De novo sequencing of TBD-1, the first beta-defensin isolated from reptiles

2 . The latter group includes also defensins, a family of evolutionary related antimicrobial peptides in vertebrates, with a characteristic beta-sheet-rich secondary structure containing three disulphide bridges. They are produced from different cell types and are classified as alpha or beta defensins based on their length and disulfide bridging, as well as theta defensins for cyclic peptides.