1. University of Bergen, Department of Physics and Technology, Bergen 5007, Norway
2. NORCE Norwegian Research Centre AS, Bergen 5008, Norway
3. University of Bergen, Department of Biological Sciences, Bergen 5006, Norway
4. Department of Cellular Biophysics, Max Planck Institute for Medical Research, Heidelberg D-69120, Germany
5. University of Bergen, Department of Chemistry, Bergen 5007, Norway