Crut A, Lasne D, Allemand J-F, Dahan M, Desbiolles P
Laboratoire Kastler Brossel, Unité de Recherche de l'Ecole Normale Supérieure et de l'Université Pierre et Marie Curie, associée au CNRS, Département de Physique, 24 rue Lhomond, F-75005 Paris, France.
Phys Rev E Stat Nonlin Soft Matter Phys. 2003 May;67(5 Pt 1):051910. doi: 10.1103/PhysRevE.67.051910. Epub 2003 May 15.
We present a simple method to stretch DNA molecules close to a surface without any chemical modification of either the molecules or the surface. By adjusting the pH of the solution, only the extremities of DNA molecules are tethered to a glass coverslip made hydrophobic, while stretching is achieved using a hydrodynamic flow. These extended molecules provide a very favorable template for DNA-protein interaction studies by purely optical means. Pursuing these experiments requires first a full characterization of the thermally driven fluctuations of the tethered DNA molecules. For this purpose, these fluctuations were recorded by fluorescence microscopy and were analyzed in terms of normal modes. Our experimental results are well described by a model accounting for the nonlinear elastic behavior of the chain. Remarkably, the proximity of the molecules to a rigid surface does not alter the main features of their dynamics, and our results are in agreement with previous studies on extended DNA in viscous solutions.
我们提出了一种简单的方法，可在不对分子或表面进行任何化学修饰的情况下，将DNA分子拉伸至靠近表面的位置。通过调节溶液的pH值，仅DNA分子的末端会附着在经过疏水化处理的玻璃盖玻片上，同时利用流体动力流实现拉伸。这些伸展的分子为通过纯光学手段进行DNA-蛋白质相互作用研究提供了非常有利的模板。进行这些实验首先需要对附着的DNA分子的热驱动涨落进行全面表征。为此，通过荧光显微镜记录了这些涨落，并根据正常模式进行了分析。我们的实验结果通过一个考虑链的非线性弹性行为的模型得到了很好的描述。值得注意的是，分子与刚性表面的接近并不会改变其动力学的主要特征，并且我们的结果与之前关于粘性溶液中伸展DNA的研究一致。
