The selectivity filter of a ligand-gated ion channel The helix-M2 model of the ion channel of the nicotinic acetylcholine receptor

AbstractEvidence from electrophysiology and biochemistry supports the hypothesis that the ion channel of the nicotinic acetylcholine receptor is formed by homologous amino acid sequences of all receptor subunits, called helices M2. A model of the ion channel is proposed and the selectivity filter is described as a ring of negatively-charged amino acid side chains [(1988) Nature 335, 645-648] which may undergo conformational changes upon permeation of the cation.Acetylcholine receptor; Ion channel; Selectivity filter; Molecular modelin