1. Institute of Biochemistry, Justus-Liebig-University, Giessen, Germany
2. Institute of Medical Virology, Justus Liebig University, Giessen, Germany
3. Rudolf-Buchheim-Institute of Pharmacology, Justus-Liebig-University, Giessen, Germany
4. Mass Spectrometry Facility, Department of Chemistry, Philipps University, Marburg, Germany
5. Center of Scientific Excellence for Influenza Viruses, National Research Centre, Cairo, Egypt
6. German Center for Infection Research, Partner Site Giessen, Giessen, Germany