1. Scuola Internazionale Superiore di Studi Avanzati, SISSA, via Bonomea 265, Trieste 34136, Italy
2. Department of Mathematics and Geosciences, University of Trieste, Trieste 34127, Italy
3. Institute of Structural Biology, Helmoltz Zentrum Muünchen, Neuherberg 85764, Germany
4. Bavarian NMR Center at Department of Chemistry, Technical University of Munich, Garching 85757, Germany
5. Center for Integrated Protein Science München and Bavarian NMR Center at Department of Chemistry, Technical University of Munich, Garching 85757, Germany