Zinkel S S, Crothers D M
Nature. 1987;328(6126):178-81. doi: 10.1038/328178a0.
Gel electrophoresis of DNA and protein-DNA complexes has been a key method used in studies of sequence-directed and protein-induced DNA bending. Natural DNA sequences can have protein binding sites adjacent to A-tract bending sites, resulting in the potential for the formation of topologically complex shapes in a localized DNA regulatory domain. An essential first step in deducing the structure and functional significance of such domains is elucidation of the relative direction of bending, which can be determined from the electrophoretic mobilities of isomers having varied helical phasing between the bends. Taking DNA bent around CAP protein as a standard, we conclude that the junction bending model correctly predicts the direction of bending at A tracts in kinetoplast DNA. The overall direction of the bend is towards the minor groove at the centre of the A tract.
DNA和蛋白质-DNA复合物的凝胶电泳一直是研究序列导向和蛋白质诱导的DNA弯曲的关键方法。天然DNA序列可能在A-序列弯曲位点附近有蛋白质结合位点，这使得在局部DNA调控域中形成拓扑复杂形状成为可能。推断此类结构域的结构和功能意义的一个重要的第一步是阐明弯曲的相对方向，这可以从弯曲之间具有不同螺旋相位的异构体的电泳迁移率来确定。以围绕CAP蛋白弯曲的DNA为标准，我们得出结论，连接弯曲模型正确地预测了动质体DNA中A序列处的弯曲方向。弯曲的总体方向是朝向A序列中心的小沟。
