Extended Data Fig. 6: Cryo-EM structure of C110–S complex and epitope mapping.

a, 3.8 Å cryo-EM reconstruction of the C110–S trimer complex. b, Composite model of C110–RBD (purple and grey, respectively) overlaid with the SARS-CoV-2 NAb REGN-10987 (yellow, PDB 6XDG) and soluble ACE2 (green, PDB 6M0J). Model was generated by aligning structures on 188 RBD Cα atoms. c–f, Surface representation of RBD epitopes for C135 (blue) (c), S309 (brown, PDB 6WSP) (d), C110 (purple) (e) and REGN-10987 (yellow, PDB 6XDG) (f). Given the low resolution of the antibody–RBD interface, epitopes were assigned by selection of any RBD residue within 7 Å of any antibody Cα atom. Mutation sites found in sequence isolates⁴⁴ (green) and in laboratory selection assays⁴⁰ (red) are shown. Representative micrograph selected from total dataset (Supplementary Table 2), 2D class averages, gold-standard FSC plot, and local resolution estimation for C135–S 2P (g–i) and C110–S 2P (j–l). Scale bars, 100 nm. Both complexes revealed binding of Fabs to both two-down and one-up RBD conformations.