Berlin 2015 – scientific programme
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BP: Fachverband Biologische Physik
BP 35: Membranes and vesicles II (joint BP/CPP)
BP 35.9: Talk
Wednesday, March 18, 2015, 17:30–17:45, H 1028
From destruction to protection - following peptide interactions with membrane interfaces — •Johannes Franz1, Denise Schach1, Joe E. Baio2, Dan Graham3, David G. Castner3, Mischa Bonn1, and Tobias Weidner1 — 1Max Planck Institute for Polymer Research, Mainz, Germany — 2Oregon State University, Corvallis, OR, USA — 3University of Washington, Seattle, WA, USA
The cell membrane is the most important biological surface as its interaction with peptides is an integral part of transport, communication, energy transduction and survivability. However, an intrinsic difficulty in monitoring peptide interaction with membranes is the required surface sensitivity. Sum frequency generation (SFG) vibrational spectroscopy is well suited to study protein monolayers at lipid surfaces because of its inherent surface specificity. In this study, two different peptides are shown to interact with model membranes in very different ways.
GALA, a peptide mimicking viral fusion proteins, can disrupt membranes and escape from endosomes when triggered at low pH. We follow GALA activity at the molecular level and probe peptide folding as well as the disturbance and hydration of individual leaflets within model bilayers. We show that the cell-penetrating peptide SAP(E) solely interacts with the lipid headgroup region proving the first step of its proposed uptake mechanism. Peptides can also help stabilize lipid membranes. We discuss preliminary results about the effects of specific antifreeze proteins on the temperature stability of lipid mono- and bilayers.