Structures and binding sites for synthesized PI polyamides A, Myc-5; B, FITC labeled Myc-5 C, Mismatch PI polyamide. Base sequence specificity depends on side-by-side pairing of Pyrrole and Imidazole amino acids in the minor groove of DNA. Black and white circles, Im and Py rings, respectively; curved line, hairpin junction,; β is β-alanine; Dp is diaminomethylene propylamide and W=A or T.