Structure/function relationships of muscarinic acetylcholine receptors

Mark R. Brann, V. J. Klimkowski, John Ellis

Research output: Contribution to journalArticle

19 Scopus citations

Abstract

The regions of muscarinic receptors that specify G-protein-coupling and ligand-binding have been defined in several recent studies. Overall, these studies have shown that amino acids within the third cytoplasmic loop of the receptors define their selectivity for different G-proteins, and that multiple, discontinuous epitopes contribute to their selectivities for different ligands. In fact, several competitive and allosteric antagonists can be classified into groups based on which of these epitopes contribute to their subtype selectivity. Site-directed mutagenesis, combined with covalent-labeling studies have suggested that ligands bind to a hydrophobic core of the receptors that is formed by multiple transmembrane (TM) domains. An aspartic acid located in TM3 is likely to bind to the ammonium headgroup of muscarinic ligands, and multiple hydroxyl-containing amino acids contribute to agonist but not antagonist binding. These data are discussed in the context of a computational model of a muscarinic receptor. Our model is based on a sequence alignment with bacteriorhodopsin, a seven TM protein for which a higher resolution structure is available. Most of the mutagenic data can be rationalized in the context of this model, and predict testable hypotheses concerning the mechanism by which ligands control the activity of muscarinic receptors.

Original languageEnglish (US)
Pages (from-to)405-412
Number of pages8
JournalLife Sciences
Volume52
Issue number5-6
DOIs
StatePublished - 1993

All Science Journal Classification (ASJC) codes

  • Biochemistry, Genetics and Molecular Biology(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)

Fingerprint Dive into the research topics of 'Structure/function relationships of muscarinic acetylcholine receptors'. Together they form a unique fingerprint.

Cite this