The ionic strength dependence of the second virial coefficient of low molar mass DNA fragments in aqueous solutions
The ionic strength dependence of the second virial coefficient of low molar mass DNA fragments in aqueous solutions
复制标题
水溶液中低摩尔质量 DNA 片段第二维里系数的离子强度依赖性
DOI：
10.1021/ma00191a080
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发表时间：
1989
期刊：
影响因子：
5.5
通讯作者：
M. Mandel
中科院分区：
文献类型：
--
作者：
T. Nicolai;M. Mandel
第二维里系数的低摩尔质量的DNA片段的约150个碱基对（摩尔质量约106克mol-1）已确定的帮助下，在7个不同的NaCl浓度（范围从0.002至0.5 M）的水溶液中的静态低角激光散射。发现A2值随盐浓度的增加而减小。A2的实验值进行了比较，理论计算的均匀带电的刚性杆。协议是令人满意的，如果结构线电荷密度的理论表达式中，线电荷的基础上，由一个有效的值，其中几种方法已被使用，包括凝聚的概念和（近似）解决方案的thepoissonBoltzmann方程。最好的结果，如果盐浓度无关的有效电荷密度的值，略大于预测的值由简单的凝聚假设，是使用。这些结果似乎证实了轮廓长度与总持续长度相同或更小的DNA片段表现为棒状颗粒的良好近似。
Second virial coefficients of low molar mass DNA fragments of approximately 150 base pairs (molar mass approximately 106 g mol-1) have been determined with the help of static low-angle laser light scattering at seven different NaCl concentrations (ranging from 0.002 to 0.5 M) in aqueous solutions. The value of A2 is found to decrease with increasing salt concentration. The experimental values of A2 are compared to theoretical ones calculated for uniformly charged rigid rods. The agreement is satisfactory if the structural linear charge density is replaced in the theoretical expressions, based on line charges, by an effective value for which several approaches have been used, including the condensation concept and the (approximate) solution of thePoisson Boltzmann equation. Best results are obtained if a salt concentration independent value of the effective charge density, slightly larger than the value predicted by the simple condensation hypothesis, is used. These results seem to confirmthat the DNA fragments with a contour length of the same order as (or smaller than) the total persistence length behave to a good approximation as rodlike particles.