Nicotinic acetylcholine receptor: A structural model for α‐subunit peptide 188–201, the putative binding site for cholinergic agents

Abstract
A peptide corresponding to amino acid sequence 188–201 of the α-subunit of Torpedo AChR binds α-Bgtx. The S-S bridge between Cys 192 and 193 is essential for the binding as Tyr in position 189. The same sequence 188–201 corresponding to human AChR, which instead of Tyr has a Thr in position 189, binds α-Bgtx with a much lower efficiency. Monoclonal antibodies raised against Torpedo peptide 188–201 recognize Torpedo AChR and antibodies against Torpedo AChR recognize peptide 188–201 indicating that the synthetic peptide and the corresponding sequence in the native molecule share some immunological epitopes. With computer graphics and energy refinement a molecular model of this peptide has been elaborated.