Multivalent II [β-d-Galp-(1→4)-β-d-GlcpNAc] and Tα [β-d-Galp-(1→3)-α-d-GalpNAc] specific Moraceae family plant lectin from the seeds of Ficus bengalensis fruits

A galactose specific lectin was isolated from the seeds of Ficus bengalensis (Moraceae) fruits and designated as F. bengalensis agglutinin (FBA). The lectin was purified by affinity repulsion chromatography on fetuin-agarose and was a monomer of molecular mass 33 kDa. Like other Moraceae family lectins, carbohydrate-binding activity of FBA was independent of any divalent cation. FBA did not bind with simple saccharides, however sugar ligands with aromatic aglycons showed pronounced binding. The combining site of FBA recognized preferably Galβ1,4GlcNAcβ1-(II) followed by Galβ1,3GalNAcα1-(Tα) containing glycotopes. Interaction with saccharides revealed that the combining site of FBA could well accommodate a tetrasaccharide, asialo GM1 glycan (Galβ1,3GalNAcβ1,4Galβ1,4Glcβ1-), whereas polyvalent Tn (GalNAcα1-Ser/Thr), one of the well-recognized ligands of Moraceae family lectin, did not interact well with FBA.

Graphical abstractFicus bengalensis agglutinin (FBA): A novel Moraceae family plant lectin of polyvalent β-d-Galp-(1→4)-β-d-GlcpNAc and/or β-d-Galp-(1→3)-α-d-GalpNAc specificity that recognizes asialo GM1 glycan β-d-Galp-(1→3)-β-d-GalpNAc-(1→4)-β-d-Galp-(1→3)-β-d-Glcp] most strongly.