Novel Inhibitors to DHPS to Probe Catalytic Mechanism & Therapeutic Potential - r

新型 DHPS 抑制剂探索催化机制

• 批准号: 8679998
• 负责人: Richard E. Lee
• 金额: $ 38.72万
• 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 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8679998
• 关键词: 4-Aminobenzoic Acid; 6-hydroxymethyl-7,8-dihydropterin; Active Sites; Amino Acids; Animals; Anions; Anti-Bacterial Agents; Anti-Infective Agents; Bacillus anthracis; Bacteria; Binding; Binding Sites; Biochemistry; Biological Assay; Biology; Calorimetry; Catalysis; Chemicals; Clinical; Communicable Diseases; Communities; Complex; Computational Biology; Crystallography; Data; Development; Diet; Dihydropteroate Synthase; Diphosphates; Disease; Drug Design; Drug effect disorder; Drug resistance; Ensure; Enzymatic Biochemistry; Enzymes; Folate; Folate Biosynthesis Pathway; Francisella tularensis; Funding; Future; Goals; Immune; Individual; Infection; Joints; Kinetics; Lead; Mammals; Measures; Microbiology; Molecular; Mutation; Organism; Pathway interactions; Patients; Pattern; Pharmaceutical Chemistry; Pharmaceutical Preparations; Pneumocystis; Principal Investigator; Pterins; Publishing; Reaction; Resistance; Resistance development; Role; Series; Site; Site-Directed Mutagenesis; Staphylococcus aureus; Structure; Sulfonamides; Techniques; Testing; Therapeutic; Therapeutic Agents; Thermodynamics; Time; X-Ray Crystallography; Yersinia pestis; analog; antimicrobial; antimicrobial drug; base; chemical synthesis; clinically significant; design; dihydropteroate; drug discovery; enzyme mechanism; feeding; flexibility; fungus; in vivo; inhibitor/antagonist; insight; methicillin resistant Staphylococcus aureus; microbial; mutant; novel; novel therapeutics; pathogen; resistance mutation; scaffold; screening; structural biology; success; sulfa drug; unpublished works

DESCRIPTION (provided by applicant): Folate biosynthesis is an essential bacterial pathway that is absent in higher animals, and it has been a target of antibacterial agents for over 70 years. Sulfa drugs inhibit the enzyme dihydropteroate synthase (DHPS) in the pathway by acting as non-productive substrate analogs of p-aminobenzoic acid (pABA). However, the flexible pABA binding site is structurally susceptible to resistance mutations, and the sulfa drugs 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 can potentially be 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 proposal. Another goal will be to understand the molecular and functional basis of sulfa drug resistance to avoid this problem in our future drug designs. This comprehensive approach will require the joint expertise of the two principal investigators in structural biology, medicinal chemistry, biochemistry, computational biology and microbiology. The project will also incorporate the relatively new technique of fragment based drug discovery to identify novel small inhibitory chemical scaffolds that can readily be elaborated by chemical synthesis. Exciting new data described in the application provide strong support that the project can realize its ultimate goal which is to rapidly develop new antimicrobials that minimize the emergence of drug resistance. Although we aim to develop broad-spectrum anti-infective agents, our microbiological screening will focus on S. aureus and P. jirovecii that have emerged as particularly problematical infectious disease agents in the U.S. in recent years.

描述（由申请人提供）：叶酸生物合成是高等动物中不存在的重要细菌途径，并且 70 多年来它一直是抗菌剂的目标。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二氢蝶酸合酶 (DHPS)。然而，灵活的 pABA 结合位点在结构上容易受到耐药性突变的影响，磺胺类药物很快就会变得无效。相比之下，第二种 DHPS 底物蝶呤焦磷酸的结合位点被埋在一个保守的口袋中，该口袋不太可能容忍突变。我们建议开发新一类有效的 DHPS 抑制剂，专门针对这个口袋。这些抑制剂有可能被开发成新型治疗剂，其仍然以叶酸合成为目标，但避免了耐药性问题。 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。 DHPS 基本上缺乏这些信息，了解 DHPS 如何在分子水平上发挥催化作用将是该提案的中心目标。另一个目标是了解磺胺类药物耐药性的分子和功能基础，以避免我们未来的药物设计中出现这个问题。这种综合方法需要两位主要研究人员在结构生物学、药物化学、生物化学、计算生物学和微生物学方面的共同专业知识。该项目还将采用相对较新的基于片段的药物发现技术，以确定可以通过化学合成轻松制作的新型小型抑制性化学支架。申请中描述的令人兴奋的新数据为该项目能够实现其最终目标提供了强有力的支持，即快速开发新的抗菌药物，最大限度地减少耐药性的出现。尽管我们的目标是开发广谱抗感染药物，但我们的微生物筛查将重点关注金黄色葡萄球菌和耶氏疟原虫，它们近年来在美国已成为特别有问题的传染病病原体。