Proceedings book download - 5Z.com

Proceedings of the 31 st European Peptide SymposiumMichal Lebl, Morten Meldal, Knud J. Jensen, Thomas Hoeg-Jensen (Editors)European Peptide Society, 2010Secondary Structure Modifications of Serine Protease InhibitorUpain-1 to Improve Binding AffinityRenée Roodbeen 1,3 , Peter A. Andreasen 2,3 , and Knud J. Jensen 1,31 IGM – bioorganic chemistry, Faculty of Life Sciences, University of Copenhagen,Frederiksberg, 1871, Denmark; 2 Department of Molecular Biology, University of Århus,Århus, 8000, Denmark; 3 Danish-Chinese Centre for Proteases and CancerIntroductionCancer is a leading cause of death with a predicted 12 million casualties in 2030 worldwide[1]. Treatment is often complicated due to the formation of metastatic tumors. Metastasisoccurs through the degradation of the extracellular matrix in which the plasminogenactivation system has a key role(Figure 1) [2,3]. It has beenshown that inhibition of thispathway reduces tumor growthand the formation of metastasesin mice [4].Plasminogen is activated byurokinase plasminogen activator(uPA). A specific cyclicpeptidylic inhibitor of uPA,upain-1, was previously isolatedfrom a phage-displayed peptideLibrary [5].Upain-1 is a selectiveinhibitor of uPA and showsFig. 1 Simplified overview of the urokinase plasminogenactivation system, adapted from [3].negligible affinity towards other serine proteases e.g. trypsin [5]. Upain-1 is a dodecamericpeptide cyclized by a disulfide bridge between the terminal cysteines [5]. An equally potentanalogue, Ac-CSWRGLENHAAC-NH 2 , has already been synthesized [6]. Even thoughupain-1 is a very specific inhibitor, its K i for uPA is 32 µM, which is too high for anapplication as a peptide drug.We hypothesize that the low binding affinity is caused by a significant loss of entropyduring the binding event. Therefore we aim to improve the affinity of upain-1 for uPA bymaking more rigid head-to-tail and sidechain-to-backbone monocyclic and bicyclicanalogues of upain-1.Results and discussionAll peptides were synthesized by sidechain-anchoring of Fmoc-Asp-OAll on a Rink amideresin (Figure 2).Fig. 2. SPPS-approach to obtain bicyclic upain-1 analogues.554