Targeting Yes-Associated Protein With Evolved Peptide Aptamers To Disrupt Tgf-Beta Signaling Pathway: Therapeutic Implication For Bone Tumor

The binding of transcription coactivator Yes-associated protein (YAP) to Smad transcription factors is an important event in activating transforming growth factor-beta (TGF-beta) signaling pathway, which is involved in the tumorigenicity and metastasis of bone tumor. Design of peptide aptamers to disrupt YAP-Smad interaction has been established as a promising approach for bone tumor therapy. Here, an evolution strategy was used to optimize Smad-derived peptides for high potency binding to YAP WW2 domain, resulting in an improved peptide population, from which those high-scoring candidates were characterized rigorously using molecular dynamics (MD) simulations and interaction free energy calculations. With the computational protocol we were able to generate a number of potential domain binders, which were then substantiated by using fluorescence spectroscopy assay. Subsequently, the complex structure of YAP WW2 domain with a high-affinity peptide was modeled and examined in detail, which was then used to guide structure-based peptide optimization to obtain several strong domain binders. Structural and energetic analysis revealed that electrostatic complementarity is primarily responsible for domain-peptide recognition, while other nonbonded interactions such as hydrogen bonding and salt bridges can contribute significantly to the recognition specificity.