biostudies-literatureUnknown287(21)Nguyen GKTCyclotides are a new class of plant biologics that display a diverse range of bioactivities with therapeutic potentials. They possess an unusual end-to-end cyclic backbone combined with a cystine knot arrangement, making them exceptionally stable to heat, chemical and enzymatic degradation. Currently, >200 cyclotides have been discovered but only three naturally occurring linear variants (also known as uncyclotides) have been isolated. In this study, we report the discovery of 18 novel peptides, chassatides C1 to C18, composed of 14 new cyclotides and four uncyclotides from Chassalia chartacea (Rubiaceae family). Thus far, this is the largest number of uncyclotides being reported in a single species. Activity testing showed that the uncyclotides not only retain the effectiveness but also aThe Journal of biological chemistry17598-17607https://www.ebi.ac.uk/biostudies/studies/S-EPMC3366795biostudies-literatureNovel cyclotides and uncyclotides with highly shortened precursors from Chassalia chartacea and effects of methionine oxidation on bioactivities.PMC3366795Nguyen PQTTam JPLim WHNguyen GKTfalseNovel cyclotides and uncyclotides with highly shortened precursors from Chassalia chartacea and effects of methionine oxidation on bioactivities.Cyclotides are a new class of plant biologics that display a diverse range of bioactivities with therapeutic potentials. They possess an unusual end-to-end cyclic backbone combined with a cystine knot arrangement, making them exceptionally stable to heat, chemical and enzymatic degradation. Currently, >200 cyclotides have been discovered but only three naturally occurring linear variants (also known as uncyclotides) have been isolated. In this study, we report the discovery of 18 novel peptides, chassatides C1 to C18, composed of 14 new cyclotides and four uncyclotides from Chassalia chartacea (Rubiaceae family). Thus far, this is the largest number of uncyclotides being reported in a single species. Activity testing showed that the uncyclotides not only retain the effectiveness but also a2012-01-01T00:00:00Z2012 May2026-04-30T17:56:30.793Z2019-03-27T00:54:07ZS-EPMC33667952246787010.1074/jbc.M111.33897010.1074/jbc.m111.338970