1. Institute for Virology, University of Marburg, D-35043 Marburg, Hessen, Germany
2. Institut für Molekulare Biologie gGmbH, D-55128 Mainz, Rheinland-Pfalz, Germany
3. Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A1, Canada
4. Institute of Pharmaceutical Chemistry, University of Marburg, D-35032 Marburg, Hessen, Germany
5. La Jolla Institute for Immunology, La Jolla, California 92037-1387, United States
6. Partnersite Giessen-Marburg-Langen, German Centre for Infection Research, D-35043 Marburg, Hessen, Germany