Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Campus C2.3, 66123 Saarbrücken, Germany.
ACS Chem Biol. 2012 Sep 21;7(9):1496-501. doi: 10.1021/cb300208g. Epub 2012 Jul 5.
The Gram-negative pathogen Pseudomonas aeruginosa produces an intercellular alkyl quinolone signaling molecule, the Pseudomonas quinolone signal. The pqs quorum sensing communication system that is characteristic for P. aeruginosa regulates the production of virulence factors. Therefore, we consider the pqs system a novel target to limit P. aeruginosa pathogenicity. Here, we present small molecules targeting a key player of the pqs system, PqsR. A rational design strategy in combination with surface plasmon resonance biosensor analysis led to the identification of PqsR binders. Determination of thermodynamic binding signatures and functional characterization in E. coli guided the hit optimization, resulting in the potent hydroxamic acid derived PqsR antagonist 11 (IC(50) = 12.5 μM). Remarkably it displayed a comparable potency in P. aeruginosa (IC(50) = 23.6 μM) and reduced the production of the virulence factor pyocyanin. Beyond this, site-directed mutagenesis together with thermodynamic analysis provided insights into the energetic characteristics of protein-ligand interactions. Thus the identified PqsR antagonists are promising scaffolds for further drug design efforts against this important pathogen.
革兰氏阴性病原体铜绿假单胞菌产生一种细胞间的烷基喹诺酮信号分子，即铜绿假单胞菌信号。铜绿假单胞菌特有的 pqs 群体感应通讯系统调节毒力因子的产生。因此，我们认为 pqs 系统是限制铜绿假单胞菌致病性的一个新靶标。在这里，我们提出了针对 pqs 系统关键因子 PqsR 的小分子。结合表面等离子体共振生物传感器分析的合理设计策略，鉴定了 PqsR 结合物。在大肠杆菌中测定热力学结合特征和功能特性，指导了命中优化，得到了有效的羟肟酸衍生的 PqsR 拮抗剂 11（IC50=12.5 μM）。值得注意的是，它在铜绿假单胞菌中的活性相当（IC50=23.6 μM），并降低了毒力因子绿脓菌素的产生。此外，定点突变与热力学分析为蛋白质-配体相互作用的能量特征提供了深入的了解。因此，鉴定的 PqsR 拮抗剂是针对这一重要病原体进一步药物设计的有前途的支架。
