The Zn(II) binding motifs of E-coli DNA topoisomerase is part of a high-affinity DNA binding domain
The Zn(II) binding motifs of E-coli DNA topoisomerase is part of a high-affinity DNA binding domain
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DOI：
10.1006/bbrc.1998.9500
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发表时间：
1998-10-20
影响因子：
3.1
通讯作者：
Tse-Dinh, YC
中科院分区：
文献类型：
--
作者：
Ahumada, A;Tse-Dinh, YC
大肠杆菌DNA拓扑异构酶I与三个四半胱氨酸基序结合三个锌离子。表达和纯化了含有这些四半胱氨酸基序的三个亚克隆。亚克隆zd1含有最小的四半胱氨酸基序序列。一个较大的亚克隆ZD2对应于两个蛋白酶敏感部位交界的区域。亚克隆ZD3还包括14 kDa的C末端结构域，该结构域已被证明与DNA结合。亚克隆ZD1和ZD2分别与1个和2个锌离子结合，均未检测到DNA结合活性。ZD3能与3个锌离子结合，其DNA结合亲和力高于14 kDa C-末端结构域。凝胶位移分析可以检测到ZD3与单链31聚体形成的复合体，而14 kDa C末端结构域形成的复合体在凝胶电泳法条件下不稳定。这三个锌离子结合基序似乎是高亲和力DNA结合域的一部分。(C)1998年学术出版社。
Escherichia coli DNA topoisomerase I binds three Zn(II) with three tetracysteine motifs. Three subclones containing these tetracysteine motifs were expressed and purified. Subclone ZD1 contained the minimal tetracysteine motifs sequence. A larger subclone ZD2 corresponded to a region bordered by two protease sensitive sites. Subclone ZD3 also included the 14-kDa C-terminal domain that has been shown to bind DNA. Subclones ZD1 and ZD2 were found to bind one and two Zn(II), respectively, and neither had detectable DNA binding activity. ZD3 could bind three Zn(II) and had higher DNA binding affinity than the 14-kDa C-terminal domain. The complex formed between ZD3 and a single-stranded 31mer could be detected by the gel shift assay while the complex formed by the 14-kDa C-terminal domain was not stable under gel electrophoresis conditions. The three Zn(II) binding motifs appeared to be part of a high-affinity DNA binding domain. (C) 1998 Academic Press.