This family acts as a lysozyme (N-acetylmuramidase), EC:3.2.1.17. It contains a conserved EGGY motif near the N-terminus, the glutamic acid within this motif is essential for catalytic activity [1]. In bacteria, it may activate the secretion of large proteins via the breaking and rearrangement of the peptidoglycan layer during secretion [2,3]. It is frequently found at the N-terminus of proteins containing a C-terminal Pfam:PF09374 domain.

1: Coliphage N4 N-acetylmuramidase defines a new family of murein hydrolases. Stojkovic EA, Rothman-Denes LB; J Mol Biol. 2007;366:406-419. PMID:17174325

2: COG3926 and COG5526: A tale of two new lysozyme-like protein families. Pei J, Grishin NV; Protein Sci 2005; [Epub ahead of print] PMID:16155206

3: Cloning and characterization of a pair of genes that stimulate the production and secretion of Zymomonas mobilis extracellular levansucrase and invertase. Kondo Y, Toyoda A, Fukushi H, Yanase H, Tonomura K, Kawasaki H, Sakai T; Biosci Biotechnol Biochem. 1994;58:526-530. PMID:7764692