PURINES & PURINE ANTIMETABOLITES IN MALARIA

嘌呤

• 批准号: 7977070
• 负责人: Vern L. Schramm
• 金额: $ 2.67万
• 依托单位: UNIVERSITY OF CALIF-LAWRNC LVRMR NAT LAB
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-04 至 2010-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7977070
• 关键词: Adenine; Adenosine; Antimetabolites; Blood; Carbon; Computer Retrieval of Information on Scientific Projects Database; Culture Media; DNA; Enzymes; Erythrocytes; Funding; Glycine; Grant; Guanosine; Human; Hypoxanthines; Inosine; Institution; Label; Malaria; Parasites; Pathway interactions; Plasmodium falciparum; Polyamines; Precipitation; Purine Nucleoside Phosphorylase Inhibitor; Purine-Nucleoside Phosphorylase; Purines; RNA; Research; Research Personnel; Resource Development; Resources; Sampling; Source; Time; United States National Institutes of Health; Xanthines; accelerator mass spectrometry; adenosine deaminase; analog; feeding; killings; purine; purine metabolism; research study

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Project Description Malaria parasites are purine auxotrophs, but grow inside human red blood cells where the concentration of purines is hundreds to thousands of time greater than the amount taken up by the parasites. We therefore need a specific and sensitive way to establish the pathways by which precursors from the blood (or culture medium) are incorporated into the parasites. We are using 14C precursors to label the purine pool in parasites growing in human erythrocytes. The purine precursors include inosine, adenosine, guanosine, 5'-methylthioadenosine, hypoxanthine, adenine, xanthine, glycine, and a newly discovered metabolite of purine metabolism in P. falciparum, 5'-methylthioinosine. These RNA and DNA precursors are fed to cultures at levels appropriate for AMS and the RNA and DNA from the parasites isolated by extraction or precipitation. Samples from these experiments are converted into carbon for AMS analysis. Immucillins, powerful inhibitors of purine nucleoside phosphorylase (PNP) are added to establish which precursors flow through this enzyme to be incorporated in RNA and DNA. Recently we found that the malarial PNP is unique in participating in the salvage of inosine, guanosine and 5'-methylthioinosine, a metabolite that arises from the polyamine pathway in P. falciparum, but not its human host. 5'-methylthioinosine arises specifically in the parasite by the action of P. falciparum adenosine deaminase on 5'-methylthioinosine. This provides an adenine salvage function. Our current hypothesis is that parasite PNP and ADA function in two purine salvage cycles. Blocking either enzyme is productive in killing parasites in the absence of added hypoxanthine. We have synthesized powerful transition state analogues for three enzymes, all of which are in the essential purine salvage of P. falciparum PNP.

该副本是利用众多研究子项目之一 由NIH/NCRR资助的中心赠款提供的资源。子弹和 调查员（PI）可能已经从其他NIH来源获得了主要资金， 因此可以在其他清晰的条目中代表。列出的机构是 对于中心，这不一定是调查员的机构。 项目描述 疟疾寄生虫是嘌呤的合子，但在人类红细胞内生长，其中嘌呤的浓度比寄生虫所吸收的数量大数百到数千倍。因此，我们需要一种特定和敏感的方式来建立从血液（或培养基）中掺入寄生虫中的前体的途径。 我们正在使用14C前体来将嘌呤池标记在人类红细胞中生长的寄生虫中。 嘌呤的前体包括肌苷，腺苷，鸟苷，5'-甲基硫代腺苷，低黄嘌呤，腺嘌呤，黄嘌呤，甘氨酸，以及在5'-甲基硫代氨酸5'-甲基硫代氨酸的恶性疟原虫中新发现的嘌呤代谢的代谢。 这些RNA和DNA前体以适合AMS的水平以及通过提取或沉淀分离的寄生虫的RNA和DNA喂食。 这些实验的样品转化为碳进行AMS分析。 添加了嘌呤核苷磷酸化酶（PNP）的强大抑制剂，以确定要在RNA和DNA中掺入该酶的前体流过哪些前体。 最近，我们发现疟疾PNP在参与肌苷，鸟嘌呤和5'-甲基噻氨基氨酸的拯救方面是独一无二的，这是一种代谢物，它来自恶性疟原虫的多胺途径，但不是其人类宿主。 5'-甲基噻氨胺是通过恶性疟原虫腺苷脱氨酶对5'-甲基噻氨基氨酸的作用而特别在寄生虫中产生的。 这提供了腺嘌呤救助功能。 我们目前的假设是两个嘌呤挽救周期中的寄生虫PNP和ADA功能。 在没有添加的低黄嘌呤的情况下，阻断任何一种酶在杀死寄生虫方面都是有效的。 我们已经合成了三种酶的强大过渡状态类似物，所有这些酶都是在恶性疟原虫PNP的必需嘌呤拯救中。