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- Jing, Xiaona, et al.
(författare)
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Interaction of Peptidomimetics with Bilayer Membranes : Biophysical Characterization and Cellular Uptake
- 2012
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 28:11, s. 5167-5175
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Tidskriftsartikel (refereegranskat)abstract
- Enzymatically stable cell-penetrating alpha-peptide/beta-peptoid peptidomimetics constitute promising drug delivery vehicles for the transport of therapeutic biomacromolecules across membrane barriers. The aim of the present study was to elucidate the mechanism of peptidomimetic-lipid bilayer interactions. A series of peptidomimetics consisting of alternating cationic and hydrophobic residues displaying variation in length and N-terminal end group were applied to fluid-phase, anionic lipid bilayers, and their interaction was investigated using isothermal titration calorimetry (ITC) and ellipsometry. Titration of lipid vesicles into solutions of peptidomimetics resulted in exothermic adsorption processes, and the interaction of all studied peptidomimetics with anionic lipid membranes was found to be enthalpy-driven. The enthalpy and Gibbs free energy (Delta G) proved more favorable with increasing chain length. However, not all charges contribute equally to the interaction, as evidenced by the charge-normalized Delta G being inversely correlated to the sequence length. Ellipsometry data suggested that the hydrophobic residues also played an important role in the interaction process. Furthermore, Delta G extracted from ellipsometry data showed good agreement with that obtained with ITC. To further elucidate their interaction with biological membranes, quantitative uptake and cellular distribution were studied in proliferating HeLa cells by flow cytometry and confocal microscopy. The cellular uptake of carboxyfluorescein-labeled peptidomimetics showed a similar ranking as that obtained from the adsorbed amount, and binding energy to model membranes demonstrated that the initial interaction with the membrane is of key importance for the cellular uptake.
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| 2. |
- Jing, Xiaona, et al.
(författare)
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Membrane adsorption and binding, cellular uptake and cytotoxicity of cell-penetrating peptidomimetics with alpha-peptide/beta-peptoid backbone : Effects of hydrogen bonding and alpha-chirality in the beta-peptoid residues
- 2012
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Ingår i: Biochimica et Biophysica Acta - Biomembranes. - : Elsevier BV. - 0005-2736 .- 1879-2642. ; 1818:11, s. 2660-2668
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Tidskriftsartikel (refereegranskat)abstract
- Cell-penetrating peptides (CPPs) provide a promising approach for enhancing intracellular delivery of therapeutic biomacromolecules by increasing transport through membrane barriers. Here, proteolytically stable cell-penetrating peptidomimetics with alpha-peptide/beta-peptoid backbone were studied to evaluate the effect of alpha-chirality in the beta-peptoid residues and the presence of guanidinium groups in the alpha-amino acid residues on membrane interaction. The molecular properties of the peptidomimetics in solution (surface and intramolecular hydrogen bonding, aqueous diffusion rate and molecular size) were studied along with their adsorption to lipid bilayers, cellular uptake, and toxicity. The surface hydrogen bonding ability of the peptidomimetics reflected their adsorbed amounts onto lipid bilayers as well as with their cellular uptake, indicating the importance of hydrogen bonding for their membrane interaction and cellular uptake. Ellipsometry studies further demonstrated that the presence of chiral centers in the beta-peptoid residues promotes a higher adsorption to anionic lipid bilayers, whereas circular dichroism results showed that alpha-chirality influences their overall mean residue ellipticity. The presence of guanidinium groups and alpha-chiral beta-peptoid residues was also found to have a significant positive effect on uptake in living cells. Together, the findings provide an improved understanding on the behavior of cell-penetrating peptidomimetics in the presence of lipid bilayers and live cells.
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