Comparative analysis of oligosaccharide specificities of fucose-specific lectins from Aspergillus oryzae and Aleuria aurantia using frontal affinity chromatography

Aleuria aurantia lectin (AAL) is widely used to estimate the extent of alpha 1,6-fucosylated oligosaccharides and to fractionate glycoproteins for the detection of specific biomarkers for developmental antigens. Our previous Studies have shown that Aspergillus oryzae lectin (AOL) reflects the extent of alpha 1,6-fucosylation more clearly than AAL. However, the subtle specificities of these lectins to fucose linked to oligosaccharides through the 2-, 3-, 4-, or 6-position remain unclear, because large amounts of oligosaccharides are required for the systematic comparative analysis using surface plasmon resonance. Here we show a direct comparison of the dissociation constants (K-d) of AOL and AAL using 113 pyridylaminated oligosaccharides with frontal affinity chromatography. As a result, AOL showed a similar specificity as AAL in terms of the high affinity for oil,6-fucosylated oligosaccharides, for smaller fucosylated oligosaccharides, and for oligosaccharides fucosylated at the reducing terminal core GlcNAc. On the other hand, AOL showed 2.9-6.2 times higher affinity constants (K-a) for alpha 1,6-fucosylated oligosaccharides than AAL and only AAL additionally recognized oligosaccharides which were alpha 1,3-fucosylated at the reducing terminal GlcNAc. These results explain why AOL reflects the extent of alpha 1,6-fucosylation on glycoproteins more clearly than AAL. This systematic comparative analysis made from a quantitative viewpoint enabled a clear physical interpretation of these fucose-specific lectins with multivalent fucose-binding sites. (C) 2008 Elsevier Inc. All rights reserved.