Structural Analysis of Bacterial Quorum Sensing Proteins

描述(由申请人提供)： 细菌种群通过一种称为群体感应的密度控制过程经历广泛的协调变化。最近发现的种间群体感应途径控制着许多细菌中的关键代谢途径，因此是抗菌治疗的一个有希望的靶点。该途径由自身诱导物-2(AI2)介导。AI2与周质受体蛋白LuxP结合，通过感受器蛋白LuxQ触发去磷酸化级联反应，刺激细胞密度依赖的转录。这一建议的总体目标是通过详细描述LuxP和LuxQ的相互作用来阐明AI2信号转导的调控。 这一建议的具体目的是：(1)解决LuxP-LuxQ蛋白复合体的晶体结构，以阐明LuxP对LuxQ信号的调节；(2)利用生化和哈维氏弧菌生物发光分析，确定在蛋白质复合体晶体结构中观察到的特定LuxP-LuxQ相互作用的意义；(3)进行生化和结构研究，以确定AI2类似物的作用机制，以便反复改进类似物，并阐明AI2配体和基团对结合能的贡献。

DESCRIPTION (provided by applicant): Bacterial populations undergo a wide range of coordinated changes via a density-controlled process termed quorum sensing. A recently-discovered interspecies quorum-sensing pathway controls critical metabolic pathways in many bacteria and is therefore a promising target for antimicrobial therapies. This pathway is mediated by autoinducer-2 (AI2). AI2 binds to the periplasmic receptor protein LuxP triggering a dephosphorylation cascade through the sensor kinase LuxQ that stimulates cell-density-dependent transcription. The overall goal of this proposal is to elucidate the regulation of AI2 signal transduction by describing the interaction of LuxP and LuxQ in mechanistic detail. The specific aims of this proposal are to: (1) solve the crystal structures of LuxP-LuxQ protein complexes to elucidate the regulation of LuxQ signaling by LuxP, (2) use biochemical and Vibrio harveyi bioluminescence assays to determine the significance of specific LuxP-LuxQ interactions observed in the protein complex crystal structure, and (3) perform biochemical and structural studies to determine the mechanism of action of AI2 analogs in order to iteratively improve the analogs as well as elucidate the contributions of AI2 ligand groups to the binding energy.