The cyclic cystine knot motif, as defined by the cyclotide peptide family, is an attractive scaffold for protein engineering. To date, however, the utilisation of this scaffold has been limited by the inability to synthesise members of the most diverse and biologically active subfamily, the bracelet cyclotides. This study describes the synthesis and first direct oxidative folding of a bracelet ...

The cyclotides are a family of circular and knotted proteins of natural origin with extreme enzymatic and thermal stability. They have a wide range of biological activities that make them promising tools for pharmaceutical and crop-protection applications. The cyclotides are divided into two subfamilies depending on the presence (Möbius) or absence (bracelet) of a cis-Pro peptide bond. In the c...

The cyclotides are a family of circular proteins with a range of biological activities and potential pharmaceutical and agricultural applications. The biosynthetic mechanism of cyclization is unknown and the discovery of novel sequences may assist in achieving this goal. In the present study, we have isolated a new cyclotide from Oldenlandia affinis, kalata B8, which appears to be a hybrid of t...

cyclotides are small disulfide-rich proteins that have the unusual feature of a cyclic backbone. cyclotides have a range of interesting biological activities and are found in a variety of tropical plants from the rubiaceae, violaceae, cucurbitaceae and fabaceae families. we have cloned and characterized cyclotides in viola modesta, a viola species native to western asia, which was collected fro...

Cyclotides are an extremely stable class of peptides, ubiquitously distributed in Violaceae. The aim the present study was to investigate presence cyclotides Sri Lankan Violaceae plants, using combined tools transcriptomics and mass spectrometry. New were discovered for first time wild flora Lanka, within Viola betonicifolia, a plant used traditional medicine as antimicrobial. Plant extracts pr...

Cyclotides are a family of plant-derived cyclic peptides comprising six conserved cysteine residues connected by three intermolecular disulfide bonds that form a knotted structure known as a cyclic cystine knot (CCK). This structural motif is responsible for the pronounced stability of cyclotides against chemical, thermal, or proteolytic degradation and has sparked growing interest in this fami...

OBJECTIVES To determine the antibacterial activity of small cyclic plant proteins, i.e. cyclotides, and the importance of the surface exposed charged residues for activity. METHODS Prototypic cyclotides, including the Möbius kalata B1 and the bracelet cycloviolacin O2 (cyO2), were isolated using reversed-phase HPLC. Initial activity screenings were conducted using radial diffusion assays (RDA...

Cyclotides are cysteine-rich cyclic peptides that have various activities and applications. Mining at the whole-genome scale facilitates profiling development of cyclotide-based markers. However, characterization cyclotide subfamilies a genome-scale in plants is an untapped area needs more studies. Here we developed four degenerate subfamily-specific (CSS) markers based on their subfamily’s sem...

Cyclotides comprise a family of circular mini-peptides that have been isolated from various plants and have a wide range of bioactivities. Previous studies have demonstrated that cyclotides have antitumor effects and cause cell death by membrane permeabilization. The present study aimed to evaluate the cytotoxicity and chemosensitizing activities of cyclotides from Clitoria ternatea in paclitax...

During the last decade there has been increasing interest in small circular proteins found in plants of the violet family (Violaceae). These so-called cyclotides consist of a circular chain of approximately 30 amino acids, including six cysteines forming three disulfide bonds, arranged in a cyclic cystine knot (CCK) motif. In this study we map the occurrence and distribution of cyclotides throu...