ABSTRACT
The structural variety that characterizes these peptides contributes to multiple bioactive roles against microbial, ranging from membrane bonding to permeabilization and the interaction with an array of intracellular target molecules. Natural AMPs are preserved in the genome of all life forms, that is from bacteria to mammals and display extraordinary structural and functional variability. Defensins are cysteine-rich AMPs described as ancient innate immunity molecules, which can be found in animals, plants, and fungi as well as in mollusks, cnidarians, annelids, and nematodes. Cathelicidins are an important family of AMPs, found mostly in vertebrates. The name of this family is based on its limited homology to cathelin, a protein acronym for cathepsin-L-inhibitor and a member of the cystatin family of cysteine protease inhibitors. Bacteriocins are an abundant and heterogeneous class of AMPs made of 20 to 60 amino acids, produced predominantly by bacteria to eradicate other bacterial species in a competitive environment, particularly species phylogenetically close to the producing strain.
