M23 family metallopeptidase, also known as beta-lytic metallopeptidase, and similar proteins
This model describes the metallopeptidase M23 family, which includes beta-lytic metallopeptidase and lysostaphin. Members of this family are zinc endopeptidases that lyse bacterial cell wall peptidoglycans; they cleave either the N-acylmuramoyl-Ala bond between the cell wall peptidoglycan and the cross-linking peptide (e.g. beta-lytic endopeptidase) or a bond within the cross-linking peptide (e.g. stapholysin, and lysostaphin). Beta-lytic metallopeptidase, formerly known as beta-lytic protease, has a preference for cleavage of Gly-X bonds and favors hydrophobic or apolar residues on either side. It inhibits growth of sensitive organisms and may potentially serve as an antimicrobial agent. Lysostaphin, produced by Staphylococcus genus, cleaves pentaglycine cross-bridges of cell wall peptidoglycan, acting as autolysins to maintain cell wall metabolism or as toxins and weapons against competing strains. Staphylolysin (also known as LasA) is implicated in a range of processes related to Pseudomonas virulence, including stimulating shedding of the ectodomain of cell surface heparan sulphate proteoglycan syndecan-1, and elastin degradation in connective tissue. Its active site is less constricted and contains a five-coordinate zinc ion with trigonal bipyramidal geometry and two metal-bound water molecules, possibly contributing to its activity against a wider range of substrates than those used by related lytic enzymes, consistent with its multiple roles in Pseudomonas virulence. The family includes members that do not appear to have the conserved zinc-binding site and might be lipoproteins lacking proteolytic activity.