1. Contribution from the Magnetic Resonance Center, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy, LANAIS RMN-300, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, 1113 Buenos Aires, Argentina, Department of Molecular Biotechnology, Chalmers University of Technology, P.O. Box 462 SE-405 30 Göteborg, Sweden, Department of Chemistry, Biochemistry and Biophysics, Göteborg University, SE-40530 Göteborg, Sweden, Department of Chemistry and...