Domain c of human poly(ADP-ribose) polymerase-1 is important for enzyme activity and contains a novel zinc-ribbon motif
Domain c of human poly(ADP-ribose) polymerase-1 is important for enzyme activity and contains a novel zinc-ribbon motif
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DOI：
10.1021/bi800018a
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发表时间：
2008-05-27
期刊：
影响因子：
2.9
通讯作者：
Liu, Hung-wen
中科院分区：
文献类型：
--
作者：
Tao, Zhihua;Gao, Peng;Liu, Hung-wen
多聚(ADP-核糖)聚合酶-1(PARP-1)是一种多模核蛋白，参与许多基本的细胞活动。在与镍DNA结合的刺激下，PARP-1以NAD(+)为底物催化受体蛋白的聚合(ADP-核糖基)。在本工作中，我们用核磁共振方法确定了人PARP-1蛋白的溶液结构。结构域C含有一个锌结合基序，该基序由三条反平行的β链和四个保守的半胱氨酸组成，除了一个螺旋区域外，四个半胱氨酸还与金属配体配位。锌结合基序在结构上类似于“锌带”折叠，但在保守的半胱氨酸之间具有新的间距(CX(2)CX(12)CX(9)C)。结构域C本身似乎并不能与DNA结合。有趣的是，C结构域对PARP-1的活性是必不可少的，因为含有NiCKDNA和PARP-1 ABDEF结构域的混合物只具有基本的酶活性，而通过基于核磁共振的分析和放射自显影技术，C结构域的加入引发了NAD(+)的水解和聚(ADPribose)的形成。C结构域在溶液中的结构模型为进一步研究提供了重要的框架，旨在提高我们对复杂PARP-1酶中的各个结构域如何在细胞处于遗传毒性应激条件下调节酶活性发挥各自作用的理解。
Poly(ADP-ribose) polymerase-1 (PARP-1) is a multimodular nuclear protein that participates in many fundamental cellular activities. Stimulated by binding to nicked DNA, PARP-1 catalyzes poly(ADP-ribosyl)ation of the acceptor proteins using NAD(+) as a substrate. In this work, NMR methods were used to determine the solution structure of human PARP-1 protein. Domain C was found to contain a zinc-binding motif of three antiparallel beta-strands with four conserved cysteines positioned to coordinate the metal ligand, in addition to a helical region. The zinc-binding motif is structurally reminiscent of the "zinc-ribbon" fold, but with a novel spacing between the conserved cysteines (CX(2)CX(12)CX(9)C). Domain C alone does not appear to bind to DNA. Interestingly, domain C is essential for PARP-1 activity, since a mixture containing nicked DNA and the PARP-1 ABDEF domains has only basal enzymatic activity, while the addition of domain C to the mixture initiated NAD(+) hydrolysis and the formation of poly(ADPribose), as detected by an NMR-based assay and autoradiography. The structural model for domain C in solution provides an important framework for further studies aimed at improving our understanding of how the various domains within the complex PARP-1 enzyme play their respective roles in regulating the enzyme activity when cells are under conditions of genotoxic stress.