Nanomechanics of Cellular Machines

Erik Schäffer

ErikSchaeffer-01 cropped
  • PhD work in polymer physics, Konstanz and Groningen Universities, 1998-2001
  • Postdoctoral training, MPI of Molecular Cell Biology and Genetics, Dresden, 2002-06
  • Group leader, TU Dresden, 2007-12
  • Professor for Cellular Nanoscience at the University of Tübingen since 2012

Research Interest

Molecular machines are fascinating devices that drive self-organization in cells. While the protein components of many biological machines have been identified, the mechanical principles that govern the operation of biological machines are poorly understood. For example, how much force can they generate; and what limits their speed and efficiency? We use and develop single-molecule fluorescence microscopy, high-resolution optical tweezers and novel trapping probes to measure intermolecular forces that are central to biological questions such as how kinesin motor proteins move and diffuse along microtubules or how damaged DNA is repaired via homologous recombination.

  • Figure Schaeffer
    click to enlarge

Left: Fluorescent image of single motor proteins. Motion of two diffusing kinesin molecules (green) on a microtubule (red) shown as a time series kymograph.

Right: Schematic. By dragging diffusing kinesin molecules with laser tweezers over a microtubule, the friction force between the motor and its microtubule track can be measured very precisely.

Available PhD Projects

High resolution tracking of kinesin motors using germanium nanospheres

Selected Reading

1) Swathi Sudhakar, Mohammad Kazem Abdosamadi, Tobias Jörg Jachowski, Michael Bugiel, Anita Jannasch, Erik Schäffer (2021) Germanium nanospheres for ultraresolution picotensiometry of kinesin motors. Science 371:eabd9944

2) Ramaiya A, Roy B, Bugiel M, Schäffer E (2017) Kinesin rotates unidirectionally and generates torque while walking on microtubules. PNAS 114: 10894–10899.

3) Bormuth V, Varga V, Howard J, Schäffer E (2009). Protein friction limits diffusive and directed movements of kinesin motors on microtubules.  Science 325:870-873.