1. Department of Experimental Medicine, TOR, University of Rome “Tor Vergata”, Rome 00133, Italy
2. Ludwig Institute for Cancer Research, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ, UK
3. Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7FZ, UK
4. Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, Frankfurt, Germany
5. Present address: State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, PR China
6. School of Molecular and Cellular Biology, Faculty of Biological Sciences, and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
7. Chinese Academy of Medical Sciences Oxford Institute, University of Oxford, Oxford, UK