Marked difference in conformational fluctuation between giant DNA molecules in circular and linear forms
Marked difference in conformational fluctuation between giant DNA molecules in circular and linear forms
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DOI：
10.1063/1.4916309
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发表时间：
2015-04-14
影响因子：
4.4
通讯作者：
Yoshikawa, Kenichi
中科院分区：
文献类型：
--
作者：
Iwaki, Takafumi;Ishido, Tomomi;Yoshikawa, Kenichi
我们使用荧光显微镜对水溶液中的线性和环状巨型 DNA (208 kbp) 进行了单分子观察。结果表明，环状DNA的构象波动程度约为。尽管环状DNA的长轴长度仅比线性DNA小10%，但比线性DNA短40%。此外，环形链的弛豫时间比直链链的弛豫时间短至少一个数量级。线性和环状 DNA 之间的这种显着差异的基本特征通过对带状大分子的数值模拟再现，作为长的半柔性双螺旋 DNA 分子的粗粒度模型。此外，我们基于平均场模型计算了圆形相互作用链的回转半径，这比传统的理论方程更好地理解了当前的实验趋势。 (C) 2015 AIP 出版有限责任公司。
We performed monomolecular observations on linear and circular giant DNAs (208 kbp) in an aqueous solution by the use of fluorescence microscopy. The results showed that the degree of conformational fluctuation in circular DNA was ca. 40% less than that in linear DNA, although the long-axis length of circular DNA was only 10% smaller than that of linear DNA. Additionally, the relaxation time of a circular chain was shorter than that of a linear chain by at least one order of magnitude. The essential features of this marked difference between linear and circular DNAs were reproduced by numerical simulations on a ribbon-like macromolecule as a coarse-grained model of a long semiflexible, double-helical DNA molecule. In addition, we calculated the radius of gyration of an interacting chain in a circular form on the basis of the mean field model, which provides a better understanding of the present experimental trend than a traditional theoretical equation. (C) 2015 AIP Publishing LLC.