Abstract

Recently, single-particle cryo-EM has blossomed to become one of the main methods of structural biology. While the technique could simply visualize low resolution “blobs” a few years ago, it is now capable of yielding high-resolution structures in a routine fashion. To achieve this, the molecules are shock-frozen in a thin layer of ice and imaged in a transmission electron microscope (TEM), resulting in 2D projections of individual molecules. Computational analysis of several hundred thousand of those images leads to a 3D structure. While such structures can give detailed insights into the function of a given macromolecular complex, there could be more information to find in the data. Different to the other main structural techniques, the signals from each individual molecule can easily be distinguished in the TEM images. With these signals, it is possible to apply sophisticated sorting techniques to calculate an ensemble of different conformations which the molecular machine adopts at once. This enables us to create movies of macromolecular machines in action. In addition, we can use statistical thermodynamics approaches to extract the thermodynamic and kinetic properties of the system. However, the underlying experimental and computational approaches are still sparse and incomplete. Their completion is one of the main efforts of the Haselbach lab. We use single molecule techniques to complement sparse kinetic data extracted through cryo-EM. I will present our current approaches to analyze protein dynamics using single particle cryo EM applied on the human proteasome and spliceosome.

David Haselbach is Fellow of the Research Institute of Molecular Pathology (IMP) and Head of the Research Group Watching molecular machines in action: www.imp.ac.at/groups/david-haselbach/

Programm: Fakultätskolloquium SoSe 2019

Bei einem nachgewiesenen Besuch von mindestens drei der vier Vorträge erhalten Studierende 0,5 ECTS für diese Lehrveranstaltung (LV 270178 SE Fakultätskolloquium).