Dresden 2011 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 19: Biological Membranes II
BP 19.5: Vortrag
Dienstag, 15. März 2011, 15:00–15:15, ZEU 260
Minimalistic model for bilayer membranes hydrophobic inclusions: application to membrane fusion — Giovanni Marelli1, Jelger Risselada2, and •Marcus Mueller1 — 1Insitut für theoretische Physik Frederich Hund Platz 1 37077 Goettingen — 2Max Planck Institute for Biophysical Chemistry, Fassberg 11 37077 Göttingen
We develop a coarse-grained solvent free model to study the interactions of a hydrophobic inclusion with a lipid membrane. For different sets of system's parameters we have calculated the mechanical properties of the self-assembled structures (eg., bending rigidity and line tension of a pore) as well as the phase behavior (lamellar vs inverted hexagonal morphology). We propose two alternative methods to describe a hydrophobic inclusion: a rigid cylinder or a collection of tightly coupled particles and place it in the hydrophobic shell of the membrane. The inclusion induces in the membrane a local ordering of the lipids (e.g. packing effects) and a long-range distortion of the membrane thickness. The surface tension induced by the protein induce pore formation at a certain distance away from its center and the superposition of many proteins result in a stable pore and we present the local pressure profile. This is a first step towards studying the role of the proteins in the fusion process and to understand how their radius and surface tension can select different fusion pathways.