Bicyclic peptide inhibitor of urokinase-type plasminogen activator: mode of action

Research output: Contribution to journalJournal articleResearchpeer-review

  • Renée Roodbeen
  • Berit Paaske Jensen
  • Longguang Jiang
  • Jan Kristian Jensen
  • Anni Christensen
  • Jakob T. Nielsen
  • Mingdong Huang
  • Frans Mulder
  • Niels Chr. Nielsen
  • Peter Andreasen
  • Jensen, Knud Jørgen
The development of protease inhibitors for pharmacological intervention has taken a new turn with the use of peptide-based inhibitors. Here, we report the rational design of bicyclic peptide inhibitors of the serine protease urokinase-type plasminogen activator (uPA), based on the established monocyclic peptide, upain-2. It was successfully converted to a bicyclic peptide, without loss of inhibitory properties. The aim was to produce a peptide cyclised by an amide bond with an additional stabilising across-the-ring covalent bond. We expected this bicyclic peptide to exhibit a lower entropic burden upon binding. Two bicyclic peptides were synthesised with affinities similar to that of upain-2, and their binding energetics were evaluated by isothermal titration calorimetry. Indeed, compared to upain-2, the bicyclic peptides showed reduced loss of entropy upon binding to uPA. We also investigated the solution structures of the bicyclic peptide by NMR spectroscopy to map possible conformations. An X-ray structure of the bicyclic-peptide-uPA complex confirmed an interaction similar to that for the previous upain-1/upain-2-uPA complexes. These physical studies of the peptide-protease interactions will aid future designs of bicyclic peptide protease inhibitors.
Original languageEnglish
Issue number16
Pages (from-to)2179-2188
Number of pages10
Publication statusPublished - 2013

ID: 99084164