Self-assembly and intracellular delivery of DNA by a truncated fragment derived from the Trojan peptide Penetratin

Mello, L. R., Hamley, I. W. ORCID: https://orcid.org/0000-0002-4549-0926, Castelletto, V., Garcia, B. B. M., Lourenço, T. C., Vassiliades, S. V., Alves, W. A., Han, S. W. and Silva, E. R. (2020) Self-assembly and intracellular delivery of DNA by a truncated fragment derived from the Trojan peptide Penetratin. Soft Matter, 16 (20). pp. 4746-4755. ISSN 1744-683X doi: 10.1039/D0SM00347F

Abstract/Summary

Penetratin is a short Trojan peptide that attracts great interest in biomedical research for its capacity to translocate biological membranes. Herein, we study in detail both self-assembly and intracellular delivery of DNA by the heptamer KIWFQNR, a truncated peptide derived from Penetratin. This shortened sequence possesses a unique design with bolaamphiphilic characteristics that preserves the longest noncationic amino acid portion found in Penetratin. These features convey amphipathicity to assist self-assembly and make it a suitable model for exploring the role of hydrophobic residues for peptide interaction and cell uptake. We show that the fragment forms peptiplexes (i.e., peptide–DNA complexes), and aggregates into long nanofibers with clear β-sheet signature. The supramolecular structure of nanofibers is likely composed of DNA cores surrounded by a peptide shell to which the double helix behaves as a template and induces fibrillization. A nucleation and growth mechanism proceeding through liquid–liquid phase separation of coacervates is proposed for describing the self-assembly of peptiplexes. We also demonstrate that peptiplexes deliver double-stranded 200 bp DNA into HeLa cells, indicating its potential for preparing non-viral vectors for oligonucleotides through noncovalent strategies. Since the main structural features of native Penetratin are conserved in this simpler fragment, our findings also highlight the role of uncharged amino acids for structuration, and thus for the ability of Penetratin to cross cell membranes.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/91719
Identification Number/DOI	10.1039/D0SM00347F
Refereed	Yes
Divisions	Life Sciences > School of Chemistry, Food and Pharmacy > Department of Chemistry
Publisher	Royal Society of Chemistry
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