Chemical Probes to Characterize the Functional States of O-GlcNAc Transferase

摘要 O-GlcNAc转移酶(O-GlcNAc Transfer ase，OGT)是哺乳动物体内重要的糖基转移酶 蛋白质中含有单糖N-乙酰氨基葡萄糖，称为O-GlcN酰化。理解OGT 功能是至关重要的，因为这种酶调节许多生物过程，其中许多 它们在人类疾病中变得异常。然而，OGT的确切作用在很大程度上仍然不清楚 面对一系列的挑战。其中包括这样一个事实，即OGT在没有蛋白质的情况下糖基化数千种蛋白质 表观序列基序与OGT催化活性和底物特异性的动态变化 (称为“功能状态”)对细胞条件作出反应。传统的O-GlcNAc检测不是 适用于直接表征OGT酶或了解其在细胞中的调节机制。我们 我设计了一种概念上的新化学探测器，它可以产生不同的修改，以报告不同的 OGT的功能状态。在这里，我们建议实施这个探测器来表征结构特征 有助于底物识别的OGT。此外，我们打算开发细胞渗透性、选择性 抑制剂和活性部位探针研究OGT的生物学作用和分子图谱 它在癌症中的功能障碍的特征。这项研究中建立的独特的化学工具 该计划将提供创新的方法和前所未有的洞察力来剖析分子基础 潜在的复杂的OGT生物学，并可能发现导致癌症的新途径。

Abstract O-GlcNAc transferase (OGT) is an essential mammalian glycosyltransferase that modifies intracellular proteins with a monosaccharide N-acetylglucosamine, called O-GlcNAcylation. Understanding OGT's function is critically important because this enzyme regulates numerous biological processes, and many of them become aberrant in human diseases. However, the precise role of OGT remains largely unclear due to a number of challenges. These include the fact that OGT glycosylates thousands of proteins without an apparent sequence motif and the dynamic changes of OGT's catalytic activity and substrate specificity (termed “functional states”) in response to cellular conditions. Conventional O-GlcNAc detection is not suitable for direct characterizing the OGT enzyme or understanding its regulatory mechanism in cells. We have designed a conceptually new chemical probe that generates distinct modifications to report different functional states of OGT. Here, we propose to implement this probe to characterize the structural features of OGT that contribute to substrate recognition. In addition, we intend to develop cell-permeable, selective inhibitors and active site probes to investigate the biological roles of OGT and to profile the molecular signatures that underlying its dysfunction in cancer. The unique chemical tools established in this research program will provide innovative approaches and unprecedented insights to dissect the molecular basis underlying complex OGT biology and may discover new pathways leading to cancer.