Catalyzes the formation of UDP-N-acetylmuramate (UDP-MurNAc), a crucial precursor of the bacterial peptidoglycan cell wall, from UTP and MurNAc-alpha-1P (By similarity). Is involved in peptidoglycan recycling as part of a cell wall recycling pathway that bypasses de novo biosynthesis of the peptidoglycan precursor UDP-MurNAc (PubMed:24819062). Plays a role in intrinsic resistance to fosfomycin, which targets the de novo synthesis of UDP-MurNAc (PubMed:24819062). H(+) + N-acetyl-alpha-D-muramate 1-phosphate + UDP = phosphate + UDP-N-acetyl-alpha-D-muramate Cell wall biogenesis; peptidoglycan recycling. Monomer. Cells lacking this gene accumulate MurNAc 1-phosphate. Deletion of this gene increases fosfomycin sensitivity. Growth rate is not affected. Belongs to the nucleotidyltransferase MurU family.