DYNAMIC SOLUTION STRUCTURE OF PROTEINS AND NUCLEIC ACIDS

蛋白质和核酸的动态溶液结构

• 批准号: 3071187
• 负责人: DON EDEN
• 金额: $ 5.95万
• 依托单位: SAN FRANCISCO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-09-01 至 1989-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3071187
• 关键词: DNA; acidity /alkalinity; birefringences; conformation; cytochromes; ionic strengths; lysozyme; nucleic acid denaturation; nucleic acid structure; plasmids; pyrimidine dimers; radiobiology; solutions; thermodynamics; ultraviolet radiation; virus DNA

The technique of transient electric birefringence will be used to study the structure of DNA in solution in order to understand the packaging of DNA in vivo and to estimate the strain arising from the mutation causing cyclobutane-type thymine-thymine dimers. The temporal responses of the field free decay and field reversal transient birefringence experiments are very sensitive to the average structure and ionic environment of nuclei acids in solution. Measurements of the rotational diffusion constant of pBR322 restriction fragments as a function of fragment size, ionic strength and temperature will give the lateral stiffness and free energy, enthalpy, and entropy associated with the flexing of DNA. Steric and electrostatic contributions to the persistence length will be separated. The amplitude and dynamics of ionic polarizability of nucleic acids will be elucidated from field reversal experiments on restriction fragments in which the species and concentration of counterions will be varied. The dynamic information will give information about the mobility of counterions in the vicinity of the phosphates in the double helix. Ultraviolet radiation of DNA converts a portion of adjacent pyrimidine bases into cyclobutane dimers. These dimers have been implicated as biological lesions. The degree of denaturing and the resulting angular deformation of DNA restriction fragments will be measured by studying the rotational diffusion of fragments before and after dimer formation. This is a very sensitive way to characterize the small bend which may be introduced in the DNA double helix. The adiabatic compressibility of proteins in aqueous solutions will be determined from ultrasonic velocity and density measurements in order to study the various forces which affects their dynamic structure and function. The electrostatic contributions to the relative stabilities and compressibilities of ferri- and ferrocytochrome c will be investigated by varying the ionic strength. Measurements on ferri- and ferrocytochrome b5 as well as on the apoprotein will yield information on the way in which the heme promotes mechanical stability to the protein. Analysis of results on lysozyme with and without substrates will help elucidate the dynamic aspects of enzyme action.

瞬态电双折射技术将被用来研究 为了了解DNA在溶液中的包装， 并估计由突变引起的菌株 环丁烷型胸腺嘧啶-胸腺嘧啶二聚体。 的时间响应， 场自由衰减和场反转瞬态双折射实验， 对原子核的平均结构和离子环境非常敏感 溶液中的酸 旋转扩散常数的测量 pBR 322限制性片段作为片段大小、离子强度 温度会给出横向刚度和自由能，焓， 以及与DNA弯曲相关的熵。 空间和静电 对持久性长度的贡献将被分离。 振幅 并阐明了核酸离子极化率的动力学 从限制性片段的田间逆转实验中， 抗衡离子的种类和浓度将变化。 动态 信息将提供有关反离子在 在双螺旋中的磷酸盐附近。 紫外辐射 DNA将一部分相邻的嘧啶碱基转化为环丁烷 二聚体。 这些二聚体被认为是生物学病变。 的 DNA的变性程度和由此产生的角变形 通过研究旋转扩散来测量限制性片段 在二聚体形成之前和之后的片段。 这是一个非常敏感 表征可能引入DNA的小弯曲的方法 双螺旋。 蛋白质在水溶液中的绝热压缩性将是 根据超声波速度和密度测量确定， 研究影响其动态结构的各种力量， 功能 静电对相对稳定性的贡献， 铁-和铁细胞色素c的压缩将被研究， 改变离子强度。 细胞色素b5铁离子和亚铁离子的测定 以及载脂蛋白将产生有关蛋白质作用方式的信息 血红素促进蛋白质的机械稳定性。 监测结果分析 有和没有底物的溶菌酶将有助于阐明 酶的作用。