This domain is the second all-beta domain from beta galactosidase enzymes which has a jelly roll fold [1]. These enzymes consist of a TIM-barrel catalytic domain and two all-beta domains (ABD), ABD1 is represented in Pfam:PF21317 and this entry represents ABD2.

1: Crystal structures of beta-galactosidase from Penicillium sp. and its complex with galactose. Rojas AL, Nagem RA, Neustroev KN, Arand M, Adamska M, Eneyskaya EV, Kulminskaya AA, Garratt RC, Golubev AM, Polikarpov I; J Mol Biol. 2004;343:1281-1292. PMID:15491613