P1 ParA interacts with the P1 partition complex at parS and an ATP-ADP switch controls ParA activities
P1 ParA interacts with the P1 partition complex at parS and an ATP-ADP switch controls ParA activities
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DOI：
10.1093/emboj/18.5.1415
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发表时间：
1999-03-01
期刊：
影响因子：
11.4
通讯作者：
Funnell, BE
中科院分区：
文献类型：
--
作者：
Bouet, JY;Funnell, BE
pi质粒的分配系统由两个蛋白质帕拉和ParB以及一个顺式作用位点parS组成，parS包裹在ParB周围，大肠杆菌称之为IHF蛋白的高级核蛋白复合物称为分配复合物。帕拉是一种ATP酶，其自动调节par操纵子的表达，并且在分配过程中具有重要但未知的功能。在这项研究中，我们证明了帕拉和π分区复杂之间的直接相互作用。这种相互作用严格依赖于ParB和ATP，这种相互作用的结果取决于ParB的浓度。在高ParB水平下，帕拉通过ParA-ParB相互作用被募集到分区复合物中，但在低ParB水平下，帕拉从分区复合物中去除或分解ParB。ADP不能支持这些相互作用，但可以促进帕拉与par操纵子的操纵子parOP的位点特异性DNA结合活性。相反，ATP不能支持帕拉与parOP的稳定相互作用。我们的数据表明，ParA-ADP是par操纵子的阻遏物，ParA-ATP通过与分配复合物相互作用，在分配中起直接作用。因此，腺嘌呤核苷酸结合和帕拉水解的作用之一是作为分子开关控制进入两个独立的途径，其中帕拉发挥不同的作用。
The partition system of pi plasmids is composed of two proteins, ParA and ParB, and a cis-acting site parS, parS is wrapped around ParB and Escherichia call IHF protein in a higher order nucleoprotein complex called the partition complex. ParA is an ATPase that autoregulates the expression of the par operon and has an essential but unknown function in the partition process. In this study we demonstrate a direct interaction between ParA and the pi partition complex. The interaction was strictly dependent on ParB and ATP, The consequence of this interaction depended on the ParB concentration. At high ParB levels, ParA was recruited to the partition complex via a ParA-ParB interaction, but at low ParB levels, ParA removed or disassembled ParB from the partition complex. ADP could not support these interactions, but could promote the site-specific DNA binding activity of ParA to parOP, the operator of the par operon. Conversely, ATP could not support a stable interaction of ParA with parOP in this assay, Our data suggest that ParA-ADP is the repressor of the par operon, and ParA-ATP, by interacting with the partition complex, plays a direct role in partition. Therefore, one role of adenine nucleotide binding and hydrolysis by ParA is that of a molecular switch controlling entry into two separate pathways in which ParA plays different roles.