The 2B subdomain of Rep helicase links translocation along DNA with protein displacement.
The 2B subdomain of Rep helicase links translocation along DNA with protein displacement.
复制标题
DOI：
10.1093/nar/gky673
复制
发表时间：
2018-09-28
影响因子：
14.9
通讯作者：
McGlynn P
中科院分区：
文献类型：
--
作者：
Brüning JG;Howard JAL;Myka KK;Dillingham MS;McGlynn P
解旋酶催化DNA和RNA链分离。为了解开DNA，与核酸结合的蛋白质也必须移位。辅助解旋酶可以在推进复制叉之前清除DNA上的蛋白质屏障。解旋酶是如何催化DNA解绕的，人们已经越来越清楚，但蛋白质的位移是如何实现的还不清楚。大肠杆菌Rep附属复制解旋酶缺乏其四个亚结构域2B中的一个，已被证明在体外对DNA解绕过度激活，但我们在这里表明RepΔ2B相反，缺乏从DNA中置换蛋白质。这种缺陷与体外无法促进蛋白质结合DNA的复制和体内缺乏辅助解旋酶功能有关。缺陷蛋白位移表现在双链和单链DNA上。因此，在解旋酶之前由2B亚结构域结合和扭曲双工DNA并不是导致这种缺陷的缺失功能。这些数据表明，DNA中的蛋白质位移不仅仅是通过解旋酶易位实现的。他们还暗示解旋酶可能已经进化出不同的特定特征来优化DNA解绕和蛋白质位移，这两者现在都被认为是核酸代谢各个方面的关键功能。
Helicases catalyse DNA and RNA strand separation. Proteins bound to the nucleic acid must also be displaced in order to unwind DNA. This is exemplified by accessory helicases that clear protein barriers from DNA ahead of advancing replication forks. How helicases catalyse DNA unwinding is increasingly well understood but how protein displacement is achieved is unclear. Escherichia coli Rep accessory replicative helicase lacking one of its four subdomains, 2B, has been shown to be hyperactivated for DNA unwinding in vitro but we show here that RepΔ2B is, in contrast, deficient in displacing proteins from DNA. This defect correlates with an inability to promote replication of protein-bound DNA in vitro and lack of accessory helicase function in vivo. Defective protein displacement is manifested on double-stranded and single-stranded DNA. Thus binding and distortion of duplex DNA by the 2B subdomain ahead of the helicase is not the missing function responsible for this deficiency. These data demonstrate that protein displacement from DNA is not simply achieved by helicase translocation alone. They also imply that helicases may have evolved different specific features to optimise DNA unwinding and protein displacement, both of which are now recognised as key functions in all aspects of nucleic acid metabolism.
登录
查看更多内容
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：
5.6
作者：
Cheng, W;Hsieh, J;Lohman, TM
通讯作者：
Lohman, TM
DOI：
10.1073/pnas.242479399
发表时间：
2002-12-10
影响因子：
11.1
作者：
Cheng, W;Brendza, KM;Lohman, TM
通讯作者：
Lohman, TM
DOI：
10.1126/science.aaa0445
发表时间：
2015-04-17
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Arslan S;Khafizov R;Thomas CD;Chemla YR;Ha T
通讯作者：
Ha T