1. Department of Chemistry, Chemical Biology, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
2. Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Box 280, Nobels väg 16, SE-171 77 Stockholm, Sweden
3. Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russian Federation