The ion channel of the nicotinic acetylcholine receptor is formed by the homologous helices M II of the receptor subunits

FEBS Letters

Lottspeich, Friedrich¹  Hucho, Ferdinand²  Oberthür, Walter² 

[1] Max-Planck-Institut für Biochemie, 8033 Martinsried, FRG;Institut für Biochemie der Freien Universität Berlin, Thielallee 63, 1000 Berlin 33, Germany

关键词: Acetylcholine receptor;    Ion channel;    Noncompetitive antagonist;    Photoaffinity labeling;   

DOI  :  10.1016/0014-5793(86)80881-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

A binding site for the channel-blocking noncompetitive antagonist [³H]triphenylmethylphosphonium ([³H]TPMP⁺) was localized in the α-, β- and δ-chains of the nicotinic acetylcholine receptor (AChR) from Torpedo marmorata electric tissue. The photolabel was found in homologous positions of the highly conserved sequence helix II, α 248, β 254, and δ 262. The site of the photoreaction appears to not be affected by the functional state of the receptor. [³H]TPMP⁺ was found in position δ 262 independent of whether photolabeling was performed with the receptor in its resting, desensitized or antagonist state. A model of the AChR ion channel is proposed, according to which the channel is formed by the five helices II contributed by the five receptor subunits.

【 授权许可】

Unknown