| 1. |
- Kilk, Kalle, et al.
(författare)
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Cellular internalization of a cargo complex with a novel peptide derived from the third helix of the islet-1 homeodomain : Comparison with the penetratin peptide
- 2001
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Ingår i: Bioconjugate chemistry. - : American Chemical Society (ACS). - 1043-1802 .- 1520-4812. ; 12:6, s. 911-916
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Tidskriftsartikel (refereegranskat)abstract
- Cellular translocation into a human Bowes melanoma cell line was investigated and compared for penetratin and pIsl, two peptides that correspond to the third helices of the related homeodomains, from the Antennapedia transcription factor of Drosophila and the rat insulin-1 gene enhancer protein, respectively. Both biotinylated peptides internalized into the cells with similar efficacy, yielding an analogous intracellular distribution. When a large cargo protein, 63 kDa avidin, was coupled to either peptide, efficient cellular uptake for both the peptide−protein complexes was observed. The interactions between each peptide and SDS micelles were studied by fluorescence spectroscopy and acrylamide quenching of the intrinsic tryptophan (Trp) fluorescence. Both peptides interacted strongly and almost identically with the membrane mimicking environment. Compared to penetratin, the new transport peptide pIsl has only one Trp residue, which simplifies the interpretation of the fluorescence spectra and in addition has a native Cys residue, which may be used for alternative coupling reactions of cargoes of different character.
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| 2. |
- Lundberg, Pontus, et al.
(författare)
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Cell membrane translocation of the N-terminal (1-28) part of the prion protein
- 2002
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Ingår i: Biochemical and Biophysical Research Communications - BBRC. - 0006-291X .- 1090-2104. ; 299:1, s. 85-90
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Tidskriftsartikel (refereegranskat)abstract
- The N-terminal (1-28) part of the mouse prion protein (PrP) is a cell penetrating peptide, capable of transporting large hydrophilic cargoes through a cell membrane. Confocal fluorescence microscopy shows that it transports the protein avidin (67 kDa) into several cell lines. The (1-28) peptide has a strong tendency for aggregation and P-structure formation, particularly in interaction with negatively charged phospholipid membranes. The findings have implications for how prion proteins with uncleaved signal peptides in the N-termini may enter into cells, which is important for infection. The secondary structure conversion into beta-structure may be relevant as a seed for the conversion into the scrapie (PrPSc) form of the protein and its arnyloidic transformation.
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| 3. |
- Magzoub, Mazin, 1977-
(författare)
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Cell-penetrating peptides in model membrane systems : Interaction, structure induction and membrane effects
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Despite continuing advances in the development of macromolecules, including peptides, proteins, and oligonucleotides, for therapeutic purposes, the successful application of these hydrophilic molecules has so far been hampered by their inability to efficiently traverse the plasma membrane. The discovery of a class of peptides (cell-penetrating peptides, CPPs) with the ability to mediate the non-invasive and efficient import of a whole host of cargoes, both in vitro and in vivo, has provided a new means by which the problem associated with cellular delivery can be circumvented.A complete understanding of the translocation mechanism(s) of CPPs has so far proven elusive. Initial studies indicated an ATP-independent, non-endocytotic mechanism, dependent on direct peptide-membrane interactions, making it an enticing challenge from a biophysical point of view. To gain an insight into this mechanism, we identified three new CPP sequences, one corresponding to the third helix of the Islet-1 homeodomain, the other two corresponding to the unprocessed N-termini of the mouse and bovine PrPs, denoted mPrPp and bPrPp, respectively. We then investigated the membrane interactions of these peptides, comparing them to two well-characterized CPPs, the Antennapedia homeodomain-derived pAntp, and the chimeric transportan, in a variety of model membrane systems, using several spectroscopic techniques. Both pAntp and transportan were found to reside in the headgroup region of the bilayer, oriented along the surface (perpendicular to the bilayer normal). However, differences were observed between the peptides – with the homeodomain-derived peptides, pAntp and pIsl, on the one hand, and transportan and the prion-derived peptides on the other – in terms of their membrane interactions, in particular their membrane perturbation effects. These differences suggest that the peptides belong to two classes of CPPs that translocate through different mechanisms. This hypothesis was given further substance by the recent re-evaluation of the translocation mechanism, which led to the conclusion that many peptides, including pAntp, translocate by an energy-dependent, endocytotic mechanism. Interesting structural behaviour was observed for the homeodomain-derived CPPs, where they readily underwent an α → β structural conversion, depending on experimental conditions. High peptide concentration and/or high negative membrane surface charge was found to promote β-sheet structure. This structural conversion characteristic was shared by the prion-derived peptides, which along with their CPP property and their membrane perturbation effects, may have implications for the infectivity and toxicity associated with prion diseases.
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| 4. |
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| 5. |
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| 6. |
- Magzoub, Mazin, et al.
(författare)
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Interaction and structure induction of cell-penetrating peptides in the presence of phospholipid vesicles
- 2001
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Ingår i: Biochimica et Biophysica Acta - Biomembranes. - 0005-2736 .- 1879-2642. ; 1512:1, s. 77-89
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Tidskriftsartikel (refereegranskat)abstract
- Certain short peptides, which are able to translocate across cell membranes with a low lytic activity, can be useful as carriers (vectors) for hydrophilic molecules. We have studied three such cell penetrating peptides: pAntp (‘penetratin’), pIsl and transportan. pAntp and pIsl originate from the third helix of homeodomain proteins (Antennapedia and Isl-1, respectively). Transportan is a synthetic chimera (galanin and mastoparan). The peptides in the presence of various phospholipid vesicles (neutral and charged) and SDS micelles have been characterized by spectroscopic methods (fluorescence, EPR and CD). The dynamics of pAntp were monitored using an N-terminal spin label. In aqueous solution, the CD spectra of the three peptides show secondary structures dominated by random coil. With phospholipid vesicles, neutral as well as negatively charged, transportan gives up to 60% α-helix. pAntp and pIsl bind significantly only to negatively charged vesicles with an induction of around 60% β-sheet-like secondary structure. With all three peptides, SDS micelles stabilize a high degree of α-helical structure. We conclude that the exact nature of any secondary structure induced by the membrane model systems is not directly correlated with the common transport property of these translocating peptides.
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