1. Macromolecular Crystallography Helmholtz-Zentrum Berlin für Materialien und Energie Albert-Einstein-Str. 15 12489 Berlin Germany
2. Macromolecular Structure and Interaction Max Delbrück Center for Molecular Medicine Robert-Rössle-Str. 10 13125 Berlin Germany
3. Current address: International Institute of Molecular and Cell Biology Ks. Trojdena Street 4 02-109 Warsaw Poland
4. Institute of Pharmacy Universität Greifswald Friedrich-Ludwig-Jahn-Str. 17 17489 Greifswald Germany
5. Institute of Pharmaceutical Sciences University of Freiburg Albertstr. 25 79104 Freiburg Germany
6. Current address: Københavns Universitet Center for Biopharmaceuticals Universitetsparken 2 2100 Copenhagen Denmark
7. Department of Molecular Biophysics Forschungsinstitut für Molekulare Pharmakologie Robert-Rössle-Str. 10 13125 Berlin Germany