Members of this family, which are found in the prokaryotic protein glycosyltrehalose trehalohydrolase, assume a gamma-crystallin-type fold with a five-stranded anti-parallel beta-sheet that packs against the C-terminal side of a beta-alpha barrel. This domain is common to family 13 glycosidases and typically contains a five to ten strand beta-sheet, however its precise fold varies [1].

1: Crystal structure of glycosyltrehalose trehalohydrolase from the hyperthermophilic archaeum Sulfolobus solfataricus. Feese MD, Kato Y, Tamada T, Kato M, Komeda T, Miura Y, Hirose M, Hondo K, Kobayashi K, Kuroki R; J Mol Biol. 2000;301:451-464. PMID:10926520