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. 2017 Dec 26;115(2):E162–E171. doi: 10.1073/pnas.1718806115

Fig. 4.

Fig. 4.

Single-nucleotide incorporation catalyzed by either the SARS-CoV polymerase complex or the DENV RdRp. (A) Sequence of the RNA primer/template used is shown: The 20-nt primer LS2 was 5′-radiolabeled (marked by an asterisk) and annealed to the 40-nt template LS15. The RNA template corresponds to the last 40 nt of the SARS-CoV 3′-nontranslated region before the polyA tail. (B) Single-nucleotide primer extension with the SARS-CoV polymerase complex (0.5 μM), LS2*/LS15 (0.5 μM), and increasing concentrations of the indicated NTP, added after 30 min of preincubation at 30 °C. Next, reactions were incubated for 18 min at 30 °C. (C) Single-nucleotide primer extension with DENV NS5 (1 μM), LS2*/LS15 (1 μM), and increasing concentrations of the indicated NTP. Reactions were incubated for 15 min at 37 °C. Conditions of enzyme purification and polymerase assay are described by Potisopon et al. (61). Watson–Crick base pairs are indicated in gray, and mismatches are indicated in black.