Molecular Basis for Inhibition of Edema Factor

抑制水肿因子的分子基础

• 批准号: 6849728
• 负责人: Alex ANDREW BOHM
• 金额: $ 20.85万
• 依托单位: TUFTS UNIVERSITY BOSTON
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-03-01 至 2006-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6849728
• 关键词: Bacillus anthracis; anthrax toxin; antibacterial agents; bioterrorism /chemical warfare; calmodulin; combinatorial chemistry; drug discovery /isolation; fluorescence resonance energy transfer; high throughput technology; method development; protein binding; small molecule

DESCRIPTION (provided by applicant): The objective of this project is to find small molecule inhibitors of the anthrax protein Edema Factor (EF). This toxin is secreted by Bacillus anthracis in a catalytically inactive state. When the toxin is transported into the cellular cytoplasm of anthrax victims by the anthrax-derived transporter, Protective Antigen, it forms a complex with calmodulin (CAM) - the key intracellular calcium-binding protein in vertebrates. This association activates EF, and converts it into an adenylyl cyclase with 1000 times greater catalytic activity than the victim's own cyclic AMP-producing enzymes. Conventional anthrax therapies (which target the anthrax bacterium, not the anthrax toxins) are highly effective, but are insufficient to save all anthrax victims. EF inhibitors represent a completely distinct, and wholly complementary approach to combating anthrax. Such inhibitors will, by treating the downstream effects of the disease, help restore cellular equilibrium, and are likely to slow the course disease. By allowing more time for conventional treatments and the immune system to work, these inhibitors may significantly increase anthrax survival rates. We have solved crystal structures of EF (the inactive state) and the EF/CaM complex (the active state). Using these structures as a guide, and in close consultation with pharmaceutical researchers, we will use structure-based, computational drug discovery methods to identify small molecules representing two distinct types of EF inhibitors; Type A, inhibitors that occlude the active site, and Type B, those that maintain EF in its CAM-free, catalytically inactive state. We already have assays for inhibitors of Type A. We will complete the development of a simple assay for inhibitors of Type B, and then apply these assays to the top approximately 1000 compounds suggested by our computational drug screens. We will also determine the crystal structures of EF in complex with those small molecules identified by this screening procedure, so that the pharmaceutical properties of these inhibitors may be improved through rational drug design methods.

描述（由申请人提供）：该项目的目的是寻找炭疽蛋白水肿因子（EF）的小分子抑制剂。这种毒素是由炭疽杆菌在催化失活状态下分泌的。当毒素被炭疽衍生的转运蛋白保护性抗原转运到炭疽受害者的细胞质中时，它与钙调蛋白（CAM）形成复合物，钙调蛋白是脊椎动物中关键的细胞内钙结合蛋白。这种关联会激活 EF，并将其转化为腺苷酸环化酶，其催化活性比受害者自身产生环 AMP 的酶高 1000 倍。传统的炭疽疗法（针对炭疽细菌，而不是炭疽毒素）非常有效，但不足以拯救所有炭疽受害者。 EF 抑制剂代表了一种完全独特且完全互补的对抗炭疽病的方法。此类抑制剂将通过治疗疾病的下游影响，帮助恢复细胞平衡，并可能减缓疾病的进程。通过让传统治疗和免疫系统有更多的时间发挥作用，这些抑制剂可能会显着提高炭疽的存活率。 我们已经解析了 EF（非活性状态）和 EF/CaM 复合物（活性状态）的晶体结构。以这些结构为指导，并与药物研究人员密切协商，我们将使用基于结构的计算药物发现方法来识别代表两种不同类型 EF 抑制剂的小分子； A 型是封闭活性位点的抑制剂，B 型是维持 EF 处于无 CAM、催化失活状态的抑制剂。我们已经对 A 型抑制剂进行了测定。我们将完成对 B 型抑制剂的简单测定的开发，然后将这些测定应用于我们的计算药物筛选建议的前约 1000 种化合物。我们还将确定EF与通过该筛选程序鉴定的小分子复合物的晶体结构，以便通过合理的药物设计方法改善这些抑制剂的药物特性。