Correction to: Nature Structural & Molecular Biology https://doi.org/10.1038/s41594-020-0461-1, published online 13 July 2020.

In the version of this article initially published, the data in Fig. 6h and Extended Data Fig. 6j were incorrect due to errors in the simulation code. The correct figures are shown below. The Fig. 6h caption has been updated to “Arrows indicate unmasking time of the best fit.”, as the panel now contains more than one arrow. The Extended Data Fig. 6j caption incorrectly stated “Simulated cleavage curves for 10 and 0.1 nM siRNA concentration using fast or slow unmasking rates (average unmasking time of 1 s and 800 s, respectively).” The correct average unmasking time for 0.1 nM siRNA is 1,200 s. The errors have been corrected in the HTML and PDF versions of the article.

Fig. 6
figure 1

Original and Corrected.

ExtendedData Fig. 6
figure 2

Original and Corrected.