The Cecropin Superfamily of Toxic Peptides

All sequenced peptide toxins of the cecropin, pleurocidin and dermaceptin/ceratotoxin families in the National Center for Biotechnology Information (NCBI) database as of May 2005 were identified and shown to comprise a single superfamily. The peptide sequences were multiply aligned, revealing conserved residues that may play roles in structure and function. Signature sequences were derived for each of the 3 constituent families. Phylogenetic analyses revealed the relationships of these peptides to each other, and average hydropathy/amphipathicity studies provided structural information. This study serves to characterize a large superfamily of toxic peptides that perform host defense functions in a range of animal kingdoms.