RecG and UvsW catalyse robust DNA rewinding critical for stalled DNA replication fork rescue
RecG and UvsW catalyse robust DNA rewinding critical for stalled DNA replication fork rescue
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DOI：
10.1038/ncomms3368
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发表时间：
2013-09-01
影响因子：
16.6
通讯作者：
Croquette, Vincent
中科院分区：
文献类型：
--
作者：
Manosas, Maria;Perumal, Senthil K.;Croquette, Vincent
解旋酶在DNA修复和基因重组中起着重要作用。与解旋相反，通过解旋酶的DNA重绕已被证明难以生物化学表征，因为其具有降解性的性质。在这里，我们使用单分子测定来机械地使DNA分子不稳定，并在真实的时间内，通过两种DNA修复解旋酶，噬菌体T4 UvsW和大肠杆菌RecG，进行解旋和重绕。我们发现这两种酶都是强大的重绕酶，可以对抗高达35 pN的相反力，揭示了它们的活性特征。在重绕反应过程中产生的工作使他们能够将重绕与DNA解旋和/或蛋白质置换反应结合起来，这些反应对拯救停滞的DNA复制叉至关重要。总体结果支持单体重绕酶的一般机制。
Helicases that both unwind and rewind DNA have central roles in DNA repair and genetic recombination. In contrast to unwinding, DNA rewinding by helicases has proved difficult to characterize biochemically because of its thermodynamically downhill nature. Here we use single-molecule assays to mechanically destabilize a DNA molecule and follow, in real time, unwinding and rewinding by two DNA repair helicases, bacteriophage T4 UvsW and Escherichia coli RecG. We find that both enzymes are robust rewinding enzymes, which can work against opposing forces as large as 35 pN, revealing their active character. The generation of work during the rewinding reaction allows them to couple rewinding to DNA unwinding and/or protein displacement reactions central to the rescue of stalled DNA replication forks. The overall results support a general mechanism for monomeric rewinding enzymes.