Functional characterization of mongoose nicotinic acetylcholine receptor α‐subunit: resistance to α‐bungarotoxin and high sensitivity to acetylcholine

FEBS Letters

Jensen, Bo S¹  Lupu-Meiri, Monica²  Fuchs, Sara¹  Asher, Orna¹  Oron, Yoram²  Paperna, Tamar¹ 

[1] Department of Immunology, The Weizmann Institute of Science, Rehovot 76100, Israel;Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv 69978, Israel

关键词: Acetylcholine receptor;    Mongoose;    α-Bungarotoxin;    Acetylcholine;    Xenopus oocyte;   

DOI  :  10.1016/S0014-5793(98)00805-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The mongoose is resistant to snake neurotoxins. The mongoose muscle nicotinic acetylcholine receptor (AChR) α-subunit contains a number of mutations in the ligand-binding domain and exhibits poor binding of α-bungarotoxin (α-BTX). We characterized the functional properties of a hybrid (α-mongoose/βγδ-rat) AChR. Hybrid AChRs, expressed in Xenopus oocytes, respond to acetylcholine with depolarizing current, the mean maximal amplitude of which was greater than that mediated by the rat AChR. The IC₅₀ of α-BTX to the hybrid AChR was 200-fold greater than that of the rat, suggesting much lower affinity for the toxin. Hybrid AChRs exhibited an apparent higher rate of desensitization and higher affinity for ACh (EC₅₀ 1.3 vs. 23.3 μM for the rat AChR). Hence, changes in the ligand-binding domain of AChR not only affect the binding properties of the receptor, but also result in marked changes in the characteristics of the current.

【 授权许可】

Unknown