Involved with EC?6.3.2.4?(D-alanine¡ªD-alanine ligase), EC?6.3.2.7?(UDP-N-acetylmuramoyl-L-alanyl-D-glutamate¡ªL-lysine ligase) or EC?6.3.2.13?(UDP-N-acetylmuramoylalanyl-D-glutamate¡ª2,6-diaminopimelate ligase), EC?6.3.2.8?(UDP-N-acetylmuramate¡ªL-alanine ligase) and EC?6.3.2.9?(UDP-N-acetylmuramoylalanine¡ªD-glutamate ligase) in the synthesis of a cell-wall peptide. This enzyme also catalyses the reaction when the C-terminal residue of the tripeptide is?meso-2,4-diaminoheptanedioate (acylated at its?L-centre), linking the?D-Ala¡ªD-Ala to the carboxy group of the?L-centre. This activity was previously attributed to EC?6.3.2.15, which has since been deleted.