Inhibition of the Activity of Both Domains of Lysostaphin through Peptidoglycan Modification by the Lysostaphin Immunity Protein

Abstract

Resistance to lysostaphin, a staphylolytic glycylglycine endopeptidase, is due to a FemABX-like immunity protein that inserts serines in place of some glycines in peptidoglycan cross bridges. These modifications inhibit both binding of the recombinant cell wall targeting domain and catalysis by the recombinant catalytic domain of lysostaphin.

Fusion with a cell wall binding domain renders autolysin LytM a potent anti-Staphylococcus aureus agent

“…For example, ssLys’s activity is compromised by removal of its CWBD (Gargis et al , 2010), and we ourselves have observed a 750-fold decrease in the bacterial lysis kinetics of truncated ssLys (ssLys ΔCWBD ; amino acids 248–400; Fig. 2a).…”

“…The CWBDs serve to target the enzymes to the bacterial outer surface, thereby facilitating direct interaction between the enzymes’ catalytic domains and their peptidoglycan substrate. This targeting function is of paramount importance in the activity of multi-domain lysins, as deletion of CWBDs greatly reduces the lytic activity of otherwise potent enzymes (Gargis et al , 2010; Frankel & Schneewind, 2012). Conversely, the selectively and activity of numerous lysins have been manipulated and enhanced via genetic fusion of different catalytic and CWBD components (Nelson et al , 2011; Pastagia et al , 2013).…”

Food applications of bacterial cell wall hydrolases

“…In the case of lysostaphin, an endopeptidase produced by some Staphylococcus species that specifically cleaves the glycine-glycine bonds in the interpeptide cross-bridge of the S. aureus cell wall (Figure 1), resistance can be achieved by the incorporation of serines in place of some glycines in the cross-bridge [17].…”

Resistance to bacteriocins produced by Gram-positive bacteria

“…Resistance to lysostaphin (a five-to 15-fold increase in MIC) occurred both in vitro (at frequencies of ,10 29 to 10 21 ) and in a rabbit model of experimental endocarditis (at a frequency of 10 26 ) (Climo et al, 2001;Kusuma & Kokai-Kun, 2005) following exposure to low doses of lysostaphin . This resistance has generally been associated with mutations in femAB and results in an alteration of the peptidoglycan cross-bridges, in which one or more serine residues replace glycine (Gargis et al, 2010;Strandén et al, 1997). Moreover, this resistance mechanism is generally accompanied by increased b-lactam susceptibility (Climo et al, 2001;Guignard et al, 2005;Kiri et al, 2002;Rohrer & Berger-Bächi, 2003) and by loss of fitness in the mutants (Kusuma et al, 2007).…”