title: The endolysin from the Enterococcus faecalis bacteriophage VD13 and conditions stimulating its lytic activity.
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.
authors.affiliation: Animal Biosciences and Biotechnology Laboratory, ARS, NEA, USDA, Beltsville, MD 20705-2350, USA.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Swift
authors.affiliation: Animal Biosciences and Biotechnology Laboratory, ARS, NEA, USDA, Beltsville, MD 20705-2350, USA.
authors.forename: D Treva
authors.initials: DT
authors.lastname: Rowley
authors.affiliation: Biology and Toxicology Department, Ashland University, Ashland, OH 44805-3796, USA.
authors.forename: Carly
authors.initials: C
authors.lastname: Young
authors.affiliation: Biology and Toxicology Department, Ashland University, Ashland, OH 44805-3796, USA.
authors.forename: Ashley
authors.initials: A
authors.lastname: Franks
authors.affiliation: Biology and Toxicology Department, Ashland University, Ashland, OH 44805-3796, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Hyman
authors.affiliation: Animal Biosciences and Biotechnology Laboratory, ARS, NEA, USDA, Beltsville, MD 20705-2350, USA.
authors.forename: David M
authors.initials: DM
authors.lastname: Donovan
keywords: 
            Enterococcus faecalis
          ; VD13; endolysin; peptidoglycan hydrolase