Fig. 3.

Conformational diversity of HIV-1 gp120 in solution. The conformational diversity of gp120 in solution is sensitive to the presence of the variable loops. (A) Entropy of ligand interactions with full-length and truncated gp120s (for measurements involving the HIV-1 clade B gp120, the YU2 strain was used; for measurements involving the HIV-1 clade C gp120, the C1086 strain was used). (B) Conformational fixation followed by ligand selection. The ratio of ligand binding to cross-linked vs. untreated gp120s is shown for full-length and truncated forms of gp120. ps, recognition by pooled sera from HIV-1-infected individuals, which was used for normalization.