This domain is found in Tlde1 family of antibacterial effectors secreted by the type VI secretion system (T6SS). Tlde1 family is evolutionarily related to l,d transpeptidases which form mDAP3-mDAP3 peptidoglycan crosslinks. Tlde1 family is widespread among Proteobacteria and is divided into three subfamilies (Tlde1a, Tlde1b and Tlde1c).
Jiyao W et al.(2023). "The conserved domain database in 2023.",