Design and mechanism of action of a novel bacteria-selective antimicrobial peptide from the cell-penetrating peptide Pep-1.
Here, we report the successful design of a novel bacteria-selective antimicrobial peptide, Pep-1-K (KKTWWKTWWTKWSQPKKKRKV). Pep-1-K was designed by replacing Glu-2, Glu-6, and Glu-11 in the cell-penetrating peptide Pep-1 with Lys. Pep-1-K showed strong antibacterial activity against reference strains (MIC = 1-2 microM) of Gram-positive and Gram-negative bacteria as well as against clinical isolates (MIC = 1-8 microM) of methicillin-resistant Staphylococcus aureus and multidrug-resistant Pseudomonas aeruginosa. In contrast, Pep-1-K did not cause hemolysis of human erythrocytes even at 200 microM. These results indicate that Pep-1-K may be a good candidate for antimicrobial drug development, especially as a topical agent against antibiotic-resistant microorganisms. Tryptophan fluorescence studies indicated that the lack of hemolytic activity of Pep-1-K correlated with its weak ability to penetrate zwitterionic phosphatidylcholine/cholesterol (10:1, w/w) vesicles, which mimic eukaryotic membranes. Furthermore, Pep-1-K caused little or no dye leakage from negatively charged phosphatidylethanolamine/phosphatidylglycerol (7:3, w/w) vesicles, which mimic bacterial membranes but had a potent ability to cause depolarization of the cytoplasmic membrane potential of intact S. aureus cells. These results suggested that Pep-1-K kills microorganisms by not the membrane-disrupting mode but the formation of small channels that permit transit of ions or protons but not molecules as large as calcein.
Zhu
Wan Long
WL
Department of Bio-Materials, Graduate School and Research Center for Proteineous Materials, Chosun University, Gwangju 501-759, Republic of Korea.
Lan
Hongliang
H
Park
Il-Seon
IS
Kim
Jae Il
JI
Jin
Hai Zhu
HZ
Hahm
Kyung-Soo
KS
Shin
Song Yub
SY
D000595:Amino Acid Sequence; D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology*; D002784:Cholesterol / Q000737:chemistry; D003543:Cysteamine / Q000031:analogs & derivatives* / Q000737:chemistry; D015195:Drug Design; D004352:Drug Resistance, Microbial; D005456:Fluorescent Dyes / Q000494:pharmacology; D006801:Humans; D008081:Liposomes / Q000737:chemistry; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D010743:Phospholipids / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013211:Staphylococcus aureus / Q000378:metabolism
D023181:Antimicrobial Cationic Peptides; D005456:Fluorescent Dyes; D008081:Liposomes; C503924:Pep-1 peptide; D010455:Peptides; D010743:Phospholipids; D003543:Cysteamine; D002784:Cholesterol