Interaction of Rep and DnaB on DNA.
Interaction of Rep and DnaB on DNA.
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DOI：
10.1093/nar/gkq975
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发表时间：
2011-03
影响因子：
14.9
通讯作者：
McGlynn P
中科院分区：
文献类型：
--
作者：
Atkinson J;Gupta MK;McGlynn P
基因组复制不仅需要模板的解旋，还需要置换与模板结合的蛋白质，这是由位于叉子处的复制解旋酶执行的功能。然而，还需要辅助解旋酶，因为复制解旋酶偶尔会在核蛋白复合物处停滞。在大肠杆菌中，初级和辅助解旋酶 DnaB 和 Rep 分别沿着滞后链和前导链模板易位，在物理上相互作用，并且在模型分叉 DNA 底物的解旋中也表现出协同性。我们在此证明这种协同性仅由 Rep 显示，而其他测试的解旋酶则不显示。 ssDNA 必须暴露在前导链模板上才能引发这种协同作用，这表明在蛋白质-DNA 复合物处被阻断的叉包含位于前导链聚合酶之前的 ssDNA。然而，稳定的 Rep-DnaB 复合物可以在线性和分支 DNA 上形成，这表明 Rep 具有与分叉处前导链或滞后链模板上的 ssDNA 相互作用的能力。因此，通过与 SSB 竞争来抑制 Rep 与滞后链模板的结合可能对于将辅助解旋酶靶向前导链模板至关重要，这表明复制体结构在促进受阻复制体上的辅助解旋酶功能方面发挥着重要作用。
Genome duplication requires not only unwinding of the template but also the displacement of proteins bound to the template, a function performed by replicative helicases located at the fork. However, accessory helicases are also needed since the replicative helicase stalls occasionally at nucleoprotein complexes. In Escherichia coli, the primary and accessory helicases DnaB and Rep translocate along the lagging and leading strand templates, respectively, interact physically and also display cooperativity in the unwinding of model forked DNA substrates. We demonstrate here that this cooperativity is displayed only by Rep and not by other tested helicases. ssDNA must be exposed on the leading strand template to elicit this cooperativity, indicating that forks blocked at protein–DNA complexes contain ssDNA ahead of the leading strand polymerase. However, stable Rep–DnaB complexes can form on linear as well as branched DNA, indicating that Rep has the capacity to interact with ssDNA on either the leading or the lagging strand template at forks. Inhibition of Rep binding to the lagging strand template by competition with SSB might therefore be critical in targeting accessory helicases to the leading strand template, indicating an important role for replisome architecture in promoting accessory helicase function at blocked replisomes.
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影响因子：
16
作者：
Ivessa, AS;Lenzmeier, BA;Zakian, VA
通讯作者：
Zakian, VA
影响因子：
16
作者：
Guy, Colin P.;Atkinson, John;Gupta, Milind K.;Mahdi, Akeel A.;Gwynn, Emma J.;Rudolph, Christian J.;Moon, Peter B.;van Knippenberg, Ingeborg C.;Cadman, Chris J.;Dillingham, Mark S.;Lloyd, Robert G.;McGlynn, Peter
通讯作者：
McGlynn, Peter
影响因子：
10.5
作者：
Azvolinsky, Anna;Dunaway, Stephen;Zakian, Virginia A.
通讯作者：
Zakian, Virginia A.
影响因子：
64.5
作者：
Lambert, S;Watson, A;Carr, AM
通讯作者：
Carr, AM
影响因子：
5.6
作者：
Cheng, W;Hsieh, J;Lohman, TM
通讯作者：
Lohman, TM