AN AMINO-TERMINAL FRAGMENT OF GAL4 BINDS DNA AS A DIMER
AN AMINO-TERMINAL FRAGMENT OF GAL4 BINDS DNA AS A DIMER
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DOI：
10.1016/0022-2836(89)90007-7
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发表时间：
1989-10-05
影响因子：
5.6
通讯作者：
PTASHNE, M
中科院分区：
文献类型：
--
作者：
CAREY, M;KAKIDANI, H;PTASHNE, M
GAL4是一种酵母转录激活蛋白，它与DNA上特定的二重旋转对称位点结合，并刺激半乳糖分解代谢所需基因的转录。该蛋白的DNA结合区域位于前74个氨基酸内，且包含一个“锌指”序列基序。我们表明，一种由GAL4的前147个氨基酸组成的多肽，被命名为GAL4（1 - 147），在体外作为二聚体与DNA结合。尽管一种仅包含前74个氨基酸的蛋白，被命名为GAL4（1 - 74），能特异性地与DNA结合，但其亲和力相对于GAL4（1 - 147）有所降低。将λ阻遏蛋白的强二聚化结构域添加到GAL4（1 - 74）中，产生了一种与GAL4（1 - 147）结合紧密程度相同的蛋白。当通过DNA酶I、核酸外切酶III和羟自由基足迹法以及磷酸乙基化干扰进行检测时，GAL4（1 - 147）与其识别位点进行旋转对称接触。GAL4（1 - 147）在体外的结合需要锌或镉。
GAL4 is a yeast transcriptional activator protein that binds to specific 2-fold rotationally symmetric sites on DNA and stimulates transcription of the genes required for galactose catabolism. The DNA binding region of the protein is located within the first 74 amino acids and contains a "zinc finger" sequence motif. We show that a polypeptide comprising the first 147 amino acids of GAL4, designated GAL4 (1-147), binds DNA as a dimer in vitro. Although a protein containing only the first 74 amino acids, designated GAL4 (1-74), binds DNA specifically, its affinity is reduced relative to GAL4 (1-147). Addition of the strong dimerization domain of .lambda. repressor to GAL4 (1-74) generates a protein that binds as tightly as GAL4 (1-147). GAL4 (1-147) makes rotationally symmetric contacts with its recognition site when assayed by DNase I, exonuclease III and hydroxyl radical footprinting and by phosphate ethylation interference. Binding of GAL4 (1-147) in vitro requires either zinc or cadmium.