Catalysis of the reaction: 2 a peptidoglycan dimer (tetrapeptide) + 3 H2O = a peptidoglycan tetramer with L,D cross-links (L-Lys-D-Asn-L-Lys) + di-trans,poly-cis-undecaprenyl diphosphate + 4 D-alanine.
peptidoglycan L,D-transpeptidase activity