D-mannose/D-glucose-binding lectin. Also binds derivatives of glucose and mannose such as more complex glycans. Homotetramer. The beta and gamma chains are produced by partial proteolytic processing of the lectin alpha chain by an asparaginyl endopeptidase. 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.