Structure of the high-affinity binding site for noncompetitive blockers of the acetylcholine receptor: serine-262 of the delta subunit is labeled by [3H]chlorpromazine.
Structure of the high-affinity binding site for noncompetitive blockers of the acetylcholine receptor: serine-262 of the delta subunit is labeled by [3H]chlorpromazine.
复制标题
乙酰胆碱受体非竞争性阻断剂的高亲和力结合位点的结构：δ亚基的丝氨酸262被[3H]氯丙嗪标记。
DOI：
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发表时间：
1986
影响因子：
11.1
通讯作者：
J. Changeux
中科院分区：
文献类型：
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作者：
J. Giraudat;M. Dennis;T. Heidmann;J. Chang;J. Changeux
在有激动剂存在的平衡条件下，用非竞争性通道阻滞剂[~3H]氯丙嗪对膜结合型乙酰胆碱受体进行光标记。放射性被合并到所有亚基中，并通过苯环利定的加入而减少，苯环利定是非竞争性阻滞剂高亲和力位点的特定配体。用胰酶纯化和消化Delta亚基，得到的片段用反相高效液相色谱分离。由于其明显的疏水性，标记的多肽不能纯化为均一，但差异CNBr亚切割和部分纯化片段的共测序相结合使我们能够鉴定Ser-262被[~3H]氯丙嗪标记。这种特殊残基的标记被苯环利定阻止，因此发生在非竞争性阻滞剂的高亲和力位点的水平或附近。Ser-262位于一个被称为MII的疏水和潜在的跨膜片段中。
The membrane-bound acetylcholine receptor from Torpedo marmorata was photolabeled by the noncompetitive channel blocker [3H]chlorpromazine under equilibrium conditions in the presence of agonist. Incorporation of radioactivity into all subunits occurred and was reduced by addition of phencyclidine, a specific ligand for the high-affinity site for noncompetitive blockers. The delta subunit was purified and digested with trypsin, and the resulting fragments were fractionated by reversed-phase HPLC. The labeled peptide could not be purified to homogeneity because of its marked hydrophobic character, but a combination of differential CNBr subcleavage and cosequencing of partially purified fragments enabled us to identify Ser-262 as being labeled by [3H]chlorpromazine. The labeling of this particular residue was prevented by phencyclidine and thus took place at the level of, or in proximity to, the high-affinity site for noncompetitive blockers. Ser-262 is located in a hydrophobic and potentially transmembrane segment termed MII.