Unprecedented Binding Mode of Hydroxamate-Based Inhibitors of Glutamate Carboxypeptidase II: Structural Characterization and Biological Activity

Inhibition of glutamate carboxypeptidase II (GCPII) is effective in preclinical models of neurological disorders associated with excessive activation of glutamatergic systems. Here we report synthesis, structural characterization, and biological activity of new hydroxamic acid-based inhibitors with nanomolar affinity for human GCPII. Crystal structures of GCPII/hydroxamate complexes revealed an unprecedented binding mode in which the putative P1′ glutarate occupies the spacious entrance funnel rather than the conserved glutamate-binding S1′ pocket. This unique binding mode provides a mechanistic explanation for the structure–activity relationship data, most notably the lack of enantiospecificity and the tolerance for bulky/hydrophobic functions as substituents of a canonical glutarate moiety. The in vivo pharmacokinetics profile of one of the inhibitors will be presented along with analgesic efficacy data from the rat chronic constrictive injury model of neuropathic pain.

谷氨酸羧肽酶II（glutamate carboxypeptidase II, GCPII）的抑制作用，在谷氨酸能系统过度激活相关的神经系统疾病临床前模型中具有显著效果。本研究报道了一类对人源GCPII具备纳摩尔级亲和力的新型异羟肟酸类抑制剂的合成、结构表征与生物学活性。GCPII与异羟肟酸复合物的晶体结构揭示了一种前所未有的结合模式：推定的P1'位戊二酸并未结合于保守的谷氨酸结合S1'口袋，而是占据了宽阔的入口漏斗区域。这种独特的结合模式为构效关系数据提供了机制层面的合理解释，尤其可阐明该类抑制剂无对映体特异性、且可耐受以大体积/疏水官能团作为典型戊二酸基团取代基的特性。本研究将展示其中一款抑制剂的体内药代动力学特征，以及其在大鼠慢性压迫损伤神经病理性疼痛模型中的镇痛功效数据。