Peptide display methods are a powerful tool for discovering new ligands of pharmacologically relevant targets. However, the selected ligands often suffer from low affinity. Using phage display, we identified a new bicyclic peptide binder of prostate-specific membrane antigen (PSMA), a metalloprotease frequently overexpressed in prostate cancer. We show that linking multiple copies of a selected low-affinity peptide to a biocompatible water-soluble N-(2-hydroxypropyl)methacrylamide copolymer carrier (iBody) improved binding of the conjugate by several orders of magnitude. Furthermore, using ELISA, enzyme kinetics, confocal microscopy, and other approaches, we demonstrate that the resulting iBody can distinguish between different conformations of the target protein. The possibility to develop stable, fully synthetic, conformation-selective antibody mimetics has potential applications for molecular recognition, diagnosis and treatment of many pathologies. This strategy could significantly contribute to more effective drug discovery and design.

Institute of Macromolecular Chemistry Czech Academy of Sciences Prague Czech Republic

Institute of Organic Chemistry and Biochemistry Czech Academy of Sciences Prague Czech Republic

Institute of Organic Chemistry and Biochemistry Czech Academy of Sciences Prague Czech Republic; 1st Medical Faculty Charles University Prague Czech Republic

Institute of Organic Chemistry and Biochemistry Czech Academy of Sciences Prague Czech Republic; Department of Cell and Developmental Biology Faculty of Science Charles University Prague Czech Republic

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Polymer-Tethered Quenched Fluorescent Probes for Enhanced Imaging of Tumor-Associated Proteases

Polymer-based antibody mimetics (iBodies) target human PD-L1 and function as a potent immune checkpoint blocker

Polymer-tethered quenched fluorescent probes for enhanced imaging of tumor associated proteases

Building the SynBio community in the Czech Republic from the bottom up: You get what you give