Crystal structure of a CRISPR RNA-guided surveillance complex, Cascade, bound to a ssDNA target[1]
The . The body is formed by a helical filament of six Cas7 subunits (Cas7.1 to 7.6) wrapped around the crRNA guide, with a head-to-tail dimer of Cse2 (Cse2.1 and Cse2.2) at the belly. Cas6e and the 3′ handle of crRNA cap the Cas7 filament atthe head while Cas5 and the 5′ handle cap the tail. The N-terminal base of Cse1 is positioned at the tail of the filament; the C-terminal four-helix bundle contacts Cse2.2. The ssDNA target is juxtaposed to the guide region of the crRNA in a groove formed by the Cas7 filament, the four-helix bundle of Cse1, and the Cse2 dimer.
Crystal structure of the E. coli CRISPR RNA-guided surveillance complex, Cascade[2]
