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Macrocyclized extended peptides: Inhibiting the substrate-recognition domain of tankyrase

DOI: 10.1021/jacs.6b10234 DOI Help

Authors: Wenshu Xu (University of Cambridge) , Yu Heng Lau (University of Cambridge) , Gerhard Fischer (University of Cambridge) , Yaw Sing Tan (University of Cambridge; Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR)) , Anasuya Chattopadhyay (University of Cambridge) , Marc De La Roche (University of Cambridge) , Marko Hyvonen (University of Cambridge) , Chandra S. Verma (Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR); Nanyang Technological University; National University of Singapore) , David R. Spring (University of Cambridge) , Laura S. Itzhaki (University of Cambridge)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of The American Chemical Society

State: Published (Approved)
Published: January 2017

Abstract: We report a double-click macrocyclization approach for the constraint of peptide inhibitors in non-helical or extended conformations. Our targets are the tankyrase proteins (TNKS), poly(ADP-ribose) polymerases that regulate Wnt signaling by targeting Axin for degradation. TNKS are deregulated in many different cancer types, and inhibition of TNKS therefore represents an attractive therapeutic strategy. However, the clinical development of TNKS-specific PARP inhibitors is challenging due to off-target effects and cellular toxicity. Here we designed a new class of specific peptide inhibitors directed against the substrate-recognition domain of TNKS, which is unique amongst PARP family members. We employed a two-component strategy, allowing the peptide and the linker to be separately engineered and then assembled in a combinatorial fashion via click chemistry. Using the consensus substrate-peptide sequence as a starting point, we optimized the length and rigidity of the linker as well as its position along the peptide. Optimization was further guided by high-resolution crystal structures of two of the macrocyclized peptides in complex with TNKS. In this way we identified peptides with sub-micromolar affinities for TNKS and having high proteolytic stability. We show that these peptides are able to disrupt the interaction between TNKS and Axin substrate and to inhibit Wnt signaling in a dose-dependent manner. Thus, the macrocylized peptides represent a promising starting point for a new class of substrate-competitive inhibitors of TNKS with potential for suppressing Wnt signaling in cancer. Moreover, by demonstrating the application of the double-click macrocyclization approach to non-helical, extended or irregular structured peptides we greatly extend its potential and scope, especially given the frequency with which such motifs mediate protein-protein interactions.

Subject Areas: Biology and Bio-materials, Chemistry

Instruments: I04-1-Macromolecular Crystallography (fixed wavelength) , I24-Microfocus Macromolecular Crystallography