Stabilization of acetylcholine receptor channels by lipids in cholate solution and during reconstitution in vesicles.

摘要: Acetylcholine receptors were solubilized from electric organ membranes of Torpedo californica in mixed micelles sodium cholate and soybean lipids. Sodium cholate, when supplemented with relatively low amounts lipids (cholate:lipid, 20:1, molar ratio), was effective solubilizing without denaturing their agonist-regulated cation channels. Another dialyzable detergent, octylglucoside, denatured the ion channel even presence excess Reassembly into vesicles achieved by dialysis. About 70% oriented toxin binding sites on external surface vesicles. Evidence suggests that all a single vesicle either right side out or inside out. During reassembly process about 10-fold greater lipid concentrations required for preservation function. At lipid/protein ratios than 16:1 (w/w), reassembled at constant protein/lipid ratio. These contained approximately 7% weight, 5-fold less native membrane. The remainder assembled small which did not contain receptors. reassociated higher weight ratios. Irreversible inactivation fraction acetylcholine receptor channels occurred proportion to packing density. This denaturation accompanied lowered susceptibility disulfide bond between delta subunits dimer reducing agents. Toxin orientation reconstituted affected reduced unexpected receptor/lipid ratio uniform within are discussed terms interactions occurring during initial nucleation events process.