Releases the terminal D-alanine residue from the cytoplasmic tetrapeptide recycling product L-Ala-gamma-D-Glu-meso-Dap-D-Ala. To a lesser extent, can also cleave D-Ala from murein derivatives containing the tetrapeptide, i.e. MurNAc-tetrapeptide, UDP-MurNAc-tetrapeptide, GlcNAc-MurNAc-tetrapeptide, and GlcNAc-anhMurNAc-tetrapeptide. Does not act on murein sacculi or cross-linked muropeptides. The tripeptides produced by the LcdA reaction can then be reused as peptidoglycan building blocks; LcdA is thereby involved in murein recycling. Is also essential for viability during stationary phase. H2O + N-acetyl-D-glucosaminyl-N-acetylmuramoyl-L-alanyl-D-glutamyl-6-carboxy-L-lysyl-D-alanine = D-alanine + N-acetyl-D-glucosaminyl-N-acetylmuramoyl-L-alanyl-D-glutamyl-6-carboxy-L-lysyl Inhibited by beta-lactams containing a D-amino acid side chain. Cell wall biogenesis; peptidoglycan recycling. Bacteriolysis during the stationary growth phase. Cells lacking this gene also accumulate UDP-MurNAc-tetrapeptide, an unusual compound that normally is not present at significant levels in E.coli cells. Belongs to the peptidase S66 family.