Studying the Potassium-Induced G-Quadruplex DNA Folding Process Using Microscale Thermophoresis
Studying the Potassium-Induced G-Quadruplex DNA Folding Process Using Microscale Thermophoresis
复制标题
使用微尺度热泳研究钾诱导的 G-四链体 DNA 折叠过程
DOI：
10.1021/acs.biochem.9b00447
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发表时间：
2019
期刊：
影响因子：
2.9
通讯作者：
Wu Wen-Qiang
中科院分区：
文献类型：
--
作者：
Zhang Ming-Li;Xu Ya-Peng;Kumar Arvind;Zhang Yu;Wu Wen-Qiang
鸟嘌呤（G）四链体（G4）可以由富含G的序列在通过阳离子（通常为K+或Na+）的结合而稳定时形成，并且在复制、重组、转录和端粒维持中起重要作用。了解G4折叠过程对于确定其细胞功能至关重要。然而，G4-K+相互作用和折叠途径仍然没有得到很好的理解。以人端粒G4（hTG 4）为例，对两种K+离子与hTG 4的结合状态进行了区分和拟合。利用微尺度热泳（MST）技术，同时监测电荷和尺寸的变化，测量和计算了G4-K+相互作用过程中的基本结合参数。G-发夹和G-三链体被认为是G4折叠和去折叠的中间体。我们进一步分析了10个可能的折叠中间体的平衡解离常数使用MST，因此，能量上有利的折叠/去折叠途径提出。这一结果不仅为研究G4-K+相互作用和G4折叠途径提供了新的思路，而且为DNA-离子相互作用的实验研究提供了范例。
Guanine (G) quadruplexes (G4s) can be formed by G-rich sequences when stabilized by the binding of cations (typically K+or Na+) and play an essential role in replication, recombination, transcription, and telomere maintenance. Understanding of the G4 folding process is crucial for determining their cellular functions. However, G4–K+interactions and folding pathways are still not well understood. By using human telomeric G4 (hTG4) as an example, two binding states corresponding to two K+cations binding to hTG4 were distinguished clearly and fitted precisely. The basic binding parameters during G4–K+interactions were measured and calculated by taking advantage of microscale thermophoresis (MST), which monitors the changes in charge and size at the same time. The G-hairpin and G-triplex have been suggested as intermediates during G4 folding and unfolding. We further analyzed the equilibrium dissociation constants of 10 possible folding intermediates using MST; thus, the energetically favorable folding/unfolding pathways were proposed. The results might not only shed new light on G4–K+interactions and G4 folding pathways but also provide an example for experimentally studying DNA–ion interactions.