From the Rudolf Virchow Center for Experimental Biomedicine, Institute for Structural Biology, University of Wuerzburg, D-97080 Wuerzburg, Germany, the Institute of Pharmacy and Food Chemistry, University of Wuerzburg, Am Hubland, D-97074 Wuerzburg, Germany.
the Institute for Chemical Biology and Drug Discovery, Department of Chemistry, and School of Dental Medicine, Department of Oral Biology and Pathology, Stony Brook University, Stony Brook, New York 11794-3400, and.
J Biol Chem. 2014 Jun 6;289(23):15987-6005. doi: 10.1074/jbc.M113.532804. Epub 2014 Apr 16.
Determining the molecular basis for target selectivity is of particular importance in drug discovery. The ideal antibiotic should be active against a broad spectrum of pathogenic organisms with a minimal effect on human targets. CG400549, a Staphylococcus-specific 2-pyridone compound that inhibits the enoyl-acyl carrier protein reductase (FabI), has recently been shown to possess human efficacy for the treatment of methicillin-resistant Staphylococcus aureus infections, which constitute a serious threat to human health. In this study, we solved the structures of three different FabI homologues in complex with several pyridone inhibitors, including CG400549. Based on these structures, we rationalize the 65-fold reduced affinity of CG400549 toward Escherichia coli versus S. aureus FabI and implement concepts to improve the spectrum of antibacterial activity. The identification of different conformational states along the reaction coordinate of the enzymatic hydride transfer provides an elegant visual depiction of the relationship between catalysis and inhibition, which facilitates rational inhibitor design. Ultimately, we developed the novel 4-pyridone-based FabI inhibitor PT166 that retained favorable pharmacokinetics and efficacy in a mouse model of S. aureus infection with extended activity against Gram-negative and mycobacterial organisms.
确定靶标选择性的分子基础在药物发现中尤为重要。理想的抗生素应该对广谱的致病生物体具有活性，而对人体靶标影响最小。CG400549 是一种针对金黄色葡萄球菌的 2-吡啶酮化合物，可抑制烯酰-酰基载体蛋白还原酶 (FabI)，最近已被证明对治疗耐甲氧西林金黄色葡萄球菌感染具有人体疗效，这对人类健康构成严重威胁。在这项研究中，我们解析了与几种吡啶酮抑制剂结合的三种不同 FabI 同源物的结构，包括 CG400549。基于这些结构，我们合理地解释了 CG400549 对大肠杆菌 FabI 的亲和力比金黄色葡萄球菌 FabI 降低了 65 倍，并实施了一些概念来提高抗菌活性谱。沿着酶促氢转移反应坐标确定的不同构象状态，为催化和抑制之间的关系提供了一个优雅的视觉描述，从而促进了合理的抑制剂设计。最终，我们开发了新型基于 4-吡啶酮的 FabI 抑制剂 PT166，它在金黄色葡萄球菌感染的小鼠模型中保留了良好的药代动力学和疗效，并对革兰氏阴性菌和分枝杆菌具有扩展的活性。
