Torsional Stiffness of Extended and Plectonemic DNA.
Torsional Stiffness of Extended and Plectonemic DNA.
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延伸和plectonemic DNA的扭转刚度。
DOI：
10.1103/physrevlett.127.028101
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发表时间：
2021-07-09
影响因子：
8.6
通讯作者：
Wang, Michelle D.
中科院分区：
文献类型：
--
作者：
Gao, Xiang;Hong, Yifeng;Ye, Fan;Inman, James T.;Wang, Michelle D.
DNA的扭转弹性在DNA结构、拓扑结构和运动蛋白的调控中起着至关重要的作用。然而，这些参数的直接测量在实验上具有挑战性。在这里，我们提出了一个恒定的延伸方法集成到一个角度的光阱直接测量DNA超螺旋过程中的扭矩。在极低的力（~ 0.02pN）下，我们测得延伸DNA的扭转持续长度为22 nm，而plectonemic DNA的扭转持续长度为24 nm。此外，我们实施了严格的数据分析方案，将我们的测量与现有的DNA扭转行为理论模型联系起来。这一套全面的扭转参数表明，至少有20%的DNA超螺旋被分配到扭曲的延伸DNA和plectonemic DNA。这项工作提供了一种新的实验方法，以及一个分析和解释的框架，这将使，扩大和加强未来的DNA扭转特性的研究。
DNA torsional elastic properties play a crucial role in DNA structure, topology, and the regulation of motor protein progression. However, direct measurements of these parameters are experimentally challenging. Here, we present a constant-extension method integrated into an angular optical trap to directly measure torque during DNA supercoiling. We measured the twist persistence length of extended DNA to be 22 nm under an extremely low force (~ 0.02 pN) and the twist persistence length of plectonemic DNA to be 24 nm. In addition, we implemented a rigorous data analysis scheme that bridged our measurements with existing theoretical models of DNA torsional behavior. This comprehensive set of torsional parameters demonstrates that at least 20% of DNA supercoiling is partitioned into twist for both extended DNA and plectonemic DNA. This work provides a new experimental methodology, as well as an analytical and interpretational framework, which will enable, expand, and enhance future studies of DNA torsional properties.