Zinc fingers, zinc clusters, and zinc twists in DNA-binding protein domains.
Zinc fingers, zinc clusters, and zinc twists in DNA-binding protein domains.
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DOI：
10.1073/pnas.88.3.999
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发表时间：
1991-02
影响因子：
11.1
通讯作者：
Bert L. Vallee;J. Coleman;D. Auld
中科院分区：
文献类型：
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作者：
Bert L. Vallee;J. Coleman;D. Auld
我们现在认识到DNA结合锌蛋白的三个不同的基序：（i）锌指，（ii）锌簇，和（iii）锌扭曲。直到最近，DNA结合锌蛋白的X射线晶体学或NMR三维结构分析还不能用作这些蛋白质家族的锌结合位点的参考标准。真菌转录因子GAL 4和大鼠糖皮质激素受体的DNA结合域的那些是第一个被确定的。两种蛋白质都含有两个锌结合位点，并且在两者中，半胱氨酸残基是唯一的锌配体。在GAL 4中，两个锌原子与六个半胱氨酸残基结合，形成类似于金属硫蛋白的“锌簇”; GAL 4的两个锌原子之间的距离约为3.5 A。在糖皮质激素受体中，每个锌原子与四个半胱氨酸残基结合;原子间的锌-锌距离约为13 A，在这种情况下，“锌扭曲”由位于两个锌原子之间的螺旋DNA识别位点表示。锌簇和锌螺旋是含多个锌原子的DNA结合蛋白中两种独特的基序。对于天然“锌指”，结构数据尚未存在;因此，锌原子之间的原子间距离尚不清楚。随着进一步的结构数据变得可用，这些不同基序在与DNA和参与遗传信息传递的其他蛋白质结合时的结构和功能意义将变得明显。
We now recognize three distinct motifs of DNA-binding zinc proteins: (i) zinc fingers, (ii) zinc clusters, and (iii) zinc twists. Until very recently, x-ray crystallographic or NMR three-dimensional structure analyses of DNA-binding zinc proteins have not been available to serve as standards of reference for the zinc binding sites of these families of proteins. Those of the DNA-binding domains of the fungal transcription factor GAL4 and the rat glucocorticoid receptor are the first to have been determined. Both proteins contain two zinc binding sites, and in both, cysteine residues are the sole zinc ligands. In GAL4, two zinc atoms are bound to six cysteine residues which form a "zinc cluster" akin to that of metallothionein; the distance between the two zinc atoms of GAL4 is approximately 3.5 A. In the glucocorticoid receptor, each zinc atom is bound to four cysteine residues; the interatomic zinc-zinc distance is approximately 13 A, and in this instance, a "zinc twist" is represented by a helical DNA recognition site located between the two zinc atoms. Zinc clusters and zinc twists are here recognized as two distinctive motifs in DNA-binding proteins containing multiple zinc atoms. For native "zinc fingers," structural data do not exist as yet; consequently, the interatomic distances between zinc atoms are not known. As further structural data become available, the structural and functional significance of these different motifs in their binding to DNA and other proteins participating in the transmission of the genetic message will become apparent.