UDP-N-acetylglucosamine 1-carboxyvinyl-transferase from Acinetobacter calcoaceticus.

We have analyzed the sequence downstream of rpoN from Acinetobacter calcoaceticus and identified an open reading frame encoding a protein with high similarity to UDP-N-acetylglucosamine 1-carboxyvinyl-transferase (MurZ). Multicopy plasmids encoding this enzyme conferred phosphomycin resistance to A. calcoaceticus. The polar effect of a rpoN mutation on the phosphomycin resistance level suggests that murZ is, in part, cotranscribed with rpoN. These observations confirm that A. calcoaceticus represents the first exception from a conserved genetic context of rpoN observed in several other Gram-negative bacteria.