STRUCTURE AND FUNCTION OF X-FORM DNA

本项目的重点是一种合成的化合物的构象性质 DNA多聚(da-dt)，特别是其异构化为 称为X-DNA的不同寻常的双螺旋形式。(1)我们建议进行调查， 使用常规圆二色(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 聚(dA-dT)的胸腺嘧啶甲基效应构象性质。 (2)我们建议使用常规CD、真空UV CD和 真空UV-LD光谱--腺嘌呤如何被氨基部分取代 2不同比例的腺嘌呤对其构象性质有影响 Poly(da-dt)。 这项协作工作将结合各种专业知识 合成多核苷酸研究其构象性质 用圆二色性和线性二色性测量DNA 真空紫外线以确定构象和碱基倾斜度。它经常是 在特殊条件下难以将这些聚合物保持在溶液中 有必要使它们呈现出某种形式，但我们一直 成功地计算出使它们保持在溶液中的条件，即使在 使用的短路径所需的高浓度 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.