Structural Analysis of Bacterial Quorum Sensing Proteins

描述（由申请人提供）： 细菌种群通过密度控制过程（称为群体感应）进行广泛的协调变化。最近发现的种间群体感应途径控制着许多细菌的关键代谢途径，因此是一个有前途的抗菌治疗靶点。该途径由自身诱导物-2（AI 2）介导。AI 2与周质受体蛋白LuxP结合，通过刺激细胞密度依赖性转录的传感器激酶LuxQ触发去磷酸化级联反应。该建议的总体目标是通过详细描述LuxP和LuxQ的相互作用机制来阐明AI 2信号转导的调节。 这项建议的具体目标是：（1）解析LuxP-LuxQ蛋白质复合物的晶体结构以阐明LuxP对LuxQ信号传导的调节，（2）使用生物化学和哈氏弧菌生物发光测定来确定在蛋白质复合物晶体结构中观察到的特异性LuxP-LuxQ相互作用的意义，和（3）进行生物化学和结构研究以确定Al 2类似物的作用机制，以便迭代地改进类似物以及阐明Al 2配体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.