1. Institute of Virology; OE 5230, Hannover Medical School; Carl-Neuberg-Straße 1 D-30623 Hannover Germany
2. Faculty of Medicine in the Galilee; Bar-Ilan University; 8 Henrietta Szold Street Safed 1311502 Israel
3. Department of Biology; Technion - Israel Institute of Technology; Haifa 32000 Israel
4. Oxford Particle Imaging Centre, Division of Structural Biology, Welcome Trust Centre for Human Genetics; University of Oxford; Oxford UK