Universität Stuttgart / Stephan Nussberger

Institute of Biomaterials and Biomolecular Systems

Biophysics Group

Professor Stephan Nussberger

Eukaryotes achieve their high performance by distributing their various functions on spatially membrane-bound subcellular compartments. By doing so, however, they are challenged by a severe problem: Subcellular confinement abolishes the principle of free intracellular accessibility for functional gain. Membranes represent a significant diffusion barrier for the majority of molecules in the cell which can only be overcome by a high energy input. Compartmentation or accessibility - an insurmountable contradiction?

To address this question we study the biological physics of how protein polymers thread through nanometer-scale pores. By using quantitative methods of protein biochemistry, cell biology, electrophysiology and single-molecule microscopy and, in collaboration with other research groups, high-resolution cryo-electron microscopy the following topics are addressed:

Protein Translocation

Of particular interest is the elucidation of architecture and function of the protein-conducting mitochondrial membrane-translocase TOM, and the question of how proteins thread through the nanometer-scale pores of this translocase.

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Apoptosis

The release of cytotoxic proteins from mitochondria regulated by proteins of the Bcl-2 family is considered a key event of apoptosis. The modification of the Bcl-2 protein BAX with a palmitic acid residue and thus its integration into mitochondrial outer membranes play a crucial role. Based on this observation, we are seeking for new concepts for the control of malignant tumor cells, in which the palmitoylation of BAX is reduced.

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Single-Molecule Biosensing

As part of the research network Functional Nanostructures of the Baden-Württemberg Foundation, we are developping new technologies for the integration of biological nanopores into supported lipid bilayers to be use for biosensor applications.

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