Crystal structures of PA-IIL mutants. Detail of binding sites of PA-IILwild type/L-fucose (PDB code 1GZT ) and PA-IIL mutants complexed with Me-α-Fuc and Me-α-Man. Mutated amino acids are in yellow, water molecules are represented as red balls. Calcium ions and corresponding coordination bonds are in beige. Hydrogen bonds and hydrophobic interactions are represented by green and yellow dashed lines, respectively. The crucial interaction between Ser22 and Asp96 is shown as dashed red lines.