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The gene encoding plantaricin A, a bacteriocin from Lactobacillus plantarum C11, is located on the same transcription unit as an agr-like regulatory system.

ABSTRACT: Purification and amino acid sequencing of plantaricin A, a bacteriocin from Lactobacillus plantarum C11, revealed that maximum bacteriocin activity is associated with the complementary action of two almost-identical peptides, alpha and beta (J. Nissen-Meyer, A. G. Larsen, K. Sletten, M. Daeschel, and I. F. Nes, J. Gen. Microbiol. 139:1973-1978, 1993). A 5-kb chromosomal HindIII restriction fragment containing the structural gene of plantaricin A was cloned and sequenced. Only one gene encoding plantaricin A was found. The gene, termed plnA, encodes a 48-amino-acid precursor peptide, of which the 22 and 23 C-terminal amino acids correspond to the purified peptides. Northern (RNA) blot analysis demonstrated that a probe complementary to the coding strand of the plantaricin A gene hybridized to a 3.3-kb mRNA transcript. Further analysis of the 3.3-kb transcript demonstrated that it contains three additional open reading frames (plnB, plnC and plnD) downstream of plnA. The DNA sequences of plnB, plnC, and plnD revealed that their products closely resemble members of bacterial two-component signal transduction systems. The strongest homology was found to the accessory gene regulatory (agr) system, which controls expression of exoproteins during post-exponential growth in Staphylococcus aureus. The finding that plnABCD are transcribed from a common promoter suggests that the biological role played by the bacteriocin is somehow related to the regulatory function of the two-component system located on the same operon.

SUBMITTER: Diep DB

PROVIDER: S-EPMC201284 | biostudies-other | 1994 Jan

REPOSITORIES: biostudies-other

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The gene encoding plantaricin A, a bacteriocin from Lactobacillus plantarum C11, is located on the same transcription unit as an agr-like regulatory system.

Diep D B DB Håvarstein L S LS Nissen-Meyer J J Nes I F IF

Applied and environmental microbiology 19940101 1

Purification and amino acid sequencing of plantaricin A, a bacteriocin from Lactobacillus plantarum C11, revealed that maximum bacteriocin activity is associated with the complementary action of two almost-identical peptides, alpha and beta (J. Nissen-Meyer, A. G. Larsen, K. Sletten, M. Daeschel, and I. F. Nes, J. Gen. Microbiol. 139:1973-1978, 1993). A 5-kb chromosomal HindIII restriction fragment containing the structural gene of plantaricin A was cloned and sequenced. Only one gene encoding p ...[more]

PMID: 8117074

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Project description:BackgroundBacteriocin production in the lactic acid bacterium Lactobacillus plantarum C11 is regulated through a quorum sensing based pathway involving two highly homologous response regulators (59% identity and 76% similarity), PlnC as a transcriptional activator and PlnD as a repressor. Previous in vitro studies have shown that both regulators bind, as homodimers, to the same DNA regulatory repeats to exert their regulatory functions. As the genes for these two proteins are located on the same auto-regulatory operon, hence being co-expressed upon gene activation, it is plausible that their opposite functions must somehow be differentially regulated, either in terms of timing and/or binding kinetics, so that their activities do not impair each other in an uncontrolled manner. To understand the nature behind this potential differentiation, we have studied the binding kinetics of the two regulators on five target promoters (PplnA, PplnM, PplnJ, PplnE and PplnG) from the bacteriocin regulon of L. plantarum C11.ResultsBy using surface plasmon resonance spectroscopy we obtained parameters such as association rates, dissociation rates and dissociation constants, showing that the two regulators indeed differ greatly from each other in terms of cooperative binding and binding strength to the different promoters. For instance, cooperativity is very strong for PlnC binding to the promoter of the regulatory operon (PplnA), but not to the promoter of the transport operon (PplnG), while the opposite is seen for PlnD binding to these two promoters. The estimated affinity constants indicate that PlnC can bind to PplnA to activate transcription of the key regulatory operon plnABCD without much interference from PlnD, and that the repressive function of PlnD might act through a different mechanism than repression of the regulatory operon.ConclusionWe have characterised the DNA binding kinetics of the two regulators PlnC and PlnD from the bacteriocin locus in L. plantarum C11. Our data show that PlnC and PlnD, despite their strong homology to each other, differ greatly from each other in terms of binding affinity and cooperativity to the different promoters of the pln regulon.

