Mammalian galectins bind carbohydrates, preferring poly-N-acetyl lactosamine (Galβ1→4GlcNAcβ1). The three structural groups are:
Proto Galectin
Galectin-1,2,5,7,10. Cross-link homologous carbohydrate ligands.
Chimera Galectin
Galectin-3. Cross-links carbohydrate and non-carbohydrate ligands.
Tandem Repeat Galectin
Galectin-4,6,8,9. Cross-link two distinct carbohydrate ligands.