Purification and genetic characterization of enterocin I from Enterococcus faecium 6T1a, a novel antilisterial plasmid-encoded bacteriocin which does not belong to the pediocin family of bacteriocins

• Published in: Applied and Environmental Microbiology Vol. 64; no. 12; pp. 4883 - 4890
• Main Authors: Floriano, B. (Instituto de la Grasa, Seville, Spain.), Ruiz-Barba, J.L, Jimenez-Diaz, R
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for Microbiology 01.12.1998
• Subjects: Amino Acid Sequence; ANTIBACTERIAL PROPERTIES; ANTIMICROBIAL PROPERTIES; BACTERIOCINAS; BACTERIOCINE; BACTERIOCINS; Bacteriocins - genetics; Bacteriocins - isolation & purification; Bacteriocins - pharmacology; Bacteriology; Base Sequence; Biological and medical sciences; Chromatography, High Pressure Liquid; Chromatography, Ion Exchange; Enterococcus faecium; Enterococcus faecium - genetics; Enterococcus faecium - isolation & purification; Enterococcus faecium - metabolism; Food Microbiology; Fundamental and applied biological sciences. Psychology; GENBANK/Y16413; Genes, Bacterial; Gram-Positive Bacteria - drug effects; Microbial Sensitivity Tests; Microbiology; MOLECULAR SEQUENCE DATA; NUCLEOTIDE SEQUENCE; Open Reading Frames; Operon; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; Plasmids; PROPIEDADES ANTIMICROBIANAS; PROPRIETE ANTIMICROBIENNE; Restriction Mapping; SECUENCIA NUCLEOTIDICA; SEQUENCE NUCLEOTIDIQUE; STREPTOCOCCUS FAECIUM; Purification; Preservation; Nucleotide sequence; Bacteriocin; Antimicrobial agent; Characterization; Plasmid; Streptococcaceae; Enterococcus faecium; Food industry; Bacteria; Micrococcales; Activity spectrum; Biological contamination; Aminoacid sequence
• ISSN: 0099-2240; 1098-5336
• DOI: 10.1128/aem.64.12.4883-4890.1998

Enterocin I (ENTI) is a novel bacteriocin produced by Enterococcus faecium 6T1a, a strain originally isolated from a Spanish-style green olive fermentation. The bacteriocin is active against many olive spoilage and food-borne gram-positive pathogenic bacteria, including clostridia, propionibacteria, and Listeria monocytogenes ENTI was purified to homogeneity by ammonium sulfate precipitation, binding to an SP-Sepharose fast-flow column, and phenyl-Sepharose CL-4B and C2/C18 reverse-phase chromatography. The purification procedure resulted in a final yield of 954% and a 170,000-fold increase in specific activity. The primary structure of ENTI was determined by amino acid and nucleotide sequencing. ENTI consists of 44 amino acids and does not show significant sequence similarity with any other previously described bacteriocin. Sequencing of the entI structural gene, which is located on the 23-kb plasmid pEF1 of E. faecium 6T1a, revealed the absence of a leader peptide at the N-terminal region of the gene product. A second open reading frame, ORF2, located downstream of entI, encodes a putative protein that is 72.7% identical to ENTI. entI and ORF2 appear to be cotranscribed, yielding an mRNA of ca. 0.35 kb. A gene encoding immunity to ENTI was not identified. However, curing experiments demonstrated that both enterocin production and immunity are conferred by pEF1