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

摘要 O-GlcNAc转移酶（OGT）是一种重要的哺乳动物糖基转移酶，可修饰细胞内 具有单糖N-乙酰葡糖胺的蛋白质，称为O-GlcNAc化。了解OGT 功能是至关重要的，因为这种酶调节许多生物过程， 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不清楚， 一系列的挑战。这些包括OGT使数千种蛋白质糖基化而没有糖基化的事实。 表观序列基序以及OGT催化活性和底物特异性的动态变化 （称为“功能状态”）。传统的O-GlcNAc检测不是 适用于直接表征OGT酶或理解其在细胞中的调节机制。我们 设计了一种概念上新的化学探针，产生不同的修饰，以报告不同的 OGT的功能状态。在这里，我们建议实现这种探测器来表征结构特征 的OGT，有助于底物识别。此外，我们打算开发细胞渗透性，选择性 抑制剂和活性位点探针，以研究OGT的生物学作用，并分析其分子特征。 在癌症中的潜在功能障碍。这项研究中建立的独特化学工具 该计划将提供创新的方法和前所未有的见解，剖析分子基础 潜在的复杂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.