Coupling of ssRNA cleavage with DNase activity in type III-A CRISPR-Csm revealed by cryo-EM and biochemistry

Overall structures of Type III-A CRISPR-Csm complex. a Apo small conformation. b Apo big conformation. c Target ssRNA-bound small conformation. d Target ssRNA-bound big conformation. In a, c, the surface representations for each component are shown in the middle and left panels; the map-derived models are shown in the right panel. e, f Models of crRNA and target ssRNA are highlighted within surface representations of the transparent maps. The legend on the right annotates the color of each subunit and the total number of subunits (in parenthesis) for the small and big state