Interaction of the Laburnum anagyroides lectin with fucoantigens

We studied interaction of the lectin from the bark of Golden Rain shrub (Laburnum anagyroides, LABA) with a number of basic fucose-containing carbohydrate antigens by changes in its tryptophan fluorescence. The strongest LABA binding was observed for the trisaccharide H of type 6 [α-L-Fucp-(1-2)-β-D-Galp-(1-4)-D-Glc, K a = 4.2 × 103 M−1]. The following antigens were bound with a weaker affinity: H-disaccharide α-L-Fucp-(1-2)-D-Gal, a glucoanalogue of tetrasaccharide Ley α-L-Fucp-(1-2)-β-D-Galp-(1-4)-[α-L-Fucp-(1-3)]-D-Glc, and 6-fucosyl-N-acetylglucosamine, a fragment of core of the N-glycans family (K a 1.1−1.7 × 103 M−1). The lowest binding was observed for L-fucose (K a = 2.7 × 102 M−1) and trisaccharide Lea, (β-Galp-(1-3)-[α-L-Fucp-(1-4)]-GlcNAc (K a = 6.4 × 102 M−1). The Led, Lea, and Lex pentasaccharides and Leb hexasaccharide were not bound to LABA.