Metabolic incorporation of chemically tagged monosaccharides is a facile means of tagging cellular glycoproteins and glycolipids. However, since the monosaccharide precursors are often shared by several pathways, selectivity has been difficult to attain. For example, N-linked glycosylation is a chemically complex and ubiquitous posttranslational modification, with three distinct classes of GlcNAc-containing N-glycan structures: oligomannose, hybrid and complex. Here we describe the synthesis of 1,3-Pr₂-6-OTs GlcNAlk (MM-JH-1) as a next-generation metabolic chemical reporter for the selective labeling of hybrid N-glycan structures. We first developed a general strategy for defining the selectivity of labeling with chemically tagged monosaccharides. We then applied this approach to establish that MM-JH-1 is selectively incorporated into hybrid N-glycans. Using this metabolic chemical reporter as a detection tool, we performed imaging and fractionation to define features of the intracellular localization and trafficking of target proteins bearing hybrid N-glycan structures.

化学标记的单糖的代谢掺入是标记细胞糖蛋白和糖脂的一种简单方法。然而，由于单糖前体通常由多个途径共享，因此很难获得选择性。例如，N-连接糖基化是一种化学复杂且普遍存在的翻译后修饰，具有三类不同的含 GlcNAc 的 N-糖结构：寡甘露糖、杂交和复合体。在这里，我们描述了 1,3-Pr 2-6-OTs GlcNAlk （MM-JH-1） 的合成，作为选择性标记杂合 N-糖结构的下一代代谢化学报告基因。我们首先开发了一种通用策略，用于定义用化学标记的单糖标记的选择性。然后，我们应用这种方法来确定 MM-JH-1 选择性地掺入杂化 N-糖中。使用这种代谢化学报告基因作为检测工具，我们进行了成像和分级分离，以确定带有杂交 N-糖结构的靶蛋白的细胞内定位和运输特征。