Institut Laue Langevin , 71, avenue des Martyrs - CS20156 - 38042 Grenoble Cedex 9 - France.
ICCRAM , University of Burgos , Plaza Misael Bañuelos , 09001 Burgos , Spain.
J Phys Chem B. 2018 Mar 8;122(9):2504-2515. doi: 10.1021/acs.jpcb.7b11608. Epub 2018 Feb 21.
The influence of molecular confinement on the melting transition of oriented Na-DNA fibers submerged in poly(ethylene glycol) (PEG) solutions has been studied. The PEG solution exerts an osmotic pressure on the fibers which, in turn, is related to the DNA intermolecular distance. Calorimetry measurements show that the melting temperature increases and the width of the transition decreases with decreasing intermolecular distance. Neutron scattering was used to monitor the integrated intensity and width of a Bragg peak from the B-form of DNA as a function of temperature. The data were quantitatively analyzed using the Peyrard-Bishop-Dauxois model. The experiments and analysis showed that long segments of double-stranded DNA persist until the last stages of melting and that there appears to be a substantial increase of the DNA dynamics as the melting temperature of the DNA is approached.
研究了分子限制对取向的 Na-DNA 纤维在聚乙二醇（PEG）溶液中熔化转变的影响。PEG 溶液对纤维施加渗透压，而渗透压又与 DNA 分子间距离有关。量热法测量表明，随着分子间距离的减小，熔化温度升高，转变宽度减小。利用中子散射监测 B 型 DNA 的布拉格峰的积分强度和宽度随温度的变化。使用 Peyrard-Bishop-Dauxois 模型对数据进行了定量分析。实验和分析表明，长链的双链 DNA 一直持续到熔化的最后阶段，并且随着 DNA 熔化温度的接近，DNA 的动力学似乎有了实质性的提高。
