Investigating the shikimate pathway in Plasmodium falciparum

描述(申请人提供)：寄生虫疟原虫是疟疾的病原体。在感染人类的疟原虫物种中，恶性疟原虫是最致命的，它占全球疟疾感染的大部分。不幸的是，这些感染的负担在非洲、南美洲和亚洲的贫穷和不发达国家尤为沉重。目前，只有少数代谢过程被证实为治疗疟疾的目标，而且越来越需要确定解决其他基本途径的药物。七步莽草酸途径是细菌和植物生产芳香族氨基酸、泛醌和叶酸所必需的。虽然莽草酸途径也被认为是顶端复合体(如恶性疟原虫)所必需的，但完整的途径不能在其基因组中确定。最近，一项生物信息学研究在恶性疟原虫中发现了两种预测的蛋白质，它们与莽草酸途径中的最后三种酶同源。尽管我们无法通过生物信息学分析确定该途径的其余部分，但有令人信服的证据表明，恶性疟原虫莽草酸途径是存在的，并且是一个可行的药物靶点。已知的针对植物中莽草酸途径酶的分子被发现抑制恶性疟原虫的生长。此外，预测的莽草酸途径酶的基因在恶性疟原虫生命周期的所有阶段都是转录活跃的。我们建议对恶性疟原虫中的莽草酸途径进行研究，主要目的如下：(1)对预测的恶性疟原虫莽草酸途径酶(莽草酸激酶、5-烯丙酮基-3-磷酸合成酶和分支酸合成酶)进行生化特征分析。(2)通过遗传互补筛选和代谢产物分析，鉴定恶性疟原虫中与莽草酸生物合成相关的其他基因。(3)通过小分子筛选鉴定路径特异性抑制物，构建基因敲除基因，以确定莽草酸途径是否对恶性疟原虫的生长是必需的。我们认为，这些实验对于确定莽草酸途径是否是治疗疟疾的可行治疗靶点至关重要。 与公共卫生相关：疟疾是一种由疟原虫引起的危及生命的疾病。我计划研究恶性疟原虫中芳香氨基酸的生物合成，以评估该途径作为治疗疟疾的药物靶点的潜力。

DESCRIPTION (provided by applicant): The parasite Plasmodium is the causative agent of the disease malaria. Among the species of Plasmodium that infects humans, Plasmodium falciparum is the deadliest, and it accounts for the majority of malaria infections worldwide. Unfortunately, the burden of these infections is particularly heavy in poor and undeveloped countries in Africa, South America and Asia. Currently, only a handful of metabolic processes have been verified as targets to treat malaria, and there is a growing need to identify agents that address other essential pathways. The seven-step shikimate pathway is essential to the production of aromatic amino acids, ubiquinone, and folate in bacteria and plants. While the shikimate pathway is also believed to be essential for apicomplexans, such as P. falciparum, the complete pathway cannot be identified in its genome. Recently, a bioinformatics study identified two predicted proteins in P. falciparum that are homologous to the last three enzymes in the shikimate pathway. Despite our inability to identify the rest of the pathway through bioinformatics analysis, there is compelling evidence that the P. falciparum shikimate pathway exists and is a viable drug target. Molecules known to target shikimate pathway enzymes in plants were found to inhibit P. falciparum growth. Additionally, the genes for the predicted shikimate pathway enzymes are transcriptionally active during all stages of the P. falciparum lifecycle. We propose to investigate the shikimate pathway in P. falciparum with the following specific aims: (1) Biochemically characterize the predicted P. falciparum shikimate pathway enzymes (shikimate kinase, 5-enolpyruvylshikimate-3-phosphate synthase, and chorismate synthase). (2) Identify other genes involved in shikimate biosynthesis in P. falciparum via a genetic complementation screen and metabolite analysis. (3) Determine if the shikimate pathway is essential to P. falciparum growth by identification of pathway specific inhibitors through small molecule screens, and the construction of genetic knockouts. We believe that these experiments are essential to determine if the shikimate pathway is a viable therapeutic target for the treatment of malaria. PUBLIC HEALTH RELEVANCE: Malaria is a life-threatening disease that is caused by the Plasmodium parasite. I plan to investigate aromatic amino acid biosynthesis in Plasmodium falciparum, the deadliest species of the parasite, to evaluate the potential of the pathway as a drug target to treat malaria.