Structure and Function of Response Regulator Proteins

项目总结：细菌中的信号转导系统为偶联提供了分子基础 将环境信号转化为适当的适应性反应。中最流行的信令策略之一 细菌是两种保守的蛋白质之间的一条磷酸转移途径，这两种蛋白质是组氨酸蛋白激酶和 响应调节器。这些路径被称为双组分系统，在&gt；9000系统中广泛存在 到目前为止，在-300个已测序的细菌基因组中确认了这一点。这个项目的重点是描述 反应调节器，作为磷酸化激活的开关来控制输出的蛋白质 系统的响应。OmpR/Phob反应调节子亚家族，以有翼的- Helix DMA结合结构域，占所有反应调节因子的三分之一和一半 调节转录因子。最近已经证实，OmpR/Phob反应调节因子在其 非活性状态显示其同源结构域的不同排列，但在磷酸化后采用 一种常见的二聚体活性状态，由保守的分子表面介导。这个项目的一个主要目标是 用FRET监测OmpR/Phob蛋白同源和异源二聚的亲和力 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二聚化， 提供了一种在单个单元内集成不同的双组分系统的机制。第二个目标是 确定非活性OmpR/Phob蛋白中不同结构域排列的机制 调节它们向主动状态的转变。第三个目标是描述转录的复杂性。 大肠杆菌OmpR/Phob反应调节子在基因组水平上的调控使用结构、 ChlP-on-Chip和生物信息学分析。其他研究将集中在结构和功能上。 OmpR/Phob和LytTR反应调节子的蛋白质-DNA相互作用的特征。 相关性：除了它们对自然环境中的基本竞争力的重要性外，还有两个- 当病原菌(如细菌)致病时，组分信号系统通常对毒力至关重要。 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， 了解信号通路及其蛋白质组分的分子细节提供了 抗菌药物开发基金会。

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.