Zinc metalloregulation of the zinc finger pair domain
Zinc metalloregulation of the zinc finger pair domain
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DOI：
10.1074/jbc.m600655200
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发表时间：
2006-09-01
影响因子：
4.8
通讯作者：
Winge, Dennis R.
中科院分区：
文献类型：
--
作者：
Bird, Amanda J.;Swierczek, Sabina;Winge, Dennis R.
酵母转录激活因子Zap 1含有两个不常见的结构基序，称为锌指对结构域。该结构域的标志是两个锌指基序在一个球状单元中的包装。Zap 1中的一个指对结构域包含AD 2反式激活结构域。锌（II）结合到这个结构域（ZF 1/2）是动力学不稳定产生锌调节的反式激活因子。第二指对结构域（ZF 3/4）位于DNA结合结构域内，并且其稳定地结合Zn（II）。本研究的目的是映射的决定因素赋予锌（II）结合不稳定性，通过使用指对嵌合体。而ZF 2包含反式激活功能，锌的调节依赖于ZF 1的存在。ZF 3可以在功能上取代ZF 1，并且ZF 3/2指对保留有限的锌调节。用ZF 1替换ZF 3产生ZF 1/4嵌合体被发现稳定地结合Zn（II），表明稳定基序（ZF 4）的存在可以赋予不稳定基序（ZF 1）结合稳定性。锌（II）结合在指对结构域是依赖于这两个图案的存在。在一个指基序的突变显着减弱锌（II）结合到第二个基序。Zn（II）结合的动力学不稳定性被映射到ZF 2的α-螺旋。在与Zn（II）螯合剂的孵育研究中，ZF 1/ZF β 2 α 4嵌合体在Zn（II）结合稳定性方面类似于ZF 3/4。目前的研究结果表明，锌调节AD活性的ZF 2是依赖于决定因素在ZF 1以及ZF 2的α-螺旋段。
The yeast transcriptional activator Zap1 contains two uncommon structural motifs designated zinc finger pair domains. The hallmark of this domain is the packing of two zinc finger motifs in one globular unit. One finger pair domain in Zap1 contains the AD2 transactivation domain. Zn(II) binding to this domain (ZF1/2) is kinetically labile yielding a zinc-regulated transactivator. The second finger pair domain (ZF3/4) lies within the DNA-binding domain, and it stably binds Zn(II). The goal of this study was to map the determinant conferring lability in Zn(II) binding by using finger pair chimeras. Whereas ZF2 contains the transactivation function, zinc regulation is dependent on the presence of ZF1. ZF3 can functionally replace ZF1, and a ZF3/2 finger pair retains limited zinc regulation. Replacement of ZF3 by ZF1 creating a ZF1/4 chimera was found to stably bind Zn(II), suggesting that the presence of a stable motif (ZF4) can impart binding stability on a labile motif (ZF1). Zn(II) binding in finger pair domains is dependent on the presence of both motifs. Mutations in one finger motif markedly attenuate Zn( II) binding to the second motif. Kinetic lability in Zn(II) binding was mapped to the alpha-helix of ZF2. A ZF1/ZF beta 2 alpha 4 chimera resembles ZF3/4 in Zn(II) binding stability in incubation studies with the Zn(II) chelators. The present results demonstrate that zinc regulation of AD activity of ZF2 is dependent on determinants in ZF1 as well as the alpha-helix segment of ZF2.