Identification of peptides as potent therapeutic and targeting agents via protein structure analysis and phage display, are adding powerful tools to our armory against disease. Covalent attachment of lipid tails onto peptides endows them with self-assembling capability and moreover has been shown to induce secondary structure of bioactive peptides. These molecules, termed peptide amphiphiles (PA), physically self-assemble into nano-structures that resemble proteins, consisting of a hydrophobic core surrounded by a corona of peptides. Mixing different PA allows integration of various functionalities on a single object while incorporation of redundant peptides allows multivalent effects. Here we present the synthesis and physicochemical characterization of such amphiphiles and their self-assembled structures. Conjugation of lipid acid to the N-terminus of peptides was accomplished by standard solid phase peptide synthesis. The cytoplasmic interaction between the p53 protein and MDM2 is of interest. A helical segment of p53 with the amino acid sequence LSQETFSDLWKLLPEN binds to MDM2; inhibition of this binding holds promising results for cancer therapy. Therefore, we have constructed a peptide amphiphile with intent to block the docking of p53 to MDM2. Circular dichroism revealed an increase of peptide helicity upon conjugation of the lipid tail compared to unmodified peptide. In order to achieve a therapeutic effect, the peptide amphiphile must reach its intracellular target. To enhance intracellular delivery we have synthesized a second PA containing the cell penetrating peptide sequence YGRKKRRQRRRGK, from pTAT protein of the HIV virus and prepared mixed aggregates. We have demonstrated their ability to increase uptake in cells in vitro. Self-assembly of the peptide amphiphiles was studied using light scattering techniques and cryo TEM. Submicron structures were prepared and their stability was investigated in different physiological media. Finally, we discuss the in vitro interaction of the peptide amphiphiples with cells deficient in p53.

Extended Abstract Status: Not Uploaded