N-acetylmuramoyl-L-alanine amidase or MurNAc-LAA (also known as peptidoglycan aminohydrolase, NAMLA amidase, NAMLAA, Amidase 3, and peptidoglycan amidase; EC 3.5.1.28) is an autolysin that hydrolyzes the amide bond between N-acetylmuramoyl and L-amino acids in certain cell wall glycopeptides. These proteins are Zn-dependent peptidases with highly conserved residues involved in cation co-ordination. MurNAc-LAA in this family is one of several peptidoglycan hydrolases (PGHs) found in bacterial and bacteriophage or prophage genomes that are involved in the degradation of the peptidoglycan. In Escherichia coli, there are five MurNAc-LAAs present: AmiA, AmiB, AmiC and AmiD that are periplasmic, and AmpD that is cytoplasmic. Three of these (AmiA, AmiB and AmiC) belong to this family, the other two (AmiD and AmpD) do not. E. coli AmiA, AmiB and AmiC play an important role in cleaving the septum to release daughter cells after cell division. In general, bacterial MurNAc-LAAs are members of the bacterial autolytic system and carry a signal peptide in their N-termini that allows their transport across the cytoplasmic membrane. However, the bacteriophage MurNAc-LAAs are endolysins since these phage-encoded enzymes break down bacterial peptidoglycan at the terminal stage of the phage reproduction cycle. As opposed to autolysins, almost all endolysins have no signal peptides and their translocation through the cytoplasmic membrane is thought to proceed with the help of phage-encoded holin proteins. The amidase catalytic module is fused to another functional module (cell wall binding module or CWBM) either at the N- or C-terminus, which is responsible for high affinity binding of the protein to the cell wall.

1,4-beta-N-acetylmuramoylhydrolase.

1,4-beta-N-acetylmuramoylhydrolase.

N-acetylmuramoyl-L-alanine amidase. This enzyme domain cleaves the amide bond between N-acetylmuramoyl and L-amino acids in bacterial cell walls.

N-acetylmuramoyl-L-alanine amidase [Cell wall/membrane/envelope biogenesis].

ChainA, Extracellular Protein 6 [Fulvia fulva],4B9H_A Chain A, Extracellular Protein 6 [Fulvia fulva]

ChainA, Putative N-acetylmuramoyl-L-alanine amidase,autolysin cwp6 [Clostridioides difficile 630],5J72_B Chain B, Putative N-acetylmuramoyl-L-alanine amidase,autolysin cwp6 [Clostridioides difficile 630]

ChainA, Cell wall hydrolase/autolysin [Nostoc punctiforme PCC 73102]

ChainA, N-acetylmuramoyl-L-alanine amidase [Clostridioides difficile 630]

Crystalstructure of the N-terminal LysM domains from the putative NlpC/P60 D,L endopeptidase from T. thermophilus [Thermus thermophilus HB8],4UZ2_B Crystal structure of the N-terminal LysM domains from the putative NlpC/P60 D,L endopeptidase from T. thermophilus [Thermus thermophilus HB8],4UZ2_C Crystal structure of the N-terminal LysM domains from the putative NlpC/P60 D,L endopeptidase from T. thermophilus [Thermus thermophilus HB8],4UZ2_D Crystal structure of the N-terminal LysM domains from the putative NlpC/P60 D,L endopeptidase from T. thermophilus [Thermus thermophilus HB8],4UZ3_A Crystal structure of the N-terminal LysM domains from the putative NlpC/P60 D,L endopeptidase from T. thermophilus bound to N-acetyl-chitohexaose [Thermus thermophilus HB8],4UZ3_B Crystal structure of the N-terminal LysM domains from the putative NlpC/P60 D,L endopeptidase from T. thermophilus bound to N-acetyl-chitohexaose [Thermus thermophilus HB8],4UZ3_C Crystal structure of the N-terminal LysM domains from the putative NlpC/P60 D,L endopeptidase from T. thermophilus bound to N-acetyl-chitohexaose [Thermus thermophilus HB8]

Peptidoglycan endopeptidase LytF OS=Bacillus subtilis (strain 168) OX=224308 GN=lytF PE=1 SV=2

Autolysin OS=Enterococcus faecalis (strain ATCC 700802 / V583) OX=226185 GN=EF_0799 PE=1 SV=2

D-gamma-glutamyl-meso-diaminopimelic acid endopeptidase CwlS OS=Bacillus subtilis (strain 168) OX=224308 GN=cwlS PE=1 SV=1

Probable peptidoglycan endopeptidase LytE OS=Bacillus subtilis (strain 168) OX=224308 GN=lytE PE=1 SV=1

Muramidase-2 OS=Enterococcus hirae (strain ATCC 9790 / DSM 20160 / JCM 8729 / LMG 6399 / NBRC 3181 / NCIMB 6459 / NCDO 1258 / NCTC 12367 / WDCM 00089 / R) OX=768486 GN=EHR_05900 PE=1 SV=1