Theory of end‐labeled free‐solution electrophoresis: Is the end effect important?
Theory of end‐labeled free‐solution electrophoresis: Is the end effect important?
复制标题
末端标记游离溶液电泳理论：末端效应重要吗？
作者：
M. Chubynsky;G. Slater
在与“拖曳标签”缀合的DNA（如DNA）的自由溶液电泳理论中，缀合物被分成具有相等流体动力学摩擦的片段，并且其电泳迁移率被计算为单个片段的迁移率的加权平均值。如果假设所有权重相等，则对于电中性拖曳标签，预测洗脱时间t线性依赖于倒数DNA长度1/M。虽然众所周知，等权重假设是近似的，而且实际上权重向两端增加，但这种“端效应”被假设为很小，因为在实验中t（1/M）依赖性似乎几乎是完美的线性。我们对这一假设提出质疑，指出一些实验线性拟合在1/M→0的限度内不能外推到游离（即未标记的）DNA洗脱时间，表明非线性超出了拟合范围。我们表明，考虑到端部效应的柔性聚合物的理论产生了一个非线性曲线，然而，可以在1/M典型的实验的有限范围内拟合直线，但有一个“错误”的截距，这解释了实验结果，而无需额外的假设。我们还研究了带电和中性部分的灵活性的影响。
In the theory of free‐solution electrophoresis of a polyelectrolyte (such as the DNA) conjugated with a “drag‐tag,” the conjugate is divided into segments of equal hydrodynamic friction and its electrophoretic mobility is calculated as a weighted average of the mobilities of individual segments. If all the weights are assumed equal, then for an electrically neutral drag‐tag, the elution time t is predicted to depend linearly on the inverse DNA length 1/M . While it is well‐known that the equal‐weights assumption is approximate and in reality the weights increase toward the ends, this “end effect” has been assumed to be small, since in experiments the t(1/M) dependence seems to be nearly perfectly linear. We challenge this assumption pointing out that some experimental linear fits do not extrapolate to the free (i.e. untagged) DNA elution time in the limit 1/M→0 , indicating nonlinearity outside the fitting range. We show that a theory for a flexible polymer taking the end effect into account produces a nonlinear curve that, however, can be fitted with a straight line over a limited range of 1/M typical of experiments, but with a “wrong” intercept, which explains the experimental results without additional assumptions. We also study the influence of the flexibilities of the charged and neutral parts.
影响因子：
4.1
作者：
McCormick, LC;Slater, GW;Drouin, G
通讯作者：
Drouin, G
影响因子：
7.4
作者：
Meagher, Robert J.;Won, Jong-In;Barron, Annelise E.
通讯作者：
Barron, Annelise E.
模拟聚电解质电流体动力学的隐式方法
影响因子：
8.6
作者：
O. A. Hickey;C. Holm;J. L. Harden;G. W. Slater
通讯作者：
G. W. Slater