Fig 2. TthCsm specifically recognizes and binds ssRNA through complementarity to its crRNA.

(A) An increasing concentration of TthCsm, from 0–300 nM, was incubated with 0.5 nM ³²P-labeled ssRNA target that was complementary (C) or noncomplementary (NC) to the crRNA guide sequence, and analyzed by an EMSA. (B) 100 nM TthCsm was incubated with 0.5 nM ³²P-labeled target ssRNA and increasing concentrations of unlabeled complementary ssRNA (ssRNA, C), noncomplementary ssRNA (ssRNA, NC), complementary ssDNA (ssDNA, C), or noncomplementary ssDNA (ssDNA, NC) competitor (0–1 μM). Samples were assayed for binding of the probe using an EMSA, as in (A).