Seminar

Structural Basis of Glycan Diversity

Marcelo Guerin, PhD

Glycans are not only one of the major components of the cell but also are essential molecules that modulate a variety of important biological processes in all living organisms. Glycans are used primarily as energy storage and metabolic intermediates as well as being main structural constituents in bacteria and plants. Moreover, as a consequence of protein and lipid glycosylation, glycans generate a significant amount of structural diversity in biological systems. This structural information is particularly apparent in molecular recognition events including cell-cell interactions during critical steps of development, the immune response and host-pathogen interactions. Most of the enzymes encoded in eukaryotic/prokaryotic/archaeans genomes that are responsible for the biosynthesis, degradation and modification of glycan structures are Carbohydrate-Modifying Enzymes, including: glycoside hydrolases (GHs), glycosyltransferases (GTs), carbohydrate esterases (CEs) and other auxiliary proteins (e.g. redox enzymes, carbohydrate binding modules). They are highly selective in nature, allowing the recognition of subtle structural differences in the sequences and stereochemistry of their carbohydrate substrates. In this context, they will discuss the contribution of their group to the understanding of the structural determinants and the modulation of substrate specificity of Carbohydrate-Modifying Enzymes at the molecular level.