This domain can be found in 2 glycoside hydrolase subfamily of beta-glucosaminidases (EC:3.2.1.165) such as CsxA, from Amycolatopsis orientalis that has exo-beta-D-glucosaminidase (exo-chitosanase) activity. It has an immunoglobulin-like topology [1].

1: The structural basis of substrate recognition in an exo-beta-D-glucosaminidase involved in chitosan hydrolysis. van Bueren AL, Ghinet MG, Gregg K, Fleury A, Brzezinski R, Boraston AB; J Mol Biol. 2009;385:131-139. PMID:18976664