Tandem Hairpin Motif for Recognition in the Minor Groove of DNA by Pyrrole–Imidazole Polyamides

Linking hairpin recognition units “tail-to-turn” in the minor groove of DNA results in the extension of hairpin polyamide binding site size to 11 base pairs. A twelve-ring tandem hairpin (see diagram) binds its match DNA site at picomolar concentrations with unprecedented sequence specificity.