The flexibility of the protein and RNA strands was calculated using the root-mean-square deviation (RMSD) to the crystal structure. The results were calculated separately for the protein backbone (Cα, C, N, O atoms), guide RNA backbone (sugar + phosphate moieties) and target RNA backbone (sugar + phosphate moieties), and they are presented in Table . The distribution of RMSD values in simulations is depicted at the kernel density estimate plots, which are smoothed versions of the histogram in Figure . The root-mean-square fluctuations (RMSF) of Cα atoms of the protein and the P atoms of the RNA are shown in Figure and Supporting Information Figures .