1. Department of Biophysics of Nucleic Acids, Institute of Biophysics of the Czech Academy of Sciences , Královopolská 135, Brno 612 00, Czech Republic
2. Central European Institute of Technology, Masaryk University , Kamenice 5, Brno 625 00, Czech Republic
3. National Centre for Biomolecular Research, Faculty of Science, Masaryk University , Kotlářská 2, Brno 611 37, Czech Republic
4. Laboratoire d’Optique & Biosciences, Institut Polytechnique de Paris , Inserm, CNRS, Ecole Polytechnique, Palaiseau 91128, France