part of the transmembrane domain, at an interface formed between adjacent subunits. A third site is also novel and is located in the extracellular domain in a hydrophobic pocket between the β7-β10 strands. Together, these results extend our understanding of pLGIC modulation and reveal several specific binding interactions that may contribute to modulator recognition, further substantiating a multisite model of allosteric modulation in this family of ion channels.