1. Department for Drug Design and Optimization Helmholtz Institute for Pharmaceutical Research Saarland (HIPS)–, Helmholtz Centre for Infection Research (HZI) Campus Building E8.1 66123 Saarbrücken Germany
2. Department of Pharmacy Saarland University Campus Building E8.1 66123 Saarbrücken Germany
3. Stratingh Institute for Chemistry University of Groningen Nijenborgh 7 9747 AG Groningen The Netherlands
4. Department of Structure and Function of Proteins HZI 38124 Braunschweig Germany
5. Department of Microbial Natural Products HIPS–HZI 66123 Saarbrücken Germany
6. Institute for Biochemistry, Biotechnology and Bioinformatics Technische Universität Braunschweig Spielmannstr. 7 38106 Braunschweig Germany