The molecular coupling between substrate recognition and ATP turnover in a AAA+ hexameric helicase loader.
The molecular coupling between substrate recognition and ATP turnover in a AAA+ hexameric helicase loader.
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DOI：
10.7554/elife.64232
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发表时间：
2021-05-26
期刊：
影响因子：
7.7
通讯作者：
Berger JM
中科院分区：
文献类型：
--
作者：
Puri N;Fernandez AJ;O'Shea Murray VL;McMillan S;Keck JL;Berger JM
在许多细菌和真核生物中，复制叉的建立需要通过AAA+（与各种细胞活性相关的ATP酶）ATP酶围绕DNA的六聚体环状解旋酶的受控加载。加载因子如何使用ATP来控制解旋酶沉积知之甚少。在这里，我们剖析了如何特定的ATP酶元件大肠杆菌DnaC，细菌DnaB解旋酶的原型加载器，发挥不同的作用，在解旋酶加载和DNA解旋的激活。我们已经确定了一个新的元素，甜菜碱耦合器，它调节DnaC的开关样行为，以防止徒劳的ATP酶循环，并保持加载程序的复制重新启动系统的响应。我们的数据有助于解释AAA+家族解旋酶加载器的ATP酶循环如何被引导到其目标上的生产行动;比较研究表明，类似于Arg偶联剂的元素存在于相关的开关样AAA+蛋白中，这些蛋白控制真核生物中的复制解旋酶加载，以及聚合酶钳加载和某些类别的DNA转座酶。
In many bacteria and eukaryotes, replication fork establishment requires the controlled loading of hexameric, ring-shaped helicases around DNA by AAA+(ATPases Associated with various cellular Activities) ATPases. How loading factors use ATP to control helicase deposition is poorly understood. Here, we dissect how specific ATPase elements of Escherichia coli DnaC, an archetypal loader for the bacterial DnaB helicase, play distinct roles in helicase loading and the activation of DNA unwinding. We have identified a new element, the arginine-coupler, which regulates the switch-like behavior of DnaC to prevent futile ATPase cycling and maintains loader responsiveness to replication restart systems. Our data help explain how the ATPase cycle of a AAA+-family helicase loader is channeled into productive action on its target; comparative studies indicate that elements analogous to the Arg-coupler are present in related, switch-like AAA+ proteins that control replicative helicase loading in eukaryotes, as well as in polymerase clamp loading and certain classes of DNA transposases.