The addition of O-linked-β-D-N-acetylglucosamine (O-GlcNAc) onto serine and threonine residues of nuclear and cytoplasmic proteins is an abundant, unique post-translational modification governing important biological processes. O-GlcNAc dysregulation underlies several metabolic disorders leading to human diseases, including cancer, neurodegeneration and diabetes. This review provides an extensive summary of the recent progress in probing O-GlcNAcylation using mainly chemical methods, with a special focus on discussing mechanistic insights and the structural role of O-GlcNAc at the molecular level. We highlight key aspects of the O-GlcNAc enzymes, including development of OGT and OGA small-molecule inhibitors, and describe a variety of chemoenzymatic and chemical biology approaches for the study of O-GlcNAcylation. Special emphasis is placed on the power of chemistry in the form of synthetic glycopeptide and glycoprotein tools for investigating the site-specific functional consequences of the modification. Finally, we discuss in detail the conformational effects of O-GlcNAc glycosylation on protein structure and stability, relevant O-GlcNAc-mediated protein interactions and its molecular recognition features by biological receptors. Future research in this field will provide novel, more effective chemical strategies and probes for the molecular interrogation of O-GlcNAcylation, elucidating new mechanisms and functional roles of O-GlcNAc with potential therapeutic applications in human health.

中文翻译：

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蛋白质 O-GlcNAc 糖基化的化学探测进展：结构作用和分子机制

在核蛋白和细胞质蛋白的丝氨酸和苏氨酸残基上添加O-连接-β- D - N-乙酰氨基葡萄糖 ( O -GlcNAc) 是一种丰富的、独特的翻译后修饰，控制着重要的生物过程。O -GlcNAc 失调是导致人类疾病的多种代谢紊乱的基础，包括癌症、神经变性和糖尿病。这篇综述对主要使用化学方法探测O -GlcNAc 化的最新进展进行了广泛的总结，特别重点讨论了O -GlcNAc 在分子水平上的机制见解和结构作用。我们重点介绍了O -GlcNAc 酶的关键方面，包括 OGT 和 OGA 小分子抑制剂的开发，并描述了用于研究O -GlcNAc化的各种化学酶和化学生物学方法。特别强调合成糖肽和糖蛋白工具形式的化学力量，用于研究修饰的位点特异性功能后果。最后，我们详细讨论了O -GlcNAc糖基化对蛋白质结构和稳定性的构象影响、相关的O -GlcNAc介导的蛋白质相互作用及其生物受体的分子识别特征。该领域的未来研究将为O -GlcNAc的分子研究提供新颖、更有效的化学策略和探针，阐明O -GlcNAc的新机制和功能作用，在人类健康中具有潜在的治疗应用。