FIG 8.

Sequence alignment of the gp120 V2 loop from different HIV strains. The gp120 V2 loop sequences from the different HIV strains tested against MAb N12-i15 for binding were aligned by using the Clustal Omega program (http://www.ebi.ac.uk/Tools/msa/clustalo/) and compared. The numbering system used is based on the BaL strain for consistency. Strand c of the Greek key fold based on the crystal structure of V1/V2 loops from the ZM109 strain (78) is shown. As MAb N12-i15 was shown to bind to elements within the Greek key fold of the V2 loop, the four residues different in the R2 V2 loop located within the Greek key fold are highlighted in dark gray. The V2 loop of the BG505 strain (both the monomer and the BG505 SOSIP trimer) is shown for comparison only, as MAb N12-i15 does not bind this strain (Fig. 1).