1. Institute for Organic and Biomolecular Chemistry; Georg-August-University Göttingen; Tammannstr. 2 37077 Göttingen Germany
2. Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB); Göttingen Germany
3. Research Group Nucleic Acid Chemistry; Max Planck Institute for Biophysical Chemistry; Am Fassberg 11 37077 Göttingen Germany