How do antibodies and lectins recognize histo-blood group antigens? A 3D-QSAR study by comparative molecular field...

The cross-reaction patterns of nine antibodies and three lectins against 12 H type 2 related oligosaccharides have been analysed by means of 3D-QSAR study. Three-dimensional descriptors of the molecular properties have been used in comparative molecular field analysis (CoMFA). Three different alignments were considered for the oligosaccharides. One, based on the superimposition of the oligosaccharide core, could be correlated to most of the antibody activities. A second alignment, based on a superimposition of the fucose residue, had to be taken into account for explaining the binding properties of Ulex europaeus isolectin I. Analysis of the QSAR data gives indications on the carbohydrate epitopes essential for antibody recognition and yields some insights about the nature of the molecular recognition. This study complements previous biochemical estimates of the H type 2 related oligosaccharide binding areas (Mollicone, R.; Cailleau, A.; Imberty, A.; Gane, P.; Pérez, S.; Oriol, R. Glycoconj. J. 1996, 13, 263-271).