Structure and Function of Response Regulator Proteins

项目概述：细菌中的信号转导系统为偶联提供分子基础 环境信号，以适当的适应性反应。其中一个最普遍的信号策略， 细菌是两个保守蛋白质之间的磷酸转移途径，组氨酸蛋白激酶和 响应调节器这些途径称为双组分系统，分布广泛，有9000多个系统 迄今为止在约300个测序的细菌基因组中鉴定出。该项目的重点是表征 反应调节剂，作为磷酸化激活开关来控制输出的蛋白质 系统的反应。OmpR/PhoB反应调节子家族，以有翼的- 螺旋DNA结合结构域，占所有反应调节因子的三分之一，占所有反应调节因子的一半。 调节转录因子最近已经确定，OmpR/PhoB反应调节剂在其 非活性状态显示其同源结构域的不同排列，但在磷酸化后， 由保守分子表面介导的常见二聚体活性状态。该项目的主要目的是 使用FRET测量OmpR/PhoB蛋白的同源和异源二聚化的亲和力以监测 体外和体内的相互作用以确定共同的活性状态是否允许异源二聚化， 提供了一种用于在单个电池内集成不同的双组分系统的机制。第二个目标是 以确定失活OmpR/PhoB蛋白中不同结构域排列的机制， 调节它们向活跃状态的转变。第三个目标是描述转录的复杂性， 调节E. coli OmpR/PhoB应答调节剂在基因组规模上使用结构， ChIP芯片和生物信息学分析。其他研究将侧重于结构和功能 OmpR/PhoB和LytTR反应调节剂的蛋白质-DNA相互作用的表征。 相关性：除了对自然环境中的基本竞争力的重要性外， 当病原菌（例如， 结核分枝杆菌、金黄色葡萄球菌、肠道沙门氏菌）感染宿主。因此，我们认为， 了解信号通路及其蛋白质组分的分子细节， 为抗菌药物的开发奠定了基础。

Project Summary: Signal transduction systems in bacteria provide the molecular basis for coupling environmental signals to appropriate adaptive responses. One of the most prevalent signaling strategies in bacteria is a phosphotransfer pathway between two-conserved proteins, a histidine protein kinase and a response regulator. These pathways, termed two-component systems, are widespread, with >9000 systems identified in -300 sequenced bacterial genomes to date. This project focuses on characterization of response regulators, proteins which function as phosphorylation-activated switches to control output responses of the systems. The OmpR/PhoB subfamily of response regulators, distinguished by a winged- helix DMA-binding domain, accounts for -one third of all response regulators and -half of all response regulator transcription factors. It has been recently established that OmpR/PhoB response regulators in their inactive states display different arrangements of their homologous domains, but upon phosphorylation adopt a common dimeric active state mediated by a conserved molecular surface. A primary aim of this project is to measure affinities for homo- and heterodimerization of OmpR/PhoB proteins using FRET to monitor interactions in vitro and in vivo to determine whether the common active state allows heterodimerization, providing a mechanism for integrating different two-component systems within a single cell. A second aim is to determine mechanisms through which different domain arrangements in inactive OmpR/PhoB proteins regulate their transition to an active state. A third aim is to characterize the complexity of transcriptional regulation by E. coli OmpR/PhoB response regulators on a genomic scale using a combination of structural, ChlP-on-chip, and bioinformatics analyses. Additional studies will focus on structural and functional characterization of protein-DNA interactions of OmpR/PhoB and LytTR response regulators. Relevance: In addition to their importance for basic competitiveness in natural environments, two- component signaling systems are often essential for virulence when pathogenic bacteria (e.g. Mycobacterium tuberculosis, Staphylococcus aureus, Salmonella enterica) infect their hosts. Hence, understanding the molecular details of signaling pathways and their protein components provides a foundation for the development of antimicrobial drugs.