Structural Identification of the Nicotinic Receptor Ion Channel.

The structural identification of the cationic channel of the acetylcholine nicotinic receptor involved its biochemical tagging by channel blockers, followed by site-directed mutagenesis analyses reported in two papers in 1988. The ion channel was demonstrated to be lined by the transmembrane segment MII, in which the binding sites of channel blockers are "framed" by anionic rings.