Extended Data Figure 7. Cryo-EM structure of C110-S complex and epitope mapping.

a, 3.8 Å cryo-EM reconstruction of C110-S trimer complex. b, Composite model of C110-RBD (purple and gray, 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 c, C135 (blue), d, S309 (brown, PDB 6WSP), e, C110 (purple) and f, REGN-10987 (yellow, PDB 6XDG). 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 isolates¹⁷ (green) and in laboratory selection assays¹⁸ (red) are shown. Representative micrograph, 2D class averages, gold-standard FSC plot, and local resolution estimation for g-i, C135-S 2P and, j-l, C110-S 2P. Both complexes revealed binding of Fabs to both 2 “down”/1 “up” RBD conformations.