This domain represents the N terminal domain in chitobiases and beta-hexosaminidases EC:3.2.1.52. It is composed of a beta sandwich structure that is similar in structure to the cellulose binding domain of cellulase from Cellulomonas fimi [1]. This suggests that this may be a carbohydrate binding domain.

1: Bacterial chitobiase structure provides insight into catalytic mechanism and the basis of Tay-Sachs disease. Tews I, Perrakis A, Oppenheim A, Dauter Z, Wilson KS, Vorgias CE; Nat Struct Biol 1996;3:638-648. PMID:8673609