1. Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Gilead Sciences and IOCB Research Center, Flemingovo nam. 2, 16610 Praha 6, Czech Republic
2. Institute of Molecular Genetics, Academy of Sciences of the Czech Republic v.v.i., Flemingovo nam. 2, 166 10 Praha 6, Czech Republic
3. Department of Biochemistry, Faculty of Science, Charles University, Hlavova 8, 128 43 Praha 2, Czech Republic
4. Department of Analytical Chemistry, Institute of Chemical Technology, Technická 5, 166 28 Praha 6, Czech Republic
5. Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic, v.v.i., Area of Research Institutes 1001, 250 68 Husinec-Řež u Prahy, Czech Republic
6. Department of Virology, University of Heidelberg, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany