Extended data 5. CMPK2 phosphorylates UDP or CDP and synthetic ddhC can be converted to ddhCTP by cellular machinery.

a, Formation of trinucleotide species (UTP, CTP or ddhCTP) from mono- and di-phosphate species (1mM UMP, UDP, CMP, CDP, or ddhCDP respectively) in the presence of either ATP or GTP as the phosphate donor by 5 μM Hs CMPK2. b, ddhCTP formation in HEK293T cells expressing either FLAG- Hs viperin (N- or C-terminal tags), FLAG- Hs viperin without N-terminal amphipathic region (delta 1-42), Hs CMPK2 only, FLAG-Hs viperin (N- or C-terminal tags), Hs CMPK2, FLAG- Hs viperin without N-terminal amphipathic region (delta 1-42) and Hs CMPK2, control plasmid, or cells only. Only in cases where the tag is on the N-terminus of the full length Hs viperin is produced ddhCTP at detectable levels. c, ddhCTP concentrations from HEK293T suspension cells that were incubated with synthetic ddh-cytidine (0, 1mM) for 24, 48 or 72 h (see Supplementary Information for details). d, ddhCTP concentrations from adherent Vero cells that were incubated with synthetic ddh-cytidine (0, 0.3, 1mM) for 24, 48 or 72 h (see Supplementary Information for details). nd = not detectable. All experiments were repeated once.