1. Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan, 200F, B-3001 Heverlee, Belgium
2. POLY-biòs Research Center, AREA Science Park, Padriciano, 99, I-34012 Trieste, Italy
3. Department of Biochemistry, Biophysics and Macromolecular Chemistry, University of Trieste, Via L. Giorgieri, 1, I-34127 Trieste, Italy