Figure 4.

Incorporation of TFV-DP and Car-TP by SARS-CoV-2 RdRp to terminate the polymerase reaction. The sequences of the primers and template used for these extension reactions, which are at the 3′ end of the SARS-CoV-2 genome, are shown at the top of the figure. Polymerase extension reactions were performed by incubating (a) TFV-DP and (b) UTP + ATP + CTP + Car-TP with preassembled SARS-CoV-2 polymerase (nsp12, nsp7, and nsp8), the indicated RNA template and primers, and the appropriate reaction buffer, followed by detection of reaction products by MALDI-TOF MS. The accuracy for m/z determination is ±10 Da.