Nucleotide sequence of themurDgene encoding the UDP-MurNAc-L-Ala-D-Glu synthetase ofEscherichia coli

The murD gene coding for the UDP-MurNAc-L-AIa-D-Glu synthetase of Escherichia coli has been recently identified at 2-min on the chromosome, within a large cluster of genes from pbpB to envA that code for proteins involved in peptidoglycan synthesis or cell division (1). Its nucleotide sequence has now been determined within the left part of a 2.6 kilobase-pair EcoRI-Sall chromosomal fragment (1) originating from pLC 2 6 6 of the Clarke and Carbon library. The coding region contains 1281 nucleotides which are translated into 427 amino acids corresponding to a protein with a molecular weight of 45893. This latter value is in agreement with that of the purified synthetase (2) or that of the protein expressed by the maxicell technique (1). The synthetase activity requires ATP hydrolysis and, as previously observed with the murF gene product (3), a domain A characteristic of ATP binding proteins is found between amino acids 100 and 110. murD is preceded by the X region (1) coding for an unknown protein and is immediately followed by the recently sequenced jisW gene (4).