FIGURE 1.

Structure of TthCasA. A, cryo-EM reconstruction of Cascade. Coloring is as in Ref. 15 as follows: magenta, CasA; yellow, CasB; cyan and gray, CasC; orange, CasD; and pink, CasE. CasA is located at the tail of the structure. B, ribbon representation of the crystal structure of CasA. The N-domain is colored magenta, and the C-domain is colored white. The N- and C-loops are labeled. C, fit of the crystal structure of CasA into the cryo-EM map of Cascade. D, fit of the crystal structure of CasA into the cryo-EM map of Cascade bound to protospacer target. C and D are colored as in A.