This beta barrel domain is found inserted in the MltA a murein degrading transglycosylase enzyme [1]. This domain may be involved in peptidoglycan binding.

1: Crystal structure of MltA from Escherichia coli reveals a unique lytic transglycosylase fold. van Straaten KE, Dijkstra BW, Vollmer W, Thunnissen AM; J Mol Biol 2005;352:1068-1080. PMID:16139297