Chemo-enzymatic synthesis of N-glycans

The access to pure and well-defined glycan structures is a key requisite for most of our projects and a major effort in our group is devoted to the chemical synthesis of glycans and glycomimetics. To be able to rapidly access large numbers of related of glycan structures we concentrate on the synthesis of core structures that are conserved in a certain class of carbohydrates and employ recombinant enzymes for their rapid and stereo-selective diversification. Most enzymes we employ are not commercially available and were cloned and expressed in-house. To be able to analyze in detail the interaction of pathogen glycans with human immune receptors involved in pathogen recognition and uptake we have focused on the synthesis of parasite glycans that share certain core structures with human glycans but often present highly immunogenic structural elements. As an example we have developed a convergent synthesis for a 6 core xylosylated glycans, which were enyzymatically diversified into a library of 33 highly complex N-glycans (Brzezicka et al. 2015)