The mutation-level escape profiles agree with structural characterizations of the fusion peptide epitope.

<p><b>A</b>. The mutation-level escape profile for regions with considerable differential selection by at least one antibody (regions with red underlay in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1007159#ppat.1007159.g001" target="_blank">Fig 1A</a>). Left to right, these include the N88 glycosylation motif and neighboring area, surface exposed gp120 residues that interact with VRC34.01, and most of the fusion peptide. The height of each amino acid is proportional to the logarithm of the relative enrichment of that mutation in the antibody selected condition relative to the non-selected control. <b>B</b>. Fab-FP peptide crystal structures of each antibody. Antibody Fabs were colored as in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1007159#ppat.1007159.g001" target="_blank">Fig 1B</a>, FP residues with significant differential selection to each antibody were colored in red. <b>C</b>. Total surface, antibody-contact surface (determined from co-crystal structures shown in Fig 2B), and positive site differential selection for each antibody.