Development of BODIPY labelled sialic acids as sialyltransferase substrates for direct detection of terminal galactose on N- and O-linked glycans

• Published in: Carbohydrate research Vol. 500; p. 108249
• Main Authors: Abukar, Tasnim, Rahmani, Sadia, Thompson, Nicole K., Antonescu, Costin N., Wakarchuk, Warren W.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01.02.2021
• ISSN: 0008-6215; 1873-426X
• DOI: 10.1016/j.carres.2021.108249

Glycans on proteins and cell surfaces are useful biomarkers for determining functional interactions with glycan binding proteins, potential disease states, or indeed level of differentiation. The ability to rapidly and sensitively detect or tag specific glycans on proteins provides a diagnostic tool with wide application in chemical glycobiology. The monosaccharide N-acetylneuraminic acid (sialic acid) is a key player in these interactions and the manipulation and control of sialylation levels has been an important research focus, particularly in the development of therapeutic proteins. Using sialyltransferases to tag specific glycans provides a rapid means of determining what types of glycans are present. We have synthesized two variants of sialic acid carrying the fluorophore BODIPY (4,4 –Difluoro-4-boro-3a,4a-diaza-s-indacene) and examined its use with several different sialyltransferases on a variety of protein substrates and cell surface glycans. Our data show that there are significant differences between various enzymes ability to transfer the labelled sialic acids, and that the type of N-glycan and target protein strongly influences this activity. [Display omitted] •Ease of synthesis.•Applicable to several enzyme types.•Sensitive detection.•Provides some glycan context based on activity.