Discrete Assembly of Synthetic Peptide-DNA Triplex Structures from Polyvalent Melamine-Thymine Bifacial Recognition

We have designed a 21-residue α-peptide that simultaneously recognizes two decadeoxyoligothymidine (dT10) tracts to form triplexes with a peptide–DNA strand ratio of 1:2. The synthetic peptide side chain displays 10 melamine rings, which provide a bifacial thymine-recognition interface along the length of the 21-residue peptide. Recognition is selective for thymine over other nucleobases and drives the formation of ternary peptide·[dT10]2 complexes as well as heterodimeric peptide·[dT10C10T10] hairpin structures with triplex stems.