Mamalaki C, Stephenson F A, Barnard E A
EMBO J. 1987 Mar;6(3):561-5. doi: 10.1002/j.1460-2075.1987.tb04791.x.
The GABAA receptor has been purified to homogeneity from bovine cerebral cortex. Under stringent conditions of isolation, the GABAA receptor was shown to consist only of alpha (Mr 53 000) and beta (Mr 57 000) subunits. A densitometric scan of SDS-PAGE gels under reducing conditions showed that these subunits were present in a 1:1 ratio. A model of the receptor as a heterologous tetramer alpha 2 beta 2 is proposed. Monoclonal antibodies have been raised to the purified bovine GABAA receptor. One of these antibodies, 1A6, was shown to react with both the alpha and beta subunits of the purified receptor. The subunits were still positive in immunoblots following the removal of the carbohydrate moieties of the respective polypeptides by endoglycosidase F treatment. This antibody has been employed to demonstrate antigenic cross-reactivity between the GABAA receptors of three vertebrate species. It is further proposed that there is partial amino acid sequence homology between the alpha and beta polypeptides and hence that they are derived from a single ancestral gene.
γ-氨基丁酸A型（GABAA）受体已从牛大脑皮层中纯化至同质状态。在严格的分离条件下，GABAA受体仅由α亚基（分子量53000）和β亚基（分子量57000）组成。在还原条件下对SDS-PAGE凝胶进行光密度扫描显示，这些亚基以1:1的比例存在。提出了一种受体模型，即异源四聚体α2β2。已针对纯化的牛GABAA受体产生了单克隆抗体。其中一种抗体1A6被证明能与纯化受体的α亚基和β亚基发生反应。在用内切糖苷酶F处理去除各多肽的碳水化合物部分后，这些亚基在免疫印迹中仍呈阳性。该抗体已被用于证明三种脊椎动物物种的GABAA受体之间的抗原交叉反应性。进一步提出α多肽和β多肽之间存在部分氨基酸序列同源性，因此它们源自单一的祖先基因。
