DNA Nunchucks: Nanoinstrumentation for Single-Molecule Measurement of Stiffness and Bending.,Nano Letters

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DNA Nunchucks: Nanoinstrumentation for Single-Molecule Measurement of Stiffness and Bending.
Nano Letters ( IF 9.6 ) Pub Date : 2019-12-24 , DOI: 10.1021/acs.nanolett.9b04980
Xinyue Cai ₁ , D Sebastian Arias ₁ , Lourdes R Velazquez _{1,

2} , Shelby Vexler ₂ , Alexander L Bevier ₁ , D Kuchnir Fygenson _{1,

2}

Affiliation

Bending of double-stranded DNA (dsDNA) has important applications in biology and engineering, but measurement of DNA bend angles is notoriously difficult and rarely dynamic. Here we introduce a nanoscale instrument that makes dynamic measurement of the bend in short dsDNAs easy enough to be routine. The instrument works by embedding the ends of a dsDNA in stiff, fluorescently labeled DNA nanotubes, thereby mechanically magnifying their orientations. The DNA nanotubes are readily confined to a plane and imaged while freely diffusing. Single-molecule bend angles are rapidly and reliably extracted from the images by a neural network. We find that angular variance across a population increases with dsDNA length, as predicted by the worm-like chain model, although individual distributions can differ significantly from one another. For dsDNAs with phased A6-tracts, we measure an intrinsic bend of 17 ± 1° per A6-tract, consistent with other methods, and a length-dependent angular variance that indicates A6-tracts are (80 ± 30)% stiffer than generic dsDNA.

中文翻译：

DNA双节棍：用于单分子测量刚度和弯曲度的纳米仪器。

双链DNA（dsDNA）的弯曲在生物学和工程学中具有重要的应用，但是众所周知，DNA弯曲角的测量非常困难，而且很少动态。在这里，我们介绍了一种纳米尺度的仪器，该仪器使短dsDNA弯曲的动态测量变得很容易常规。该仪器的工作原理是将dsDNA的末端嵌入荧光标记的刚性DNA纳米管中，从而机械放大其方向。DNA纳米管很容易被限制在平面上并在自由扩散的同时成像。通过神经网络从图像中快速可靠地提取单分子弯曲角。我们发现，像蠕虫样链模型所预测的那样，整个种群的角度方差随dsDNA长度的增加而增加，尽管各个个体之间的分布可能存在明显差异。

更新日期：2020-01-10

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