nQuant Enables Precise Quantitative N‑Glycomics

N-glycosylation is a highly heterogeneous post-translational
modification
that modulates protein function. Defects in N-glycosylation are directly
linked to various human diseases. Despite the importance of quantifying
N-glycans with high precision, existing glycoinformatics tools are
limited. Here, we developed nQuant, a glycoinformatics tool that enables
label-free and isotopic labeling quantification of N-glycomics data
obtained via LC-MS/MS, ensuring a low false quantitation rate. Using
the label-free quantification module, we profiled the N-glycans released
from purified glycoproteins and HEK293 cells as well as the dynamic
changes of N-glycosylation during mouse corpus callosum development.
Through the isotopic labeling quantification module, we revealed the
dynamic changes of N-glycans in acute promyelocytic leukemia cells
after all-trans retinoic acid treatment. Taken together, we demonstrate
that nQuant enables fast and precise quantitative N-glycomics.

N-糖基化 (N-glycosylation) 是一种高度异质性的翻译后修饰 (post-translational modification)，可调控蛋白质功能。N-糖基化异常与多种人类疾病直接相关。尽管高精度定量N-聚糖 (N-glycans) 具有重要科学价值，但现有的糖信息学 (glycoinformatics) 工具仍存在诸多局限。本研究开发了一款糖信息学工具nQuant，可对液相色谱-串联质谱 (LC-MS/MS) 获取的N-糖组学 (N-glycomics) 数据开展无标记 (label-free) 与同位素标记定量分析，有效降低定量假阳性率。借助无标记定量模块，我们对纯化糖蛋白与HEK293细胞释放的N-聚糖，以及小鼠胼胝体 (corpus callosum) 发育过程中N-糖基化的动态变化进行了谱析表征。通过同位素标记定量模块，我们揭示了急性早幼粒细胞白血病细胞经全反式维甲酸 (all-trans retinoic acid) 处理后N-聚糖的动态变化规律。综上，本研究证实nQuant可实现快速且高精度的N-糖组学定量分析。