Giniger E, Ptashne M
Department of Biochemistry and Molecular Biology, Harvard University, Cambridge, Massachusetts 02138.
Nature. 1987;330(6149):670-2. doi: 10.1038/330670a0.
Gene activation by a DNA-binding regulatory protein in yeast requires the protein to have two components: one to recognize a specific DNA sequence and a second, the 'activating region', to interact with a general transcription factor or perhaps with RNA polymerase. The activating regions that have been characterized are acidic, and mutational analysis of one indicates that this acidity is important for activity. Here we report the design of an artificial protein bearing a novel 15-amino acid peptide linked to a DNA binding fragment of the yeast regulatory protein GAL4). The synthetic peptide is acidic and should it form an alpha-helix, that helix would be amphipathic, having one hydrophilic face bearing the acidic residues, and one hydrophobic face. When expressed in yeast, the artificial protein bearing this peptide efficiently activates the GAL1 gene which is ordinarily activated by GAL4. An otherwise identical protein with the novel 15 amino acids in a scrambled order, and which is thus unable to form an amphipathic structure, does not activate GAL1 transcription.
酵母中一种与DNA结合的调节蛋白激活基因需要该蛋白具备两个组分：一个组分识别特定的DNA序列，另一个组分即“激活区域”与通用转录因子或可能与RNA聚合酶相互作用。已被鉴定的激活区域呈酸性，对其中一个激活区域的突变分析表明这种酸性对活性很重要。在此我们报告一种人工蛋白质的设计，该蛋白质带有一个与酵母调节蛋白GAL4的DNA结合片段相连的新型15氨基酸肽。合成肽呈酸性，若它形成α螺旋，该螺旋将是两亲性的，有一个带有酸性残基的亲水面和一个疏水面。当在酵母中表达时，带有这种肽的人工蛋白质能有效激活通常由GAL4激活的GAL1基因。另一种含有以混乱顺序排列的新型15个氨基酸、因而无法形成两亲结构的相同蛋白质则不能激活GAL1转录。
