Versatile Biosensor Deciphering Glycoenzymatic Activities

To date, glycosyltransferases (GTs) are an essential family of enzymes poorly characterize both structurally and mechanistically which is being a major bottleneck in Glycoscience. They play a crucial role in living organisms catalysing the stereo- and regiospecific transfer of an activate donor sugar to an acceptor moiety to build up complex oligosaccharides onto the cell surface [1]. It requires the development of new methodologies able to elucidate and characterize the interactions between the glycosyl moiety and the enzyme. Surface plasmon resonance imaging (SPRi) has spread as a powerful analytical tool for deciphering many biomolecular processes exploring the kinetics and monitoring multiple interactions of biological and chemical substrates at real time and without any labels [2]. We aim at the development of a biosensor enable to rationalize the characterization of glycosyltransferases activities involved in the plant cell wall biosynthesis. To this aim, a fucosyltransferase from the plant Arabidosis thaliana (AtFUT1) (CAZY family GT37), was selected as model glycosyltransferase. This enzyme participates in the last step in the biosynthesis of xyloglucan (XG) transferring L-Fucose molecule from GDP-Fucose (donor) to a galactose sugar (acceptor) [3]. To that end, multiple chemical strategies to functionalize large moieties of xyloglucan to graft it on the gold surface have been developed [4] [5]. Depicting and monitoring the interactions between the AtFUT1 and the xyloglucan in terms of both specificity and activity represent a strong challenge. Complementary techniques such as isothermal titration calorimetry (iTC) may guide to streamline the comprehension and support the rationalization of the glycosylation process [6].