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. 2021 Aug 6;373(6555):eabi6226. doi: 10.1126/science.abi6226

Fig. 4. Details of the B.1.1.7 spike modulation of the Ser982-Ala570 latch.

Fig. 4.

(A) Zoomed-in view of the region of the A570D (red spheres) and S982A (orange spheres) substitutions in the B.1.1.7 spike; S protomers are colored pale cyan and salmon. (B) Overlay of 3-RBD-down structures of the D614G spike (PDB 7KDK; orange and slate blue) and the B.1.1.7 spike (PDB 7LWS; pale cyan and salmon). (C) Zoomed-in view of region around the B.1.1.7 spike S982A substitution (PDB 7LWS). Residues Ala982 and Thr547 are shown in sticks. (D) Overlay of 3-RBD-down (PDB 7KDK, orange and slate blue) and 1-RBD-up (PDB 7KDL, teal) structures of S-GSAS-D614G, showing movement of the Thr547 and Ala570 loops and loss in H-bond between Thr547 and Ser982 upon transition from the down to the up state. (E) Overlay of 3-RBD-down structures of S-GSAS-D614G (PDB 7KDK, orange and slate blue) and S-GSAS-B.1.1.7 (PDB 7LWS, pale cyan and salmon), and 1-RBD-up structure of S-GSAS-B.1.1.7 (PDB 7LWV, green). Relative to the S-GSAS-D614G down state, the Thr547 loop in the B.1.1.7 spike down state protomer is shifted toward the loop position in the up protomer. Residues 908 to 1035 were used for the overlays. Hydrogen bonds are shown as dashed lines. (F) Top left: Zoomed-in view of the S1 interaction network spanning ProtomerA and ProtomerB highlighting the locations of the NTD′s, SD2s, SD1s, and the interprotomer contact point between SD1 and the NTD′. Top right: S ectodomain trimer indicating the zoomed-in location. Bottom: Vector network connecting the protomer NTD′, SD2, and SD1 domains. The SD2 anchor point (SD2a) is indicated by the asterisk. Interactive, interprotomer contact units involving SD1/RBD to NTD/NTD′ pairs are identified with RBD-to-RBD communication (Com) points highlighted. Dashed box indicates the visible region in the structure at upper left. (G) Angular measures for the interprotomer network. Top left: Angle formed by SD2, SD2a, and SD1s. Top right: Angle formed by NTD′, SD2, and SD2a. Bottom left: Interprotomer dihedral rotation of SD2a relative to SD2 about an SD1-to-NTD′ axis. Bottom right: Interprotomer dihedral rotation between SD1 and SD2 about an NTD′-to-SD2 axis.