Involved in peptidoglycan biosynthesis. Transports lipid-linked peptidoglycan precursors from the inner to the outer leaflet of the cytoplasmic membrane. Cell wall biogenesis; peptidoglycan biosynthesis. Belongs to the MurJ/MviN family. Was originally (PubMed:2680969) thought to be involved in mouse virulence. It was later shown that the mutation responsible for the virulence phenotype maps to nearby genes (PubMed:8288531).