Uncoupling the Folding-Function Paradigm of Lytic Peptides to Deliver Impermeable Inhibitors of Intracellular Protein-Protein Interactions

J Am Chem Soc. 2020 Nov 25;142(47):19950-19955. doi: 10.1021/jacs.0c07921. Epub 2020 Nov 11.


Here, we describe the use of peptide backbone N-methylation as a new strategy to transform membrane-lytic peptides (MLPs) into cytocompatible intracellular delivery vehicles. The ability of lytic peptides to engage with cell membranes has been exploited for drug delivery to carry impermeable cargo into cells, but their inherent toxicity results in narrow therapeutic windows that limit their clinical translation. For most linear MLPs, a prerequisite for membrane activity is their folding at cell surfaces. Modification of their backbone with N-methyl amides inhibits folding, which directly correlates to a reduction in lytic potential but only minimally affects cell entry. We synthesized a library of N-methylated peptides derived from MLPs and conducted structure-activity studies that demonstrated the broad utility of this approach across different secondary structures, including both β-sheet and helix-forming peptides. Our strategy is highlighted by the delivery of a notoriously difficult class of protein-protein interaction inhibitors that displayed on-target activity within cells.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Amino Acid Sequence
  • Cell Cycle Checkpoints / drug effects
  • Cell Cycle Proteins / antagonists & inhibitors
  • Cell Cycle Proteins / metabolism
  • Cell Line, Tumor
  • Cell Membrane / chemistry
  • Cell Membrane / metabolism
  • Cell Survival
  • Drug Carriers / chemistry
  • Humans
  • Microscopy, Confocal
  • Peptides / chemistry
  • Peptides / metabolism*
  • Peptides / pharmacology
  • Protein Folding
  • Protein Interaction Domains and Motifs
  • Protein Kinase Inhibitors / chemistry
  • Protein Kinase Inhibitors / metabolism
  • Protein Serine-Threonine Kinases / antagonists & inhibitors
  • Protein Serine-Threonine Kinases / metabolism
  • Protein Structure, Secondary
  • Proto-Oncogene Proteins / antagonists & inhibitors
  • Proto-Oncogene Proteins / metabolism
  • Structure-Activity Relationship


  • Cell Cycle Proteins
  • Drug Carriers
  • Peptides
  • Protein Kinase Inhibitors
  • Proto-Oncogene Proteins
  • Protein Serine-Threonine Kinases
  • polo-like kinase 1