School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Stranmillis Road, Belfast, BT9 5AG, Northern Ireland, UK.
Phys Chem Chem Phys. 2018 Aug 22;20(33):21660-21667. doi: 10.1039/c8cp02860e.
Fosfomycin Resistance Kinase A (FomA) catalyzes the phosphorylation of fosfomycin, which is an effective antibiotic for treating urinary tract infections. Understanding the chemical reaction mechanism is essential for developing strategies to counter the resistance of fosfomycin in clinical settings. Here the catalytic mechanism of FomA was investigated using molecular dynamic simulations in conjunction with quantum mechanics/molecular mechanics calculations (B97d/AMBER99). Our QM/MM study disclosed that the phosphorylation reaction catalyzed by FomA follows a dissociative mechanism, in contrast to the previously proposed associative mechanism. In addition, we found that His58, a characteristic residue in the AAK family, plays a key role in positioning the phosphate group of fosfomycin in the transition state. Molecular dynamic simulations revealed the important roles of Lys9 and Lys18 in arranging the nucleotide for phosphate transfer. Furthermore, we identified a four-membered water network mediated by Asp171 and Ser13 that is critical in ordering ATP for phosphate transfer. The active structure and reaction mechanism of FomA will provide valuable insights for developing new strategies to tackle the resistance to Fosfomycin-based antibiotic therapies.
磷霉素耐药激酶 A（FomA）催化磷霉素的磷酸化，磷霉素是治疗尿路感染的有效抗生素。了解化学反应机制对于开发在临床环境中对抗磷霉素耐药的策略至关重要。在这里，我们使用分子动力学模拟结合量子力学/分子力学计算（B97d/AMBER99）研究了 FomA 的催化机制。我们的QM/MM 研究表明，FomA 催化的磷酸化反应遵循解离机制，而不是先前提出的缔合机制。此外，我们发现 AAK 家族中的特征残基 His58 在过渡态中磷霉素的磷酸基团定位中起着关键作用。分子动力学模拟揭示了 Lys9 和 Lys18 在为磷酸转移排列核苷酸方面的重要作用。此外，我们确定了由 Asp171 和 Ser13 介导的四元水分子网络，该网络对于为磷酸转移排列 ATP 至关重要。FomA 的活性结构和反应机制将为开发新策略以解决基于磷霉素的抗生素治疗的耐药性提供有价值的见解。
