The regions of alpha-neurotoxin binding on the extracellular part of the alpha-subunit of human acetylcholine receptor.

A set of 18 synthetic uniform overlapping peptides spanning the entire extracellular part (residues 1-210) of the alpha-subunit of human acetylcholine receptor were studied for their binding activity of 125I-labeled alpha-bungarotoxin and cobratoxin. A major toxin-binding region was found to reside within peptide alpha 122-138. In addition, low-binding activities were obtained with peptides alpha 34-49 and alpha 194-210. It is concluded that the region within residues alpha 122-138 constitutes a universal major toxin-binding region for acetylcholine receptor of various species.