This domain is found in Beta-galactosidase from Streptococcus pneumoniae (BgaA) and similar bacterial sequences. BgaA is specific for terminal galactose residues beta-1-4 linked to glucose or N-acetylglucosamine. It is involved in pneumococcal growth, resistance to opsonophagocytic killing, and adherence. This entry represents two non-enzymatic carbohydrate-binding modules (CBMs) that mediate adherence to the host cell surface displayed lactose or N-acetyllactosamine. Each of these CBMs folds into a beta-sandwich fold comprising opposing sheets of 4- and 5-antiparallel beta-strands [1].

1: Unravelling the multiple functions of the architecturally intricate Streptococcus pneumoniae beta-galactosidase, BgaA. Singh AK, Pluvinage B, Higgins MA, Dalia AB, Woodiga SA, Flynn M, Lloyd AR, Weiser JN, Stubbs KA, Boraston AB, King SJ; PLoS Pathog. 2014;10:e1004364. PMID:25210925