Berlin 2008 – scientific programme
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BP: Fachverband Biologische Physik
BP 7: Posters I
BP 7.54: Poster
Monday, February 25, 2008, 17:00–19:30, Poster A
Diffusion of glycosylphosphatidylinositol (GPI)-anchored bovine prion protein (PrPc) in supported lipid membranes studied by single-molecule and complementary ensemble methods. — •Thomas Schubert1,2, Michael Bärmann2, Monika Rusp2, Walter Gränzer3, and Motomu Tanaka1,2 — 1Biophysikalische Chemie II und BIOQUANT, Universität Heidelberg, 69120 Heidelberg, Germany — 2E22, Technische Universität München, James-Frank-Str, 85748 Garching, Germany — 3Institut für Tierhygiene, TU München, Weihenstephaner Berg 3, 85354 Freising-Weihenstephan, Germany
In this work bovine cellular bovine prion protein (PrPc) was incorporated in supported lipid membranes and its lateral diffusion was studied by single-dye tracking (SDT) and a complementary ensemble method, fluorescence recovery after photobleaching (FRAP). FRAP results demonstrated very high mobile fractions of up to 94 %, confirming that most of the GPI-anchored PrPc are freely diffusive in the fluid supported membrane matrix. Moreover, the lateral diffusivity of PrPc significantly depends on the pH of the buffer. To complement the ensemble results obtained by FRAP, the statistical variation of lateral diffusion coefficients of individual PrPc molecules in the supported membranes were measured with SDT. Simulation-based statistical analysis indicated that in addition to the expected statistical scatter there is a significant spread of diffusion coefficients. In further experiments, 2D membrane electrophoresis also indicated non-uniform PrPc molecules.