DNA dynamics can only be understood by taking into account its complex mechanical behavior at different length scales. At the micrometer level, the mechanical properties of single DNA molecules have been well-characterized by polymer models and are commonly quantified by a persistence length of 50 nm (~150 bp). However, at the base pair level (~3.4 Å), the dynamics of DNA involves complex molecular mechanisms that are still being deciphered. Here, we review recent single-molecule experiments and molecular dynamics simulations that are providing novel insights into DNA mechanics from such a molecular perspective. We first discuss recent findings on sequence-dependent DNA mechanical properties, including sequences that resist mechanical stress and sequences that can accommodate strong deformations. We then comment on the intricate effects of cytosine methylation and DNA mismatches on DNA mechanics. Finally, we review recently reported differences in the mechanical properties of DNA and double-stranded RNA, the other double-helical carrier of genetic information. A thorough examination of the recent single-molecule literature permits establishing a set of general ‘rules’ that reasonably explain the mechanics of nucleic acids at the base pair level. These simple rules offer an improved description of certain biological systems and might serve as valuable guidelines for future design of DNA and RNA nanostructures.

中文翻译：

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DNA灵活性的分子观点

DNA 动力学只能通过考虑其在不同长度尺度上的复杂机械行为来理解。在微米级，单个 DNA 分子的机械性能已被聚合物模型很好地表征，并且通常通过 50 nm (~150 bp) 的持续长度来量化。然而，在碱基对水平（~3.4 Å），DNA 的动力学涉及复杂的分子机制，这些机制仍在被破译中。在这里，我们回顾了最近的单分子实验和分子动力学模拟，它们从这种分子角度为 DNA 力学提供了新的见解。我们首先讨论了关于序列依赖性 DNA 机械特性的最新发现，包括抵抗机械应力的序列和可以适应强烈变形的序列。然后，我们评论了胞嘧啶甲基化和 DNA 错配对 DNA 力学的复杂影响。最后，我们回顾了最近报道的 DNA 和双链 RNA（遗传信息的另一种双螺旋载体）的机械特性的差异。对最近的单分子文献进行彻底检查，可以建立一套通用的“规则”，合理地解释碱基对水平的核酸机制。这些简单的规则提供了对某些生物系统的改进描述，并可能作为未来 DNA 和 RNA 纳米结构设计的宝贵指南。对最近的单分子文献进行彻底检查，可以建立一套通用的“规则”，合理地解释碱基对水平的核酸机制。这些简单的规则提供了对某些生物系统的改进描述，并可能作为未来 DNA 和 RNA 纳米结构设计的宝贵指南。对最近的单分子文献进行彻底检查，可以建立一套通用的“规则”，合理地解释碱基对水平的核酸机制。这些简单的规则提供了对某些生物系统的改进描述，并可能作为未来 DNA 和 RNA 纳米结构设计的宝贵指南。