Cliotides are a group of related peptides that have been isolated from the heat-stable fraction of Clitoria ternatea (Cliotides) extracts.[1] Cliotides belong to a larger classification of peptides, the cyclotides.
Preliminary studies show that cliotides display a variety of biochemical properties which have attracted scientific interest in the possibility of developing antimicrobial and anti-cancer agents from them.
Cliotides also possess immunostimulating activity. At a concentration of 1 μM, cationic cliotides are capable of augmenting the secretion of various cytokines and chemokines in human monocytes at both resting and LPS-stimulated states.[3] Chemokines such as RANTES, MIP-1β, MIP-1α, IP-10, IL-8 and TNF-α were among the most upregulated with up to 129-fold increase in secretion level.
Different cyclotides have protein sequences which engender different biophysical and functional properties, to be expressed in different organs.[4] For example, cyclotides from aerial organs possess tighter binding activity to insect-like membranes, whereas cyclotides from roots and seed, two organs that contact soil, have relatively higher effectiveness against juveniles of the model nematode Caenorhabditis elegans.[4] The isolated Cter M cyclotide that is highly expressed in aerial organs was shown to effectively slow the growth and kill moth larvae.[5]
The enzyme responsible for the biosynthesis and backbone cyclization of cliotides has recently been isolated. It was named butelase 1 in accordance with its local name in Malaysia and Singapore (bunga telang ligase). Butelase 1 is the fastest peptide ligase known capable of catalyzing peptide cyclization at an extraordinary efficiency.[6]