Catalyzes the formation of UDP-N-acetylmuramate (UDP-MurNAc), a crucial precursor of the bacterial peptidoglycan cell wall, from UTP and MurNAc-alpha-1P (PubMed:23831760, PubMed:25767118). 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:23831760). Plays a role in intrinsic resistance to fosfomycin, which targets the de novo synthesis of UDP-MurNAc (PubMed:23831760). Is not able to use GlcNAc-alpha-1P and GalNAc-alpha-1P as substrates (PubMed:23831760). Cannot accept other nucleotide triphosphates (ATP, CTP, TTP, or GTP) than UTP (PubMed:25767118). H(+) + N-acetyl-alpha-D-muramate 1-phosphate + UDP = phosphate + UDP-N-acetyl-alpha-D-muramate Is completely inhibited by EDTA in vitro. Cell wall biogenesis; peptidoglycan recycling. Monomer. Cells lacking this gene accumulate MurNAc phosphate. Deletion of this gene increases fosfomycin sensitivity. Belongs to the nucleotidyltransferase MurU family.