STRUCTURE AND DYNAMICS OF A DNA PROTEIN COMPLEX

DNA 蛋白质复合物的结构和动力学

• 批准号: 6395893
• 负责人: DON EDEN
• 金额: $ 12.7万
• 依托单位: SAN FRANCISCO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-01-01 至 2000-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6395893
• 关键词: DNA; DNA methylation; birefringences; cofactor; elasticity; enzyme complex; enzyme structure; lasers; light scattering; methyltransferase; molecular dynamics; nucleic acid structure; physical model; protein binding; protein protein interaction; protein structure function; solutions

The long range goal of this project is to develop an understanding of functional important interactions that occur between proteins and DNA in solution which result in the formation of highly specific complexes. The project will focus on EcoRI methyltransferase and its interaction with target DNA. Methylation performs many functions ranging from protection of host DNA against bacterial restriction endonucleases to the regulation of gene expression in eukaryotes. The EcoRI methyltransferase, which is one of the most characterized methyltransferases, uses the co-factor S adenosylmethionine to methylate the central adenine in the canonical site 5'GAATTC3'. There is considerable evidence that the structure of both the DNA and the methyltransferase are significantly distorted when the complex is formed. The distortions are likely to add specificity to the formation of the complex. A complete description of the distortions and the forces that are required to cause them is not available. The techniques of transient electric birefringence and optical Kerr effect will be used to characterize the mechanical and electrical properties of the methyltransferase and the DNA, separately and in a ternary complex with a co-factor analog. Changes in shape and mechanical stiffness of the methyltransferase upon the addition of co-factors will be determined. We will determine the angle of the putative bend that is induced in the DNA and the position of the methyltransferase relative to the bend. The results will be compared with those for other DNA-protein complexes with an aim of developing a physical model to explain the interactions in solution. The mechanical properties of the methyltransferase will be compared with those of other proteins of similar size that are believed to have elastic hinges between their domains.

本项目的长期目标是了解 蛋白质和DNA之间发生的功能性重要相互作用， 溶液，导致形成高度特异性的复合物。的 该项目将侧重于EcoRI甲基转移酶及其与 目标DNA。甲基化执行许多功能，从保护 宿主DNA对细菌限制性内切酶的调节 真核生物中的基因表达。EcoRI甲基转移酶， 最具特征的甲基转移酶，使用辅因子S 腺苷甲硫氨酸甲基化的中央腺嘌呤在典型的网站 5 'GAATTC 3'。有相当多的证据表明， DNA和甲基转移酶显着扭曲时，复合物 形成有这种扭曲可能会增加地层的特异性 复杂的。对扭曲和力的完整描述 导致它们所需的物质是不可用的。 瞬态电双折射和光学克尔效应技术 将被用来表征机械和电气性能， 甲基转移酶和DNA，分别和三元复合物 辅因子类似物。形状和机械刚度的变化 将测定添加辅因子后的甲基转移酶。我们 将决定在DNA中诱导的假定弯曲的角度 以及甲基转移酶相对于弯曲的位置。 并与其它DNA-蛋白质复合物的结果进行了比较 目的是建立一个物理模型来解释 溶液甲基转移酶的机械性质将是 与其他类似大小的蛋白质相比， 在它们的域之间具有弹性铰链。