title: The reaction site of a non-competitive antagonist in the delta-subunit of the nicotinic acetylcholine receptor.
abstract: A site in the primary structure of the nicotinic acetylcholine receptor from Torpedo marmorata covalently labeled with the non-competitive antagonist [3H]triphenylmethylphosphonium (TPMP+) was localized. The label was found in position 262 of the delta-polypeptide chain. This site is specifically labeled in the presence of the agonist carbamoylcholine. Labeling is prevented by the non-competitive antagonist histrionicotoxin. Position 262, probably a serine, is located in the highly conserved membrane-spanning helix M2 (according to the predicted folding scheme of Finer-Moore and Stroud (1984). The relationship of this site to the receptor's ion channel and its regulation is discussed.
mesh_terms: D000595:Amino Acid Sequence; D000664:Amphibian Venoms / Q000494:pharmacology*; D000818:Animals; D001665:Binding Sites; D002217:Carbachol / Q000494:pharmacology*; D004557:Electric Organ / Q000378:metabolism; D007700:Kinetics; D046911:Macromolecular Substances; D009861:Onium Compounds / Q000378:metabolism*; D011978:Receptors, Nicotinic / Q000187:drug effects / Q000378:metabolism*; D014101:Torpedo; D014320:Triphenylmethyl Compounds / Q000378:metabolism*
chemical_list: D000664:Amphibian Venoms; D046911:Macromolecular Substances; D009861:Onium Compounds; D011978:Receptors, Nicotinic; D014320:Triphenylmethyl Compounds; C011561:triphenylmethylphosphonium; D002217:Carbachol; C007948:histrionicotoxin