Figure 1.

Structural scheme and RNA target-dependent ssDNA cleavage of the Csm complex. (A) Schematic representation depicting the subunits of the Csm complex in conjunction with the crRNA, resulting in the formation of a binary complex. (B) RNA target recognition by Csm leads to formation of a ternary complex that cleaves single-stranded DNA via the HD domain of the Cas10 subunit. Although rapid RNA cleavage and target recognition are observed, the DNase activity persists over an extended period. The dynamic interplay between RNA fragment release and the extent of ssDNA cleavage activity, so far, remained unresolved.