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.

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.

Glycosyl hydrolases family 25.

Lyc muramidase is an autolytic lysozyme (autolysin) from Clostridium acetobutylicum encoded by the lyc gene. Lyc has 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.

Lys-1 is a lysozyme encoded by the Caenorhabditis elegans lys-1 gene. This gene is one of a several lysozyme genes upregulated upon infection by the Gram-negative bacterial pathogen Serratia marcescens. Lys-1 contains a glycosyl hydrolase family 25 (GH25) catalytic domain. This family also includes Lys-5 from Caenorhabditis elegans.

Thestructure of a family GH25 lysozyme from Aspergillus fumigatus [Aspergillus fumigatus Af293],2X8R_B The structure of a family GH25 lysozyme from Aspergillus fumigatus [Aspergillus fumigatus Af293],2X8R_C The structure of a family GH25 lysozyme from Aspergillus fumigatus [Aspergillus fumigatus Af293],2X8R_D The structure of a family GH25 lysozyme from Aspergillus fumigatus [Aspergillus fumigatus Af293],2X8R_E The structure of a family GH25 lysozyme from Aspergillus fumigatus [Aspergillus fumigatus Af293],2X8R_F The structure of a family GH25 lysozyme from Aspergillus fumigatus [Aspergillus fumigatus Af293]

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

Lysozyme M1 OS=Streptomyces globisporus OX=1908 GN=acm PE=1 SV=1