Figure 3.

Polyacrylamide coelectrophoresis of the peptide binder MFβ2 with and without specific competitors at pH 7.5, 4°C. (A) A peptide concentration gradient was established across the different lanes of the gel, as indicated. [5′-³²P]RNA was electrophoresed into the peptide-containing gel, and the RNA was shifted according to the extent of binding. (B) Competition assays with unlabeled microhelices containing G-U, I-U, G-C, and U-G base pairs. Only the G-U-containing microhelix is an effective competitor. (C) Competition assays with a DNA microhelix containing a G-T base pair.