Fig. 4
Glycan interactions with V3/N332gp120 bNAbs in structures including natively glycosylated Env. a, b Comparison of the orientations on gp120 (gray surface and cartoon) of the CDR loops from (a) BG18 (blue, ribbon) and (b) 10-1074 (magenta, ribbon) demonstrating that the BG18 variable domains are rotated clockwise about CDRH3 relative to the 10-1074 variable domains. The distinct BG18 orientation on gp120 resulted in contacts with N156gp120, N386gp120, and N392gp120 glycans (cyan, sticks) in proximity to the V3-base. Red dotted outline: Differences in the N332gp120 glycan conformation on BG505 Env bound to BG18 (a) or to 10-1074 (b). c Close-up of BG18 interaction with the N332gp120 glycan showing CDRH3, CDRH1 and CDRL2 loops at the glycan interface. d Overlay of BG18-BG505 and 10-1074–BG505 (PDB 5T3Z (http://dx.doi.org10.2210/pdb5T3Z/pdb)) structures showed that the BG18-bound N332gp120 glycan conformation would clash (yellow star) with light chain CDR loops of 10-1074 and other PGT121-like bNAbs that display nearly identical binding modes. e Surface representation of BG18 interactions with the N392gp120 and N386gp120 glycans showing the N392gp120 glycan buried (~800 Å2 total BSA) inside cleft 2 located between the CDRH3 and CDRL1/3 loops. The N386gp120 glycan associates weakly with light chain BG18 (45 Å2 total BSA), but forms branch–branch interactions with the N392gp120 glycan. c, e Electron density contoured at 1σ from 2Fobs−Fcalc composite annealed omit maps calculated with phases from models with glycan coordinates omitted to reduce potential phase bias (gray mesh)
