Glancy P
Department of Physics and Astronomy, University of California, Riverside, Riverside, CA, 92521, USA,
J Biol Phys. 2015 Jun;41(3):247-56. doi: 10.1007/s10867-015-9377-0. Epub 2015 Feb 21.
Using terahertz time-domain spectroscopy (THz-TDS), the frequency-dependent dielectric constant of deoxyribonucleic acid (DNA) in solution was measured. The response of the buffer solution is dominated by two Debye modes in this frequency range, and, from an analysis of the concentration dependence, the presence of the DNA increases the main relaxation time and dielectric constant. This reflects the fact that the water in the hydration layer is more tightly bound under the influence of the DNA molecule in comparison to bulk water. This dynamical slowing down with increasing DNA concentration is similar to what is observed with purine nucleotides, but opposite to the behavior of pyrimidine nucleotides. In addition, a suspension model was used with the concentration-dependent data to isolate the dielectric response of the hydrated DNA molecule. The data for the hydrated DNA molecule is still dominated by a Debye response. It is also possible to determine the thickness of the hydration layer, and the DNA molecule influences the surrounding water out to 16 or 17 Å, which corresponds to about six effective hydration layers.
利用太赫兹时域光谱（THz - TDS）测量了溶液中脱氧核糖核酸（DNA）的频率相关介电常数。在此频率范围内，缓冲溶液的响应由两个德拜模式主导，并且通过对浓度依赖性的分析可知，DNA的存在增加了主要弛豫时间和介电常数。这反映出一个事实，即与 bulk 水相比，在DNA分子的影响下，水化层中的水结合得更紧密。随着DNA浓度增加，这种动力学减慢现象与嘌呤核苷酸的情况相似，但与嘧啶核苷酸的行为相反。此外，使用悬浮模型结合浓度依赖性数据来分离水化DNA分子的介电响应。水化DNA分子的数据仍然以德拜响应为主导。还可以确定水化层的厚度，DNA分子对周围水的影响范围可达16或17 Å，这大约相当于六个有效水化层。
