Novel Inhibitors to DHPS to Probe Catalytic Mechanism & Therapeutic Potential

新型 DHPS 抑制剂探索催化机制

• 批准号: 7132164
• 负责人: STEPHEN W WHITE
• 金额: $ 60.11万
• 依托单位: ST. JUDE CHILDREN'S RESEARCH HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-06-01 至 2011-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7132164
• 关键词: active sites; analog; antibiotics; binding sites; biochemistry; biosynthesis; bioterrorism /chemical warfare; conformation; drug discovery /isolation; enzyme mechanism; enzymes; folate; gene mutation; library; pteridines; pyrophosphates; structural biology; sulfonamides

DESCRIPTION (provided by applicant): Folate biosynthesis is an essential bacterial pathway that is absent in higher animals, and it has been an effective target of antibacterial agents for over 70 years. The sulfonamide drugs inhibit a key enzyme in the pathway, dihydropteroate synthase (DHPS), by acting as non-productive substrate analogs of paminobenzoic acid (pABA). However, the flexible pABA binding site is structurally susceptible to resistance mutations, and the sulfonamides are rapidly becoming therapeutically ineffective. In contrast, the binding site of the second DHPS substrate, pterin-pyrophosphate, is buried in a conserved pocket that is less likely to tolerate mutations. We propose to generate new classes of potent DHPS inhibitors that specifically engage this pocket. These inhibitors have the potential of being developed into novel therapeutic agents that still target folate synthesis but which avoid the problems of resistance. To generate effective inhibitors of any enzyme, it is crucial to understand the structure and mechanism of its active site. This information is largely absent for DHPS, and understanding how DHPS performs catalysis at the molecular level will be a central goal of the application. This comprehensive project will encompass biochemistry, structural biology, medicinal chemistry, computational biology, and microbiology, and will be performed in two laboratories at neighboring institutions in Memphis. The central focus of the project is the design and synthesis of novel small molecules that can be used to probe the DHPS mechanism and also be evaluated as DHPS inhibitors. Promising inhibitor scaffolds will then be tested for their potential as anti-microbials by direct screening of select organisms. The more potent inhibitors will be used to create derivative libraries for further screening and evaluation. The use of state-of-the-art drug discovery software, library synthesis, high-throughput screening and X-ray crystallography are central features of the research. Our goal is to provide a solid platform for the development of new, desperately-needed, broad-spectrum anti-infectives agents. However, we are also focused on developing specific therapies for the category A biowarfare agents B. anthracis, Y. pestis and F. tularensis, as well as for pathogenic protozoa and fungi.

描述（由申请人提供）：叶酸生物合成是一种基本的细菌途径，在高等动物中不存在，70多年来一直是抗菌剂的有效靶点。磺胺类药物通过充当对氨基苯甲酸（pABA）的非生产性底物类似物来抑制途径中的关键酶二氢蝶酸合酶（DHPS）。然而，柔性PABA结合位点在结构上易受耐药性突变的影响，并且磺胺类药物在治疗上迅速变得无效。相比之下，第二DHPS底物的结合位点，蝶呤-焦磷酸，被埋在一个保守的口袋，是不太可能容忍突变。我们建议产生新的有效的DHPS抑制剂，专门从事这个口袋。这些抑制剂有潜力被开发成新的治疗剂，仍然靶向叶酸合成，但避免了耐药性的问题。为了产生任何酶的有效抑制剂，了解其活性位点的结构和机制至关重要。这些信息在很大程度上是缺乏的DHPS，了解DHPS如何在分子水平上进行催化将是该应用程序的中心目标。 这个综合性的项目将包括生物化学，结构生物学，药物化学，计算生物学和微生物学，并将在孟菲斯邻近机构的两个实验室进行。该项目的重点是设计和合成新型小分子，可用于探测DHPS机制，也可作为DHPS抑制剂进行评估。有前途的抑制剂支架将通过直接筛选选定的生物体来测试其作为抗微生物剂的潜力。更有效的抑制剂将用于创建衍生物库，以进行进一步的筛选和评估。使用最先进的药物发现软件，库合成，高通量筛选和X射线晶体学是研究的中心特征。我们的目标是为开发新的、急需的、广谱的抗感染药物提供一个坚实的平台。然而，我们也专注于开发A类生物战剂B的特定疗法。anthracis，Y. pestis和F.土拉菌以及致病性原生动物和真菌。