This domain has a lysozyme like fold. It is found in the tail protein of various phages probably giving them the ability to degrade the host cell wall peptidoglycan layer [1].

1: Crystal and cryoEM structural studies of a cell wall degrading enzyme in the bacteriophage phi29 tail. Xiang Y, Morais MC, Cohen DN, Bowman VD, Anderson DL, Rossmann MG; Proc Natl Acad Sci U S A. 2008;105:9552-9557. PMID:18606992