Project description:Bacteriocins from lactic acid bacteria (LAB) are of increasing interest in recent years due to their potential as natural preservatives against food and beverage spoilage microorganisms. In a screening study for LAB, we isolated from olives a strain, Lactobacillus plantarum NI326, with activity against the beverage-spoilage bacterium Alicyclobacillus acidoterrestris Genome sequencing of NI326 enabled the identification of a gene cluster (designated plc) encoding a putative circular bacteriocin and proteins involved in its modification, transport, and immunity. This novel bacteriocin, named plantaricyclin A (PlcA), was grouped into the circular bacteriocin subgroup II due to its high degree of similarity with other gassericin A-like bacteriocins. Purification of PlcA from the supernatant of Lb. plantarum NI326 resulted in an active peptide with a molecular mass of 5,570 Da, corresponding to that predicted from the (processed) PlcA amino acid sequence. The plc gene cluster was cloned and expressed in Lactococcus lactis NZ9000, resulting in the production of an active 5,570-Da bacteriocin in the supernatant. PlcA is believed to be produced as a 91-amino-acid precursor with a 33-amino-acid leader peptide, which is predicted to be removed, followed by joining of the N and C termini via a covalent linkage to form the mature 58-amino-acid circular bacteriocin PlcA. We report the characterization of a circular bacteriocin produced by Lb. plantarum The inhibition displayed against A. acidoterrestris highlights its potential use as a preservative in food and beverages.IMPORTANCE In this work, we describe the purification and characterization of an antimicrobial peptide, termed plantaricyclin A (PlcA), produced by a Lactobacillus plantarum strain isolated from olives. This peptide has a circular structure, and all genes involved in its production, circularization, and secretion were identified. PlcA shows antimicrobial activity against different strains, including Alicyclobacillus acidoterrestris, a common spoilage bacterium, which causes substantial economic losses in the beverage industry every year. In this study, we describe a circular antimicrobial peptide, PlcA, for a Lactobacillus plantarum strain.

Project description:Lactobacillus plantarum zrx03 was a bacteriocin-producing strain isolated from infant's feces. The fermentation supernatant produced by this strain could strongly inhibit Escherichia coli JM109 ATCC 67387, Staphylococcus aureus ATCC 25923, and Listeria monocytogenes CICC 21633, in which the diameter of inhibition zone was 12.83 ± 0.62 mm, 15.08 ± 0.31 mm, 6.75 ± 0.20 mm, respectively, compared with lactic acid bacteria N1, N2, M13, M21, M31, and M37. According to amplification of 16S rRNA gene and identification of phylogenetic tree, this strain had a 1,450 bp sequence and 100% identity to the L. plantarum strain. Based on the influence of different protease treatments, such as pepsin, trypsin, papain, and proteinase K on the antimicrobial activity, this antimicrobial substance was considered to be a natural protein. Using bacteriocin produced by this strain as study object of this experiment, it had been extracted from ammonium sulfate precipitation and different organic solvents. The results showed that ethyl acetate was selected as the optimal solution to crude extraction of bacteriocin after comparing ammonium sulfate precipitation method and organic solvent extraction method, such as n-butanol, n-hexane, dichloromethane, trichloromethane, in which the diameter of the inhibition zones was above 28 mm. Results also showed the inhibition spectrum of the obtained bacteriocin had a broad spectrum of inhibition which could inhibit Gram-positive, Gram-negative, yeast. Especially, it could effectively inhibit S. aureus ATCC 25923, Bacillus subtilis CICC 10002, Bacillus anthracis CICC 20443, E. coli JM109 ATCC 67387, and Salmonella CMCC 541, and the zone diameter of inhibition has reached more than 28 mm. Moreover, it had a good thermal stability which antibacterial activity was retained 70.58% after treatment at 121°C for 30 min, and pH-stability was between pH 2.0-9.0. These results suggested bacteriocin produced by L. plantarum zrx03 had potential application prospects in food preservation.

Dataset Information

The gene encoding plantaricin A, a bacteriocin from Lactobacillus plantarum C11, is located on the same transcription unit as an agr-like regulatory system.

Publications

The gene encoding plantaricin A, a bacteriocin from Lactobacillus plantarum C11, is located on the same transcription unit as an agr-like regulatory system.

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