Fig. 2

Preparation and stability of the recombinant endolysin LysSYL. A Schematic diagram showing the recombinant plasmid pET21a-LysSYL. B SDS-PAGE analysis of the purified endolysin LysSYL. Lane 1, E. coli BL21/pET21a-LysSYL. Lane 2, Supernatant of the IPTG-induced bacteria after sonication. Lane 3, Pellet of the IPTG-induced bacteria after sonication. Lane 4, endolysin LysSYL after purification with Ni-NTA column. M, protein marker. The sizes of the marker are indicated on the left. C Stability of the recombinant endolysin LysSYL in diverse temperature. The activity was shown relative to that of LysSYL at 4 °C. LysSYL stability in various (D) pH, and (E) EDTA (black line) and NaCl (blue line). F Bactericidal activity of LysSYL in different concentrations of mouse sera. PBS served as control. Viable bacteria were counted with plate dilution assay. The experiment was conducted three times. Data were presented as mean ± standard derivation (SD). Significance was calculated by two-way ANOVA between LysSYL treatment and PBS control. ***, P < 0.001