Abstract
Four structurally related peptides (pseudins 1-4) with antimicrobial activity were isolated from an extract of the skin of the paradoxical frog Pseudis paradoxa (Pseudidae). Pseudin-2 (GLNALKKVFQGIHEAIKLINNHVQ) was the most abundant peptide (22 nmol/g tissue) and also the most potent (minimum inhibitory concentrations, MIC = 2.5 microM against Escherichia coli, 80 microM against Staphylococcus aureus, and 130 microM against Candida albicans). The concentration of pseudin-2 producing 50% hemolysis of human erythrocytes was >300 microM. Circular dichroism studies showed that the pseudins belong to the class of cationic, amphipathic alpha-helical antimicrobial peptides but their amino acid sequences are not similar to any previously characterized peptides from frog skin. The pseudins do, however, show sequence similarity with a region at the C-terminus of DEFT, a death effector domain-containing protein expressed in mammalian testicular germ cells that is involved in the regulation of apoptosis.
Copyright 2001 Academic Press.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Amphibian Proteins*
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Animals
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Anti-Bacterial Agents
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Anti-Infective Agents / chemical synthesis
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Anti-Infective Agents / chemistry
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Anti-Infective Agents / isolation & purification
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Anti-Infective Agents / pharmacology*
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Antimicrobial Cationic Peptides / chemical synthesis
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Antimicrobial Cationic Peptides / chemistry
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Antimicrobial Cationic Peptides / isolation & purification
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Antimicrobial Cationic Peptides / pharmacology*
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Anura*
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Candida albicans / drug effects
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Cell Death / drug effects
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Chromatography, High Pressure Liquid
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Circular Dichroism
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DNA-Binding Proteins*
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Death Domain Receptor Signaling Adaptor Proteins
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Erythrocytes / drug effects
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Escherichia coli / drug effects
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Hemolysis / drug effects*
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Humans
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Intracellular Signaling Peptides and Proteins
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Microbial Sensitivity Tests
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Molecular Sequence Data
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Peptides / chemical synthesis
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Peptides / chemistry
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Peptides / isolation & purification
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Peptides / pharmacology*
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Protein Structure, Secondary
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Proteins / chemistry
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Sequence Alignment
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Skin / chemistry*
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Staphylococcus aureus / drug effects
Substances
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Amphibian Proteins
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Anti-Bacterial Agents
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Anti-Infective Agents
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Antimicrobial Cationic Peptides
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DEDD protein, human
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DNA-Binding Proteins
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Death Domain Receptor Signaling Adaptor Proteins
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Intracellular Signaling Peptides and Proteins
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Peptides
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Proteins
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pseudin-2 protein, Pseudis paradoxa