1. Department of Inorganic Chemistry,
Faculty of Science, Universita Karlova (Charles
University), Hlavova 2030, 128 43 Prague 2, Czech Republic
2. Centre de Biophysique Moléculaire, CNRS, rue Charles Sadron, 45071 Orléans, France
3. Ecole Polytechnique Fédérale de Lausanne, BCH, Lausanne, Switzerland