Tools and tactics to define specificity of metabolic chemical reporters.

Metabolic chemical reporters (MCRs) provide easily accessible means to study glycans in their native environments. However, because monosaccharide precursors are shared by many glycosylation pathways, selective incorporation has been difficult to attain. Here, a strategy for defining the selectivity and enzymatic incorporation of an MCR is presented. Performing β-elimination to interrogate O -linked sugars and using commercially available glycosidases and glycosyltransferase inhibitors, we probed the specificity of widely used azide (Ac ₄ GalNAz) and alkyne (Ac ₄ GalNAlk and Ac ₄ GlcNAlk) sugar derivatives. Following the outlined strategy, we provide a semiquantitative assessment of the specific and non-specific incorporation of this bioorthogonal sugar (Ac ₄ GalNAz) into numerous N - and O -linked glycosylation pathways. This approach should be generally applicable to other MCRs to define the extent of incorporation into the various glycan species.
Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer CF declared a past co-authorship with the author JAH to the handling editor.
(Copyright © 2023 Mukherjee, Bond, Abramowitz, Biesbrock, Woodroofe, Kim, Swenson and Hanover.)