1. Institute for Advanced Chemistry of Catalonia, Department of Biological Chemistry, IQAC-CSIC, Jordi Girona 18-24, Barcelona 08034, Spain
2. Prozomix Ltd. West End Industrial Estate, Haltwhistle, Northumberland NE49 9HA, U.K.
3. Institut für Anorganische Chemie, J.-W.-Goethe-Universität, Frankfurt/Main, Germany
4. Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, Bellaterra, Spain