Monovalent and bivalent N-fucosyl amides as high affinity ligands for Pseudomonas aeruginosa PA-IIL lectin

The adhesion of bacteria to human glycoconjugates can be inhibited by soluble glycomimetics that compete with the natural target. Four monovalent and one divalent α-fucosyl amides have been tested for their affinity for a fucose-binding lectin from Pseudomonas aeruginosa. Isothermal calorimetric titrations demonstrated that they bind to the lectin in the micromolar range, with highest affinity for the divalent ligand. Molecular modelling established that, compared to J -fucoside compounds, the glycomimetic amide group resulted in the loss of water-bridged hydrogen bonds that could be partially compensated by additional contact of the aglycone with the protein surface.