Cryo-Electron Tomography (CET) is used for the study of the supramolecular architecture of frozen hydrated cells in three dimensions at nanometer resolution. CET is based on the principle of any 'tomographic' technique: the acquisition of images from different viewing angles of a three dimensional object and the subsequent reconstruction of that particular structure.
This project explores the mostly uncharted area of alternative phase contrast methods for TEM. In particular, the development and applications of thin film phase plates and the associated hardware and software.
The 26S proteasome is 2.6 MDa multisubunits protease responsible for the regulated degradation of polyubiquitylated proteins. To understand how the 26S proteasome executes its function, we take a multidisciplinary approach combining cryo-EM single particle analysis with biochemical and computational studies.
This serine protease of the subtilisin type consists of 150 KDa monomers, which assemble into a 6 MDa complex. Its biological functions are degradation of oligopeptides into tripeptides, it is implicated in muscle sepsis and apoptosis, trimming of antigenic peptides and degradation of neuropeptides.
This ribonucleoprotein particle (ca. 2.7 MDa) is responsible for translation, the expression of the genetic code from mRNA into protein. Its activity depends on the interaction with many other macromolecules and it is highly regulated.
The cell envelope of bacteria and archaea contains proteins for transport or translocation of ions, nutrients and macromolecules as well as proteins supporting the structural integrity of the cell. Porins of the bacterial outer membrane, the structure of the mycobacterial outer membrane, and surface proteins from archaea and bacteria are in the focus of our projects.
Synapses are functional connection points between neurons, transmitting a presynaptic electrical signal (action potential) to the postsynaptic neuron. We use cryo-electron tomography to reveal the architecture of complexes involved in synaptic transmission and to obtain more information about their function.