Fig. 4.
dsRBD1 and -2 as indispensable components for diffusion. (A) Representative single-molecule trace of wild-type TRBP diffusion on 38 bp dsRNA. (B–D) Several truncation mutants of TRBP show that both dsRBD1 and -2 are required for diffusion. (B) DsRBD1/2 shows a similar FRET trace as those from wild-type TRBP. (C) Short-lived binding but no diffusion was observed with dsRBD2/3, dsRBD1 only, and dsRBD2 only. (D) DsRBD3 does not bind to dsRNA. (E) Representative FRET traces of Alexa 647–labeled PACT with Cy3-labeled 38 bp dsRNA showing its repetitive diffusion motion. (F) R3D1-L also showed a similar diffusion motion on 38 bp dsRNA as seen in the wild-type TRBP.