title: Structural and Antimicrobial Features of Peptides Related to Myticin C, a Special Defense Molecule from the Mediterranean Mussel Mytilus galloprovincialis.
abstract: Mussels (Mytilus spp.) have a large repertoire of cysteine-stabilized α,β peptides, and myticin C (MytC) was identified in some hundreds of transcript variants after in vivo immunostimulation. Using a sequence expressed in Italian mussels, we computed the MytC structure and synthesized the mature MytC and related peptide fragments (some of them also prepared in oxidized form) to accurately assess their antibacterial and antifungal activity. Only when tested at pH 5 was the reduced MytC as well as reduced and oxidized fragments including structural β-elements able to inhibit Gram-positive and -negative bacteria (MIC ranges of 4-32 and 8-32 μM, respectively). Such fragments caused selective Escherichia coli killing (MBC of 8-32 μM) but scarcely inhibited two fungal strains. In detail, the antimicrobial β-hairpin MytC[19-40]SOX caused membrane-disrupting effects in E. coli despite its partially ordered conformation in membrane-mimetic environments. In perspective, MytC-derived peptides could be employed to protect acidic mucosal tissues, in cosmetic and food products, and, possibly, as adjuvants in aquaculture.
authors.affiliation: Department of Biology, University of Padova , Via Ugo Bassi 58/B, 35131 Padova, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Domeneghetti
authors.affiliation: Department of Biology, University of Padova , Via Ugo Bassi 58/B, 35131 Padova, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Franzoi
authors.affiliation: CRIBI, University of Padova , Via Ugo Bassi 58/B, 35131 Padova, Italy.
authors.forename: Nunzio
authors.initials: N
authors.lastname: Damiano
authors.affiliation: Department of Biomedical Sciences, University of Padova , Via Ugo Bassi 58/B, 35131 Padova, Italy.
authors.forename: Rosa
authors.initials: R
authors.lastname: Norante
authors.affiliation: Department of Botany and Microbiology, Alexandria University , Moharam Bey 21511, 21526 Alexandria, Egypt.
authors.forename: Nancy M
authors.initials: NM
authors.lastname: El Halfawy
authors.affiliation: Department of Chemical Sciences, University of Padova , Via Marzolo 1, 35131 Padova, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Mammi
authors.affiliation: CRIBI, University of Padova , Via Ugo Bassi 58/B, 35131 Padova, Italy.|Department of Biomedical Sciences, University of Padova , Via Ugo Bassi 58/B, 35131 Padova, Italy.
authors.forename: Oriano
authors.initials: O
authors.lastname: Marin
authors.affiliation: Department of Chemical Sciences, University of Padova , Via Marzolo 1, 35131 Padova, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Bellanda
authors.affiliation: Department of Biology, University of Padova , Via Ugo Bassi 58/B, 35131 Padova, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Venier
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000890:Anti-Infective Agents / Q000737:chemistry* / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry* / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects; D001798:Blood Proteins / Q000737:chemistry* / Q000494:pharmacology*; D005658:Fungi / Q000187:drug effects; D008969:Molecular Sequence Data; D049878:Mytilus / Q000737:chemistry*
chemical_list: D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; D001798:Blood Proteins; C400201:myticin
keywords: Mytilus galloprovincialis; antimicrobial peptides; mussel; myticin C