Talanian R V, McKnight C J, Kim P S
Whitehead Institute for Biomedical Research, Nine Cambridge Center, MA 02142.
Science. 1990 Aug 17;249(4970):769-71. doi: 10.1126/science.2389142.
A recently described class of DNA binding proteins is characterized by the "bZIP" motif, which consists of a basic region that contacts DNA and an adjacent "leucine zipper" that mediates protein dimerization. A peptide model for the basic region of the yeast transcriptional activator GCN4 has been developed in which the leucine zipper has been replaced by a disulfide bond. The 34-residue peptide dimer, but not the reduced monomer, binds DNA with nanomolar affinity at 4 degrees C. DNA binding is sequence-specific as judged by deoxyribonuclease I footprinting. Circular dichroism spectroscopy suggests that the peptide adopts a helical structure when bound to DNA. These results demonstrate directly that the GCN4 basic region is sufficient for sequence-specific DNA binding and suggest that a major function of the GCN4 leucine zipper is simply to mediate protein dimerization. Our approach provides a strategy for the design of short sequence-specific DNA binding peptides.
最近描述的一类DNA结合蛋白的特征是具有“bZIP”基序，它由与DNA接触的碱性区域和介导蛋白质二聚化的相邻“亮氨酸拉链”组成。已开发出一种酵母转录激活因子GCN4碱性区域的肽模型，其中亮氨酸拉链被二硫键取代。这个34个残基的肽二聚体，而非还原后的单体，在4℃时以纳摩尔亲和力结合DNA。通过脱氧核糖核酸酶I足迹法判断，DNA结合具有序列特异性。圆二色光谱表明，该肽与DNA结合时会形成螺旋结构。这些结果直接证明GCN4碱性区域足以实现序列特异性DNA结合，并表明GCN4亮氨酸拉链的主要功能仅仅是介导蛋白质二聚化。我们的方法为设计短的序列特异性DNA结合肽提供了一种策略。
