Cyclotides: Disulfide-rich peptide toxins in plants

Toxicon. 2019 Oct 25:172:33-44. doi: 10.1016/j.toxicon.2019.10.244. Epub 2019 Nov 1.

Abstract

Cyclotides are a plant-derived family of peptides that comprise approximately 30 amino acid residues, a cyclic backbone and a cystine knot. Due to their unique structure, cyclotides are exceptionally stable to heat or proteolytic degradation and are tolerant to amino acid substitutions in their backbone loops between conserved cysteine residues. Their toxicity to insect pests and their make-up of natural amino acids has led to their applications in eco-friendly crop protection. Furthermore, their stability and cell penetrating properties make cyclotides ideal scaffolds for bioactive epitope grafting. This article gives a brief overview of cyclotide discovery, characterization, distribution, synthesis and mode of action mechanisms. We focus on their toxicities to insect pests and their medical and agricultural applications.

Keywords: Applications; Cell penetrating peptide; Cyclotides; Cytotoxicity; Insecticidal peptide; Stability.

Publication types

  • Review

MeSH terms

  • Amino Acid Motifs
  • Amino Acid Sequence
  • Animals
  • Cyclotides / chemistry*
  • Cyclotides / pharmacology
  • Cyclotides / toxicity
  • Insecta / drug effects
  • Magnoliopsida / chemistry*
  • Toxins, Biological / chemistry
  • Toxins, Biological / toxicity

Substances

  • Cyclotides
  • Toxins, Biological