ELECTRIC BIREFRINGENCE OF DNA RESTRICTION FRAGMENTS

DNA限制性片段与电场的相互作用 将使用瞬变电学技术进行研究 双折射。将特别强调对……的研究 DNA限制性片段的定向和迷向 包埋在琼脂糖凝胶和聚丙烯酰胺凝胶中。电式 双折射对于这些研究来说是一种特别有用的技术， 因为它直接测量DNA的方向 凝胶基质中的分子。我们将与您一起学习培训 不同幅度和持续时间的脉冲电场，具有 脉冲之间的延迟可变，并具有快速换向的电 菲尔兹。线性聚丙烯酰胺溶液中的取向 不同电荷密度的分子也将被研究。 电双折射研究将继续在 取向、失定向、反转场和饱和度 两个147碱基对限制性片段的行为 表达载体pBR322。这两个碎片的移动性不同 在聚丙烯酰胺凝胶上，以及在其他物理性质上，以及 典型的与序列相关的结构差异在沃森- 克里克·螺旋。其他正常和异常缓慢的配对 迁移的DNA片段将被研究，以及合成 多核苷酸。 更多的电双折射研究将集中在 DNA片段的饱和和反转场行为 在自由溶液中，不同的分子量，B，A DNA限制性片段的构象转变 限制性内切酶与DNA片段的结合 溴化乙锭和其他配体到DNA片段， 溴化乙锭和其他配体与DNA片段的结合， 和线性聚丙烯酰胺的电双折射。 不同的分子量和电荷密度。许多人 电双折射测量将与 圆二色谱和/或凝胶电泳法研究。结果 这些实验将有助于阐明凝胶的作用机理 在不同的凝胶介质中进行电泳，并鉴定一些 序列依赖的构象差异对DNA序列的影响 DNA的物理性质。这项研究的长期目标 是了解DNA分子在溶液中的行为，以及 描述DNA与其他物质相互作用的机制 具有电场的多离子。

The interaction of DNA restriction fragments with electric fields will be investigated using the technique of transient electric birefringence. Particular emphasis will be placed on a study of the orientation and disorientation of DNA restriction fragments imbedded in agarose and in polyacrylamide gels. Electric birefringence is a particularly useful technique for these studies, because it measures directly the orientation of the DNA molecules in the gel matrix. Orientation will be studied with pulsed electric fields of different amplitudes and durations, with a variable delay between pulses, and with rapidly reversing electric fields. Orientation in a solution containing linear polyacrylamide molecules of different charge densities will also be studied. Electric birefringence studies will be continued on the orientation, disorientation, reversing field, and saturation behavior of two 147 base pair restriction fragments obtained from the plasmid pBR322. These two fragments differ in their mobility on polyacrylamide gels, and in other physical properties, and typify sequence-related structural differences in the Watson- Crick helix. Other pairs of normally and abnormally slowly migrating DNA fragments will be studied, as well as synthetic polynucleotides. Additional electric birefringence studies will focus on the saturation and reversing field behavior of DNA fragments of different molecular weights in free solution, the B A conformational transition of DNA restriction fragments, the binding of restriction enzymes to DNA fragments, the binding of ethidium bromide and other ligands to DNA fragments, the binding of ethidium bromide and other ligands to DNA fragments, and the electric birefringence of linear polyacrylamides of different molecular weights and charge densities. Many of the electric birefringence measurements will be correlated with circular dichroism and/or gel electrophoretic studies. The result of these experiments will clarify the mechanism of gel electrophoresis in different gel media and identify some of the effects of sequence-dependent conformation differences on the physical properties of DNA. The long range goals of this research are to understand the behavior of DNA molecule in solution and to characterize the mechanism of interaction of DNA and other polyions with electric fields.