Figure 3
Details of the hydrogen-bond interactions in the oxyanion region of new-inactive Mpro. (a) The new conformation of the oxyanion loop is stabilized by several backbone hydrogen bonds (blue dashed lines) as described in the main text. The side chain of catalytic Cys145 has a double conformation. (b) Comparison between the new-inactive (green) and active (light magenta; PDB entry 6y2e) oxyanion loops. There are large movements (blue dashed lines) of the side chains of Asn142 and Phe140. In the new-inactive conformation, Asn142 moves from an exposed position with an ASA of 153.74 Å2 to a buried position with an ASA of 49.00 Å2 and Phe140 moves from a buried position with an ASA of 14.79 Å2 to an exposed position with an ASA of 143.29 Å2. Gly143 NH (G-NH) of the oxyanion hole, which is involved in the stabilization of the tetrahedral intermediate, moves 8.8 Å away. |