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BP: Fachverband Biologische Physik

BP 16: Biological Membranes I

BP 16.4: Vortrag

Dienstag, 15. März 2011, 11:15–11:30, ZEU 260

Bending and breaking the influenza lipid envelope — •Sai Li¹, Frederic Eghiaian¹, Christian Sieben², Andreas Herrmann², and Iwan Schaap¹ — ¹Drittes Physikalishes Institut, Georg-August-Universität Göttingen, Germany — ²Division of Molecular Biophysics, Humboldt-Universität zu Berlin, Germany

Lysosomes, enveloped viruses, synaptic and secretory vesicles are all examples of natural nano-containers (diameter ~100 nm) which specifically rely on their lipid bilayer to protect and exchange their contents with the cell. We have used Atomic Force Microscopy (AFM) and Finite Element Modeling to investigate the mechanical properties of the influenza virus lipid envelope. The mechanical properties of small, spherical vesicles made out of PR8 influenza lipids were probed by an AFM tip applying forces up to 0.2 nN, which led to an elastic deformation up to 20% on average. We found that influenza liposomes were much softer than what would be expected for a gel phase bilayer and highly deformable. We observed that the stiffness of the influenza envelope increased weakly (within one order of magnitude) with temperature, which is consistent with previous suggestion that influenza lipids do not undergo a major phase transition. Influenza liposomes were in most cases able to withstand wall-to-wall deformation, and forces over 1 nN were generally required to rupture the influenza envelope. In contrast to other viruses that pack their contents in stiff protein shells, the influenza virus seems to rely mainly on its highly flexible lipid envelope to protect its genome.