Time-Resolved Tracking and Secretome Mapping of Intracellular, Cell Surface, and Extracellular Glycoconjugates with a Mini-Tetrazine N-Acetylglucosamine.

Glycosylation is instrumental in governing essential biological processes that dictate health outcomes. Herein we describe a mini-tetrazine N-acetylglucosamine (HTz-GlcNAc) that is incorporated into N-linked glycans and through rapid live-cell labeling with trans-cyclooctene (TCO) reagents enables real-time visualization and evaluation of glycoconjugate trafficking in living cells. We utilize cell-permeable and impermeable TCO-fluorophores to perform time-resolved, multicolor live labeling of cell-surface glycoconjugates, as well as intracellular, and internalized glycoconjugates. We observe intracellular glycoconjugate trafficking throughout the secretory pathway of live cells in real-time, as well as cell surface glycan turnover and extracellular vesicle secretion across three days. In the toolkit of probes for metabolic oligosaccharide engineering, HTz-GlcNAc brings the capability of precise interrogation of intracellular and extracellular glycoconjugate trafficking, and selective tagging of intra-and-extracellular vesicles, while providing a handle for the purification and enrichment of glycans for immunoblot and proteomic analyses.