Steric exclusion and wrapping of the excluded DNA strand occurs along discrete external binding paths during MCM helicase unwinding.
Steric exclusion and wrapping of the excluded DNA strand occurs along discrete external binding paths during MCM helicase unwinding.
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DOI：
10.1093/nar/gkr345
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发表时间：
2011-08
影响因子：
14.9
通讯作者：
Trakselis MA
中科院分区：
文献类型：
--
作者：
Graham BW;Schauer GD;Leuba SH;Trakselis MA
微小染色体维持(MCM)解旋酶复合体对于真核和古生物中DNA复制的启动和延长都是必不可少的。来自Sulfolobus solfararicus的古细菌同源六聚体MCM解旋酶是理解DNA解离机制的一个模型。在这份报告中，移位的5‘-尾被证明为DNA上的MCM复合体提供了稳定性，并有助于解离。MCM六角体外表面正电斑块的突变破坏了这种相互作用的稳定性，改变了移位的5‘-尾DNA的路径，减少了解离。DNA足迹和单分子荧光实验支持以前未知的5‘-尾巴的包裹。这种六聚体解旋酶DNA的解离模式被称为空间排斥和缠绕(SEW)模式，其中3‘-尾部被解旋酶包围，而错位的5’-尾部缠绕在解旋酶外部的特定路径上。新的包裹机制以正向解离模式稳定MCM复合体，保护移位的单链DNA尾部，并防止再退火。
The minichromosome maintenance (MCM) helicase complex is essential for the initiation and elongation of DNA replication in both the eukaryotic and archaeal domains. The archaeal homohexameric MCM helicase from Sulfolobus solfataricus serves as a model for understanding mechanisms of DNA unwinding. In this report, the displaced 5′-tail is shown to provide stability to the MCM complex on DNA and contribute to unwinding. Mutations in a positively charged patch on the exterior surface of the MCM hexamer destabilize this interaction, alter the path of the displaced 5′-tail DNA and reduce unwinding. DNA footprinting and single-molecule fluorescence experiments support a previously unrecognized wrapping of the 5′-tail. This mode of hexameric helicase DNA unwinding is termed the steric exclusion and wrapping (SEW) model, where the 3′-tail is encircled by the helicase while the displaced 5′-tail wraps around defined paths on the exterior of the helicase. The novel wrapping mechanism stabilizes the MCM complex in a positive unwinding mode, protects the displaced single-stranded DNA tail and prevents reannealing.
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影响因子：
4.8
作者：
Gómez-Llorente, Y;Fletcher, RJ;Martín, CS
通讯作者：
Martín, CS
影响因子：
64.8
作者：
Li, DW;Zhao, R;Chen, XJS
通讯作者：
Chen, XJS
DOI：
10.1073/pnas.0808037105
发表时间：
2008-12-23
影响因子：
11.1
作者：
Brewster, Aaron S.;Wang, Ganggang;Chen, Xiaojiang S.
通讯作者：
Chen, Xiaojiang S.
影响因子：
9.2
作者：
MADINE, MA;KHOO, CY;LASKEY, RA
通讯作者：
LASKEY, RA
通过与CDC45和杜松子蛋白缔合对MCM2-7解旋酶的激活。
影响因子：
16
作者：
Ilves I;Petojevic T;Pesavento JJ;Botchan MR
通讯作者：
Botchan MR