U‐Pin Polyamide Motif for Recognition of the DNA Minor Groove

DNA‐binding hairpin pyrrole–imidazole polyamides with γ ‐aminobutyric acid as a turn‐forming residue tolerate A ⋅ T or T ⋅ A base pairs under the turn. U‐pins—polyamides with a different turn—have been synthesized and their DNA binding properties were studied. The two turn‐forming residues are connected via the ring nitrogens using variable length aliphatic linkers ((CH 2 ) n , n =3–6). Through optimization of the linker length and the substituents at the 2‐position of the pyrrole residue on the U‐turn, polyamides with G ⋅ C/C ⋅ G tolerant turns could be found, which bind to DNA in a predictable manner.