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. 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.