Figure 4. Interaction between UL16 and MICBpf.

(A), Ribbon tracing of the complex using the color code from Figure 1. Also shown in the lower right corner of panel A is a schematic representation of the “saddle on horseback” arrangement between UL16 and MICB. (B–D), The three major contact regions A, B and C of the complex. Nitrogen, oxygen and sulfur atoms are colored blue, red, and yellow, respectively. Hydrogen bonds and salt bridges are represented with dashed green and red lines, respectively, and hydrophobic contacts (distance<4.0 Å) are shown as dashed magenta lines. The dashed blue line indicates π-π interactions of two arginine guanidinium groups. Water molecules are shown as red spheres.