1. Gilead Sciences and IOCB Research Center, Institute of Organic Chemistry and Biochemistry of the ASCR, v. v. i., Flemingovo n. 2, 166 10 Prague 6, Czech Republic
2. Department of Biochemistry, Faculty of Science, Charles University, Hlavova 8, Prague 2, Czech Republic
3. Institute of Chemical Process Fundamentals of the ASCR, v. v. i., Rozvojová 135, 165 02 Prague 6, Czech Republic