1. Nucleic Acid Center, Department of Physics and Chemistry, University of Southern Denmark, DK-5230 Odense M, Denmark, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Miklukho-Maklaya 16/10, 117997 Moscow, Russia, and Interdisciplinary Nanoscience Center, Department of Molecular Biology, University of Aarhus, DK-8000 Aarhus, Denmark