The LytC lysozyme of Streptococcus pneumoniae is a bacterial cell wall hydrolase that cleaves the beta1-4-glycosydic bond located between the N-acetylmuramoyl-N-glucosaminyl residues of the cell wall polysaccharide chains. LytC is composed of a C-terminal glycosyl hydrolase family 25 (GH25) domain and an N-terminal choline-binding module (CBM) consisting of eleven homologous repeats that specifically recognizes the choline residues of pneumococcal lipoteichoic and teichoic acids. This domain arrangement is the reverse of the major pneumococcal autolysin, LytA, and the CPL-1-like lytic enzymes of the pneumococcal bacteriophages, in which the CBM (consisting of six repeats) is at the C-terminus. This model represents the C-terminal catalytic domain of the LytC-like enzymes.

Endo-N-acetylmuramidases (muramidases) are lysozymes (also referred to as peptidoglycan hydrolases) that degrade bacterial cell walls by catalyzing the hydrolysis of 1,4-beta-linkages between N-acetylmuramic acid and N-acetyl-D-glucosamine residues. This family of muramidases contains a glycosyl hydrolase family 25 (GH25) catalytic domain and is found in bacteria, fungi, slime molds, round worms, protozoans and bacteriophages. The bacteriophage members are referred to as endolysins which are involved in lysing the host cell at the end of the replication cycle to allow release of mature phage particles. Endolysins are typically modular enzymes consisting of a catalytically active domain that hydrolyzes the peptidoglycan cell wall and a cell wall-binding domain that anchors the protein to the cell wall. Endolysins generally have narrow substrate specificities with either intra-species or intra-genus bacteriolytic activity.

PlyB is a bacteriophage endolysin that displays potent lytic activity toward Bacillus anthracis. PlyB has an N-terminal glycosyl hydrolase family 25 (GH25) catalytic domain and a C-terminal bacterial SH3-like domain, SH3b. Both domains are required for effective catalytic activity. Endolysins are produced by bacteriophages at the end of their life cycle and participate in lysing the bacterial cell in order to release the newly formed progeny. Endolysins (also referred to as endo-N-acetylmuramidases or peptidoglycan hydrolases) degrade bacterial cell walls by catalyzing the hydrolysis of 1,4-beta-linkages between N-acetylmuramic acid and N-acetyl-D-glucosamine residues.

Lysin Motif is a small domain involved in binding peptidoglycan. LysM, a small globular domain with approximately 40 amino acids, is a widespread protein module involved in binding peptidoglycan in bacteria and chitin in eukaryotes. The domain was originally identified in enzymes that degrade bacterial cell walls, but proteins involved in many other biological functions also contain this domain. It has been reported that the LysM domain functions as a signal for specific plant-bacteria recognition in bacterial pathogenesis. Many of these enzymes are modular and are composed of catalytic units linked to one or several repeats of LysM domains. LysM domains are found in bacteria and eukaryotes.

Uncharacterized bacterial muramidase containing a glycosyl hydrolase family 25 (GH25) catalytic domain. Endo-N-acetylmuramidases are lysozymes (also referred to as peptidoglycan hydrolases) that degrade bacterial cell walls by catalyzing the hydrolysis of 1,4-beta-linkages between N-acetylmuramic acid and N-acetyl-D-glucosamine residues.

High-resolutionstructure of catalytic domain of endolysin ply40 from bacteriophage P40 of Listeria monocytogenes [Listeria phage P40]

3D-structureof the modular autolysin LytC from Streptococcus pneumoniae at 1.6 A resolution [Streptococcus pneumoniae R6],2WWD_A 3D-structure of the modular autolysin LytC from Streptococcus pneumoniae in complex with pneummococcal peptidoglycan fragment [Streptococcus pneumoniae R6]

3D-structureof the modular autolysin LytC from Streptococcus pneumoniae in complex with synthetic peptidoglycan ligand [Streptococcus pneumoniae R6]

Crystalstructure of the bacterial lysozyme from Streptomyces coelicolor at 1.65 A resolution [Streptomyces coelicolor]

Structurebasis of a novel virulence factor GHIP a glycosyl hydrolase 25 of Streptococcus pneumoniae participating in host cell invasion [Streptococcus pneumoniae]

N-acetylmuramoyl-L-alanine amidase sle1 OS=Staphylococcus saprophyticus subsp. saprophyticus (strain ATCC 15305 / DSM 20229 / NCIMB 8711 / NCTC 7292 / S-41) OX=342451 GN=sle1 PE=3 SV=1

N-acetylmuramoyl-L-alanine amidase sle1 OS=Staphylococcus epidermidis (strain ATCC 12228 / FDA PCI 1200) OX=176280 GN=sle1 PE=3 SV=1

N-acetylmuramoyl-L-alanine amidase sle1 OS=Staphylococcus epidermidis (strain ATCC 35984 / RP62A) OX=176279 GN=sle1 PE=3 SV=1

N-acetylmuramoyl-L-alanine amidase sle1 OS=Staphylococcus aureus (strain N315) OX=158879 GN=sle1 PE=1 SV=1

N-acetylmuramoyl-L-alanine amidase sle1 OS=Staphylococcus aureus OX=1280 GN=sle1 PE=3 SV=1