Targeting Trypanosoma brucei S-adenosylmethionine decarboxylase in Drug Discovery

药物发现中的靶向布氏锥虫 S-腺苷甲硫氨酸脱羧酶

• 批准号: 8225263
• 负责人: Nahir Velez
• 金额: $ 2.96万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-03-01 至 2013-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8225263
• 关键词: Adenosylmethionine Decarboxylase; Affinity; Africa; Africa South of the Sahara; African Trypanosomiasis; Alanine; Allosteric Regulation; Amino Acids; Blood; Cations; Cell physiology; Cells; Complex; DL-alpha-Difluoromethylornithine; Data; Decarboxylation; Development; Disease; Enzymes; Future; Genetic Transcription; Glutathione; Goals; Health; Homologous Gene; Human; Insecta; Kinetics; Lead; Left; Leishmania donovani; Libraries; Maintenance; Metabolic Pathway; Mutagenesis; N-terminal; Ornithine Decarboxylase; Parasites; Parasitic Diseases; Pathway interactions; Patients; Pharmaceutical Preparations; Pharmacotherapy; Play; Polyamines; Production; Proteins; Protozoa; Putrescine; Resistance; Role; S-Adenosylmethionine; Scanning; Spermidine; Sulfhydryl Compounds; Testing; Toxic effect; Translations; Trypanosoma; Trypanosoma brucei brucei; Trypanosoma cruzi; Trypanosomiasis; Tsetse Flies; Work; carbanion; cell growth; chemical genetics; chemotherapeutic agent; chemotherapy; cofactor; decarboxylase inhibitor; drug development; drug discovery; high throughput screening; in vivo; inhibitor/antagonist; insight; mutant; novel; research study; small molecule; small molecule libraries; species difference; suicide inhibitor; tool development; trypanothione

DESCRIPTION (provided by applicant): Human African Trypanosomiasis (HAT), commonly called sleeping sickness, is caused by single-celled parasites, Trypanosoma brucei, which are transmitted to humans by infected tsetse flies. Trypanosomiasis has a profound impact on the health of a large number of people in sub-Saharan Africa. It is fatal if left untreated and current drug therapy is problematic because of toxicity and emerging resistance. The polyamine biosynthetic pathway is a validated target for the development of drugs against HAT and the emerging evidence provides a compelling case that S-adenosylmethionine decarboxylase (AdoMetDC) is a highly promising target for the development of new anti-trypanosomal agents. AdoMetDC catalyses the ratelimiting step in the production of the polyamine spermidine from putrescine. Mammalian AdoMetDC is a homodimer that uses a pyruvoyl group as a cofactor to stabilize the carbanion intermediate formed during the decarboxylation of AdoMet. Recently, our lab demonstrated that the trypanosomatid AdoMetDC is regulated by a unique mechanism, heterodimer formation with a catalytically dead AdoMetDC homolog. This protein, designated prozyme, forms a high-affinity heterodimer with AdoMetDC and increases its activity by >1,000-fold. Further we confirmed that the heterodimer is the functional enzyme in vivo. My primary goals are to elucidate the mechanisms that regulate the AdoMetDC activation by the prozyme and to identify and characterize novel AdoMetDC inhibitors essential for the development of new anti-trypanosomal drugs. In order to do that, I will first focus on the identification of crucial amino acid residues involved in the activation in an attempt to gain insights into the mechanism of allosteric regulation. Next I will characterize species differences in the activation of AdoMetDC by prozyme by comparing the T. brucei AdoMetDC/prozyme complex to the homologs from T. cruzi and L. donovani. Finally I will perform a high-throughput screen (HTS) of a small molecule compound library to identify novel inhibitors of T. brucei AdoMetDC and to test these for activity against cultured parasites. Upon completion of these studies I will have identified and validated a number of novel inhibitors of AdoMetDC for future lead optimization studies that may lead to the discovery of new, less toxic drugs for the treatment of HAT. Project Narrative: Human African Trypanosomiasis is a insect borne disease that is fatal if untreated, yet current drug therapies are toxic and difficult to administer. The work described in this proposal characterizes an essential enzyme that has unique features in the parasite, with the goal of developing new chemotherapeutic agents against this devastating disease.

描述（由申请方提供）：非洲人锥虫病（HAT），通常称为昏睡病，由单细胞寄生虫布氏锥虫引起，通过受感染的采采蝇传播给人类。锥虫病对撒哈拉以南非洲许多人的健康产生深远影响。如果不及时治疗是致命的，目前的药物治疗是有问题的，因为毒性和新出现的耐药性。多胺生物合成途径是开发抗HAT药物的有效靶点，新出现的证据提供了一个令人信服的案例，即S-腺苷甲硫氨酸脱羧酶（S-adenosylmethionine decarboxylase，S-MetDC）是开发新的抗锥虫药物的非常有前途的靶点。在从腐胺生产多胺亚精胺的过程中，DIMetDC催化限速步骤。哺乳动物的α-MetDC是一种同源二聚体，其使用α-乙酰基作为辅因子来稳定α-Met脱羧过程中形成的碳负离子中间体。最近，我们的实验室证明，锥虫MetDC是 由独特的机制调节，异二聚体形成与催化死亡的MetDC同源物。这种蛋白质，称为prozyme，与cDNAMetDC形成高亲和力的异源二聚体，并使其活性增加> 1，000倍。进一步证实了异源二聚体是体内的功能酶。我的主要目标是阐明的机制，调节cDNAMetDC激活的prozyme，并确定和表征新的cDNAMetDC抑制剂的开发新的抗锥虫药物必不可少的。为了做到这一点，我将首先专注于识别参与激活的关键氨基酸残基，试图深入了解变构调节的机制。接下来，我将通过比较T.布氏杆菌MetDC/prozyme复合物与T. cruzi和L. donovani。最后，我将进行高通量筛选（HTS）的小分子化合物库，以确定新的T。布鲁氏菌感染MetDC，并测试这些抗培养寄生虫的活性。在完成这些研究后，我将确定并验证一些新的HAT MetDC抑制剂，用于未来的铅优化研究，可能会发现新的，毒性较小的药物用于治疗HAT。项目叙述：人类非洲锥虫病是一种昆虫传播的疾病，如果不治疗是致命的，但目前的药物治疗是有毒的，难以管理。本提案中描述的工作描述了一种在寄生虫中具有独特功能的必需酶，其目标是开发针对这种毁灭性疾病的新化疗药物。