ELECTRIC BIREFRINGENCE OF DNA RESTRICTION FRAGMENTS

DNA 限制性片段的电双折射

• 批准号: 3277316
• 负责人: NANCY C STELLWAGEN
• 金额: $ 10.3万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 1981
• 资助国家: 美国
• 起止时间: 1981-07-01 至 1987-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3277316
• 关键词: DNA; acrylamides; birefringences; dipole moment; dyes; electric field; endonuclease; fluorescence polarization; intermolecular interaction; molecular weight; nucleic acid structure; nucleobase; plasmids; solvents; urea

The interaction of DNA restriction fragments with strong electric fields will be investigated using the technique of transient electric birefringence. Reversing field experiments will demonstrate whether the DNA molecules undergo a progressive change in conformation with increasing field strength. Studies of the Kerr constant as a function of counterion concentration and type will provide a test of the Manning theory of counterion condensation, as well as the Mandel and O'Konski theories of electric polarizability. Studies of the Kerr constant of very small fragments will show whether the recently observed L2 dependence of the electric polarizability (and hence the induced dipole) on length extends to fragments smaller than 100 base pairs. Birefringence saturation curves will be measured as a function of counterion concentration and type. The results will be correlated with the birefringence decay curves in order to interpret the apparent linear dependence of the birefringence on electric field strength in intermediate field strength regions. Intercalation of dye molecules into the DNA helix will be investigated with monodisperse fragments, in order to show whether or not the DNA helix is actually elongated by intercalation. Finally, the effect of electric fields on the thermal denaturation of DNA will be studied. The results of all these experiments will clarify the behavior of DNA molecules in strong electric fields, and thus can identify the electrical forces acting on the DNA molecule in the cell; the electrical potential across a typical cell membrane is of the same order of magnitude as the fields used in electric birefringence experiments. The long range goals of this research are to understand the physical properties of DNA and to determine the electrical forces acting on polyelectrolytes.

强电场作用下DNA酶切片段的相互作用 将使用瞬态电 双折射 反向场实验将证明 随着DNA分子构象的增加， 磁场强度 克尔常数随电荷数变化的研究 浓度和类型将提供曼宁理论的测试， 反凝聚，以及曼德尔和奥孔斯基的理论， 电极化率 对极微小粒子克尔常数的研究 片段将显示最近观察到的L2依赖性是否 长度上的电极化（以及因此诱导的偶极子）延伸到 小于100个碱基对的片段。 双折射饱和曲线 将被测量为反离子浓度和类型的函数。 的 结果将与双折射衰减曲线相关联， 解释了双折射对电的明显线性依赖性， 中等场强区域的场强。 插层 染料分子进入DNA螺旋将被研究与单分散 片段，以显示DNA螺旋是否实际上是 通过插入而延长。 最后，研究了电场对 将研究DNA的热变性。 所有这些的结果 实验将阐明DNA分子在强电场中的行为。 电场，从而可以识别作用在DNA上的电力 细胞中的分子;通过一个典型细胞的电势 膜的大小与电场中使用的场的大小相同。 双折射实验 这项研究的长期目标是 了解DNA的物理性质，并确定其电学性质。 作用在聚电解质上的力。