1. a Medicinsk Fysik, Department of Medical Biochemistry and Biophysics , Karolinska Institutet , Doktorsringen 6A, 2tr., S-17177, Stockholm , Sweden.
2. b Department of Biochemistry B , Center for Biomolecular Recognition, The Panum Institute , Blegdamsvej 3c, DK-2200, Copenhagen N , Denmark
3. c Medicinsk Fysik, Department of Medical Biochemistry and Biophysics , Karolinska Institutet , Doktorsringen 6A, 2tr., S-17177, Stockholm , Sweden.