Figure 4.

In-line probing analysis with two internal labels. (a) Schematic representation of the experiment. The panels labelled with Cy5–Cy3 and Cy3–Cy5 are subtraction images with all values <0 set to zero. Yellow bands in the superimposed image indicate cleavage products present in both scans. The dashed box shows the part of the sequence that can be analysed unambiguously. The dashed line shows the border above which only cleavage products carrying both labels are present. (b) In-line probing analysis of four DAse ribozyme constructs (A–D). The images show a section of the unmodified Cy3 scan from the gels visible in Figure 2d, 3a and Supplementary Figure S3. Below each image, the relative catalytic activity, with respect to the wild-type ribozyme, is given.