Thermal unfolding studies of a leucine zipper domain and its specific DNA complex: implications for scissor's grip recognition.
Thermal unfolding studies of a leucine zipper domain and its specific DNA complex: implications for scissor's grip recognition.
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亮氨酸拉链结构域及其特定 DNA 复合物的热展开研究：对剪刀握力识别的影响。
DOI：
10.1021/bi00487a004
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发表时间：
1990
期刊：
影响因子：
2.9
通讯作者：
Weiss,MA
中科院分区：
文献类型：
--
作者：
Weiss,MA
马萨诸塞州波士顿哈佛医学院生物化学和分子药理学教研室02115和马萨诸塞州波士顿马萨诸塞州总医院医学系1990年6月4日收到修订稿件1990年7月11日收到修订稿件摘要：一类新发现的真核转录因子具有两部分序列基序，由C-末端二聚化区(亮氨酸拉链)和N-末端碱性区(介导DNA结合)组成。在对分离的亮氨酸拉链多肽的研究中，二聚化区域被表征为平行螺旋的盘绕。为了将这些研究扩展到一个功能DNA结合域，我们描述了Gcn4的58个残基片段的热展开和复性的CD研究，Gcn4是c-jun原癌蛋白的酵母同源物。该片段包含完整的亮氨酸拉链和碱性区域，保留了完整蛋白质的DNA结合特性。Gcn4DNA结合域呈现两个独立的螺旋-螺旋展开转变。主要的转变(中点65℃)是由于二聚体的解离，这与先前对分离的亮氨酸拉链的研究一致。还观察到了在0-40℃温度范围内的新的预跃迁，这反映了新生的螺旋在碱性区域中部分稳定。值得注意的是，碱性区域作为a-螺旋的完整折叠需要特定的DNA结合，而蛋白质-DNA复合体表现出单一的协同展开转变。这些结果支持最近提出的DNA识别的“剪刀柄”模型的一个主要特征，即基本区域从亮氨酸拉链延伸为分叉螺旋臂。Otein-DNA识别是由一类相关的结构基序介导的，如螺旋-转弯-螺旋(Pabo&Sauer，1984)和锌指(Klug&Rhodes，1987)。最近在一类高度保守的真核转录因子中描述了一个新的基序，它由一个C-末端二聚元件、“亮氨酸拉链”和一个介导DNA结合的N-末端碱性区域组成(Landschultz等人，1988)。最初在禽癌蛋白(v-Jun；Maki等人，1987)及其酵母同系物Gcn4(Jones&
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, and Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114 Received June 4, 1990; Revised Manuscript Received July 11, 1990 abstract: A newly recognized class of eukaryotic transcription factors is characterized by a bipartite sequence motif, consisting of a C-terminal dimerization region (the leucine zipper) and an N-terminal basic region (which mediates DNA binding). In studies of isolated leucine zipper peptides, the dimerization region has been characterized as a coiled coil of parallel-helices. To extendthese studies to a functional DNA-binding domain, we describe CD studies of the thermalunfolding and refolding of a 58-residue fragment of GCN4, the yeast homologue of the c-Jun protooncoprotein. This fragment, which contains the complete leucine zipper and basic region, retains the DNA-binding properties of the intact protein. The GCN4 DNA-binding domain exhibits two independent helix-coil unfolding transitions. The major transition (midpoint 65 C) is due to dissociation of the dimer in accord with previous studies of an isolated leucine zipper. A novel pretransition in the temperature range 0-40 C is also observed, which reflects partial stabilization of the nascent helix in the basic region. Remarkably, complete folding of the basic region as an a-helix requires specific DNA binding, and the protein-DNA complex exhibits a single cooperative unfolding transition. These results support a major feature of the recently proposed “scissor’s grip” model of DNA recognition, in which the basic regions extend from the leucine zipper as bifurcating-helical arms.^^ otein-DNA recognition is mediated by classes of related structural motifs, such as the helix-turn-helix (Pabo & Sauer, 1984) and Zn finger (Klug & Rhodes, 1987). A novel motif has recently been described in a highly conserved class of eukaryotic transcription factors, consisting of a C-terminal dimerization element, the “leucine zipper”, and an N-terminal basic region, which mediates DNA binding (Landschultz et al., 1988). Originally described in an avian oncoprotein (v-Jun; Maki et al., 1987) and its yeast homologue GCN4 (Jones &