1. Molecular Pathology, University of Tartu Tartu 50411 Estonia
2. Biomolecular NMR Laboratory, Dulbecco Telethon Institute c/o S. Raffaele Scientific Institute Milan 20132 Italy
3. Institute of Chemical Physics, University of Tartu Tartu 51010 Estonia
4. Istituto di Ricerche di Biologia Molecolare via Pontina km 30.600 Pomezia (Rome) 00040 Italy