Défontaines A D, Viovy J L
Laboratoire de Physicochimie théorique, ESPCI, Paris, France.
Electrophoresis. 1994 Feb;15(2):111-9. doi: 10.1002/elps.1150150120.
A theory for field-inversion gel electrophoresis of a flexible polyelectrolyte bearing an uncharged bulky label at one end is described, and the evolution of the mobility with chain length, field strength, friction of the label, and the duration of the forward and reverse pulses is predicted. A new critical size, Ndetrap, is introduced, and its value calculated. It increases roughly linearly with the duration of the reverse pulses. Chains smaller than Ndetrap are detrapped by reverse pulses, and may have a high mobility, whereas chains larger than Ndetrap are not trapped, and have a very small mobility. This leads to an increase of the mobility (as compared with constant field) in a given range of sizes, and to a strong selectivity around Ndetrap. Depending on the parameters, numerous other effects, including a secondary mobility plateau and band inversion, may appear. The corresponding regimes are predicted and discussed. All predictions are qualitatively consistent with available experimental data. We use them to suggest efficient conditions for the development of pulsed-field trapping electrophoresis, a possible tool for improved DNA sequencing. In particular, we recommend using a ramping of pulse times, with a constant ratio of forward to reverse time in the range 3 to 5.
本文描述了一种关于一端带有不带电大体积标记的柔性聚电解质的场反转凝胶电泳理论，并预测了迁移率随链长、场强、标记物摩擦力以及正向和反向脉冲持续时间的变化情况。引入了一个新的临界尺寸Ndetrap，并计算了其值。它大致随反向脉冲的持续时间线性增加。小于Ndetrap的链会被反向脉冲解捕获，可能具有较高的迁移率，而大于Ndetrap的链不会被捕获，迁移率非常小。这导致在给定尺寸范围内迁移率（与恒定场相比）增加，并在Ndetrap周围产生很强的选择性。根据参数的不同，可能会出现许多其他效应，包括二级迁移率平台和条带反转。对相应的情况进行了预测和讨论。所有预测与现有的实验数据在定性上是一致的。我们利用这些预测为脉冲场捕获电泳的发展提出了有效的条件，脉冲场捕获电泳是一种可能用于改进DNA测序的工具。特别是，我们建议使用脉冲时间的斜坡变化，正向与反向时间的恒定比例在3到5的范围内。
