Peptidoglycan degrading activity of the broad-range Salmonella bacteriophage S-394 recombinant endolysin

Various outer membrane permeabilizers were analyzed in combination with Lys394 to degrade laboratory strain of E. coli CR63. Permeabilizing activity was evaluated using a periplasmic β-lactamase leakage test with untreated E. coli cells as a substrate. The highest rate of planktonic E. coli lysis was reached for Lys394 applied together with 25 μg/ml of poly-l-arginine with molecular weight distribution from 5 to 15 kDa or 20 μg/ml PGLa peptide. Lawn E. coli colony forming ability was decreased by 4 orders of magnitude after 30 min treatment with 25 μg of Lys394, 1 mM EDTA and 50 μg/ml of PGLa peptide at a room temperature.