Wiggins Paul A, van der Heijden Thijn, Moreno-Herrero Fernando, Spakowitz Andrew, Phillips Rob, Widom Jonathan, Dekker Cees, Nelson Philip C
Whitehead Institute, Cambridge Massachusetts 02142, USA.
Nat Nanotechnol. 2006 Nov;1(2):137-41. doi: 10.1038/nnano.2006.63. Epub 2006 Nov 3.
The mechanics of DNA bending on intermediate length scales (5-100 nm) plays a key role in many cellular processes, and is also important in the fabrication of artificial DNA structures, but previous experimental studies of DNA mechanics have focused on longer length scales than these. We use high-resolution atomic force microscopy on individual DNA molecules to obtain a direct measurement of the bending energy function appropriate for scales down to 5 nm. Our measurements imply that the elastic energy of highly bent DNA conformations is lower than predicted by classical elasticity models such as the worm-like chain (WLC) model. For example, we found that on short length scales, spontaneous large-angle bends are many times more prevalent than predicted by the WLC model. We test our data and model with an interlocking set of consistency checks. Our analysis also shows how our model is compatible with previous experiments, which have sometimes been viewed as confirming the WLC.
DNA在中等长度尺度（5 - 100纳米）上的弯曲机制在许多细胞过程中起着关键作用，在人工DNA结构的制造中也很重要，但之前关于DNA力学的实验研究关注的长度尺度比这些更长。我们使用高分辨率原子力显微镜对单个DNA分子进行测量，以直接获得适用于低至5纳米尺度的弯曲能量函数。我们的测量结果表明，高度弯曲的DNA构象的弹性能低于经典弹性模型（如蠕虫状链（WLC）模型）的预测。例如，我们发现在短长度尺度上，自发的大角度弯曲比WLC模型预测的要普遍得多。我们通过一系列相互关联的一致性检查来测试我们的数据和模型。我们的分析还表明了我们的模型如何与之前的实验兼容，而这些实验有时被视为证实了WLC模型。
