Effects of Pro Peptoid Residue Substitution on Cell Selectivity and Mechanism of Antibacterial Action of Tritrpticin-Amide Antimicro
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- 作者：Wan Long Zhu ; Hongliang Lan ; Yoonkyung Park ; Sung-Tae Yang ; Jae Il Kim ; Il-Seon Park ; Ho Jin You ; Jung Sup Lee ; Yong Sun Park ; Yangmee Kim ; Kyung-Soo Hahm ; Song Yub Shin
- 刊名：Biochemistry
- 出版年：2006
- 出版时间：October 31, 2006
- 年：2006
- 卷：45
- 期：43
- 页码：13007 - 13017
- 全文大小：299K
- 年卷期：v.45,no.43(October 31, 2006)
- ISSN：1520-4995
文摘
To investigate the effect of Pro 
peptoid residue substitution on cell selectivity and themechanism of antibacterial action of Pro-containing 
-turn antimicrobial peptides, we synthesized tritrpticin-amide (TP, VRRFPWWWPFLRR-NH2) and its peptoid residue-substituted peptides in which two Proresidues at positions 5 and 9 are replaced with Nleu (Leu peptoid residue), Nphe (Phe peptoid residue),or Nlys (Lys peptoid residue). Peptides with Pro Nphe (TPf) or Pro Nleu substitution (TPl) retainedantibacterial activity but had significantly higher toxicity to mammalian cells. In contrast, Pro Nlyssubstitution (TPk) increased the antibacterial activity but decreased the toxicity to mammalian cells.Tryptophan fluorescence studies indicated that the bacterial cell selectivity of TPk is closely correlatedwith a preferential interaction with negatively charged phospholipids. Interestingly, TPk was much lesseffective at depolarizing of the membrane potential of Staphylococus aureus and Escherichia colispheroplasts and causing the leakage of a fluorescent dye entrapped within negatively charged vesicles.Furthermore, confocal laser-scanning microscopy showed that TPk effectively penetrated the membraneof both E. coli and S. aureus and accumulated in the cytoplasm, whereas TP and TPf did not penetratethe cell membrane but remained outside or on the cell membrane. These results suggest that the bactericidalaction of TPk is due to inhibition of the intracellular components after penetration of the bacterial cellmembrane. In addition, TPK with Lys substitution effectively depolarized the membrane potential of S.aureus and E. coli spheroplasts. TPK induced rapid and effective dye leakage from bacterial membrane-mimicking liposomes and did not penetrate the bacterial cell membranes. These results suggested that theability of TPk to penetrate the bacterial cell membranes appears to involve the dual effects that are relatedto the increase in the positive charge and the peptide's backbone change by peptoid residue substitution.Collectively, our results showed that Pro Nlys substitution in Pro-containing -turn antimicrobial peptidesis a promising strategy for the design of new short bacterial cell-selective antimicrobial peptides withintracellular mechanisms of action.
peptoid residue substitution on cell selectivity and themechanism of antibacterial action of Pro-containing -turn antimicrobial peptides, we synthesized tritrpticin-amide (TP, VRRFPWWWPFLRR-NH2) and its peptoid residue-substituted peptides in which two Proresidues at positions 5 and 9 are replaced with Nleu (Leu peptoid residue), Nphe (Phe peptoid residue),or Nlys (Lys peptoid residue). Peptides with Pro Nphe (TPf) or Pro Nleu substitution (TPl) retainedantibacterial activity but had significantly higher toxicity to mammalian cells. In contrast, Pro Nlyssubstitution (TPk) increased the antibacterial activity but decreased the toxicity to mammalian cells.Tryptophan fluorescence studies indicated that the bacterial cell selectivity of TPk is closely correlatedwith a preferential interaction with negatively charged phospholipids. Interestingly, TPk was much lesseffective at depolarizing of the membrane potential of Staphylococus aureus and Escherichia colispheroplasts and causing the leakage of a fluorescent dye entrapped within negatively charged vesicles.Furthermore, confocal laser-scanning microscopy showed that TPk effectively penetrated the membraneof both E. coli and S. aureus and accumulated in the cytoplasm, whereas TP and TPf did not penetratethe cell membrane but remained outside or on the cell membrane. These results suggest that the bactericidalaction of TPk is due to inhibition of the intracellular components after penetration of the bacterial cellmembrane. In addition, TPK with Lys substitution effectively depolarized the membrane potential of S.aureus and E. coli spheroplasts. TPK induced rapid and effective dye leakage from bacterial membrane-mimicking liposomes and did not penetrate the bacterial cell membranes. These results suggested that theability of TPk to penetrate the bacterial cell membranes appears to involve the dual effects that are relatedto the increase in the positive charge and the peptide's backbone change by peptoid residue substitution.Collectively, our results showed that Pro Nlys substitution in Pro-containing -turn antimicrobial peptidesis a promising strategy for the design of new short bacterial cell-selective antimicrobial peptides withintracellular mechanisms of action.