Lundqvist Tomas, Fisher Stewart L, Kern Gunther, Folmer Rutger H A, Xue Yafeng, Newton D Trevor, Keating Thomas A, Alm Richard A, de Jonge Boudewijn L M
AstraZeneca Global Structural Chemistry, AstraZeneca R&D Mölndal, SE-431 83, Mölndal, Sweden.
Nature. 2007 Jun 14;447(7146):817-22. doi: 10.1038/nature05689.
Glutamate racemase is an enzyme essential to the bacterial cell wall biosynthesis pathway, and has therefore been considered as a target for antibacterial drug discovery. We characterized the glutamate racemases of several pathogenic bacteria using structural and biochemical approaches. Here we describe three distinct mechanisms of regulation for the family of glutamate racemases: allosteric activation by metabolic precursors, kinetic regulation through substrate inhibition, and D-glutamate recycling using a d-amino acid transaminase. In a search for selective inhibitors, we identified a series of uncompetitive inhibitors specifically targeting Helicobacter pylori glutamate racemase that bind to a cryptic allosteric site, and used these inhibitors to probe the mechanistic and dynamic features of the enzyme. These structural, kinetic and mutational studies provide insight into the physiological regulation of these essential enzymes and provide a basis for designing narrow-spectrum antimicrobial agents.
谷氨酸消旋酶是细菌细胞壁生物合成途径中必不可少的一种酶，因此一直被视为抗菌药物研发的靶点。我们运用结构和生化方法对几种病原菌的谷氨酸消旋酶进行了表征。在此，我们描述了谷氨酸消旋酶家族三种不同的调控机制：代谢前体的变构激活、通过底物抑制进行的动力学调控，以及利用d -氨基酸转氨酶进行的D -谷氨酸循环利用。在寻找选择性抑制剂的过程中，我们鉴定出了一系列特异性靶向幽门螺杆菌谷氨酸消旋酶的非竞争性抑制剂，这些抑制剂与一个隐蔽的变构位点结合，并利用这些抑制剂探究该酶的机制和动态特征。这些结构、动力学和突变研究为深入了解这些必需酶的生理调控提供了见解，并为设计窄谱抗菌剂奠定了基础。
