Referenced in: none

Automatically associated channels: Kv2.1

Title: Conotoxin MI inhibits the alpha-delta acetylcholine binding site of the Torpedo marmorata receptor.

Authors: Leonardo M Cortez, Sergio G del Canto, Fernando D Testai, Mirtha J Biscoglio de Jiménez Bonino

Journal, date & volume: Biochem. Biophys. Res. Commun., 2002 Jul 26 , 295, 791-5

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/12127962

Abstract
The muscle-type nicotinic receptor has two pharmacologically distinguishable acetylcholine binding sites at the alpha-gamma and alpha-delta subunit interfaces; alpha-conotoxins can bind them selectively. As reported, alpha-conotoxin MI has greater affinity for the site near the alpha-delta interface of the BC(3)H1 cell receptor but, in the case of the Torpedo californica receptor, displays greater affinity for that near the alpha-gamma interface. To further investigate ligand selectivity, we study the conotoxin MI-Torpedo marmorata receptor interaction. In this work, we show the binding of alpha-conotoxin MI to the T. marmorata receptor and the influence of the antagonist alpha-Bungarotoxin and the agonist carbamylcholine on such binding; in addition, and contrasting with the results for the Torpedo californica receptor, we identify the alpha-delta subunit interface as the high affinity binding site. This is the first work describing different characteristics of the interaction between alpha-conotoxin MI and receptors from different species of the same genus.