1. Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance Goethe University Frankfurt Max-von-Laue-Str. 7 60438 Frankfurt am Main Germany
2. Department of Theoretical Biophysics Max Planck Institute of Biophysics Max-von-Laue-Str. 3 60438 Frankfurt am Main Germany
3. Department of Chemistry Science Institute University of Iceland Dunhagi 3 107 Reykjavík Iceland
4. Institute for Biophysics Goethe University Frankfurt Max-von-Laue-Str. 9 60438 Frankfurt am Main Germany