DNA Polymerase IIIE, A New Antibiotic Target

描述（由申请人提供）：耐药细菌感染的管理存在全球性危机。特别是革兰氏阳性（革兰氏+）细菌，如金黄色葡萄球菌、粪肠球菌和屎肠球菌对传统抗生素的耐药性越来越强。 该项目的重点是在革兰氏阳性菌中新描述的DNA聚合酶的抑制剂，pol IIIE，并建立在我们以前的工作与pol IIIC的抑制剂，6-苯胺尿嘧啶（AU），在抗菌药物发现的结果。我们已经从革兰氏阳性细菌中鉴定出pol IIIE的有效先导抑制剂- N2，7-二取代鸟嘌呤-其充当pol IIIE的竞争性活性定点抑制剂。基于这些观察结果，我们将通过这些特定目标进行抗生素药物发现： 1.采用平行合成法合成N2-取代鸟嘌呤、7-取代-N2-取代鸟嘌呤和N2，7-二取代鸟嘌呤; 2.合成最有效的N2，7-二取代的鸟嘌呤的电子等排体-3-脱氮、8-氮和3-脱氮-8-氮鸟嘌呤，这些鸟嘌呤被预测为高度有效的pol Ⅲ E抑制剂; 3.测定化合物抑制分离自革兰氏阳性菌B的pol IIIE和pol IIIC的能力。枯草芽孢杆菌S. aureus和E. fecalis和革兰氏杆菌E.大肠杆菌; 4.测定化合物对革兰氏+和革兰氏-细菌的作用，以及对人细胞的细胞毒性; 5.根据目标1-3的结果，设计一种或多种pol IIIE抑制剂，适用于该项目第二阶段小鼠感染模型的药代动力学和疗效研究。 有效抑制革兰氏阳性聚合物IIIE将导致候选抗菌药物耐药性发生率降低。此外，还测定了E.我们的先导抑制剂对大肠杆菌的抑制表明，有可能设计出一种真正的广谱抗菌化合物。 拟议的商业应用：一种能够治疗由耐药细菌引起的感染的新型抗生素药物可能有很大的市场。 在该项目中开发的化合物具有对抗由革兰氏+细菌引起的感染的潜在效用，并且由于对一种以上的酶靶点具有活性，因此将具有较低的产生耐药性的倾向。 如果这些化合物抑制革兰氏阳性菌和革兰氏阴性菌中的靶标，则可以开发真正的广谱药物。

DESCRIPTION (provided by applicant): There is a worldwide crisis in management of drug-resistant bacterial infections. In particular Gram-positive (Gram+) bacteria such as Staphylococcus aureus, Enterococcus fecalis and Enterococcus fecium are increasingly resistant to traditional antibiotics. This project focuses on inhibitors of a newly described DNA polymerase in Gram+ bacteria, pol IIIE, and builds upon previous results obtained from our work with inhibitors of pol IIIC, the 6-anilinouracils (AUs), in antibacterial drug discovery. We have identified potent lead inhibitors of pol IIIE from Gram+ bacteria - N2,7-disubstituted guanines - that act as competitive, active site-directed inhibitors of pol IIIE. Based on these observations we will pursue antibiotic drug discovery through these specific aims: 1. to use parallel synthesis methods to synthesize N2-substituted guanines, 7-substituted-N2-substituted guanines, and N2,7-disubstituted guanines; 2. to synthesize isosteres of the most potent N2,7-disubstituted guanines - 3-deaza, 8-aza and 3-deaza-8-aza guanines predicted to be highly potent pol IIIE inhibitors; 3. to assay compounds for their capacity to inhibit pol IIIE and pol IIIC isolated from the Gram+ bacteria B. subtilis, S. aureus, and E. fecalis, and from the Gram- bacterium E. coli; 4. to assay compounds against Gram+ and Gram- bacteria, and for cytotoxicity against human cells; 5. to design, based on the results of aims 1-3, one or more pol IIIE inhibitors suitable for pharmacokinetic and efficacy studies in mouse infection models during phase II of the project. Potent inhibition of Gram+ pol IIIE will lead to candidate antibacterials with reduced incidence of resistance. In addition, activity against the Gram- pol IIIE from E. coli by our lead inhibitor indicates the possibility of designing a truly broad spectrum antibacterial compound derived from this scaffold. PROPOSED COMMERCIAL APPLICATION: A new antibiotic drug capable of curing infections caused by drug-resistant bacteria can have a significant market. The compounds developed in this project have potential utility against infections caused by Gram+ bacteria, and, by virtue of being active against more than one enzymatic target, will have a low tendency to develop resistance. Truly broad spectrum drugs may be developed if such compounds inhibit targets in both Gram+ and Gram- bacteria.