Simultaneous Incorporation of Modified dU and dC Derivatives in the Growing DNA Chain Using PEX and PCR

The substrate efficiency of modified derivatives of 2'-deoxyuridine-(mod-dUTP) and 2'-deoxycytidine-5'-triphosphates (mod-dCTP) was studied in the regime of simultaneous incorporation using the primer elongation reaction (PEX) and PCR with complete replacement of natural deoxytimidine (dT) and deoxycytidine (dC). Polymerases with missing 3'–5' exonuclease activity were used: Taq and Vent (exo-), as well as natural and constructed DNA templates. DNA fragments modified simultaneously by two types of nucleotides with similar and different functional groups were obtained. Research is important for obtaining aptamers with extended properties.