Fig. 2.
The Csy complex facilitates sequence-specific hybridization. (A) A 32-nt target sequence (dashed line) located in the center of the of a 100-nt ssDNA is recognized and bound by the Csy complex (cyan oval) with a Kd of 0.5 nM (left lanes), whereas the Csy complex does not interact with nontarget DNA (far right two lanes). Nucleic acids are 5′ end labeled with 32P (5*). (B) Hybridization between the crRNA and the ssDNA target are nearly undetectable in the absence of the Csy proteins (faint band). (C) The Csy complex binds complementary sequences in preformed dsDNA duplexes, however binding affinities are significantly weaker than that observed to ssDNA targets. The arrow indicates the location of the shifted product.