Efficient delivery of cyclic peptides into mammalian cells with short sequence motifs

ACS Chem Biol. 2013 Feb 15;8(2):423-31. doi: 10.1021/cb3005275. Epub 2012 Nov 12.


Cyclic peptides hold great potential as therapeutic agents and research tools, but their broad application has been limited by poor membrane permeability. Here, we report a potentially general approach for intracellular delivery of cyclic peptides. Short peptide motifs rich in arginine and hydrophobic residues (e.g., FΦRRRR, where Φ is l-2-naphthylalanine), when embedded into small- to medium-sized cyclic peptides (7-13 amino acids), bound to the plasma membrane of mammalian cultured cells and were subsequently internalized by the cells. Confocal microscopy and a newly developed peptide internalization assay demonstrated that cyclic peptides containing these transporter motifs were translocated into the cytoplasm and nucleus at efficiencies 2-5-fold higher than that of nonaarginine (R(9)). Furthermore, incorporation of the FΦRRRR motif into a cyclic peptide containing a phosphocoumaryl aminopropionic acid (pCAP) residue generated a cell permeable, fluorogenic probe for detecting intracellular protein tyrosine phosphatase activities.

Publication types

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

MeSH terms

  • Amino Acid Motifs
  • Cell Membrane / metabolism
  • Drug Delivery Systems*
  • Humans
  • MCF-7 Cells
  • Microscopy, Confocal
  • Molecular Conformation
  • Peptides, Cyclic / chemical synthesis
  • Peptides, Cyclic / chemistry*
  • Peptides, Cyclic / metabolism*
  • Tumor Cells, Cultured


  • Peptides, Cyclic