1. Max Planck Institute of Molecular Physiology Dortmund Germany
2. Current address: School of Physical and Chemical Sciences University of Canterbury Christchurch New Zealand
3. Faculty of Chemistry and Chemical Biology Technical University Dortmund Dortmund Germany
4. Department of Chemistry Umeå Centre for Microbial Research Umeå University Umeå Sweden
5. Current address: Department of Chemistry Technical University of Denmark Copenhagen Denmark
6. Compound Management and Screening Centre Dortmund Germany