title: A novel antifungal peptide designed from the primary structure of a natural antimicrobial peptide purified from Argopecten purpuratus hemocytes.
abstract: We have isolated and purified a natural antimicrobial peptide from Argopecten purpuratus hemocytes. 47 residues were determined from its primary structure representing the N-terminal of the complete sequence. This peptide of 5100.78Da was chemically synthesized and named Ap. The peptide has 25% of hydrophobic amino acids with a net charge of +1, and partial homology with known active antimicrobial peptides. Based on that sequence, a new peptide was designed and modeled to increase hydrophobicity and cationicity. The designed 30-residue peptide was chemically synthesized resulting in a novel 38% hydrophobic molecule named peptide Ap-S, with a net charge of +5 and 3028Da. A secondary structure was shown by circular dichroism, thus exposing a hydrophobic epitope toward the N-terminus and a hydrophilic one toward the C-terminus, improving amphipathicity. Ap-S was much more active than the parental Ap. Ap-S up to 100microM has no cytotoxic effect against fish cell line CHSE-214. We demonstrated that the chemical modification of a natural peptide and the chemical synthesis of derived molecules may be a powerful tool for obtaining substitutes to conventional antibiotics, displaying the many advantages of antimicrobial peptides and overcoming the limitations of natural peptides for large-scale production and application, such as the low specific activity and the minute amounts recovered in vivo. This peptide may have a relevant application in aquaculture by controlling Saprolegna sp., a parasitic pathogen fungus that attacks the culture of fish in different stages of their growth, from egg to adult.
authors.affiliation: Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Chile. garenas@ucv.cl
authors.forename: Gloria
authors.initials: G
authors.lastname: Arenas
authors.forename: Fanny
authors.initials: F
authors.lastname: Guzmán
authors.forename: Constanza
authors.initials: C
authors.lastname: Cárdenas
authors.forename: Luis
authors.initials: L
authors.lastname: Mercado
authors.forename: Sergio H
authors.initials: SH
authors.lastname: Marshall
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000890:Anti-Infective Agents / Q000737:chemistry / Q000302:isolation & purification*; D000935:Antifungal Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002942:Circular Dichroism; D006434:Hemocytes / Q000378:metabolism*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D049897:Pectinidae / Q000378:metabolism*; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology*; D012487:Salmonidae; D017386:Sequence Homology, Amino Acid
chemical_list: D000890:Anti-Infective Agents; D000935:Antifungal Agents; D010455:Peptides