SITE-SPECIFIC ENERGETICS OF PROTEIN-DNA INTERACTIONS

这项研究计划的目标是阐明 通过相互作用介导的遗传控制过程的机制 蛋白质在DNA上的特定位置。 方案的组成部分 包括：（a）开发新技术，用于研究场址- 特异性蛋白质-DNA相互作用，（B）关于 偶联单个位点结合反应的热力学 多位点基因控制系统，（c） 特定基因控制系统中的功能能量学，（d） 能量性质与结构特征的相关性 （e）开发和测试 基因控制系统的物理化学模型。 我们计划扩展我们之前对阻遏物操纵基因的研究 噬菌体λ的控制系统，这是一个原型， 协作多位点基因控制系统的大家族。 使用定量DNA酶足迹滴定技术， 最近发展，我们将进行详细的研究， 温度、pH值和离子相互作用对网站的影响- cI和cro的比能（包括协同效应） 阻遏物与DNA操纵子位点的结合。结果将 为质子结合的详细作用提供了新的见解， 阳离子结合，以及各种非共价力 监管互动。 我们将研究合作互动的生物学作用 通过体内和体外研究， 的突变阻遏物，改变了协同性，使用 基因控制的物理化学模型。 我们还计划进一步发展理论和技术， 理解位点特异性蛋白质-DNA相互作用。

The goal of this research program is to elucidate the physical mechanism of genetic control processes mediated by the interactions of proteins at specific sites on DNA. Components of the program include: (a) development of new techniques for the study of site- specific protein-DNA interactions, (b) theoretical work on the thermodynamic of coupled individual-site binding reactions in multi-site gene control systems, (c) experimental studies of functional energetics in specific gene control systems, (d) correlation of the energetic properties with structural features of the interacting molecules, (e) development and testing of physical-chemical models for gene control systems. We plan to extend our previous studies on the repressor-operator control system of bacteriophage lambda, which is a prototype for a large family of cooperative multi-site gene control systems. Using the Quantitative DNase Footprint Titration technique that we have recently developed, we will carry out a detailed study of the effects of temperature, pH, and ionic interactions on the site- specific energetics (including cooperativity effects) of cI and cro repressor binding to the DNA operator sites. The results will provide new insights into the detailed roles of proton binding, cation binding, and the various non-covalent forces responsible for the regulatory interactions. We will study the biological role of cooperative interactions between operator-bound repressors by in vivo and in vitro studies of mutant repressors that have altered cooperativity, using a physical-chemical model of gene control. We also plan further development of theory and techniques for understanding site-specific protein-DNA interactions.