Figure 3.

Comparison of the structures of (A) (+)-3/gp120 (4DKQ)²¹ and (B) (+)-4/gp120 (Clade E, copy A) indicates that (+)-3 interacts with Met426_gp120 via a network of water molecules whereas the guanidinium group of (+)-4 hydrogen bonds directly to the backbone carbonyl of Met426_gp120. Coloring is by atom type: nitrogen (blue), oxygen (red), chlorine (neon-green), fluorine (neon-yellow-green), and carbon [magenta for (+)-3 and sky blue for (+)-4]. Hydrogen bonds are represented by dashed lines.