STRUCTURE AND FUNCTION OF X-FORM DNA

该项目的重点是合成的构象特性 DNA聚（dA-dT），特别是其异构化成 一种不寻常的双螺旋形式，称为X-DNA。 (1)我们提议调查， 使用常规的圆二色性（CD）、真空UV CD和真空UV 线性二色性（LD）光谱，脂肪族取代基如何到位 胸腺嘧啶甲基效应聚（dA-dT）的构象性质。 (2)我们建议调查，使用传统的CD，真空紫外CD， 真空紫外LD光谱，如何部分取代腺嘌呤的氨基 2腺嘌呤的不同比例影响构象性质的 聚（dA-dT）。 这项合作努力将联合收割机的专业知识，利用各种 合成的多核苷酸来研究构象特性 DNA的圆二色性和线性二色性测量， 真空紫外测定构象和碱基倾斜度。 往往 难以在特殊条件下将这些聚合物保持在溶液中 必须使他们采取他们的形式之一，但我们一直在 成功地制定出条件，使他们在解决方案，即使在 所用的短路径长度所需的高浓度， 真空紫外线工作

This project is focused on the conformational properties of a synthetic DNA poly(dA-dT), especially on its capability to isomerize into an unusual double helical form called X-DNA. (1) We propose to investigate, using conventional circular dichroism (CD), vacuum UV CD, and vacuum UV linear dichroism (LD) spectroscopy, how aliphatic substituents in place of the thymine methyl effect conformational properties of poly(dA-dT). (2) We propose to investigate, using conventional CD, vacuum UV CD, and vacuum UV LD spectroscopy, how partial replacement of adenine by amino 2adenine to various proportions affects conformational properties of poly(dA-dT). This collaborative effort will combine the expertise using various synthetic polynucleotides to investigate the conformational properties of DNA with making circular and linear dichroism measurements in the vacuum UV to determine conformation and base inclination. It is often difficult to keep these polymers in solution under the special conditions necessary to cause them to assume one of their forms, but we has been successful in working out conditions to keep them in solution, even at the high concentrations necessary for the short pathlengths used in vacuum UV work.