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A peptide derived from phage display library exhibits antibacterial activity against E. coli and Pseudomonas aeruginosa.

Sainath Rao S, Mohan KV, Atreya CD - PLoS ONE (2013)

Bottom Line: Emergence of drug resistant strains to currently available antibiotics has resulted in the quest for novel antimicrobial agents.The peptide was highly active against gram-negative organisms and showed significant bactericidal activity against E. coli and P. aeruginosa resulting in a reduction of 5 log(10) CFU/ml.Thus this study demonstrates that peptides identified to bind to bacterial cell surface through phage-display screening may additionally aid in identifying and developing novel antimicrobial peptides.

View Article: PubMed Central - PubMed

Affiliation: Section of Cell Biology, Laboratory of Cellular Hematology, Division of Hematology, Center for Biologics Evaluation and Research, US Food and Drug Administration, Bethesda, Maryland, United States of America.

ABSTRACT
Emergence of drug resistant strains to currently available antibiotics has resulted in the quest for novel antimicrobial agents. Antimicrobial peptides (AMPs) are receiving attention as alternatives to antibiotics. In this study, we used phage-display random peptide library to identify peptides binding to the cell surface of E. coli. The peptide with sequence RLLFRKIRRLKR (EC5) bound to the cell surface of E. coli and exhibited certain features common to AMPs and was rich in Arginine and Lysine residues. Antimicrobial activity of the peptide was tested in vitro by growth inhibition assays and the bacterial membrane permeabilization assay. The peptide was highly active against gram-negative organisms and showed significant bactericidal activity against E. coli and P. aeruginosa resulting in a reduction of 5 log(10) CFU/ml. In homologous plasma and platelets, incubation of EC5 with the bacteria resulted in significant reduction of E. coli and P. aeruginosa, compared to the peptide-free controls. The peptide was non-hemolytic and non-cytotoxic when tested on eukaryotic cells in culture. EC5 was able to permeabilize the outer membrane of E. coli and P. aeruginosa causing rapid depolarization of cytoplasmic membrane resulting in killing of the cells at 5 minutes of exposure. The secondary structure of the peptide showed a α-helical conformation in the presence of aqueous environment. The bacterial lipid interaction with the peptide was also investigated using Molecular Dynamic Simulations. Thus this study demonstrates that peptides identified to bind to bacterial cell surface through phage-display screening may additionally aid in identifying and developing novel antimicrobial peptides.

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Related in: MedlinePlus

Structure and properties of EC5.A. Edmundson helical wheel presentation of 12-mer EC5. Hydrophobic residues are represented by diamonds and positive charge as pentagons. The most hydrophobic residue is green, with the amount of green decreasing proportionally to the hydrophobicity with least hydrophobic being yellow. B. Ribbon and surface representation of EC5. Ribbon model shows α-helical peptide as the conformation. Green-most hydrophobic. Secondary structure of the peptide was determined and viewed using PYMOLv0.99.
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pone-0056081-g002: Structure and properties of EC5.A. Edmundson helical wheel presentation of 12-mer EC5. Hydrophobic residues are represented by diamonds and positive charge as pentagons. The most hydrophobic residue is green, with the amount of green decreasing proportionally to the hydrophobicity with least hydrophobic being yellow. B. Ribbon and surface representation of EC5. Ribbon model shows α-helical peptide as the conformation. Green-most hydrophobic. Secondary structure of the peptide was determined and viewed using PYMOLv0.99.

Mentions: The peptide EC5 exhibited some properties of antimicrobial peptides: cationic with a net positive charge (+7) and a total hydrophobic ratio of 41% (http://aps.unmc.edu/AP/prediction/prediction_main.php) (Table 1) [17]. By using feature selection method and sequence alignment as a method for prediction of antimicrobial peptide, it was found that EC5 may exhibit antimicrobial properties (http://amp.biosino.org/) [36]. The peptide showed no significant similarity to other sequences in the Antimicrobial Peptide Database. Secondary structure of EC5 was determined and shown to have α-helix conformation (Fig. 2) with a molecular formula of C75H139N29O13. Helical wheel presentation of the peptide was illustrated using the program: (http://rzlab.ucr.edu/scripts/wheel/wheel.cgi).


