Isolation of two proteins with high affinity for guanine nucleotides from membranes of bovine brain.
Isolation of two proteins with high affinity for guanine nucleotides from membranes of bovine brain.
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DOI：
10.1016/s0021-9258(18)89817-9
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发表时间：
1984-11
期刊：
影响因子：
--
通讯作者：
P. Sternweis;J. Robishaw
中科院分区：
文献类型：
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作者：
P. Sternweis;J. Robishaw
来自牛脑的膜以高亲和力结合相对大量的鸟苷5 '-（3-O-硫代）三磷酸（GTP γ S）。负责大部分这种活性的两种蛋白质被纯化;它们占膜蛋白的1.5%。这两种蛋白质含有39，000或41，000 Da的α亚基，36，000或35，000 Da的β亚基和潜在的γ亚基（11，000 Da）。这些结构与包括转导素和腺苷酸环化酶的调节蛋白GS和GI的蛋白质家族相同。41，000-Da和39，000-Da多肽可以与来自百日咳杆菌的胰岛激活蛋白进行ADP核糖基化，特异性结合鸟嘌呤核苷酸，并以分别与GI和转导素的α亚基相似的速率通过聚丙烯酰胺凝胶迁移。36，000-和35，000-Da多肽类似于GI和GS的β亚基。只要有β亚基存在，就可以发现γ亚基。41，000-和39，000-Da多肽（具有β和γ）分别命名为来自脑的GI和GO。GO的α亚基是在不使用已知解离其他G蛋白的配体的情况下分离的。GO α在不存在Mg 2+的情况下可逆地结合GTP γ S，并且在胆酸盐中相对稳定。这种分离的α亚基应该是非常有用的，在阐明这个家庭的GTP结合蛋白的作用机制。
Membranes from bovine brain bind relatively large quantities of guanosine 5'-(3-O-thio)triphosphate (GTP gamma S) with high affinity. The two proteins responsible for most of this activity were purified; they account for 1.5% of the membrane protein. The two proteins contain alpha subunits of either 39,000 or 41,000 Da, beta subunits of 36,000 or 35,000 Da, and a potential gamma subunit (11,000 Da). These structures are the same as a family of proteins that includes transducin and the regulatory proteins, GS and GI, of adenylate cyclase. The 41,000- and 39,000-Da polypeptides can be ADP-ribosylated with islet-activating protein from Bordetella pertussis, bind guanine nucleotides specifically, and migrate through polyacrylamide gels with rates similar to the alpha subunits of GI and transducin, respectively. The 36,000- and 35,000-Da polypeptides are similar to the beta subunits of GI and GS. The gamma subunit is found whenever beta subunits are present. The 41,000- and 39,000-Da polypeptides (with beta and gamma) are designated, respectively, GI and GO from brain. The alpha subunit of GO was isolated without the use of ligands known to dissociate other G proteins. GO alpha binds GTP gamma S reversibly in the absence of Mg2+ and is relatively stable in cholate. This isolated alpha subunit should be of great utility in elucidating the mechanism of action of this family of GTP-binding proteins.