Chrambach A, Wheeler D L
Section on Macromolecular Analysis, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD.
Electrophoresis. 1994 Aug-Sep;15(8-9):1021-7. doi: 10.1002/elps.11501501152.
Transverse pore gradient gel electrophoresis is important as a tool for obtaining nonlinear Ferguson plots [log(mobility) vs. gel concentration], e.g. in application to DNA in polyacrylamide gels or to agarose gels, with the purpose of evaluating molecular properties (size, conformation, malleability) and gel fiber properties (fiber radius and length per unit volume). To date, it is capable of (i) yielding gel patterns ("Ferguson curves") of migration distance vs. predicted % T-range of the pore gradient, assuming its linearity; (ii) yielding information regarding molecular conformation from the intersection of Ferguson curves of unknowns (e.g. bent DNA) with those of standards; (iii) acquisition of Ferguson curves by computer, using prototype instrumentation; (iv) mathematical manipulation of acquired Ferguson curves to yielding Ferguson plots, providing that mobility in free solution has been assessed by capillary zone electrophoresis. The potentialities of the method remain unfulfilled to date due to (i) the unavailability, with a single exception, of an accurate and precise way to produce pore gradients of known shape; (ii) unavailability of a routinely applicable analysis for % T; (iii) unavailability of optimized, user-friendly and foolproof instrumentation for computer acquisition of Ferguson curves, including the present inapplicability of a commercially available electrophoresis apparatus with intermittent optical detection to transverse pore gradient gels; and (iv) unresolved problems in the statistical evaluation of Ferguson curves.
横向孔径梯度凝胶电泳作为一种获取非线性弗格森图（对数迁移率与凝胶浓度关系图）的工具非常重要，例如应用于聚丙烯酰胺凝胶或琼脂糖凝胶中的DNA，目的是评估分子特性（大小、构象、柔韧性）和凝胶纤维特性（纤维半径和单位体积长度）。迄今为止，它能够：（i）在假设孔径梯度呈线性的情况下，得出迁移距离与预测的孔径梯度%T范围的凝胶图谱（“弗格森曲线”）；（ii）从未知物（如弯曲DNA）与标准物的弗格森曲线交点获取有关分子构象的信息；（iii）使用原型仪器通过计算机获取弗格森曲线；（iv）对获取的弗格森曲线进行数学处理以得到弗格森图，前提是已通过毛细管区带电泳评估了自由溶液中的迁移率。由于以下原因，该方法的潜力至今尚未实现：（i）除了一个例外，没有准确精确的方法来产生已知形状的孔径梯度；（ii）没有适用于%T的常规分析方法；（iii）没有用于计算机获取弗格森曲线的优化、用户友好且万无一失的仪器，包括目前市售的具有间歇光学检测功能的电泳仪不适用于横向孔径梯度凝胶；以及（iv）弗格森曲线的统计评估中存在未解决的问题。
