Mechanism of antibacterial action of a synthetic peptide with an Ala-peptoid residue based on the scorpion-derived antimicrobial peptide IsCT

A novel bacterial cell-selective antimicrobial peptide, IsCT-P (ILKKIWKPIKKLF-NH₂), was designed based on the scorpion-derived α-helical antimicrobial peptide, IsCT. Here, we investigated the effect of substituting Pro⁸ of IsCT-P with the Ala-peptoid residue (N-methylglycine) on the peptide's s...

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Bibliographic Details
Published in:Biotechnology letters 2006-09, Vol.28 (18), p.1431-1437
Main Authors: Lim, Shin Saeng, Yoon, Sang-Pil, Park, Yoonkyoung, Zhu, Wan Long, Park, Il-Seon, Hahm, Kyung -Soo, Shin, Song Yub
Format: Article
Language:English
Subjects:
Ala-peptoid residue
Amino Acid Sequence
Anti-Infective Agents - pharmacology
Antibacterial action
Antimicrobial Cationic Peptides - chemistry
Antimicrobial Cationic Peptides - pharmacology
Bacteria
Biological and medical sciences
Biotechnology
Cell Membrane - drug effects
Circular Dichroism
Fluoresceins - metabolism
Fundamental and applied biological sciences. Psychology
Hemolytic Agents - pharmacology
Humans
Liposomes - metabolism
Mechanism
Membrane Potentials - drug effects
Microbiology
Peptides
Peptoids - pharmacology
Scorpion Venoms - chemistry
Scorpion-derived antimicrobial peptide IsCT
Staphylococcus aureus
Staphylococcus infections
Structuralflexibility
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Summary:A novel bacterial cell-selective antimicrobial peptide, IsCT-P (ILKKIWKPIKKLF-NH₂), was designed based on the scorpion-derived α-helical antimicrobial peptide, IsCT. Here, we investigated the effect of substituting Pro⁸ of IsCT-P with the Ala-peptoid residue (N-methylglycine) on the peptide's structure and mechanism of action. Circular dichroism analysis revealed that the modified peptide, IsCT-a, has a much lower α-helicity than IsCT-P in membrane mimicking conditions, suggesting the peptoid residue provides much more structural flexibility than the proline residue. IsCT-a was also much less effective than IsCT-P at causing leakage of fluorescent dye entrapped within negatively charged vesicles and at dissipating the membrane potential of Staphylococcus aureus. Collectively, our results suggest that the antibacterial action of IsCT-a is due to the inhibition of intracellular targets rather than the disruption and depolarization of bacterial cell membranes.
ISSN:0141-5492
1573-6776
DOI:10.1007/s10529-006-9107-6