HOLOLUXP:LUXQ

全息图：LUXQ

• 批准号: 7957300
• 负责人: Matthew B Neiditch
• 金额: $ 0.48万
• 依托单位: BROOKHAVEN SCIENCE ASSOC-BROOKHAVEN LAB
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2010-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7957300
• 关键词: Anti-Bacterial Agents; Antibiotics; Bacteria; Binding; Bioluminescence; Cell Density; Communication; Complex; Computer Retrieval of Information on Scientific Projects Database; Crystallography; Cytoplasm; DNA; Development; Environment; Funding; Gene Expression; Grant; Institution; Ligand Binding; Light; Marines; Mediating; Membrane; Microbial Biofilms; Mind; Monitor; Mutation; Phosphoric Monoester Hydrolases; Phosphotransferases; Population; Process; Production; Regulation; Research; Research Personnel; Resistance; Resources; Signal Transduction; Signaling Molecule; Source; Structure; Synchrotrons; United States National Institutes of Health; VAI-2; Vibrio; Virulence Factors; antimicrobial; density; design; extracellular; periplasm; quorum sensing; receptor; response; sensor

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. The extracellular signal molecule autoinducer-2 (AI-2) mediates quorum sensing communication in diverse bacterial species. In marine vibrios, binding of AI-2 to the periplasmic receptor LuxP modulates the activity of the inner membrane sensor kinase LuxQ, transducing the AI-2 information into the cytoplasm. At low cell density, when LuxP is not bound to AI-2, LuxQ functions as a kinase, whereas at high cell density, when LuxP is bound to AI-2, LuxQ acts as a phosphatase. We have shown that Vibrio harveyi LuxP associates constitutively with LuxQ in both the presence and absence of AI-2. The 1.9 ¿¿¿ x-ray crystal structure of apoLuxP, complexed with the periplasmic domain of LuxQ, reveals that the latter contains two tandem PAS (Per/ARNT/Simple-minded) folds. Thus, although many prokaryotic PAS folds themselves bind ligands, the LuxQ periplasmic PAS folds instead bind LuxP, monitoring its AI-2 occupancy. Mutations that disrupt the apoLuxP:LuxQ interface sensitize V. harveyi to AI-2, implying that AI-2 binding causes the replacement of one set of LuxP:LuxQ contacts with another. These conformational changes switch LuxQ between two opposing enzymatic activities, each of which conveys information to the cytoplasm about the cell density of the surrounding environment. Comparison of the apo complex and holo complex (proposed here) structures will reveal AI-2-induced conformational changes, and therefore, the mechanism of AI-2 signaling regulation. Bacteria modulate gene expression in response to changes in cell density via a mechanism termed quorum sensing. This density-triggered response results in coordinated phenotypic changes within bacterial populations. Quorum sensing directs processes including virulence factor expression, biofilm development, bioluminescence, antibiotic production, and DNA exchange. Our studies will facilitate the rational design of broad-spectrum antibacterial compounds that interfere with quorum sensing. Discovery of such compounds is critical as bacteria increasingly become resistant to current antimicrobial therapies.

该子项目是利用该技术的众多研究子项目之一 资源由 NIH/NCRR 资助的中心拨款提供。子项目和 研究者 (PI) 可能已从 NIH 的另一个来源获得主要资金， 因此可以在其他 CRISP 条目中表示。列出的机构是 对于中心来说，它不一定是研究者的机构。 细胞外信号分子自诱导子 2 (AI-2) 介导不同细菌物种中的群体感应通讯。在海洋弧菌中，AI-2 与周质受体 LuxP 的结合调节内膜传感器激酶 LuxQ 的活性，将 AI-2 信息转导到细胞质中。在低细胞密度下，当LuxP未与AI-2结合时，LuxQ充当激酶，而在高细胞密度下，当LuxP与AI-2结合时，LuxQ充当磷酸酶。我们已经证明，在存在和不存在 AI-2 的情况下，哈维弧菌 LuxP 与 LuxQ 都具有组成型关联。 apoLuxP 的 1.9 英寸 X 射线晶体结构与 LuxQ 的周质结构域复合，揭示后者包含两个串联的 PAS（Per/ARNT/Simple-thought）折叠。因此，尽管许多原核 PAS 折叠本身结合配体，但 LuxQ 周质 PAS 折叠反而结合 LuxP，监测其 AI-2 占据。破坏 apoLuxP:LuxQ 界面的突变使哈维弧菌对 AI-2 敏感，这意味着 AI-2 的结合导致一组 LuxP:LuxQ 接触点被另一组取代。这些构象变化使 LuxQ 在两种相反的酶活性之间切换，每种酶活性都向细胞质传递有关周围环境细胞密度的信息。 比较 apo 复合体和 Holo 复合体（此处提出）结构将揭示 AI-2 诱导的构象变化，从而揭示 AI-2 信号传导调节的机制。 细菌通过一种称为群体感应的机制来响应细胞密度的变化来调节基因表达。 这种密度触发的反应导致细菌群体内协调的表型变化。 群体感应指导毒力因子表达、生物膜发育、生物发光、抗生素生产和 DNA 交换等过程。 我们的研究将有助于合理设计干扰群体感应的广谱抗菌化合物。 随着细菌对当前抗菌疗法的耐药性日益增强，此类化合物的发现至关重要。