Photoaffinity labeling of Torpedo acetylcholine receptor by physostigmine
- 1 September 1993
- journal article
- Published by Wiley in European Journal of Biochemistry
- Vol. 216 (2), 671-677
- https://doi.org/10.1111/j.1432-1033.1993.tb18187.x
Abstract
The plant alkaloid physostigmine, an established anti-cholinesterase agent of the carbamate type, has recently been shown to bind to the nicotinic acetylcholine receptor from Torpedo marmorata electrocytes [Okonjo, K. O., Kuhlmann, J. & Maelicke, A. (1991) Eur. J. Biochem. 200, 671–677]. Pharmacological studies of physostigmine-induced ion flux into nicotinic-acetylcholine-receptor-rich membrane vesicles, indicated distinct binding sites for physostigmine and acetylcholine. As shown in this study by photoaffinity labeling with [phenyl-(n)-3H](-)physostigmine, the physostigmine-binding site is located within the same subunit (α polypeptide) of the receptor as the acetylcholine-binding site. Using a variety of proteolytic cleavage conditions for the purified α polypeptide, several [3H]physostigmine-labeled peptides were isolated and sequenced. From the radioactivity released in the course of the Edman degradations of the labeled peptides, it was found that the label was associated in all cases with Lys125. These results identify a novel ligand-binding site for the Torpedo nicotinic acetylcholine receptor that is different in location from binding sites identified previously for acetylcholine, its established agonists and antagonists, and direct channel blockers.Keywords
This publication has 41 references indexed in Scilit:
- Lounging in a lysosome: the intracellular lifestyle of Coxiella burnetiiCellular Microbiology, 2007
- A second pathway of activation of the Torpedo acetylcholine receptor channelEuropean Journal of Biochemistry, 1991
- Desensitization is a property of the cholinergic binding region of the nicotinic acetylcholine receptor, not of the receptor‐integral ion channelFEBS Letters, 1991
- Comparison of the toxin binding sites of the nicotinic acetylcholine receptor from Drosophila to humanBiochemistry, 1990
- Nicotinic acetylcholine receptor: A structural model for α‐subunit peptide 188–201, the putative binding site for cholinergic agentsFEBS Letters, 1988
- The Molecular Basis of Anticholinesterase Actions on Nicotinic and Glutamatergic SynapsesaAnnals of the New York Academy of Sciences, 1987
- The ion channel of the nicotinic acetylcholine receptor is formed by the homologous helices M II of the receptor subunitsFEBS Letters, 1986
- Functional and structural analysis of acetylcholine receptor‐rich membranes after negative stainingFEBS Letters, 1984
- Conformations of Torpedo acetylcholine receptor associated with ion transport and desensitizationBiochemistry, 1982
- Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4Nature, 1970