Fig. 7: Comparison of Nsp15 and RNase A active sites.
From: Tipiracil binds to uridine site and inhibits Nsp15 endoribonuclease NendoU from SARS-CoV-2
A Nsp15/5’GpU complex compared with RNase A/5’dApdTpdApdA complex (PDB id 1RCN). The least square superposition is calculated with the Nsp15/RNase A residues H250/H12, S294/T35, K290/K41, and U/T bases using COOT (RMSD 0.6 Å on Cα atoms). Nsp15 is shown in dark blue, RNase A in aqua, 5’GpU in yellow and 5’dApdTpdApdA oligonucleotide in pink. Base positions B0-B3 and phosphoryl groups positions P0 and P1 are indicated in red (bold). B Model of 5'GpUpU oligonucleotide binding to the Nsp15 active site. Red arrows show proton flows (extraction and donation) in A & B.
