LAUSR

Biochemistry Lysostaphin is a bacteriolytic enzyme that is active against methicillin-resistant Staphylococcus aureus . It targets cell wall peptidoglycan, which comprises short glycan chains that cross-link to form the bacterial cell wall. In staphylococci, the cross-link is pentaglycine, which can be cleaved by lysostaphin. Lysostaphin weakly binds to pentaglycine through the enzyme's SH3b domain. Gonzalez-Delgado et al. used nuclear magnetic resonance, x-ray crystallography, and mutational analysis to show that the SH3b domain has two binding sites on opposite sides of the enzyme. One site binds the pentaglycine cross-bridge, and the other site binds the peptide stem. Binding to the two sites induces clustering of lysostaphin. Weak binding, combined with high local concentration, likely allows the enzyme to rapidly and progressively degrade the peptidoglycan surface. Nat. Chem. Biol. 16 , 24 (2020).