STRUCTURAL AND FUNCTION STUDIES OF QUINOLONE SIGNALING IN PSEUDOMONAS AERUGINOSA

铜绿假单胞菌中喹诺酮信号传导的结构和功能研究

• 批准号: 8168050
• 负责人: Yong-Mei Zhang
• 金额: $ 29.2万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8168050
• 关键词: Accounting; Anabolism; Anti-Bacterial Agents; Biochemical; Chronic; Coenzyme A; Computer Retrieval of Information on Scientific Projects Database; Cystic Fibrosis; Data; Funding; Genes; Genetic; Goals; Grant; Infection; Institution; Lung; Molecular; Nosocomial Infections; Operon; Pathogenicity; Patients; Physical condensation; Production; Proteins; Pseudomonas; Pseudomonas aeruginosa; Quinolones; Reaction; Regulation; Research; Research Personnel; Resources; Role; Signal Transduction; Source; System; United States National Institutes of Health; Virulence; Virulence Factors; X-Ray Crystallography; extracellular; insight; mortality; mutant; novel; pathogen; protein function; protein structure function; quorum sensing; therapeutic development

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 goal of this research is to determine the molecular mechanisms that regulate the biosynthesis and signaling activity of the Pseudomonas quinolone signal (PQS). Opportunistic pathogen Pseudomonas aeruginosa causes chronic lung infections which are the major causes of mortality in patients suffering from cystic fibrosis. Moreover, P. aeruginosa is one of the most common nosocomial pathogens that accounts for 10% of all hospital-acquired infections. The pathogenicity of Pseudomonas is controlled by a set of extracellular molecules collectively known as the quorum sensing signals, which activate the production of extracellular virulence factors. Because of the essential roles of quorum sensing in the pathogenicity of P. aeruginosa, proteins involved in quorum-sensing have been recognized as targets for new antibacterial therapeutic development. Although the importance of PQS in Pseudomonas virulence is well established, some key steps in PQS biosynthesis are not characterized. Nor are the functions of PQS in the regulation of virulence fully understood. Genetic studies using P. aeruginosa mutant strains, which are defective in PQS signaling, have identified that proteins encoded by the pqs gene operon are required. Specifically, PqsA, PqsB, PqsC and PqsD are involved in PQS synthesis; whereas PqsE, which is the product of the last gene of the operon, is required for the PQS-dependent activation of the downstream virulence factors. However, there is very limited research on the functions of these proteins at the molecular level. We have preliminary data that PqsD catalyzes the formation of DHQ, a unacylated quinolone secreted by P. aeruginosa, by the Claisen condensation of malonyl-ACP (or CoA) with anthraniloyl-CoA. The aims of this proposal are: 1) to determine the exact order and reactions catalyzed by PqsB, PqsC and PqsD in the synthesis of PQS; 2) to determine the role(s) of PqsE in the PQS signaling network and Pseudomonas virulence. We propose to use integrated approaches to study the functions and structures of these proteins with biochemical analyses and X-ray crystallography. The findings of the proposed research will not only allow us to better understand the PQS quorum sensing system, but also provide novel insights on new targets for antibacterial discovery by the inhibition of virulence.

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。 本研究的目的是确定调节假单胞菌喹诺酮信号（PQS）的生物合成和信号活性的分子机制。 细菌病原体铜绿假单胞菌引起慢性肺部感染，这是患有囊性纤维化的患者死亡的主要原因。 此外，铜绿假单胞菌是最常见的医院病原体之一，占所有医院获得性感染的10%。 假单胞菌的致病性由一组统称为群体感应信号的细胞外分子控制，这些分子激活细胞外毒力因子的产生。 由于群体感应在铜绿假单胞菌致病性中的重要作用，参与群体感应的蛋白已被认为是新的抗菌治疗开发的靶点。 虽然PQS在假单胞菌毒力中的重要性已经得到很好的确立，但PQS生物合成中的一些关键步骤还没有被表征。 PQS在毒力调节中的功能也没有完全了解。使用PQS信号传导缺陷的铜绿假单胞菌突变株的遗传研究已经确定需要由pqs基因操纵子编码的蛋白质。 具体而言，PqsA、PqsB、PqsC和PqsD参与PQS合成;而PqsE是操纵子的最后一个基因的产物，是下游毒力因子的PQS依赖性激活所必需的。 然而，在分子水平上对这些蛋白质的功能的研究非常有限。 我们有初步的数据表明，PqsD通过丙二酰-ACP（或CoA）与邻氨基苯酰-CoA的克莱森缩合催化形成DHQ，DHQ是铜绿假单胞菌分泌的一种未酰化的喹诺酮。 本研究的目的是：1）确定PqsB、PqsC和PqsD在PQS合成中催化的确切顺序和反应; 2）确定PqsE在PQS信号网络和假单胞菌毒力中的作用。 我们建议使用综合的方法来研究这些蛋白质的功能和结构与生化分析和X射线晶体学。拟议研究的结果不仅使我们能够更好地了解PQS群体感应系统，而且还为通过抑制毒力发现抗菌新靶点提供了新的见解。