Thesis presented March 16, 2021

Abstract:
To date, glycosyltransferases (GTs) are an essential family of enzymes poorly characterized both structurally and mechanistically which is being a major bottleneck in Glycoscience. They play a crucial role in living organisms catalysing the stereoand regiospecic transfer of an activated donor sugar to an acceptor moiety to build up complex oligosaccharides onto the cell surface. New analytical tools are required to screen enzyme-glycan interactions in high-throughput manner. In this context, Surface Plasmon Resonance imaging (SPRi) has spread as a versatile methodology to overcome this glycoscientic demand for ligands screening and biomolecular interaction monitoring at real time and without any labels.
Therefore, this multidisciplinary project is organized in three main axes: first, we address the heterologous expression of a fucosyltransferase from the plant Arabidopsis thaliana (AtFUT1) (CAZy family GT37) that participates in the last step in the biosynthesis of xyloglucan (XyG) ligand. Then, specic immobilization approaches using DNA architectures motivate the design of chemoselective strategies to conjugate XyG building-blocks to oligonucleotidic scafolds in good yields. The versatility of having ODN structures conjugated to glycans provides powerful insights for glycan purication, characterization and also immobilization approaches on solid support. In this matter, the third axis is dedicated towards the conception and construction of a versatile XyG glycochip for its specic immobilization approach by DNA-Directed Immobilization (DDI). This strategy is envisioned through the powerful SPRi technique that allows the simultaneous visualization of binding events without using any label molecule in real time measurements.

Keywords:
Glycosyltransferase, Biosensor, SPR imaging, DNA, DDI

On-line thesis.