Antibodies to synthetic peptides as probes of acetylcholine receptor structure.
Peptides containing the C-terminus of the alpha-chain of the nicotinic acetylcholine receptor (nAChR), as deduced from cDNA data, were synthesised and shown to bind to antibodies to denatured nAChR. Conversely, peptide-specific antibodies bound both to native and to denatured nAChR. Binding was exclusively to the alpha-chain. Trypsinization experiments and the use of the unique C-terminal hexapeptide of the alpha-chain demonstrated that the proposed C-terminus does exist on the mature alpha-chain, and that post-translational cleavage can be discounted as an explanation of the discrepancy of the molecular masses of the alpha-chain deduced from SDS gel electrophoresis (40 kDa) and from the DNA sequencing (50 kDa). Cleavage of the alpha-chain in the membrane occurs at two closely linked sites, resulting in the formation of a large fragment (approximately 35 kDa) and the remainder of the chain (approximately 9-10 kDa). No signs of experimental myasthenia gravis were observed in rabbits immunised with C-terminal peptide coupled to carrier protein.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D000915:Antibody Affinity; D055598:Chemical Phenomena; D002621:Chemistry; D004557:Electric Organ; D004591:Electrophoresis, Polyacrylamide Gel; D007120:Immunochemistry; D010446:Peptide Fragments / Q000138:chemical synthesis* / Q000276:immunology; D011950:Receptors, Cholinergic / Q000276:immunology; D014101:Torpedo
D000596:Amino Acids; D010446:Peptide Fragments; D011950:Receptors, Cholinergic