Design of a MCoTI-Based Cyclotide with Angiotensin (1-7)-Like Activity

We report for the first time the design and synthesis of a novel cyclotide able to activate the unique receptor of angiotensin-(1–7) (AT1–7), the MAS1 receptor. This was accomplished by grafting an AT 1–7 peptide analog onto loop 6 of cyclotide MCoTI-I using isopeptide bonds to preserve the α-amino and C-terminal carboxylate groups of AT1–7, which are required for activity. The resulting cyclotide construct was able to adopt a cyclotide-like conformation and showed similar activity to that of AT1–7. This cyclotide also showed high stability in human serum thereby providing a promising lead compound for the design of a novel type of peptide-based in the treatment of cancer and myocardial infarction.