Abstract：
UDP-N-acetylglucosamine pyrophosphorylase (UAP) catalyzes the last step in the hexosamine biosynthesis pathway to directly produce UDP-N-acetylglucosamine (UDP-GlcNAc). Because UAPs play important physiological and pathological roles in organisms, they are considered potential targets for drug and pesticide development. However, the lack of efficient and selective inhibitors is a bottleneck that must be overcome. This study reports the first crystal structure of the insect UAP from Spodoptera frugiperda (SfUAP) in complex with UDP-GlcNAc. SfUAP has two insect-specific structural characteristics in the active pocket, namely, a free Cys (Cys334) and a Mg2+ binding site, which differentiate it from human UAP (HsAGX1) and fungal UAP (AfUAP) in terms of substrate and inhibitor binding. N-(4-Nitrophenyl)maleimide (pNPMI) and myricetin are discovered as potent covalent and noncovalent inhibitors of SfUAP, respectively. Moreover, myricetin can significantly reduce the level of cellular O-GlcNAcylation by inhibiting both UAP and O-GlcNAc transferase. These findings provide novel insights into the development of UAP-based drugs and pesticides.
摘要：
UDP-N-乙酰葡糖胺焦磷酸化酶（UAP）催化己糖胺生物合成途径的最后一步，直接产生UDP-N-乙酰葡糖胺（UDP-GlcNAc）。由于UAP在生物体中发挥重要的生理和病理作用，它们被认为是药物和农药开发的潜在目标。然而,缺乏有效和选择性的抑制剂是必须克服的瓶颈。这项研究报告了与UDP-GlcNAc复合的节食夜蛾（SfUAP）昆虫UAP的第一个晶体结构。SfUAP在活动袋中具有两个昆虫特有的结构特征，即,一个游离的Cys（Cys334）和一个Mg2+结合位点，在底物和抑制剂结合方面将其与人类UAP（HsAGX1）和真菌UAP（AfUAP）区分开。N-（4-硝基苯基）马来酰亚胺（pNPMI）和杨梅素被发现是SfUAP的有效共价和非共价抑制剂，分别。此外，杨梅素可以通过抑制UAP和O-GlcNAc转移酶显著降低细胞O-GlcNAc的水平。这些发现为基于UAP的药物和农药的开发提供了新的见解。
