Interchain doubly-bridged α-helical peptides for the development of protein binders

Constrained peptide scaffolds that are tolerant to extensive sequence manipulation and amenable to bioactive peptide design are of great value to the development of novel protein binders and peptide therapeutics. In this work, we reported strategies for the design and synthesis of a kind of novel interchain doubly-bridged α-helical peptides, involving mutual stabilization of two peptide α-helices linked by two interchain bisthioether crosslinkers. By taking a MDM2-binding peptide with an α-helical tendency as a model, we demonstrated that α-helical dimers with significantly improved structural and proteolytic stability and nanomolar binding affinity to the target protein can be obtained. By modulating the surface charges on the dimeric peptides, we also obtained a dimeric peptide with enhanced cellpenetrating capability, which can efficiently penetrate into cancer cells and inhibit the intracellular MDM2-p53 interactions to promote cell apoptosis. Considering that many proteins take a surface α-helical segment as the binding motif to mediate their interactions with other proteins, we believe that our interchain doubly-bridged α-helical peptides would provide a promising scaffold for the development of novel high-affinity protein binders.

N-cap helix nucleation： methods and their applications

Recapitulation of well-defined α-helices could result in constrained peptide mimetics with preferable secondary structures and enhanced therapeutic properties for various purposes. Among the helix-stabilizing strategies, the nucleation strategies are able to maximize recognition specificity of the original sequence without compromising the molecular recognition surface. In this review,current methodologies of helix nucleation are introduced including their constructing strategies, structure features and proof of concept biological applications.