Mannose/glucose binding bark lectin. Bark lectins are storage proteins that probably maintain stocks of nitrogen during dormant period. Self-aggregatable molecules that can bind their own carbohydrate side chains. They could also play a role in the plant's defense against phytophagous invertebrates or herbivorous higher animals. Homotetramer of four 32 kDa monomers which are post-translationally cleaved into a two subunits: A and B. Binds one manganese (or another transition metal) ion and one calcium ion. The metal ions are essential for the saccharide-binding and cell-agglutinating activities (By similarity). Belongs to the leguminous lectin family.