1. Institute of Pharmaceutical Biology and Biotechnology, and Institute of Pharmaceutical and Medicinal Chemistry, Heinrich-Heine University, 40225 Düsseldorf, Germany, Institute of Complex Systems (ICS-6), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany, Helmholtz Centre for Infection Research, D-38124 Braunschweig, Germany, and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100191, P. R. China