Structural glycobiology is the branch of biology that study the structure and interaction of glycomolecules that play key roles in all living systems The first part of this thesis deals with the 3D structure of two glycoconjugates, the tricolorin A and an O-glycan from Tamm-Horsfall glycoprotein, with the use of x-ray crystallography and molecular modelling. The second part is focused on the interaction of carbohydrates with their molecular receptors: lectins. Lectins are an important class of proteins with the ability to “read” the biological information encoded in the 3D structure of carbohydrates. Macromolecular crystallography in combination with biophysical techniques, mainly isothermal titration calorimetry, has been used to dissect the structural basis and the energetics of lectin-sugar recognition. Two bacterial lectins have been studied which are believed to play important roles in the infection of the opportunistic bacteria Pseudomonas aeruginosa and Chromobacterium violaceum. Attention was also focussed on the new family of mushroom lectins and the crystal structure of the lectin from Psathyrella velutina was determined
