1. University of Duisburg-Essen
2. Research Group Structural and Medicinal Biochemistry
3. Centre for Medical Biotechnology (ZMB)
4. 45117 Essen
5. Germany
6. Research Group Organic Chemistry
7. Max-Planck-Institut für Kohlenforschung
8. Kaiser-Wilhelm-Platz 1
9. 45470 Mülheim an der Ruhr
10. Research Group Molecular Biology I