Representation of the GE356 Fab crystal structure and paratope mapping analysis.

(A) The GE356 heavy chain is shown in dark blue and light chain in light blue. The HCDR and LCDR loops are colored as follows: CDR1s (green), CDR2s (orange), CDR3s (magenta). (B) Effects of alanine substitutions in the CDRs of the heavy and light chain of GE356 on YU2 and SF162 gp120 binding (left) by ELISA and neutralization capacity (HXBc2 and SF162, right), as measured using the TZM-bl pseudovirus assay, compared to WT GE356. Residues are numbered based on the Kabat numbering system. EC50 (Ab concentration for half-maximal binding) and IC50 (Ab concentration for 50% neutralization) values are shown. The color-coding reflects fold-decrease in binding or of neutralization activity as compared to WT, in red (>50× WT), dark orange (20–50× WT), light orange (10–20× WT) and yellow (5–10× WT). HCDR3 A93 and LCDR3 A95b were not included in the analysis as there were alanines in these positions in the WT sequence.