Characterization and Cloning of the Genes Encoding Enterocin 1071A and Enterocin 1071B, Two Antimicrobial Peptides Produced by Enterococcus faecalis BFE 1071
AUTOR(ES)
Balla, E.
FONTE
American Society for Microbiology
RESUMO
The pH-neutral cell supernatant of Enterococcus faecalis BFE 1071, isolated from the feces of minipigs in Göttingen, inhibited the growth of Enterococcus spp. and a few other gram-positive bacteria. Ammonium sulfate precipitation and cation-exchange chromatography of the cell supernatant, followed by mass spectrometry analysis, yielded two bacteriocin-like peptides of similar molecular mass: enterocin 1071A (4.285 kDa) and enterocin 1071B (3.899 kDa). Both peptides are always isolated together. The peptides are heat resistant (100°C, 60 min; 50% of activity remained after 15 min at 121°C), remain active after 30 min of incubation at pH 3 to 12, and are sensitive to treatment with proteolytic enzymes. Curing experiments indicated that the genes encoding enterocins 1071A and 1071B are located on a 50-kbp plasmid (pEF1071). Conjugation of plasmid pEF1071 to E. faecalis strains FA2-2 and OGX1 resulted in the expression of two active peptides with sizes identical to those of enterocins 1071A and 1071B. Sequencing of a DNA insert of 9 to 10 kbp revealed two open reading frames, ent1071A and ent1071B, which coded for 39- and 34-amino-acid peptides, respectively. The deduced amino acid sequence of the mature Ent1071A and Ent1071B peptides showed 64 and 61% homology with the α and β peptides of lactococcin G, respectively. This is the first report of two new antimicrobial peptides representative of a fourth type of E. faecalis bacteriocin.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=91984Documentos Relacionados
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