title: Lactococcus lactis LMG2081 Produces Two Bacteriocins, a Nonlantibiotic and a Novel Lantibiotic.
abstract: Bacteriocin producers normally possess dedicated immunity systems to protect themselves from their own bacteriocins.Lactococcus lactis strains LMG2081 and BGBM50 are known as lactococcin G producers. However, BGBM50 was sensitive to LMG2081, which indicated that LMG2081 might produce additional bacteriocins that are not present in BGBM50. Therefore, whole-genome sequencing of the two strains was performed, and a lantibiotic operon (called lctLMG) was identified in LMG2081 but not in BGBM50. The lctLMG operon contains six open reading frames; the first three genes,lmgA ,lmgM, and lmgT, are involved in the biosynthesis and export of bacteriocin, while the other three genes,lmgF,lmgE, and lmgG, are involved in lantibiotic immunity. Mutational analysis confirmed that the lctLMG operon is responsible for the additional antimicrobial activity. Specifically, site-directed mutation within this operon rendered LMG2081 inactive toward BGBM50. Subsequent purification and electrospray ionization-time of flight mass spectrometric analysis confirmed that the lantibiotic bacteriocin called lacticin LMG is exported as a 25-amino-acid peptide. Lacticin LMG is highly similar to the lacticin 481 group. It is interesting that a bacteriocin producer produces two different classes of bacteriocins, whose operons are located in the chromosome and a plasmid.
authors.affiliation: Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia.|Department for Food Microbiology, Faculty of Agriculture, University of Belgrade, Belgrade, Serbia.
authors.forename: Nemanja
authors.initials: N
authors.lastname: Mirkovic
authors.affiliation: Department of Biochemistry, Faculty of Chemistry, University of Belgrade, Belgrade, Serbia.
authors.forename: Natalija
authors.initials: N
authors.lastname: Polovic
authors.affiliation: Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia.|Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Belgrade, Belgrade, Serbia.
authors.forename: Goran
authors.initials: G
authors.lastname: Vukotic
authors.affiliation: Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia.|Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Belgrade, Belgrade, Serbia.
authors.forename: Branko
authors.initials: B
authors.lastname: Jovcic
authors.affiliation: Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia.
authors.forename: Marija
authors.initials: M
authors.lastname: Miljkovic
authors.affiliation: Department for Food Microbiology, Faculty of Agriculture, University of Belgrade, Belgrade, Serbia.
authors.forename: Zorica
authors.initials: Z
authors.lastname: Radulovic
authors.affiliation: Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, Ås, Norway.
authors.forename: Dzung B
authors.initials: DB
authors.lastname: Diep
authors.affiliation: Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia mkojic@imgge.bg.ac.rs.
authors.forename: Milan
authors.initials: M
authors.lastname: Kojic
mesh_terms: D001430:Bacteriocins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D053898:Biosynthetic Pathways / Q000235:genetics; D002876:Chromosomes, Bacterial; D004252:DNA Mutational Analysis; D005798:Genes, Bacterial; D016680:Genome, Bacterial; D013294:Lactococcus lactis / Q000235:genetics / Q000378:metabolism*; D009842:Oligopeptides / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D016366:Open Reading Frames; D009876:Operon; D010957:Plasmids; D017422:Sequence Analysis, DNA; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D001430:Bacteriocins; D009842:Oligopeptides