TY - JOUR
T1 - Design of potent, non-toxic antimicrobial agents based upon the structure of the frog skin peptide, pseudin-2
AU - Pál, Tibor
AU - Sonnevend, Ágnes
AU - Galadari, Sehamuddin
AU - Conlon, J. Michael
N1 - Funding Information:
This work was supported by an Interdisciplinary Grant (03/12-8-03-01) from the United Arab Emirates University and a Faculty Support Grant (NP/02/04) from the Faculty of Medicine and Health Sciences, U.A.E. University. The authors thank Mahendra Patel, Anne John, and Bency Varghese for technical assistance.
PY - 2005/7/15
Y1 - 2005/7/15
N2 - Pseudin-2, a naturally occurring 24 amino-acid-residue antimicrobial peptide first isolated from the skin of the South American paradoxical frog Pseudis paradoxa, has weak hemolytic and cytolytic activity but also relatively low potency against microorganisms. In a membrane-mimetic environment, the peptide exists in an amphipathic α-helical conformation. Analogs of the peptide with increased cationicity and α-helicity were chemically synthesized by progressively substituting neutral and acidic amino acid residues on the hydrophilic face of the α-helix by lysine. Analogs with up to three L-lysine substitutions showed increased potency against a range of gram-negative and gram-positive bacteria (up to 16-fold) whilst retaining low hemolytic activity. The analog [d-Lys3, d-Lys10, d-Lys14]pseudin-2 showed potent activity against gram-negative bacteria (minimum inhibitory concentration, MIC=5 μM against several antibiotic-resistant strains of Escherichia coli) but very low hemolytic activity (HC50>500 μM) and cytolytic activity against L929 fibroblasts (LC50=215 μM). Increasing the number of l-lysines to four and five did not enhance antimicrobial potency further but increased hemolytic activity towards human erythrocytes. Time-kill studies demonstrated that the analog [Lys3, Lys10, Lys14, Lys 21]pseudin-2 at a concentration of 1×MIC was bacteriocidal against E. coli (99.9% cell death after 96 min) but was bacteriostatic against S. aureus. Increasing the hydrophobicity of pseudin-2, while maintaining the amphipathic character of the molecule, by substitution of neutral amino acids on the hydrophobic face of the α-helix by l-phenylalanine, had only minor effects on antimicrobial and hemolytic activities.
AB - Pseudin-2, a naturally occurring 24 amino-acid-residue antimicrobial peptide first isolated from the skin of the South American paradoxical frog Pseudis paradoxa, has weak hemolytic and cytolytic activity but also relatively low potency against microorganisms. In a membrane-mimetic environment, the peptide exists in an amphipathic α-helical conformation. Analogs of the peptide with increased cationicity and α-helicity were chemically synthesized by progressively substituting neutral and acidic amino acid residues on the hydrophilic face of the α-helix by lysine. Analogs with up to three L-lysine substitutions showed increased potency against a range of gram-negative and gram-positive bacteria (up to 16-fold) whilst retaining low hemolytic activity. The analog [d-Lys3, d-Lys10, d-Lys14]pseudin-2 showed potent activity against gram-negative bacteria (minimum inhibitory concentration, MIC=5 μM against several antibiotic-resistant strains of Escherichia coli) but very low hemolytic activity (HC50>500 μM) and cytolytic activity against L929 fibroblasts (LC50=215 μM). Increasing the number of l-lysines to four and five did not enhance antimicrobial potency further but increased hemolytic activity towards human erythrocytes. Time-kill studies demonstrated that the analog [Lys3, Lys10, Lys14, Lys 21]pseudin-2 at a concentration of 1×MIC was bacteriocidal against E. coli (99.9% cell death after 96 min) but was bacteriostatic against S. aureus. Increasing the hydrophobicity of pseudin-2, while maintaining the amphipathic character of the molecule, by substitution of neutral amino acids on the hydrophobic face of the α-helix by l-phenylalanine, had only minor effects on antimicrobial and hemolytic activities.
KW - Amphibian
KW - Antimicrobial
KW - Cytolytic
KW - Hemolytic
KW - Pseudin-2
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U2 - 10.1016/j.regpep.2005.01.015
DO - 10.1016/j.regpep.2005.01.015
M3 - Article
C2 - 15927702
AN - SCOPUS:20144376875
SN - 0167-0115
VL - 129
SP - 85
EP - 91
JO - Regulatory Peptides
JF - Regulatory Peptides
IS - 1-3
ER -