title: Purification and genetic characterization of plantaricin NC8, a novel coculture-inducible two-peptide bacteriocin from Lactobacillus plantarum NC8.
abstract: A new, coculture-inducible two-peptide bacteriocin named plantaricin NC8 (PLNC8) was isolated from Lactobacillus plantarum NC8 cultures which had been induced with Lactococcus lactis MG1363 or Pediococcus pentosaceus FBB63. This bacteriocin consists of two distinct peptides, named alpha and beta, which were separated by C(2)-C(18) reverse-phase chromatography and whose complementary action is necessary for full plantaricin NC8 activity. N-terminal sequencing of both purified peptides showed 28 and 34 amino acids residues for PLNC8 alpha and PLNC8 beta, respectively, which showed no sequence similarity to other known bacteriocins. Mass spectrometry analysis showed molecular masses of 3,587 Da (alpha) and 4,000 Da (beta). The corresponding genes, designated plNC8A and plNC8B, were sequenced, and their nucleotide sequences revealed that both peptides are produced as bacteriocin precursors of 47 and 55 amino acids, respectively, which include N-terminal leader sequences of the double-glycine type. The mature alpha and beta peptides contain 29 and 34 amino acids, respectively. An open reading frame, orfC, which encodes a putative immunity protein was found downstream of plNC8B and overlapping plNC8A. Upstream of the putative -35 region of plNC8B, two direct repeats of 9 bp were identified, which agrees with the consensus sequence and structure of promoters of class II bacteriocin operons whose expression is dependent on an autoinduction mechanism.
authors.affiliation: Departamento de Biotecnología de Alimentos, Instituto de la Grasa, Consejo Superior de Investigaciones Científicas, 41012 Seville, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Maldonado
authors.forename: José Luis
authors.initials: JL
authors.lastname: Ruiz-Barba
authors.forename: Rufino
authors.initials: R
authors.lastname: Jiménez-Díaz
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001430:Bacteriocins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification* / Q000378:metabolism; D001483:Base Sequence; D018920:Coculture Techniques; D015964:Gene Expression Regulation, Bacterial; D007778:Lactobacillus / Q000254:growth & development* / Q000378:metabolism; D013294:Lactococcus lactis / Q000254:growth & development; D008969:Molecular Sequence Data; D010376:Pediococcus / Q000254:growth & development; D010455:Peptides / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D001430:Bacteriocins; D010455:Peptides