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Identification of Residues in the Adult Nicotinic Acetylcholine Receptor That Confer Selectivity for Curariform Antagonists

Journal of Biological ChemistryPublished 1 December 1997Open access
Nina Bren, Steven M. Sine
Citations35
SJR quartileQ1
SJR score1.71
SNIP1.00
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TL;DR

Alternative residues confer DMT selectivity in fetal and adult acetylcholine receptors.

Abstract

We identify residues in the epsilon and delta subunits of the adult nicotinic acetylcholine receptor that give the alphaepsilon and alphadelta binding sites different affinities for the curariform antagonist dimethyl d-tubocurarine (DMT). By constructing epsilon-delta subunit chimeras, coexpressing them with complementary subunits, and measuring DMT binding, we identify two pairs of residues, Ileepsilon58/Hisdelta60 and Aspepsilon59/Aladelta61, responsible for DMT site selectivity in the adult receptor. The two determinants contribute approximately equally to the binding site and interact in contributing to the site. Exchange of these residues from one subunit to the other exchanges the affinities of the resulting binding sites. These determinants in the adult receptor are far from those that confer site selectivity in the fetal receptor; determinants in the fetal receptor are Ilegamma116/Valdelta118, Tyrgamma117/Thrdelta119, and Sergamma161/Lysdelta163. Thus, alternative residues confer DMT selectivity in fetal and adult acetylcholine receptors.

Keywords

MedicineBiochemistry, Genetics and Molecular Biology