Characterization and cloning of the genes encoding enterocin 1071A and enterocin 1071B, two antimicrobial peptides produced by Enterococcus faecalis BFE 1071
E. Balla et al., Characterization and cloning of the genes encoding enterocin 1071A and enterocin 1071B, two antimicrobial peptides produced by Enterococcus faecalis BFE 1071, APPL ENVIR, 66(4), 2000, pp. 1298-1304
The pH-neutral cell supernatant of Enterococcus faccalis BFE 1071, isolated
from the feces of minipigs in Gottingen, inhibited the growth of Enterococ
cus spp, and a few other gram-positive bacteria. Ammonium sulfate precipita
tion and cation-exchange chromatography of the cell supernatant, followed b
y mass spectrometry analysis, yielded two bacteriocin-like peptides of simi
lar molecular mass: enterocin 1071A (4.285 kDa) and enterocin 1071B (3.899
kDa). Both peptides are always isolated together. The peptides are heat res
istant (100 degrees C, 60 min; 50% of activity remained after 15 min at 121
degrees C), remain active after 30 min of incubation at pH 3 to 12, and ar
e sensitive to treatment with proteolytic enzymes. Curing experiments indic
ated that the genes encoding enterocins 1071A and 1071B are located on a 50
-kbp plasmid (pEF1071). Conjugation of plasmid pEF1071 to E.faecalis strain
s FA2-2 and OGX1 resulted in the expression of two active peptides with siz
es identical to those of enterocins 1071A and 1071B, Sequencing of a DNA in
sert of 9 to 10 kbp revealed two open reading Frames, ent1071A and ent1071B
, which coded for 39- and M-amino-acid peptides? respectively. The deduced
amino acid sequence of the mature Ent1071A and Ent1071B peptides showed 64
and 61% homology with the alpha and beta peptides of lactococcin G, respect
ively. This is the first report of tno nem antimicrobial peptides represent
ative of a fourth type of E. faecalis bacteriocin.