FUNCTIONAL DOMAINS OF THE ARAC PROTEIN
FUNCTIONAL DOMAINS OF THE ARAC PROTEIN
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DOI：
10.1073/pnas.90.12.5638
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发表时间：
1993-06-15
影响因子：
11.1
通讯作者：
SCHLEIF, RF
中科院分区：
文献类型：
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作者：
BUSTOS, SA;SCHLEIF, RF
在大肠杆菌中调节L-阿拉伯糖操纵子的AraC蛋白被分解为在嵌合蛋白中起作用的两个结构域。一种提供二聚化能力并结合配体阿拉伯糖，另一种提供位点特异性DNA结合能力并激活转录。体内和体外实验表明，由AraC蛋白的N-末端一半和莱克萨阻遏物的DNA结合结构域组成的融合蛋白二聚化，与莱克萨操纵子良好结合，并以阿拉伯糖响应的方式抑制莱克萨操纵子-β-半乳糖苷酶融合基因的表达。体内和体外实验还表明，由AraC蛋白的C-末端一半和来自C/EBP转录激活因子的亮氨酸拉链二聚化结构域组成的融合蛋白结合到arthalopathy并激活来自p（BAD）启动子-β-半乳糖苷酶融合基因的转录。二聚化对于野生型AraC结合位点的占据和激活是必要的。
The AraC protein, which regulates the L-arabinose operons in Escherichia coli, was dissected into two domains that function in chimeric proteins. One provides a dimerization capability and binds the ligand arabinose, and the other provides a site-specific DNA-binding capability and activates transcription. In vivo and in vitro experiments showed that a fusion protein consisting of the N-terminal half of the AraC protein and the DNA-binding domain of the LexA repressor dimerizes, binds well to a LexA operator, and represses expression of a LexA operator-beta-galactosidase fusion gene in an arabinose-responsive manner. In vivo and in vitro experiments also showed that a fusion protein consisting of the C-terminal half of the AraC protein and the leucine zipper dimerization domain from the C/EBP transcriptional activator binds to araI and activates transcription from a p(BAD) promoter-beta-galactosidase fusion gene. Dimerization was necessary for occupancy and activation of the wild-type AraC binding site.