Fig. 3.

Substrate specificity of TRBP binding and its diffusion along dsRNA. (A–F) PresiRNA, DNA–RNA heteroduplex, ssRNA, and three dsRNAs with different secondary structure were prepared for testing the substrate specificity. (G) The fraction (±SEM) of the substrate (A–F) bound to TRBP was calculated from ∼5,000 substrate molecules at 10 nM TRBP concentration. TRBP does not bind to DNA–RNA heteroduplex and ssRNA, but binds to all dsRNAs to varying degrees at 10 nM TRBP concentration. (H) The fraction (±SEM) of diffusion among TRBP-bound substrates shows that TRBP diffuses on dsRNAs with several single mismatches but not on dsRNA with more complex secondary structures.