DCL4 DUF283 resembles dsRBD fold for protein target selection (A) Stereoview diagram of the superimposition of DCL4 DUF283 (red) and the dsRBD domain from Aquifex aeolicus RNase III (1RC7, gray). Invariable histidine side chain of Aquifex aeolicus RNase III dsRBD involved in dsRNA binding shown in stick. For clarification purpose, the C-terminal disordered region (residues: 735–752) was omitted. (B) Electrostatic potential surface view of DCL4 DUF283 and Aquifex aeolicus RNase III dsRBD with the blue, red, and white colors representing the positive, negative, and neutral charges, respectively. Three regions within Aquifex aeolicus RNase III dsRBD involved in dsRNA recognition are also labeled. (C) DCL4 DUF283 selectively binds to DRB4 dsRBD1. Similar amounts of recombinant His-DCL4-DUF283 (left panel) or His-DCL1-DUF283 (right panel) was loaded onto the prebound GST-fused DRB4 fragments (dsRBD1: residues 3–70 and dsRBD2: residues 81–155). His-DCL4-DUF283 or His-DCL1-DUF283 was detected by Western blotting with anti-His antibody. (D) DCL1 DUF283 selectively binds to HYL1 dsRBD2. Similar amount of recombinant His-DCL1-DUF283 (left panel) or His-DCL4-DUF283 (right panel) was loaded onto the prebound GST-fused HYL1 fragments (dsRBD1: residues 11–85 and dsRBD2: residues 100–172). His-DCL4-DUF283 or His-DCL1-DUF283 was detected by Western blotting with anti-His antibody.
