Measuring inter-DNA potentials in solution
Measuring inter-DNA potentials in solution
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DOI：
10.1103/physrevlett.96.138101
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发表时间：
2006-04-07
影响因子：
8.6
通讯作者：
Pollack, L
中科院分区：
文献类型：
--
作者：
Qiu, XY;Kwok, LW;Pollack, L
短链DNA之间的相互作用可以通过不同的溶液条件从排斥调节到吸引，并已使用小角X射线散射技术进行了量化。用广义单分量方法和DNA间Yukawa对势能对散射曲线进行拟合，提取了DNA相互作用的有效电荷。在低到中等的单价反离子浓度下测量到显著的电荷，导致强烈的DNA间排斥力。随着二价反离子的加入，电荷和斥力迅速减小。在令人惊讶的低二价阳离子浓度下，观察到一个有趣的短程吸引力，类似于16 mM的镁离子。DNA间相互作用势的定量测量对于改进生物系统中的基本相互作用模型是必不可少的。
Interactions between short strands of DNA can be tuned from repulsive to attractive by varying solution conditions and have been quantified using small angle x-ray scattering techniques. The effective DNA interaction charge was extracted by fitting the scattering profiles with the generalized one-component method and inter-DNA Yukawa pair potentials. A significant charge is measured at low to moderate monovalent counterion concentrations, resulting in strong inter-DNA repulsion. The charge and repulsion diminish rapidly upon the addition of divalent counterions. An intriguing short range attraction is observed at surprisingly low divalent cation concentrations, similar to 16 mM Mg2+. Quantitative measurements of inter-DNA potentials are essential for improving models of fundamental interactions in biological systems.