Interaction of the Nicotinic Acetylcholine Receptor with Ligands and Membrane Lipids Studied by Fourier-Transform Infrared Spectroscopy and Photoaffinity Labeling

摘要: Monitoring of the amide I band by Fourier-transform infrared spectroscopy (FT-IR) is a valid and flexible approach to monitor changes in secondary structure reconstituted Acetylcholine Receptor (AcChR). The continuous exposure AcChR cholinergic agonist (carbamylcholine), which drives into desensitized state, produces only minor structure. Nevertheless, carbamylcholine alters tertiary or quaternary structure, as indicated increased thermal stability protein assessed from temperature-dependence spectrum. On contrary, presence competitive antagonist (d-tubocurarine) no detectable effects on Cholesterol neut-al lipids present asolectin extracts produce an ordering observed FT-IR also enable increase its response carbamylcholine. These cholesterol neutral seem mediated direct interaction all subunits with lipids, suggested labeling photoactivatable analogue. between analogue sensitive desensitization since during photolysis decreases extent stoichiometry subunits. This suggests occurrence agonist-induced change arrangement transmembrane portion protein, consistent alteration detected FT-IR.