ESCHERICHIA COLI SSB PROTEIN-DNA INTERACTIONS

大肠杆菌 SSB 蛋白质-DNA 相互作用

• 批准号: 2175831
• 负责人: Timothy M Lohman
• 金额: $ 23.43万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-07-01 至 1995-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2175831
• 关键词: DNA binding protein; Escherichia coli; bacterial DNA; bacterial proteins; chemical binding; chemical kinetics; fluorescence; intermolecular interaction; nucleic acid structure; thermodynamics

DESCRIPTION (Adapted from applicant's abstract): The proposed research is designed to obtain a molecular understanding of the interactions of the E. coli Single Strand Binding (SSB) protein with single stranded (ss) nucleic acids, using thermodynamic, kinetic, biochemical and structural approaches. The SSB protein is a helix-destabilizing protein, which binds selectively and cooperatively to ss nucleic acids. It is an essential protein in E. coli, which is required for DNA replication and is involved in a variety of recombination and repair processes in vivo. The E. coli SSB tetramer has recently been shown to bind to ss nucleic acids in a number of different modes, depending on the solution conditions, each possessing different site sizes. This reflects, in part, the different degrees of DNA wrapping about the tetramer. It also binds to ss polynucleotides with at least two different types of positive cooperativity between tetramers, yet it is not clear which of these modes or cooperativities is used by the SSB protein in its various functions. The applicant's intent is to understand the binding properties of the SSB protein and the structures of the complexes in the different modes. Effects of solution conditions on the stability of the different complexes and the transitions among the binding modes in vitro are of particular interest. The binding of the SSB protein to ss nucleic acids in each of these binding modes will be characterized by determining the equilibrium binding parameters (affinity and positive cooperativity). These binding parameters will be obtained as a function of solution variables (salt concentration and type, temperature and pH) in order to understand the thermodynamic basis for the stability of each mode, as well

描述（改编自申请人摘要）：拟议的研究是 旨在获得对E. 具有单链（ss）核酸的大肠杆菌单链结合（SSB）蛋白 酸，使用热力学，动力学，生物化学和结构的方法。 SSB蛋白是一种螺旋不稳定蛋白， 并协同作用于ss核酸。 它是大肠杆菌的必需蛋白质。 大肠杆菌，这是DNA复制所必需的，并参与了各种各样的 重组和修复过程。 急诊大肠杆菌SSB四聚体具有 最近显示在许多不同的细胞中与SS核酸结合 模式，取决于溶液条件，每种模式具有不同的位点 尺寸. 这在一定程度上反映了不同程度的DNA包裹 四聚体。 它还与至少两个 四聚体之间存在不同类型的正协同性，但它不是 明确SSB蛋白使用这些模式或协同作用中的哪一种， 它的各种功能。 申请人的意图是理解 SSB蛋白的性质和复合物的结构， 不同的模式。 溶液条件对稳定性的影响 不同的复合物和体外结合模式之间的转换 特别令人感兴趣。 SSB蛋白与ss核酸的结合 这些结合模式中的每一种中的酸将通过确定 平衡结合参数（亲和力和正协同性）。 这些结合参数将作为解的函数得到 变量（盐浓度和类型、温度和pH值），以便 理解每种模式稳定性的热力学基础，以及