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Following Cell-fate in E. coli After Infection by Phage Lambda
Published on: October 14, 2011
The endolysin from the Enterococcus faecalis bacteriophage VD13 and conditions stimulating its lytic activity
Steven M Swift1, D Treva Rowley1, Carly Young2
1Animal Biosciences and Biotechnology Laboratory, ARS, NEA, USDA, Beltsville, MD 20705-2350, USA.
Abstract:
Bacteriophages produce endolysins (peptidoglycan hydrolases) to lyse the host cell from within and release nascent bacteriophage particles. Recombinant endolysins can lyse Gram-positive bacteria when added exogenously. As a potential alternative antimicrobial, we cloned and expressed the enterococcal VD13 bacteriophage endolysin. VD13 endolysin has a CHAP catalytic domain with 92% identity with the bacteriophage IME-EF1 endolysin. The predicted size of VD13 endolysin is ∼27 kDa as verified by SDS-PAGE. The VD13 endolysin lyses Enterococcus faecalis strains, but not E. faecium or other non-enterococci. VD13 endolysin has activity from pH 4 to pH 8, with peak activity at pH 5, and exhibits greater activity in the presence of calcium. Optimum activity at pH 5 occurs in the absence of NaCl. VD13 endolysin, in ammonium acetate (C2H3O2NH4) calcium chloride (CaCl2) buffer pH 5, is stimulated to higher activity upon heating at temperatures up to 65°C for 30 min, whereas activity is lost upon heating to 42°C, in pH 7 buffer.
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