STRUCTURAL MECHANISM OF THE T GONDII UPRT, A TARGET FOR STRUCTURAL-BASED DRUG D

这个子项目是许多利用 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 布伦南实验室的主要研究重点是了解蛋白质的三维结构与其生化和生物功能之间的关系。 这些方法正被用于研究原生动物的转录调控、蛋白质-核酸相互作用、多药物识别和结合以及嘌呤和嘧啶补救机制。我们的兴趣还在于基于结构的药物设计。一种感兴趣的蛋白质是来自机会寄生原生动物刚地弓形虫的尿嘧啶磷酸核糖转移酶（UPRT），其催化尿嘧啶转移至D-磷酸核糖焦磷酸（PRPP），释放焦磷酸并产生核苷酸单磷酸UMP。 然后，回收的UMP可以用于许多代谢途径。这种酶提供了一个很好的目标，以利用我们试图发现新的药物对这种机会寄生虫。 必须充分理解UPRT的底物识别和催化机制。我们实验室以前的研究已经为UPRT的完整结构和机理表征奠定了基础，我们正在进行下一组关键研究。具体来说，我们正在研究apo UPRT的超高分辨率（1.05 <$resolution）结构和一些关键二元和三元复合物的高分辨率结构的改进。 与此同时，我们正在对她的野生型蛋白和一些定点突变体进行彻底的动力学评估。 最后，这些信息开始开发将指导我们未来药物设计尝试的结构参数。

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. The major research focus of the Brennan Laboratory is to understand the relationship between the 3-D structures of proteins and their biochemical and biological functions. These approaches are being used to study transcription regulation, protein-nucleic acid interaction, multidrug recognition and binding and the mechanisms of purine and pyrimidine salvage in protozoa. Our interest is also directed in structure-based drug design. One protein of interest is the uracil phosphoribosyltransferase (UPRT) from the opportunistic parasitic protozoan, Toxoplasma gondii, which catalyzes the transfer of uracil to D-phosphoribosyl pyrophosphate (PRPP) releasing pyrophosphate and creating the nucleotide monophosphate UMP. The salvaged UMP can then be used in a number of metabolic pathways. This enzyme presents a very good target to exploit in our attempts to discover new drugs against this opportunistic parasite. The substrate recognition and catalytic mechanisms of UPRT must be understood fully. Previous studies from our lab have set the groundwork for the complete structural and mechanistic characterization of UPRT and we are carrying out the next key set of studies. Specifically, we are working on the refinement of the ultra high resolution (1.05 ¿ resolution) structure of apo UPRT and the high resolution structures of a number of key binary and ternary complexes. In parallel, we are carrying out a thorough kinetic evaluation of her wild type protein and a number of site directed mutants. Finally, this information starts to develop the structural parameters that will guide our future drug design attempts.