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BP: Fachverband Biologische Physik

BP 9: Posters: Membranes

BP 9.7: Poster

Monday, March 11, 2013, 17:30–19:30, Poster B2

The interaction between polyproline containg cell-penetrating peptides and a lipid bilayer — •Johannes Franz, Kalina Peneva, Mischa Bonn, and Tobias Weidner — Max Planck Institute for Polymer Research, 55118 Mainz, Germany

Cell-penetrating peptides (CPPs) are membrane-permeable, short amino acid sequences that can be used to deliver covalently and non-covalently bound cargoes, i.e. drugs, into cells without damaging the cell membrane. However, the mechanism for CPP internalization is still subject of ongoing research. CPPs are divided into different subfamilies, depending on their chemical properties. They differ not only in their primary structure and overall charge, but also in their local folding. We used a modified form of SAP (sweet arrow peptide), an anionic CPP containing repetitive polyproline motifs, as a model peptide. The secondary structure of SAP(E), polyproline II (PPII), allows aggregation and could contribute to the peptides membrane permeability. Membrane models omit the complexity of the natural cell membrane while ensuring the full functionality of embedded peptides. We built up a polymer-assisted lipid bilayer to enable an unimpeded translocation of CPPs across the model membrane. Sum frequency generation (SFG) vibrational spectroscopy was used to investigate molecular interactions between SAP(E) and the tethered lipid bilayer during membrane translocation.