This domain is found associated with pfam01464. It is the N-terminal structural domain of MltC (Membrane-bound lytic murein transglycosylase C), one of the seven lytic transglycosylases found in the genome of the Gram-negative bacterium Escherichia coli. The role of the N-terminal domain is suggested to be important not as a mere structural extension of the active site beyond what is seen in other lytic transglycosylases but one that creates a peptide-binding site at position +2.