Fig. 3. Structural analysis of remdesivir-induced RdRp stalling.

a Position of RNA scaffolds 1–3 as observed in RdRp-RNA complex structures 1–3. Template and product strands are on the top and bottom, respectively. b Cryo-EM density of RNA in the active center of structures 1–3. The active site metal ion was modeled⁴¹ and is shown as a magenta sphere. c The C1ʹ-cyano group of the RMP ribose moiety (violet) is accommodated at position –3 (left), but would clash with the side chain of nsp12 residue serine-861 (red) at position –4 (right). Spheres indicate atomic van der Waals surfaces.