1. Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic ResonanceGoethe University Frankfurt Max-von-Laue-Straße 7 60438 Frankfurt am Main Germany
2. Department of ChemistryScience InstituteUniversity of Iceland Dunhaga 3 107 Reykjavík Iceland
3. Department of Theoretical BiophysicsMax Planck Institute of Biophysics Max-von-Laue-Straße 3 60438 Frankfurt am Main Germany