Figure 3.
Overview of the structures involved in viral RNA replication and posttranscriptional processing.
(A) Cryo-electron microscopy structures of the pre and post-translocated (B) (PDB: 7BZF & 7C2K), RNA polymerase complex encompassing Nsp7, Nsp8 and Nsp12 coloured aqua, pale green and pale yellow with the NiRAN domain, ‘Fingers’, ‘palm’,’ thumb’ and RNA (coloured pink, raspberry, forest green, wheat & light grey). (C) Coordination and incorporation of Remdesivir-monophosphate (Remdesivir-RMP) in the pretranslocated complex (yellow sticks). (D) Nsp13 helicase bound RdRp structure with the Nsp13 chains shown with the zinc binding domain (ZBD), 1B domain, RecA-like helicase (RECA) domains 1 & 2 coloured red, blue, salmon and purple, respectively (PDB:6XEZ). (E) The Nsp9 homodimer, coloured pale blue and pale green, highlighting the cavities about the GxxxG helical dimer interface (wheat) and the peptide bound within this cavity (red) (PDB: 6WC1) (F). The Nsp10–16 complex (shown as a semi-transparent surface over a cartoon representation in pale blue and green, respectively with the bound S-adenosyl-L-methionine (SAM), RNA cap, and adenosine shown as blue, yellow and white sticks, respectively. Electrostatic surface representation of Nsp16 bound to the RNA cap (G) in comparison with the binding modes of SAM (blue sticks) and the pan inhibitor Sinefungin (pink sticks) (PDB: 6WKS) (H).