Sequence-specific hybridization between two different types of peptide nucleic acids

Nielsen's-type peptide nucleic acids (PNA) and the oxy-PNA (OPNA), both car rying thymine or adenine bases, were prepared. Hybridizations were observed not only between the complementary pairs of PNA(A(12))-DNA(T-12) and OPNA( A(12))-DNA(T-12), but also between the complementary pairs of the artificia l nucleic acid analogues, OPNA(A(12))-PNA(T-12). In the three-component mix ture of PNA(T-12)-DNA(T-12)-OPNA(A(12)), OPNA(A(12)) was found to hybridize preferentially with DNA(T-12). Addition of DNA(T-12) to a preformed duplex of OPNA(A(12))-PNA(T-12) gave rise to a strand displacement to form a OPNA (A(12))-DNA(T-12) duplex. No tripler formation was detected in the three-co mponent mixture.