Translocating proline-rich peptides from the antimicrobial peptide bactenecin 7.
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.
Sadler
Kristen
K
Department of Microbiology and Immunology, Vanderbilt University, Nashville, Tennessee 37232, USA.
Eom
Khee Dong
KD
Yang
Jin-Long
JL
Dimitrova
Yoana
Y
Tam
James P
JP
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
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