Determination of the apparent dissociation constants (Ka) of the complexes of recombinant YB-1 (A,B) and CSD (C,D) with RNA and DNA.

<p>A and C, Chemically synthesized RNA or DNA fragments of similar sequence and length (7 pmol) were incubated with increasing amounts of recombinant YB-1 (A) or CSD (C) in 10 μl of reaction buffer. The resultant RNA-protein or DNA-protein complexes were analyzed by 8% PAGE followed by silver staining. Protein/NA molar ratio are mentioned at the top of the figures for each experimental condition. B and D, Binding curves were drawn according to quantification of band intensities for free RNA or DNA using ImageJ software. The apparent dissociation constant (Ka) was estimated as protein concentration sufficient for 50% saturation. Solid and dotted lines show the RNA-protein and DNA-protein complex, respectively.