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Interaction of antimicrobial peptide Plantaricin149a and four analogs with lipid bilayers and bacterial membranes.

de Souza Lopes JL, Hissa DC, Melo VM, Beltramini LM - Braz. J. Microbiol. (2014)

Bottom Line: The analogs presented similar action of Plantaricin149a; three of them with no hemolytic effect (< 5%) until 0.5 mM, in addition to the induction of a helical element when binding to negative liposomes.The N-terminus difference between the analogs and Plantaricin149a retained the antibacterial effect on S. aureus and P. aeruginosa for all peptides (MIC50 of 19 μM and 155 μM to Plantaricin149a, respectively) but resulted in a different mechanism of action against the microorganisms, that was bactericidal for Plantaricin149a and bacteriostatic for the analogs.This difference was confirmed by a reduction in leakage action for the analogs.

View Article: PubMed Central - PubMed

Affiliation: Grupo de Biofísica Molecular "Sérgio Mascarenhas", Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil.

ABSTRACT
The amidated analog of Plantaricin149, an antimicrobial peptide from Lactobacillus plantarum NRIC 149, directly interacts with negatively charged liposomes and bacterial membranes, leading to their lysis. In this study, four Pln149-analogs were synthesized with different hydrophobic groups at their N-terminus with the goal of evaluating the effect of the modifications at this region in the peptide's antimicrobial properties. The interaction of these peptides with membrane models, surface activity, their hemolytic effect on red blood cells, and antibacterial activity against microorganisms were evaluated. The analogs presented similar action of Plantaricin149a; three of them with no hemolytic effect (< 5%) until 0.5 mM, in addition to the induction of a helical element when binding to negative liposomes. The N-terminus difference between the analogs and Plantaricin149a retained the antibacterial effect on S. aureus and P. aeruginosa for all peptides (MIC50 of 19 μM and 155 μM to Plantaricin149a, respectively) but resulted in a different mechanism of action against the microorganisms, that was bactericidal for Plantaricin149a and bacteriostatic for the analogs. This difference was confirmed by a reduction in leakage action for the analogs. The lytic activity of Plantaricin149a is suggested to be a result of the peptide-lipid interactions from the amphipathic helix and the hydrophobic residues at the N-terminus of the antimicrobial peptide.

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Leakage action of Pln149a and the four analogs peptides on membrane models. Calcein leakage was promoted by the addition of increasing concentrations of the peptides (0.25 to 4 μM) to LUVs of POPG. 100% leakage occurred with the addition of Triton X-100.
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f3-bmj-44-4-1291: Leakage action of Pln149a and the four analogs peptides on membrane models. Calcein leakage was promoted by the addition of increasing concentrations of the peptides (0.25 to 4 μM) to LUVs of POPG. 100% leakage occurred with the addition of Triton X-100.

Mentions: The effects of vesicle perturbation by the presence of each antimicrobial peptide analog to Pln149 were determined by calcein leakage experiments on POPG vesicles. Pln149a and all the four analog peptides showed the capability of promoting the total leakage of calcein from the liposomes. According to Figure 3, the percent of calcein released from the vesicles increased proportionally to the amount of peptide used in the assay, reaching approximately 100% leakage to the lowest lipid/peptide ratio in cuvette to each analog.


Interaction of antimicrobial peptide Plantaricin149a and four analogs with lipid bilayers and bacterial membranes.

de Souza Lopes JL, Hissa DC, Melo VM, Beltramini LM - Braz. J. Microbiol. (2014)

Leakage action of Pln149a and the four analogs peptides on membrane models. Calcein leakage was promoted by the addition of increasing concentrations of the peptides (0.25 to 4 μM) to LUVs of POPG. 100% leakage occurred with the addition of Triton X-100.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3958201&req=5

f3-bmj-44-4-1291: Leakage action of Pln149a and the four analogs peptides on membrane models. Calcein leakage was promoted by the addition of increasing concentrations of the peptides (0.25 to 4 μM) to LUVs of POPG. 100% leakage occurred with the addition of Triton X-100.
Mentions: The effects of vesicle perturbation by the presence of each antimicrobial peptide analog to Pln149 were determined by calcein leakage experiments on POPG vesicles. Pln149a and all the four analog peptides showed the capability of promoting the total leakage of calcein from the liposomes. According to Figure 3, the percent of calcein released from the vesicles increased proportionally to the amount of peptide used in the assay, reaching approximately 100% leakage to the lowest lipid/peptide ratio in cuvette to each analog.

Bottom Line: The analogs presented similar action of Plantaricin149a; three of them with no hemolytic effect (< 5%) until 0.5 mM, in addition to the induction of a helical element when binding to negative liposomes.The N-terminus difference between the analogs and Plantaricin149a retained the antibacterial effect on S. aureus and P. aeruginosa for all peptides (MIC50 of 19 μM and 155 μM to Plantaricin149a, respectively) but resulted in a different mechanism of action against the microorganisms, that was bactericidal for Plantaricin149a and bacteriostatic for the analogs.This difference was confirmed by a reduction in leakage action for the analogs.

View Article: PubMed Central - PubMed

Affiliation: Grupo de Biofísica Molecular "Sérgio Mascarenhas", Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil.

ABSTRACT
The amidated analog of Plantaricin149, an antimicrobial peptide from Lactobacillus plantarum NRIC 149, directly interacts with negatively charged liposomes and bacterial membranes, leading to their lysis. In this study, four Pln149-analogs were synthesized with different hydrophobic groups at their N-terminus with the goal of evaluating the effect of the modifications at this region in the peptide's antimicrobial properties. The interaction of these peptides with membrane models, surface activity, their hemolytic effect on red blood cells, and antibacterial activity against microorganisms were evaluated. The analogs presented similar action of Plantaricin149a; three of them with no hemolytic effect (< 5%) until 0.5 mM, in addition to the induction of a helical element when binding to negative liposomes. The N-terminus difference between the analogs and Plantaricin149a retained the antibacterial effect on S. aureus and P. aeruginosa for all peptides (MIC50 of 19 μM and 155 μM to Plantaricin149a, respectively) but resulted in a different mechanism of action against the microorganisms, that was bactericidal for Plantaricin149a and bacteriostatic for the analogs. This difference was confirmed by a reduction in leakage action for the analogs. The lytic activity of Plantaricin149a is suggested to be a result of the peptide-lipid interactions from the amphipathic helix and the hydrophobic residues at the N-terminus of the antimicrobial peptide.

Show MeSH
Related in: MedlinePlus