1. Institute for Biophysical Chemistry and Centre for Biomolecular Magnetic Resonance (BMRZ), Goethe University, Max von Laue Str. 9, 60438 Frankfurt, Germany
2. School of Biochemistry, University Walk, University of Bristol, Bristol BS8 1TD, United Kingdom
3. Department of Chemistry, University of Hull, Hull HU6 7RX, United Kingdom