Anchored cyclic peptides for use in crop protection
Final Report Abstract
This project aimed to develop a new class of insecticides using peptide-based molecules. The strategy involved combining two components: an anchor peptide that sticks to plant surfaces and an insecticidal cyclotide. MBP1 was identified from a peptide library as a suitable anchor peptide for plants. MBP1 was then grafted into kalata B1 (kB1), the model cyclotide, by replacing a non-essential loop with the anchor peptide. Efforts to make this molecule synthetically (by solid-phase peptide synthesis) or recombinantly (E. coli) failed, presumably due to high internal strain inferred by the rigid structure of MBP1. A novel method to generate cyclic peptides from recombinant precursors, based on conditional inteins, was developed to overcome production issues. By using conditional inteins and a bridging sequence to induce flexibility, a kB1-MBP1 chimera was successfully produced. The workflow established here was also used to produce wildtype cyclotides, which were shown to be identical to native peptides.
