Fig. 6: Structure of Env gp151 MPER ND in complex with bnAbs BG18, VRC01 and 10E8 resolved by cryo-EM.

a Low-pass filtered map of different Fab occupancy states and the location of the bilayer. BG18 Fab is highlighted in green, VRC01 in pink and 10E8 in blue. b 90° clockwise rotated side views showing the Env tilt angle in relation to the lipid bilayer surface. c Top view and side views of the highest resolution maps of both 10E8 occupancy states. Densities are highlighted as follows: gp120 in blue, gp41 in orange, BG18 in green, VRC01 in pink, HC of 10E8 in white, LC of 10E8 in dark gray and MPER peptide in red. d The highest resolution reconstruction with a single 10E8 was used for model building. Insets show interfaces of the three bound bnAbs and key amino acid and glycan interactions with BG18 HC (dark green) and LC (light green) in insets 1–2, VRC01 HC (magenta) and LC (pink) in insets 3-4, and 10E8 HC (white) and LC (dark gray) in insets 5-7. Glycans are highlighted in purple. Insets 2 and 4 exemplify the electron density used to build interacting glycans (transparent blue. e Epitope-paratope analysis of 10E8 binding interface shown in d. Contacting residues are separated into three components corresponding to insets 5–7. f Binding pocket of 3BC315 (salmon) HCDR3 with key interactions highlighted. g gp41 protomer distance analysis in the nanodisc complex structure with 10E8 Fab, and soluble Env structure with 3BC315 showing widened interface between protomers A and B due to antibody binding.