Crystallization of mouse RIG-I ATPase domain: in situ proteolysis

RIG-I is a key pattern recognition receptor that recognizes cytoplasmic viral RNA. Upon ligand binding, it undergoes a conformational change that induces an active signaling conformation. However, the details of this conformational change remain elusive until high-resolution crystal structures of different functional conformations are available. X-ray crystallography is a powerful tool to study structure-function relationships, but crystallization is often the limiting step of the method. Here, we describe the in situ in-drop proteolysis of RIG-I that yielded crystals of the ATPase domain of mouse RIG-I suitable for structure determination.