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Traveling Through Proteomes Using 3D-EM and AFM Nanoanalysis, July 10, 2006, ETHZ Andreas Engel Maurice E. Müller Institiute, Biozentrum University of Basel, Switzerland
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Electron Tomography
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MPI of Biochemistry Max Planck Society 3D-object => set of 2D-projections 2D-projections => 3D- reconstruction Principle of electron tomography W. Baumeister, R. Grimm, J. Walz: Trends Cell Biol 9 (1999) 81-85
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Weighted Backprojection
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MPI of Biochemistry Max Planck Society Sporozoites (Plasmodium berghei)
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MPI of Biochemistry Max Planck Society membrane microtubules ER dense granules rhoptries micronemes polar rings Apical part of a sporozoite cell
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Nanoanalytics of Soluble Complexes: Scanning Transmission Electron Microscopy (STEM)
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Scanning Transmission EM 200 Å Philippe Ringler
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STEM Hardware BFDF Acceleration voltage 100 kV Pressure: < 10 -10 Torr Beam current Single electron counting PM
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TMV Analysis 14 nm
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Actin Collaboration with Ueli Aebi, M.E. Müller Insitute
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STEM Mueller et al, J Mol Biol 99 From mass to shape
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Nanoanalytics of Membrane Complexes: Atomic Force Microscopy (AFM)
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Membrane Proteins exist in the Bilayer Bert de Groot & Helmut Grubmüller
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Example: Bacteriorhodopsin
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Cytosolic Surface of Bacteriorhodopsin Dimitrios Fotiadis, unpublished
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CS of Bacteriorhodopsin: Force-induced Conformational Changes Müller et al. (1995), J. Mol. Biol. & Fotiadis et al. (2002), Micron 10 nm (A), 4 nm (B, C and D)
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The Surface Dynamics of Bacteriorhodopsin Scheuring et al., European Biophysics Journal Similarity ranked images are assembled into a movie Low force High force
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Bacteriorhodopsin: Surface Energy Landscape 6 kT p d (r) peak position probability of domain d F d = -kTlnp d (r) Scheuring et al. Eur Biophys J 2002 Low force High force Low forceHigh force
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Unzipping Bacteriorhodopsin Oesterhelt et al. Science 2000
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Conclusions Electron and atomic force microscopies offer great tools for cellular nanoanalytics Electron tomography provides entire picture of a cell STEM makes the link between mass and shape AFM is an ideal tool for assessing structure & dynamics of membrane proteins
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Acknowledgments AFM Daniel Müller* Simon Scheuring* Dimitrios Fotiadis Patrick Frederix 2D crystallization Hervé Rémigy Thomas Kaufmann Thomas Walz* Protein expression Nora Eifler Myriam Duckely Paul Werten Peter Agre Wolfgang Baumeister Yoshi Fujiyoshi Helmut Grubmüller Bert deGroot Kris Palczewski STEM Shirley Müller Philippe Ringler Francoise Erne-Brand
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