The noncompetitive blocker [3H]chlorpromazine labels segment M2 but not segment M 1 of the nicotinic acetylcholine receptor α‐subunit

FEBS Letters

Giraudat, Jérôme¹  Haumont, Pierre-Yves²  Revah, Frédéric¹  Lederer, Florence²  Changeux, Jean-Pierre¹  Galzi, Jean-Luc¹ 

[1] URA CNRS 0210, ‘Neurobiologie Moléculaire’, Département des Biotechnologies, Institut Pasteur, 75724 Paris Cédex 15, France;Unité 25 de l'Institut National de la Santé et de la Recherche Médicale et Laboratoire Associé au Centre National de la Recherche Scientifique, LA 122, Hôpital Necker, 75730 Paris Cédex 15, France

关键词: Acetylcholine receptor;    Ion channel;    Noncompetitive blocker;    AChR;    acetylcholine receptor;    NCB;    non-competitive blocker;    CPZ;    chlorpromazine;    rp HPLC;    reversephase HPLC;    PTH;    phenylthiohydantoin;   

DOI  :  10.1016/0014-5793(89)80957-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The membrane bound acetylcholine receptor from Torpedo marmorata was photolabeled by the noncompetitive channel blocker [³H]chlorpromazine under equilibrium conditions in the presence of the agonist carbamoylcholine. The radioactivity incorporated into the AChR subunits was reduced by addition of phencyclidine, a specific ligand for the high-affinity site for noncompetitive blockers. The α-subunit was purified digested with trypsin and/or CNBr and the resulting fragments fractionated by HPLC. Sequence analysis resulted in the identification of Ser-248 as a major residue labeled by [³H]chlorpromazine in a phencyclidine-sensitive manner. This residue is located in the hydrophobic and putative transmembrane segment M2 of the α-subunit, a region homologous to that containing the chlorpromazine-labeled Ser-262 in the δ-chain [1] and the Ser-254 and Leu-257 in the β-chain [2]. Extended sequence analysis of the hydrophobic segment M 1 further showed that no labeling occurred in this region.

【 授权许可】

Unknown