Functions as a peptidoglycan terminase that cleaves nascent peptidoglycan strands endolytically to terminate their elongation. Mutations in this gene suppress deletion of PBP2b (penA); truncation at residue 168, undefined changes between residue Ile-447 and Ala-505, and mutation of Ala-505 suppress the penA deletion. Probably part of the elongasome which synthesizes peripheral peptidogylcan. Interacts with RodZ. Interacts with MreC in the elongasome; interaction is strongly reduced when the 90 C-terminal residues of MreC are missing (PubMed:28710862). Interacts with KhpB (also called EloR/Jag) via MltG's N-terminus, suggesting the N-terminus of MltG is cytoplasmic (PubMed:33558392). Localizes to midcell in the presence and absence of khpB (also called eloR/jag). Essential, it cannot be deleted. Belongs to the transglycosylase MltG family.