Binding of different monosaccharides by lectin PA-IIL from Pseudomonas aeruginosa:: Thermodynamics data correlated with X-ray structures

The lectin from Pseudomonas aeruginosa (PA-IIL) is involved in host recognition and biofilm formation. Lectin not only displays an unusually high affinity for fucose but also binds to L-fucose, L-galactose and D-arabinose that differ only by the group at position 5 of the sugar ring. Isothermal calorimetry experiments provided precise determination of affinity for the three methyl-glycosides and revealed a large enthalpy contribution. The crystal structures of the complexes of PA-IIL with L-galactose and Met-beta-D-arabinoside have been determined and compared with the PA-IIL/fucose complex described previously. A combination of the structures and thermodynamics provided clues for the role of the hydrophobic group in affinity. (c) 2006 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.