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）：叶酸的生物合成是一种必不可少的细菌途径，在高等动物中不存在，它一直是抗菌剂的有效靶标，已有70多年的历史了。磺酰胺药物通过充当帕氨苯甲酸（PABA）的非生产性底物类似物来抑制途径中的关键酶，即二氢蛋白酶合酶（DHPS）。但是，柔性PABA结合位点在结构上易受耐药突变，磺酰胺在治疗上迅速变得无效。相比之下，第二DHPS底物（ptherin-磷酸盐）的结合位点被埋在保守的口袋中，该袋耐受突变的可能性较小。我们建议生成新的有效DHP抑制剂，这些抑制剂专门接合该口袋。这些抑制剂的潜力可能被发展成新型的治疗剂，这些治疗剂仍靶向叶酸合成，但避免了抗性问题。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。 DHP在很大程度上不存在此信息，并且了解DHP在分子水平上的催化作用将是应用的核心目标。 这个全面的项目将涵盖生物​​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中进行。该项目的主要重点是新型小分子的设计和合成，这些分子可用于探测DHPS机制，也可以评估为DHPS抑制剂。然后，将通过直接筛选某些生物体来测试有希望的抑制剂支架作为抗微生物的潜力。更有效的抑制剂将用于创建衍生文库，以进行进一步筛选和评估。该研究的主要特征是使用最先进的药物发现软件，图书馆合成，高通量筛选和X射线晶体学的使用。我们的目标是为开发新的，迫切需要的，广谱的反感染者提供坚实的平台。但是，我们还专注于为生物果剂的类别开发特定的疗法。