title: Translocating proline-rich peptides from the antimicrobial peptide bactenecin 7.
abstract: The intracellular delivery of most peptides, proteins, and nucleotides to the cytoplasm and nucleus is impeded by the cell membrane. To allow simplified, noninvasive delivery of attached cargo, cell-permeant peptides that are either highly cationic or hydrophobic have been utilized. Because cell-permeable peptides share half of the structural features of antimicrobial peptides containing clusters of charge and hydrophobic residues, we have explored antimicrobial peptides as templates for designing cell-permeant peptides. We prepared synthetic fragments of Bac 7, an antimicrobial peptide with four 14-residue repeats from the bactenecin family. The dual functions of cell permeability and antimicrobial activity of Bac 7 were colocalized at the N-terminal 24 residues of Bac 7. In general, long fragments of Bac(1-24) containing both regions were bactericidal and cell-permeable, whereas short fragments with only a cationic or hydrophobic region were cell-permeant without the attendant microbicidal activity when measured in a fluorescence quantitation assay and by confocal microscopy. In addition, the highly cationic fragments were capable of traversing the cell membrane and residing within the nucleus. A common characteristic shared by the cell-permeant Bac(1-24) fragments, irrespective of their number of charged cationic amino acids, is their high proline content. A 10-residue proline-rich peptide with two arginine residues was capable of delivering a noncovalently linked protein into cells. Thus, the proline-rich peptides represent a potentially new class of cell-permeant peptides for intracellular delivery of protein cargo. Furthermore, our results suggest that antimicrobial peptides may represent a rich source of templates for designing cell-permeant peptides.
authors.affiliation: Department of Microbiology and Immunology, Vanderbilt University, Nashville, Tennessee 37232, USA.
authors.forename: Kristen
authors.initials: K
authors.lastname: Sadler
authors.forename: Khee Dong
authors.initials: KD
authors.lastname: Eom
authors.forename: Jin-Long
authors.initials: JL
authors.lastname: Yang
authors.forename: Yoana
authors.initials: Y
authors.lastname: Dimitrova
authors.forename: James P
authors.initials: JP
authors.lastname: Tam
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents / Q000138:chemical synthesis / Q000378:metabolism* / Q000494:pharmacology / Q000633:toxicity; D000935:Antifungal Agents / Q000494:pharmacology; D002176:Candida albicans / Q000187:drug effects; D002412:Cations / Q000378:metabolism; D002460:Cell Line; D002463:Cell Membrane Permeability / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D016503:Drug Delivery Systems / Q000379:methods; D004926:Escherichia coli / Q000187:drug effects; D057927:Hydrophobic and Hydrophilic Interactions; D051379:Mice; D008969:Molecular Sequence Data; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology / Q000633:toxicity; D010455:Peptides / Q000138:chemical synthesis / Q000378:metabolism* / Q000494:pharmacology / Q000633:toxicity; D010456:Peptides, Cyclic / Q000138:chemical synthesis / Q000378:metabolism* / Q000494:pharmacology / Q000633:toxicity; D011392:Proline / Q000378:metabolism*; D055232:Proline-Rich Protein Domains; D021381:Protein Transport; D020449:Repetitive Sequences, Amino Acid; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D000935:Antifungal Agents; D002412:Cations; D010446:Peptide Fragments; D010455:Peptides; D010456:Peptides, Cyclic; C056454:bactenecin; D011392:Proline