A Cyclized Helix-Loop-Helix Peptide as a Molecular Scaffold for the Design of Inhibitors of Intracellular Protein-Protein Interactions by Epitope and Arginine Grafting

作者：Fujiwara Daisuke; Kitada Hidekazu; Oguri Masahiro; Nishihara Toshio; Michigami Masataka; Shiraishi Kazunori; Yuba Eiji; Nakase Ikuhiko; Im Haeri; Cho Sunhee; Joung Jong Young; Kodama Seiji; Kono Kenji; Ham Sihyun^*; Fujii Ikuo^*

来源：Angewandte Chemie International Edition, 2016, 55(36): 10612-10615.

DOI：10.1002/anie.201603230

• cell-penetrating peptides
• epitope grafting
• helix-loop-helix peptides
• inhibitors
• protein-protein interactions

The design of inhibitors of intracellular protein-protein interactions (PPIs) remains a challenge in chemical biology and drug discovery. We propose a cyclized helix-loop-helix (cHLH) peptide as a scaffold for generating cell-permeable PPI inhibitors through bifunctional grafting: epitope grafting to provide binding activity, and arginine grafting to endow cell-permeability. To inhibit p53-HDM2 interactions, the p53 epitope was grafted onto the C-terminal helix and six Arg residues were grafted onto another helix. The designed peptide cHLHp53-R showed high inhibitory activity for this interaction, and computational analysis suggested a binding mode for HDM2. Confocal microscopy of cells treated with fluorescently labeled cHLHp53-R revealed cell membrane penetration and cytosolic localization. The peptide inhibited the growth of HCT116 and LnCap cancer cells. This strategy of bifunctional grafting onto a well-structured peptide scaffold could facilitate the generation of inhibitors for intracellular PPIs.

• 出版日期2016-8-26