The dermaseptin superfamily: A gene-based combinatorial library of antimicrobial peptides

Skin secretions of hylid frogs show amazing levels of interspecific and intraspecific diversity and are comprised of a cocktail of genetically-related, but markedly diverse antimicrobial peptides that are grouped into a superfamily, termed the dermaseptins, comprising several families: dermaseptins (sensu stricto), phylloseptins, plasticins, dermatoxins, phylloxins, hyposins, caerins, and aureins. Dermaseptin gene superfamily evolution is characterized by repeated gene duplications and focal hypermutations of the mature peptide coding sequence, followed by positive (diversifying) selection. We review here molecular mechanisms leading to these vast combinatorial peptide libraries, and structural and functional properties of antimicrobial peptides of the dermaseptin and plasticin families, as well as those of dermaseptin S9, an amyloidogenic peptide with antimicrobial and chemoattractant activities.