Precision mapping of glycans at structural and site-specific level is still one of the most challenging tasks in the glycobiology field. Here, we describe a modularization strategy for de novo interpretation of N-glycan structures on intact glycopeptides using tandem mass spectrometry. An algorithm named StrucGP is also developed to automate the interpretation process for large-scale analysis. By dividing an N-glycan into three modules and identifying each module using distinct patterns of Y ions or a combination of distinguishable B/Y ions, the method enables determination of detailed glycan structures on thousands of glycosites in mouse brain, which comprise four types of core structure and 17 branch structures with three glycan subtypes. Owing to the database-independent glycan mapping strategy, StrucGP also facilitates the identification of rare/new glycan structures. The approach will be greatly beneficial for in-depth structural and functional study of glycoproteins in the biomedical research.

在结构和位点特异性水平上精确定位聚糖仍然是糖生物学领域最具挑战性的任务之一。在这里，我们描述了一种模块化策略，用于使用串联质谱法从头解释完整糖肽上的 N-聚糖结构。还开发了一种名为 StrucGP 的算法来自动化大规模分析的解释过程。通过将 N-聚糖分为三个模块，并使用不同的 Y 离子模式或可区分的 B/Y 离子组合识别每个模块，该方法能够确定小鼠大脑中数千个糖位点的详细聚糖结构，这些糖位点包括四种类型核心结构和具有三种聚糖亚型的 17 个分支结构。由于独立于数据库的聚糖作图策略，StrucGP 还有助于识别稀有/新聚糖结构。该方法对生物医学研究中糖蛋白结构和功能的深入研究将大有裨益。