CTP SYNTHETASES: STRUCTURE, REGULATION, AND THERAPEUTIC DESIGN

该子项目是利用 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来源获得主要资金， 因此可以在其他CRISP条目中表示。列出的机构是 中心，不一定是研究者的机构。 为了研究CTP合成酶（CTPSs）的催化，变构调节和药物相互作用的机制，我们将解决来自各种来源的载脂蛋白，底物结合和核苷酸调节形式的结构。CTPS是关键的保守的核苷酸生物合成酶，并且是抗肿瘤、抗真菌和抗寄生虫剂的靶标，其中一些最终可以为治疗HIV患者提供有用的。在嘧啶生物合成的最后一步，CTPS催化从谷氨酰胺到UTP的ATP依赖性氨基转移反应。此外，EcCTPS被其产物CTP抑制，但被GTP激活，并在酵母中受磷酸化调节。我们最近解决了载脂蛋白大肠杆菌酶（EcCTPS）的2.3 º分辨率结构，这是此类酶中的第一种酶。为了确定配体结合位点，绘制原子水平的相互作用，并研究调控机制，我们将确定关键配体CTPS复合物的结构。此外，我们还将确定CTPS结构与现有的治疗化合物的复合物，以了解作用模式和抗性的演变。最后，对人、酵母、T.布氏杆菌和衣原体酶将为基于结构的物种特异性治疗药物设计提供底物。

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. To investigate mechanisms of catalysis, allosteric regulation, and drug interactions of CTP synthetases (CTPSs), we will solve structures from a variety of sources in their apo, substrate-bound,and nucleotide-regulated forms. CTPSs are key conserved nucleotide biosynthesic enzymes and are targets for anti-neoplastic,anti-fungal,and anti-parasitic agents, some of which could provide useful eventually for treatment of HIV patients. CTPS catalyzes an ATP-dependent aminotransfer reaction from glutamine to UTP in the last step of pyrimidine biosynthesis. In addition, EcCTPS is repressed by its product, CTP, but is activated by GTP,and regulated by phosphorylation in yeast. We recently solved the 2.3 ¿ resolution structure of the Apo E.coli enzyme (EcCTPS), the first enzyme in this class. To identify ligand-binding sites, to map the atomic level interactions, and to investigate regulatory mechanisms, we will determine the structures key ligand CTPS complexes. In addition, we will also determine the CTPS structures in complex with existing thereapeutic compounds to understand mode of action and the evolution of resistance. Finally, the structures of human, yeast, T. brucei, and Chlamydia enzymes will provide substrates for structure-based drug design of species-specific therapeutics.