CTP SYNTHETASES: STRUCTURE, REGULATION, AND THERAPEUTIC DESIGN

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 为了研究CTP合成酶(CTPS)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结构的载脂蛋白、底物结合和核苷酸调节的形式。CTPS是关键的保守核苷酸生物合成酶，是抗肿瘤、抗真菌和抗寄生虫药物的靶点，其中一些药物最终可能用于HIV患者的治疗。在嘧啶生物合成的最后一步，CTPs催化依赖于ATP的氨基转移反应从谷氨酰胺到UTP。此外，在酵母中，ecCTPS被其产物CTP抑制，但被GTP激活，并受磷酸化调节。我们最近解决了载脂蛋白大肠杆菌酶(EcCTPS)的2.3°分辨结构，这是这类酶中的第一种酶。为了确定配体结合部位，绘制原子水平的相互作用图，并研究调控机制，我们将确定关键的配体CTPS络合物的结构。此外，我们还将测定CTPS与现有药效化合物的复合体结构，以了解其作用方式和耐药性的演变。最后，人类、酵母、布氏支原体和衣原体酶的结构将为特定物种疗法的基于结构的药物设计提供底物。

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.