WGA is found in three forms, known as isolectins A, B, and D. Each isolectin consists of two identical polypeptide chains, totaling 171 amino acid residues and forming dimers with a mass of about 36 kDa. Within each polypeptide, there are four similar domains. These domains share structural folds and are stabilized by four conserved intradomain disulfide bonds. The two lectin subunits come together in a head-to-tail manner to create the dimeric structure of WGA.