Structural basis for ADP-mediated transcriptional regulation by P1 and P7 ParA
Structural basis for ADP-mediated transcriptional regulation by P1 and P7 ParA
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DOI：
10.1038/emboj.2009.120
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发表时间：
2009-06-17
期刊：
影响因子：
11.4
通讯作者：
Schumacher, Maria A.
中科院分区：
文献类型：
--
作者：
Dunham, Thomas D.;Xu, Weijun;Schumacher, Maria A.
准确的DNA分离对遗传信息的忠实遗传至关重要。原型P1质粒par系统的分离需要两种蛋白，ParA和ParB，以及一个着丝粒。当与ATP结合时，ParA通过与着丝粒结合的ParB相互作用介导分离，但当与ADP结合时，ParA发挥不同的功能：dna结合转录自动调节。ParA的结构是未知的，不同的核苷酸是如何决定其不同的功能的。为了解决这些问题，我们进行了结构和生化研究。晶体结构表明，ParA由一个细长的n端α -螺旋组成，出乎意料地介导二聚化，一个翼状hth和一个含有c结构域的Walker-box。生化数据证实apoParA在生理浓度下形成二聚体。四种apoParA结构的比较揭示了一个惊人的灵活的二聚体界面，允许ParA采用多种构象。ParA-ADP结构表明adp结合通过两部分机制激活DNA结合。首先，它锁定一个特定的二聚体构象，其次，它诱导两个dna结合基本基序的折叠，我们表明这对操作符结合至关重要。EMBO杂志（2009）28,1792-1802。doi: 10.1038 / emboj.2009.120;2009年5月21日在线发布
The accurate segregation of DNA is essential for the faithful inheritance of genetic information. Segregation of the prototypical P1 plasmid par system requires two proteins, ParA and ParB, and a centromere. When bound to ATP, ParA mediates segregation by interacting with centromere-bound ParB, but when bound to ADP, ParA fulfils a different function: DNA-binding transcription autoregulation. The structure of ParA is unknown as is how distinct nucleotides arbitrate its different functions. To address these questions, we carried out structural and biochemical studies. Crystal structures show that ParA consists of an elongated N-terminal alpha-helix, which unexpectedly mediates dimerization, a winged-HTH and a Walker-box containing C-domain. Biochemical data confirm that apoParA forms dimers at physiological concentrations. Comparisons of four apoParA structures reveal a strikingly flexible dimer interface that allows ParA to adopt multiple conformations. The ParA-ADP structure shows that ADP-binding activates DNA binding using a bipartite mechanism. First, it locks in one specific dimer conformation, and second, it induces the folding of two DNA-binding basic motifs that we show are critical for operator binding. The EMBO Journal (2009) 28, 1792-1802. doi:10.1038/emboj.2009.120; Published online 21 May 2009