Molecular properties of neurotensin receptors in rat brain. Identification of subunits by covalent labeling.
Molecular properties of neurotensin receptors in rat brain. Identification of subunits by covalent labeling.
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大鼠脑中神经降压素受体的分子特性。
DOI：
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发表时间：
1985
影响因子：
4.8
通讯作者：
J. Vincent
中科院分区：
文献类型：
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作者：
J. Mazella;P. Kitabgi;J. Vincent
通过两种方法特异性和共价标记大鼠脑突触膜中的神经降压素结合位点。首先，合成了神经降压素的光反应性和高放射性类似物，125I标记的叠氮苯甲酰基[Trp11]神经降压素，并用于光亲和标记神经降压素受体。在第二种方法中，神经降压素受体和 125I 标记的[Trp11]神经降压素（一种放射性但非光反应性的神经降压素类似物）之间的可逆关联通过双功能交联剂二琥珀酰亚胺基辛二酸酯变得不可逆。通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳和放射自显影对突触膜的分析表明，使用这两种方法，表观分子量分别为 49,000 和 51,000 的相同两条蛋白质条带被特异性标记。在电泳前用或不用β-巯基乙醇还原光标记膜都获得了相同的结果。配体浓度的变化不会改变两条带的相对标记强度，表明先前在大鼠脑突触膜中检测到的高亲和力和低亲和力神经降压素结合位点具有相似的分子结构。这些结果表明，大鼠脑中的神经降压素受体可能由两种不同的蛋白质亚基组成，其分子量相似，约为50,000，通过非共价键连接在一起。
Neurotensin binding sites in rat brain synaptic membranes were specifically and covalently labeled by two methods. In the first, a photoreactive and highly radioactive analogue of neurotensin, 125I-labeled azidobenzoyl[Trp11]neurotensin, was synthesized and used to photoaffinity label neurotensin receptors. In the second, the reversible association between neurotensin receptors and 125I-labeled[Trp11]neurotensin, a radioactive but nonphotoreactive analogue of neurotensin, was made irreversible by means of disuccinimidyl suberate, a bifunctional cross-linking reagent. Analysis of synaptic membranes by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography revealed that using both methods the same two protein bands with apparent molecular weights of 49,000 and 51,000 were specifically labeled. Identical results were obtained with or without reduction of the photolabeled membranes by beta-mercaptoethanol before electrophoresis. Variation of the ligand concentration did not modify the relative labeling intensities of the two bands, indicating that the high- and low-affinity neurotensin binding sites previously detected in rat brain synaptic membranes have similar molecular structures. These results indicate that neurotensin receptors in rat brain may be composed of two different protein subunits with similar molecular weight of about 50,000, that are linked together by noncovalent bonds.