Figure 4.
Structural basis of 5′ triphosphate dsRNA recognition by RIG-I CTD. (A) Stereo close up of the interface between RIG-I CTD (Chain A) and the terminus of the 14-bp 5′ ppp dsRNA. RIG-I CTD is shown as cyan ribbons and the dsRNA is shown as stick models. Key residues of RIG-I CTD involved in RNA binding are shown as stick models. (B) Stereo close up of the interactions between RIG-I CTD and the 5′ triphosphate of the 14-bp GC-rich dsRNA. (C) Surface representation of RIG-I CTD bound to 5′ ppp dsRNA showing the shape and charge complementarity between RIG-I CTD and the terminus of the 5′ ppp dsRNA. Positively charged surfaces are colored blue and negatively charged surfaces are red. The orientation of RIG-I CTD relative to the dsRNA on the left panel is similar to the orientation of the protein in panel A.