Poster Presentation 10th Australian Peptide Conference 2013

Membrane interactions of modified helical cell-penetrating peptides (#102)

Marco Jan Klein 1 , Manfred Kansy 2 , Anne S. Ulrich 1
  1. Institute of Biological Interfaces (IBG-2) and Institute of Organic Chemistry, KIT - Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, BW, Germany
  2. pRED, Pharma Research & Early Development, Non-Clinical Safety, F. Hoffmann-La Roche Ltd., CH-4070 Basel, Switzerland
Cell penetrating peptides (CPPs) are able to translocate across cellular membranes and transport various cargoes, but the uptake mechanisms are yet not fully understood. Our goal is to determine the membrane binding properties and conformational features of two different types of CPPs, in order to correlate them with the uptake efficiency and toxicological effects. On the one hand, we compare stapeled amphiphilic α-helical CPPs with their linear analogues. Furthermore, we have designed amphiphilic α-helical CPPs with a “charge zipper” motif that utilizes intramolecular ladders of salt bridges for compensating the net charge. Circular dichroism (CD) is used to determine the extent of helicity in different lipid vesicles, and Oriented CD reveals the helix alignment in the membrane. A high-throughput screening in model membranes is used to measure the uptake efficiency of the CPP and leakage of the lipid vesicles simultaneously. These experiments allow us to detect any aggregation tendency of the CPPs and at the same time provide insight in the correlation between the uptake efficiency with peptide structure, lipid composition, and membrane curvature.