Dual Role of DNA in Regulating ATP Hydrolysis by the SopA Partition Protein
Dual Role of DNA in Regulating ATP Hydrolysis by the SopA Partition Protein
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DOI：
10.1074/jbc.m109.044800
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发表时间：
2009-10-30
影响因子：
4.8
通讯作者：
Bouet, Jean-Yves
中科院分区：
文献类型：
--
作者：
Ah-Seng, Yoan;Lopez, Frederic;Bouet, Jean-Yves
在细菌中，质粒和许多染色体的有丝分裂稳定性取决于复制子特异性系统，其包括着丝粒、着丝粒结合蛋白和ATP酶。ATP酶的动态自组装似乎能够将复制子拷贝主动分配到细胞半部分中，但对于沃克盒分配ATP酶，其分子机制尚不清楚。ATP酶活性似乎是这个过程中必不可少的。已知DNA和着丝粒结合蛋白刺激ATP酶活性，但刺激机制的分子细节尚未报道。我们研究了质粒F的SopA分配ATP酶刺激ATP水解的相互作用。通过使用DNA结合缺陷的SopA和SopB蛋白，我们发现SopA水解ATP的内在能力需要SopA而不是SopB直接结合DNA。我们的研究结果表明，两个独立的相互作用的SOPA的协同作用，以刺激其ATP酶。SopA必须与（i）DNA相互作用，通过其ATP依赖性非特异性DNA结合结构域和（ii）SopB，我们在这里显示，以提供一个腺嘌呤指基序。此外，后者的相互作用最大限度地刺激ATP酶时，SopB是分区复合物的一部分。因此，我们的数据表明，DNA作用于SopA的两种方式，直接作为非特异性DNA和通过SopB作为着丝粒DNA，完全激活SopA ATP水解。
In bacteria, mitotic stability of plasmids and many chromosomes depends on replicon-specific systems, which comprise a centromere, a centromere-binding protein and an ATPase. Dynamic self-assembly of the ATPase appears to enable active partition of replicon copies into cell-halves, but for Walker-box partition ATPases the molecular mechanism is unknown. ATPase activity appears to be essential for this process. DNA and centromere-binding proteins are known to stimulate the ATPase activity but molecular details of the stimulation mechanism have not been reported. We have investigated the interactions which stimulate ATP hydrolysis by the SopA partition ATPase of plasmid F. By using SopA and SopB proteins deficient in DNA binding, we have found that the intrinsic ability of SopA to hydrolyze ATP requires direct DNA binding by SopA but not by SopB. Our results show that two independent interactions of SopA act in synergy to stimulate its ATPase. SopA must interact with (i) DNA, through its ATP-dependent nonspecific DNA binding domain and (ii) SopB, which we show here to provide an arginine-finger motif. In addition, the latter interaction stimulates ATPase maximally when SopB is part of the partition complex. Hence, our data demonstrate that DNA acts on SopA in two ways, directly as nonspecific DNA and through SopB as centromeric DNA, to fully activate SopA ATP hydrolysis.