Cyclotide

Cyclotides are small disulfide rich peptides isolated from plants. Typically containing 28-37 amino acids, they are characterized by their head-to-tail cyclised peptide backbone and the interlocking arrangement of their three disulfide bonds. These combined features have been termed the cyclic cystine knot (CCK) motif. To date, over 100 cyclotides have been isolated and characterized from species of the Rubiaceae, Violaceae, and Cucurbitaceae families. Cyclotides have also been identified in agriculturally important families such as the Fabaceae and Poaceae.