This domain belongs to family 53 of the glycosyl hydrolase classification [1]. These enzymes are enzymes are endo-1,4- beta-galactanases (EC:3.2.1.89). The structure of this domain is known [2] and has a TIM barrel fold.

1: An evolving hierarchical family classification for glycosyltransferases. Coutinho PM, Deleury E, Davies GJ, Henrissat B; J Mol Biol 2003;328:307-317. PMID:12691742

2: Aspergillus aculeatus beta-1,4-galactanase: substrate recognition and relations to other glycoside hydrolases in clan GH-A. Ryttersgaard C, Lo Leggio L, Coutinho PM, Henrissat B, Larsen S; Biochemistry 2002;41:15135-15143. PMID:12484750