Strand displacement recognition of mixed adenine–cytosine sequences in double stranded DNA by thymine–Guanine PNA (Peptide nucleic acid) Original Research Article

Mixed pyrimidine–purine peptide nucleic acids (PNAs) composed of thymines and guanines are shown to form a PNA2–DNA triplex with Watson–Crick complementary adenine–cytosine oligonucleotides and to bind complementary adenine–cytosine targets in double stranded DNA by helix invasion. These results for the first time demonstrate binding of an unmodified PNA oligomer to a mixed pyrimidine–purine target in double stranded DNA and illustrate a novel binding mode of PNA.