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N-acetylmuramidase Endolysins are bacteriophage encoded proteins synthesized at the end of the lytic infection cycle. They degrade the peptidoglycan (PG) of the host bacterium to allow viral progeny release. This domain family is found in bacteria and viruses. It is also found associated with pfam01471. One of the family members is the modular Gp110 endolysin found in the Salmonella phage. This domain represents the catalytic region found in the C-terminal of Gp110. It has been demonstrated to have N-acetylmuramidase (lysozyme) activity cleaving the beta-(1,4) glycosidic bond between N-acetylmuramic acid and N-acetylglucosamine residues in the sugar backbone of the PG. Furthermore, sequence alignments containing this domain show that the Gp110 E101 residue is conserved (suggesting that is is the catalytic residue), and followed by serine (a common feature in lysozymes). The structure of endolysins varies depending on their origin. In general, most of the endolysins from phages infecting Gram-positive bacteria have a modular structure consisting of one or two N-terminal enzymatic active domains (EADs) and a C-terminal cell wall binding domain (CBD) separated by a short linker. In silico analysis indicate that this endolysin has a modular structure harboring this EAD family at the C terminus and a PG_binding_1 CBD at the N terminus. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",