Institute for Theoretical Physics and BioQuant, Heidelberg University, Heidelberg, Germany.|Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.|Institute for Theoretical Physics and BioQuant, Heidelberg University, Heidelberg, Germany.|Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.|Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.|Institute for Theoretical Physics and BioQuant, Heidelberg University, Heidelberg, Germany.