1. Institute of Chemistry and Metabolomics Center of Structural and Cell Biology in Medicine University of Lübeck Ratzeburger Allee 160 23562 Lübeck Germany
2. Institute of Biochemistry Center of Structural and Cell Biology in Medicine University of Lübeck Ratzeburger Allee 160 23562 Lübeck Germany
3. Centre for Structural Systems Biology (CSSB) Notkestraße 85 22607 Hamburg Germany
4. German Center for Infection Research (DZIF) Partner Site Hamburg-Luebeck-Borstel-Riems Ratzeburger Allee 160 23562 Lübeck Germany
5. Cluster of Excellence RESIST (EXC 2155) and Institute of Virology Hannover Medical School Carl-Neuberg-Straße 1 30625 Hannover Germany
6. Biognos AB 40274 Göteborg Sweden
7. Present address R.C.: Virology Section Infectious Diseases and Immunology Division Department of Biomolecular Health Sciences Faculty of Veterinary Medicine University of Utrecht Yalelaan 1 3584 CL Utrecht (The Netherlands