Oligosaccharide specificity of the fucolectin from the bark of laburnum Laburnum anagyroides

Abstract

A comparative study of thin carbohydrate specificity of the lectin from the bark of laburnum Laburnum anagyroides (LABA) and fucolectin from asparagus pea Tetragonolobus purpureus (TPA) was performed using inhibition of agglutination of the complex formed by H-active neoglycoprotein and nanoparticles of colloidal gold. Both lectins bound most strongly the H type 2 oligosaccharides comprising O-glycanes; however, TPA was almost unable to discriminate between them. LABA bound more weakly the H type 6 trisaccharide (Fuc alpha 1-2Gal beta 1-4Glc) and difucosyllactose (Fuc alpha 1-2Gal beta 1-4[Fuc alpha 1-3]Glc), a glucoanalogue of the Le(y) antigen, and, even more weakly, the Le(a) pentasaccharide lacto-N-fucopentaose II (Gal beta 1-3[Fuc alpha 1-4]GlcNAc beta 1-3Gal beta 1-4Glc). However, LABA did not bind the antigens Le(b), Le(c), and Le(d), very poorly interacted with the terminal Le(x), and somewhat more strongly bound the internal Le(x). The lectin also had a hydrophobic binding site. Both lectins exhibited a cluster effect with polymeric ligands (neoglycoproteins).