G-quadruplex and G-rich sequence stimulate Pif1p-catalyzed downstream duplex DNA unwinding through reducing waiting time at ss/dsDNA junction.
G-quadruplex and G-rich sequence stimulate Pif1p-catalyzed downstream duplex DNA unwinding through reducing waiting time at ss/dsDNA junction.
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G-四链体和富含 G 的序列通过减少 ss/dsDNA 连接处的等待时间来刺激 Pif1p 催化的下游双链体 DNA 解旋
DOI：
10.1093/nar/gkw669
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发表时间：
2016-09-30
影响因子：
14.9
通讯作者：
Xi XG
中科院分区：
文献类型：
--
作者：
Zhang B;Wu WQ;Liu NN;Duan XL;Li M;Dou SX;Hou XM;Xi XG
偏离b型双链DNA的替代DNA结构，如g -四重体（G4） DNA，可以由广泛分布于整个人类基因组的富含g的序列形成。我们之前已经证明Pif1p不仅展开G4，而且还以G4刺激的方式解开下游双工DNA。在本研究中，我们通过单分子荧光共振能量转移进一步表征了g4刺激的双链DNA解绕现象。研究发现，Pif1p在展开上游G4结构后并没有立即解开部分双工DNA，而是在ss/dsDNA连接处停留了一段“等待时间”。进一步的研究表明，等待时间实际上与蛋白质二聚化过程有关，该过程对ssDNA序列敏感，如果序列富含g，则会变得快速。此外，我们发现富含g的序列，如G4结构，同样刺激双链DNA解绕。本研究揭示了G4解绕解旋酶Pif1p分解细胞中生理G4/双链DNA结构的分子机制。
Alternative DNA structures that deviate from B-form double-stranded DNA such as G-quadruplex (G4) DNA can be formed by G-rich sequences that are widely distributed throughout the human genome. We have previously shown that Pif1p not only unfolds G4, but also unwinds the downstream duplex DNA in a G4-stimulated manner. In the present study, we further characterized the G4-stimulated duplex DNA unwinding phenomenon by means of single-molecule fluorescence resonance energy transfer. It was found that Pif1p did not unwind the partial duplex DNA immediately after unfolding the upstream G4 structure, but rather, it would dwell at the ss/dsDNA junction with a ‘waiting time’. Further studies revealed that the waiting time was in fact related to a protein dimerization process that was sensitive to ssDNA sequence and would become rapid if the sequence is G-rich. Furthermore, we identified that the G-rich sequence, as the G4 structure, equally stimulates duplex DNA unwinding. The present work sheds new light on the molecular mechanism by which G4-unwinding helicase Pif1p resolves physiological G4/duplex DNA structures in cells.
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DOI：
10.1038/nrg3296
发表时间：
2012-11
期刊：
Nature reviews. Genetics
影响因子：
--
作者：
通讯作者：
--
影响因子：
46.9
作者：
Chambers, Vicki S.;Marsico, Giovanni;Balasubramanian, Shankar
通讯作者：
Balasubramanian, Shankar
影响因子：
3.8
作者：
Bochman ML;Sabouri N;Zakian VA
通讯作者：
Zakian VA
影响因子：
4.8
作者：
Dou, SX;Wang, PY;Xi, XG
通讯作者：
Xi, XG
影响因子：
11.4
作者：
Lopes, Judith;Piazza, Aurele;Nicolas, Alain
通讯作者：
Nicolas, Alain