Functional characterization of mongoose nicotinic acetylcholine receptor alpha-subunit: resistance to alpha-bungarotoxin and high sensitivity to acetylcholine.
FEBS Lett
; 431(3): 411-4, 1998 Jul 24.
Article
en En
| MEDLINE
| ID: mdl-9714553
ABSTRACT
The mongoose is resistant to snake neurotoxins. The mongoose muscle nicotinic acetylcholine receptor (AChR) alpha-subunit contains a number of mutations in the ligand-binding domain and exhibits poor binding of alpha-bungarotoxin (alpha-BTX). We characterized the functional properties of a hybrid (alpha-mongoose/beta gamma delta-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 alpha-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 microM 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.
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Base de datos:
MEDLINE
Asunto principal:
Bungarotoxinas
/
Acetilcolina
/
Receptores Nicotínicos
Tipo de estudio:
Diagnostic_studies
Límite:
Animals
Idioma:
En
Revista:
FEBS Lett
Año:
1998
Tipo del documento:
Article
País de afiliación:
Israel