Expression and activity of cyclic and linear analogues of esculentin-1, an anti-microbial peptide from amphibian skin.
Esculentin-1 is a potent anti-microbial peptide present in minute amounts in skin secretions of Rana esculenta. It contains 46 amino-acid residues and a C-terminal disulfide bridge. We have explored the possibility of producing analogues of this peptide by recombinant expression in Escherichia coli of a fusion protein which is sequestered in inclusion bodies. The peptide of interest has been inserted at the N-terminus of the protein, from which it can be released by cyanogen bromide cleavage. The anti-microbial activities of the recombinant peptide as well as that of a mutant linear form devoid of the disulfide bridge are presented. The recombinant analogues retain the biological activity of the natural peptide, as tested with an inhibition zone assay against a variety of microorganisms. However, experiments on the rate of bacterial killing show that gram-negative bacteria are more sensitive to the peptides than the gram-positive bacterium, the effect of the cyclic peptide being in all cases faster than that of the linear molecule. Moreover, the activity against gram-negative bacteria for both peptides is not affected by salts, whereas the activity against Staphylococcus aureus is lost at high salt concentration.
Ponti
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Dipartimento di Scienze Biochimiche A Rossi Fanelli, Universitá La Sapienza, Roma, Italy.
Mignogna
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G
Mangoni
M L
ML
De Biase
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D
Simmaco
M
M
Barra
D
D
D000595:Amino Acid Sequence; D029845:Amphibian Proteins; D000818:Animals; D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents / Q000737:chemistry* / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides; D001419:Bacteria / Q000187:drug effects; D002176:Candida albicans / Q000187:drug effects; D002942:Circular Dichroism; D003001:Cloning, Molecular; D017931:DNA Primers; D004912:Erythrocytes / Q000187:drug effects; D006801:Humans; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010455:Peptides / Q000737:chemistry* / Q000494:pharmacology*; D016133:Polymerase Chain Reaction; D011893:Rana esculenta; D011994:Recombinant Proteins / Q000737:chemistry / Q000494:pharmacology; D012867:Skin / Q000737:chemistry*; D013329:Structure-Activity Relationship
D029845:Amphibian Proteins; D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; D017931:DNA Primers; D010455:Peptides; D011994:Recombinant Proteins; C092874:esculentin protein, Rana esculenta