Figure 2.

Model of Ternary Complex Formation. The model is based on the crystal structure of a V3 loop-containing structure of gp120, bound to a soluble fragment of CD4 [81]. The gp120 core (blue) is bound to the first Ig-like domain of CD4 (cyan). This interaction stabilizes the core molecule bridging sheet domain, which is composed of a series of antiparallel β-sheets. The V3 loop (yellow) extends outward from the gp120 core inner domain. The V3 crown is thought to mediate interaction with the second extracellular loop of CCR5 (black). The CCR5 N-terminus is thought to contact both the bridging sheet domain as well as the V3 base.