A peptide derived from phage display library exhibits antibacterial activity against E. coli and Pseudomonas aeruginosa.

Sainath Rao S, Mohan KV, Atreya CD - PLoS ONE (2013)

Structure and properties of EC5.A. Edmundson helical wheel presentation of 12-mer EC5. Hydrophobic residues are represented by diamonds and positive charge as pentagons. The most hydrophobic residue is green, with the amount of green decreasing proportionally to the hydrophobicity with least hydrophobic being yellow. B. Ribbon and surface representation of EC5. Ribbon model shows α-helical peptide as the conformation. Green-most hydrophobic. Secondary structure of the peptide was determined and viewed using PYMOLv0.99.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3569419&req=5

pone-0056081-g002: Structure and properties of EC5.A. Edmundson helical wheel presentation of 12-mer EC5. Hydrophobic residues are represented by diamonds and positive charge as pentagons. The most hydrophobic residue is green, with the amount of green decreasing proportionally to the hydrophobicity with least hydrophobic being yellow. B. Ribbon and surface representation of EC5. Ribbon model shows α-helical peptide as the conformation. Green-most hydrophobic. Secondary structure of the peptide was determined and viewed using PYMOLv0.99.
Mentions: The peptide EC5 exhibited some properties of antimicrobial peptides: cationic with a net positive charge (+7) and a total hydrophobic ratio of 41% (http://aps.unmc.edu/AP/prediction/prediction_main.php) (Table 1) [17]. By using feature selection method and sequence alignment as a method for prediction of antimicrobial peptide, it was found that EC5 may exhibit antimicrobial properties (http://amp.biosino.org/) [36]. The peptide showed no significant similarity to other sequences in the Antimicrobial Peptide Database. Secondary structure of EC5 was determined and shown to have α-helix conformation (Fig. 2) with a molecular formula of C75H139N29O13. Helical wheel presentation of the peptide was illustrated using the program: (http://rzlab.ucr.edu/scripts/wheel/wheel.cgi).

Bottom Line: Emergence of drug resistant strains to currently available antibiotics has resulted in the quest for novel antimicrobial agents.The peptide was highly active against gram-negative organisms and showed significant bactericidal activity against E. coli and P. aeruginosa resulting in a reduction of 5 log(10) CFU/ml.Thus this study demonstrates that peptides identified to bind to bacterial cell surface through phage-display screening may additionally aid in identifying and developing novel antimicrobial peptides.

View Article: PubMed Central - PubMed

Affiliation: Section of Cell Biology, Laboratory of Cellular Hematology, Division of Hematology, Center for Biologics Evaluation and Research, US Food and Drug Administration, Bethesda, Maryland, United States of America.

ABSTRACT
Emergence of drug resistant strains to currently available antibiotics has resulted in the quest for novel antimicrobial agents. Antimicrobial peptides (AMPs) are receiving attention as alternatives to antibiotics. In this study, we used phage-display random peptide library to identify peptides binding to the cell surface of E. coli. The peptide with sequence RLLFRKIRRLKR (EC5) bound to the cell surface of E. coli and exhibited certain features common to AMPs and was rich in Arginine and Lysine residues. Antimicrobial activity of the peptide was tested in vitro by growth inhibition assays and the bacterial membrane permeabilization assay. The peptide was highly active against gram-negative organisms and showed significant bactericidal activity against E. coli and P. aeruginosa resulting in a reduction of 5 log(10) CFU/ml. In homologous plasma and platelets, incubation of EC5 with the bacteria resulted in significant reduction of E. coli and P. aeruginosa, compared to the peptide-free controls. The peptide was non-hemolytic and non-cytotoxic when tested on eukaryotic cells in culture. EC5 was able to permeabilize the outer membrane of E. coli and P. aeruginosa causing rapid depolarization of cytoplasmic membrane resulting in killing of the cells at 5 minutes of exposure. The secondary structure of the peptide showed a α-helical conformation in the presence of aqueous environment. The bacterial lipid interaction with the peptide was also investigated using Molecular Dynamic Simulations. Thus this study demonstrates that peptides identified to bind to bacterial cell surface through phage-display screening may additionally aid in identifying and developing novel antimicrobial peptides.

Show MeSH
Related in: MedlinePlus