This domain is found in bacteria, and is approximately 40 amino acids in length. This domain is found in bacillus cereus group bacteria and functionally related to antimicrobial activity. It has been reported linked to CHAP, PGBD and SH3 domains in a putative cysteine protease [1]. This domain consists of three antiparallel beta-strands in a beta1-beta3-beta2 topology.

1: Functional and structural characterization of a novel putative cysteine protease\tcell wall-modifying multi-domain enzyme selected from a microbial metagenome. Faheem M, Martins-de-Sa D, Vidal JF, Alvares AC, Brandao-Neto J, Bird LE, Tully MD, von Delft F, Souto BM, Quirino BF, Freitas SM, Barbosa JA; Sci Rep. 2016;6:38031. PMID:27934875