Mutations in the channel domain of a neuronal nicotinic receptor convert ion selectivity from cationic to anionic.

Galzi, J L; Devillers-Thiéry, A; Hussy, N; Bertrand, S; Changeux, J P; Bertrand, D · Nature · 1992

basic_science · Level V

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Abstract

Introduction by site-directed mutagenesis of three amino acids from the MII segment of glycine or gamma-aminobutyric acid (GABAA) receptors into the MII segment of alpha 7 nicotinic receptor was sufficient to convert a cation-selective channel into an anion-selective channel gated by acetylcholine. A critical mutation was the insertion of an uncharged residue at the amino-terminal end of MII, stressing the importance of protein geometrical constraints on ion selectivity.

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