LysA is a cell wall endolysin produced by Lactobacillus fermentum, which degrades bacterial cell walls by catalyzing the hydrolysis of 1,4-beta-linkages between N-acetylmuramic acid and N-acetyl-D-glucosamine residues. The N-terminal glycosyl hydrolase family 25 (GH25) domain of LysA has sequence similarity with other murein hydrolase catalytic domains while the C-terminal domain has sequence similarity with putative bacterial cell wall-binding SH3b domains. This domain family also includes LysL of Lactococcus lactis.