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: 7236066
• 负责人: STEPHEN W WHITE
• 金额: $ 58.9万
• 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/7236066
• 关键词: 4-Aminobenzoic Acid; Acids; Active Sites; Affinity; Amino Acids; Animals; Anti-Bacterial Agents; Anti-Infective Agents; Antibiotics; Arts; Bacillus anthracis; Binding; Binding Sites; Biochemistry; Biological Warfare; Candida albicans; Catalysis; Categories; Class; Collaborations; Computational Biology; Computer software; Data; Development; Dihydropteroate Synthase; Diphosphates; Disease; Drug Design; Drug resistance; Enzymes; Escherichia coli; Evaluation; Folate; Folate Biosynthesis Pathway; Folic Acid Antagonists; Francisella tularensis; Funding; Genes; Genomics; Goals; Immunocompromised Host; Individual; Infection; Institution; Laboratories; Libraries; Ligands; Locales; Methods; Microbiology; Modeling; Molecular; Molecular Conformation; Mutation; Mycobacterium tuberculosis; Numbers; Organism; Orthologous Gene; Pathway interactions; Pharmaceutical Chemistry; Pharmaceutical Preparations; Proteins; Protozoa; Protozoan Infections; Pseudomonas aeruginosa; Pterins; Quantitative Structure-Activity Relationship; Rate; Research; Research Personnel; Resistance; Role; Salmonella; Screening procedure; Serum; Site; Site-Directed Mutagenesis; Solid; Specificity; Staphylococcus aureus; Streptococcus pneumoniae; Structure; Sulfonamides; Techniques; Testing; Therapeutic; Therapeutic Agents; X-Ray Crystallography; Yersinia pestis; analog; antimicrobial; bacterial resistance; base; biodefense; chemical synthesis; cytotoxicity; design; dihydropteroate; drug discovery; enzyme mechanism; fungus; high throughput screening; in vivo; inhibitor/antagonist; insight; interest; mecarzole; methicillin resistant Staphylococcus aureus; microorganism; molecular dynamics; novel; novel therapeutics; programs; scaffold; small molecule; structural biology; text searching; virtual

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）：叶酸生物合成是高等动物缺乏的重要细菌途径，70多年来一直是抗菌药物的有效靶点。磺胺类药物通过作为氨基苯甲酸（pABA）的非生产性底物类似物来抑制该途径中的关键酶——二氢蝶呤合成酶（DHPS）。然而，柔性pABA结合位点在结构上易受耐药突变的影响，磺胺类药物在治疗上迅速失效。相比之下，第二种DHPS底物pterin-焦磷酸的结合位点被埋在一个保守的口袋中，不太可能耐受突变。我们建议产生新的有效的DHPS抑制剂，专门参与这个口袋。这些抑制剂有潜力被开发成新的治疗药物，仍然针对叶酸合成，但避免了耐药性的问题。为了产生有效的酶抑制剂，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不存在于DHPS中，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。