SIGNAL TRANSDUCTION OF TWO-COMPONENT SYSTEM

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 对于细菌来说，感知和适应环境变化和压力的能力对于持久性和生存至关重要。双组分系统（Two-component system，TCS）是细菌、真菌和某些植物感知外界或内部信号并通过基因表达调控做出适当反应的基本机制。TCS在许多致病性大肠杆菌的发病机制和/或抗生素耐药性中起关键作用。 微生物的典型的TCS由两种蛋白质组成：监测环境信号的多结构域、多功能传感器组氨酸激酶（HK），和通过磷酸转移反应接收来自传感器激酶的信号并通过例如，调节某些基因的表达。TCS信号转导的分子机制仍然知之甚少。本研究以枯草芽孢杆菌YycFG为模型，在高分辨率下研究TCS信号转导的分子基础。YycFG是一种必需的TCS，对葡萄球菌、链球菌和肠球菌等低G+C革兰氏阳性菌具有特异性，这些细菌是人类感染的主要病原体，可引起肺炎、脑膜炎、心内膜炎和菌血症等疾病。其中一些病原体，如炭疽杆菌和肉毒梭菌，被列为潜在的生物恐怖剂。我们力求：（i）通过确定YycG的截短形式的结构，以高分辨率探索YycG的结构域组织，（ii）定义YycF的三维结构，以及（iii）研究对于磷酸转移至关重要的YycG和YycF之间的分子相互作用。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. For bacteria, the ability to sense and adapt to environmental change and stress is crucial to persistence and survival. Two-component system (TCS) is a fundamental mechanism utilized by bacteria as well as fungi and some plants to sense external or internal signals and make appropriate responses through regulation of gene expression. TCSs play pivotal roles in pathogenesis and/or antibiotic resistance in many pathogenic microorganisms. A paradigmatic TCS consists of two proteins: a multi-domain, multi-function sensor histidine kinase (HK) that monitors environmental signals, and a response regulator (RR) that receives the signal from the sensor kinase through phosphotransfer reactions and trigger downstream responses through, e.g., regulation of expression of certain genes. Molecular mechanisms underlying TCS signal transduction remain poorly understood. The proposed research is aimed at molecular basis of TCS signal transduction at high resolution, using the YycFG of Bacillus subtilis as a model. YycFG is an essential TCS and is specific to low G+C Gram-positive bacteria such as Staphylococcus, Streptococcus and Enterococcus, which are leading causative agents of human infections and cause diseases ranging from pneumonia to meningitis, endocarditis and bacteremia. Some of these pathogens, such as Bacillus anthracis and Clostridium botulinum, are classified as potential bioterror agents. We seek to: (i) explore the domain organization of YycG at high resolution by determination of the structure of a truncated form of YycG, (ii) define the three-dimensional architecture of YycF, and (iii) investigate the molecular interactions between YycG and YycF that are critical for phosphotransfer.