This domain is found in endo-alpha-N-acetylgalactosaminidase present in Streptococcus pneumoniae. Endo-alpha-N-acetylgalactosaminidase is a cell surface-anchored glycoside hydrolase involved in the breakdown of mucin type O-linked glycans. The domain, known as domain 2, exhibits strong structural similarlity to the galactose mutarotase-like fold but lacks the active site residues. Domains, found in a number of glycoside hydrolases, structurally similar to domain 2 confer stability to the multidomain architectures [1].

1: The structural basis for T-antigen hydrolysis by Streptococcus pneumoniae: a target for structure-based vaccine design. Caines ME, Zhu H, Vuckovic M, Willis LM, Withers SG, Wakarchuk WW, Strynadka NC; J Biol Chem. 2008;283:31279-31283. PMID:18784084