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Proceedings of the National Academy of Sciences of the United States of America logoLink to Proceedings of the National Academy of Sciences of the United States of America
. 1983 Jan;80(1):156–159. doi: 10.1073/pnas.80.1.156

Oligomeric structure of muscarinic receptors is shown by photoaffinity labeling: subunit assembly may explain high- and low-affinity agonist states.

S Avissar, G Amitai, M Sokolovsky
PMCID: PMC393329  PMID: 6571990

Abstract

The potent muscarinic photoaffinity reagent N-methyl-4-piperidyl p-azidobenzilate (azido-4NMPB) was used to covalently label specific muscarinic binding sites in various brain regions and in the heart. In the cortex and hippocampus, a single specifically labeled protein with an apparent molecular mass of 86,000 daltons was detected by gel electrophoresis. In the medulla pons, cerebellum, and cardiac atria, there was a 160,000-dalton band in addition to the 86,000-dalton polypeptide. Under certain conditions, alkali or hydroxylamine treatment dissociated both macromolecules into a single 40,000-dalton polypeptide. These results suggest that the muscarinic receptor exists in oligomeric forms and that a dimer and tetramer of a basic 40,000-dalton peptide may exist as interconvertible species. We propose a model to explain the biological architecture of the muscarinic receptors and suggest a possible correlation between the azido-4NMPB-labeled polypeptides and the two states of the receptor observed in agonist binding experiments.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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