Synthesis of DNAs with succinamide internucleoside linkages and its application in discrimination of T-C mismatch

Abstract

Peptide nucleic acid (PNA) has many applications in molecular biology and biotechnology, and research continues on modifying the PNA backbone to improve its functionality. We synthesized PNA in our case, artificial DNA that contains neutral succimamide as internucleoside linkages and applied it to mismatch recognition. We embedded the succinamide linkages into DNA by incorporating thymidine–succinamide–thymidine (TST) phosphoramidite at specific sites via standard DNA synthesis. Ultraviolet spectroscopy and melting temperature experiments suggested that such mixed-backbone DNA forms a B-type duplex with natural DNA. We observed a 20 kJ/mol decrease in enthalpy when we incorporated a succinamide linkage into a DNA–PNA duplex. We examined mismatch recognition of the mixed-backbone DNA, and observed that TST embedded DNA recognizes T-C mismatches.