Dissection of the 66 000-dalton subunit of the acetylcholine receptor.
Dissection of the 66 000-dalton subunit of the acetylcholine receptor.
复制标题
乙酰胆碱受体 66 000 道尔顿亚基的解剖。
作者：
L. Wennogle;R. Oswald;T. Saitoh;J. Changeux
用5-叠氮基[3 H]三甲异喹（5-A[3 H]T）（一种局麻药三甲异喹的光亲和衍生物），在氨甲酰胆碱存在下，共价标记花斑电鳐（Torpedo marmorata）乙酰胆碱受体的66000-道尔顿或δ亚基。在用浓度增加的胰蛋白酶攻击纯化的受体后，δ链相继产生表观分子量为50 000（与β亚基不同，称为50 000-bis（片段））、49 000和47 000的片段。对于非变性（胆酸钠溶解或膜结合）受体，47000-道尔顿片段对胰蛋白酶不敏感，并含有所有的共价5-A[3 H]T标记。该片段仍然是糖基化的，并且具有与完整δ链相同的氨基酸N末端缬氨酸。δ亚基的一个特异性体外磷酸化位点位于49 000-和50 000-道尔顿胰蛋白酶切割片段之间，并且最有可能暴露于膜的细胞质侧。鉴定了δ链的16 000-道尔顿片段，其携带能够将非还原受体9 S单体交联成12 S二聚体的二硫键。该片段在胰蛋白酶处理后不与受体分子结合。
The 66 000-dalton or delta subunit of the acetylcholine receptor from Torpedo marmorata was covalently labeled in the presence of carbamoylcholine by 5-azido [3H]trimethisoquin (5-A[3H]T), a photoaffinity derivative of the local anesthetic trimethisoquin. After the attack of purified receptor with increasing concentrations of trypsin, the delta chain successively yielded fragments with apparent molecular weights of 50 000 (distinct from the beta subunit and referred to as the 50 000-bis (fragment), 49 000, and 47 000. With nondenatured (sodium cholate solubilized or membrane-bound) receptor, the 47 000-dalton fragment was not sensitive to trypsin and contained all of the covalent 5-A[3H]T label. This fragment was still glycosylated and had the same amino acid N terminus, valine, as the intact delta chain. A specific in vitro phosphorylation site of the delta subunit was located between the 49 000- and 50 000-dalton trypsin cleavage fragment and most likely is exposed to the cytoplasmic side of the membrane. A 16 000-dalton fragment of the delta chain was identified, which carriers a disulfide bond (or bonds) capable of cross-linking nonreduced receptor 9S monomerse into 12S dimers. The fragment did not remain associated with the receptor molecule after trypsin treatment.
鱼雷乙酰胆碱受体亚基作为跨膜复合物的形貌研究。
DOI：
10.1073/pnas.77.10.5807
发表时间：
1980
影响因子：
11.1
作者：
Strader,CD;Raftery,MA
通讯作者：
Raftery,MA