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: 7615785
• 负责人: Nahir Velez
• 金额: $ 2.85万
• 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/7615785
• 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; 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（由申请人提供）：人类非洲锥虫病 (HAT)，通常称为昏睡病，是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地区大量人民的健康产生深远影响。如果不及时治疗，这是致命的，并且由于毒性和新出现的耐药性，目前的药物治疗存在问题。多胺生物合成途径是开发抗 HAT 药物的经过验证的靶点，新出现的证据提供了令人信服的证据，证明 S-腺苷甲硫氨酸脱羧酶 (AdoMetDC) 是开发新型抗锥虫药物的一个非常有前景的靶点。 AdoMetDC 催化从腐胺生产聚胺亚精胺的限速步骤。哺乳动物 AdoMetDC 是一种同二聚体，使用丙酮酰基作为辅助因子来稳定 AdoMet 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 AdoMetDC 是 受一种独特的机制调节，即与催化死亡的 AdoMetDC 同系物形成异二聚体。这种蛋白质被称为原酶，与 AdoMetDC 形成高亲和力异二聚体，并将其活性提高 1,000 倍以上。进一步我们证实异二聚体是体内的功能酶。我的主要目标是阐明原酶调节 AdoMetDC 激活的机制，并鉴定和表征对于开发新型抗锥虫药物至关重要的新型 AdoMetDC 抑制剂。为了做到这一点，我将首先重点关注参与激活的关键氨基酸残基的鉴定，试图深入了解变构调节的机制。接下来，我将通过比较 T. brucei AdoMetDC/prozyme 复合物与来自 T. cruzi 和 L. donovani 的同源物来表征 Prozyme 激活 AdoMetDC 的物种差异。最后，我将对小分子化合物库进行高通量筛选 (HTS)，以鉴定 T. brucei AdoMetDC 的新型抑制剂，并测试它们对培养寄生虫的活性。完成这些研究后，我将鉴定并验证许多新型 AdoMetDC 抑制剂，用于未来的先导优化研究，这可能会导致发现用于治疗 HAT 的新的、毒性较小的药物。项目叙述：非洲人类锥虫病是一种昆虫传播的疾病，如果不治疗的话会致命，但目前的药物疗法有毒且难以施用。该提案中描述的工作描述了一种在寄生虫中具有独特特征的必需酶，其目标是开发针对这种毁灭性疾病的新化疗药物。