Fig. 1: Structural and functional effects of mutations in the S protein of the SARS-CoV-2 B.1.1.7 (Alpha) variant on human lung cells. | Cell Discovery

Fig. 1: Structural and functional effects of mutations in the S protein of the SARS-CoV-2 B.1.1.7 (Alpha) variant on human lung cells.

From: Structure-based evidence for the enhanced transmissibility of the dominant SARS-CoV-2 B.1.1.7 variant (Alpha)

Fig. 1

a Schematic representation of the B.1.1.7 SARS-CoV-2 S protein with ten natural mutations. The S1 subunit contains mainly an N-terminal domain (NTD), a receptor-binding domain (RBD), and subdomains 1 and 2 (SD1 and SD2). The S2 subunit contains a fusion peptide (FP), fusion peptide proximal region (FPPR), heptad repeats 1 and 2 (HR1 and HR2), a central helix (CH), a connector domain (CD), a transmembrane domain (TM) and a cytoplasmic tail (CT). b Overall structure of SARS-CoV-2 B.1.1.7 S in the 1-RBD-up state, indicating the natural mutations. c Overall structure of the SARS-CoV-2 B.1.1.7 S-ACE2 complex. The interface between the RBD and ACE2 is magnified to compare the structures of WT S-ACE2 (gray) and N501Y S-ACE2 (light blue). d The N501Y mutation site in the three structures mentioned in (c). e The A570D, D614G, P681H, T716I, S982A and D1118H mutation sites in the three structures mentioned in (c). f Structural model of furin with the cleavage sites in the SARS-CoV-2 and B.1.1.7 variants. g Representative images of cell–cell fusion between 293T/SARS-CoV-2(WT)/EGFP, 293T/SARS-CoV-2(D614G)/EGFP, 293T/SARS-CoV-2(B.1.1.7)/EGFP effector cells and target cells (Calu-3) after coculture for 6 h. Scale bars, 400 µm. h Western blot analysis of S protein expression in effector cells. i–m Statistical analysis of fusion rates mediated by the WT, D614G, and B.1.1.7 S protein after coculture for 1 h (i), 2 h (j), 3 h (k), 4 h (l), and 12 h (m). Asterisks indicate significant differences. *P < 0.05, **P < 0.01, ***P < 0.001. NS, not significant.

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