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.

Glycosyl hydrolases family 25.

Cpl-1 lysin (also known as Cpl-9 lysozyme / muramidase) is a bacterial cell wall endolysin encoded by the pneumococcal bacteriophage Cp-1, which cleaves the glycosidic N-acetylmuramoyl-(beta1,4)-N-acetylglucosamine bonds of the pneumococcal glycan chain, thus acting as an enzymatic antimicrobial agent (an enzybiotic) against streptococcal infections. Cpl-1 belongs to the CP family of lysozymes (CPL lysozymes) which includes the Cpl-7 lysin. Cpl-1 has a glycosyl hydrolase family 25 (GH25) catalytic domain with an irregular (beta/alpha)5-beta3 barrel and a C-terminal cell wall-anchoring module formed by six similar choline-binding repeats (ChBr's). The ChBr's facilitate the anchoring of Cpl-1 to the choline-containing teichoic acid of the pneumococcal cell wall. Other members of this domain family have an N-terminal CHAP (cysteine, histidine-dependent amidohydrolases/peptidases) domain similar to that of the firmicute CHAP lysins and associated with endopeptidase activity. The Cpl-7 lysin is also included here as is LysB of Lactococcus phage, and the Mur lysin of Lactobacillus phage.

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.

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

Amylopullulanase OS=Thermoanaerobacterium thermosulfurigenes OX=33950 GN=amyB PE=3 SV=2

Exoglucanase XynX OS=Acetivibrio thermocellus OX=1515 GN=xynX PE=3 SV=1

Endo-1,4-beta-xylanase A OS=Paenibacillus sp. (strain JDR-2) OX=324057 GN=xynA1 PE=1 SV=1

Cell surface glycoprotein 1 OS=Acetivibrio thermocellus (strain ATCC 27405 / DSM 1237 / JCM 9322 / NBRC 103400 / NCIMB 10682 / NRRL B-4536 / VPI 7372) OX=203119 GN=olpB PE=3 SV=2

Endo-1,4-beta-xylanase A OS=Thermoanaerobacterium saccharolyticum OX=28896 GN=xynA PE=1 SV=1