No abstract

Linear or branched 1,3-diketone-linked thymidine 5'-O-mono-and triphosphate were synthesized through CuAAC click reaction of diketone-alkynes with 5-azidomethyl-dUMP or -dUTP. The triphosphates were good substrates for KOD XL DNA polymerase in primer extension synthesis of modified DNA. The nucleotide bearing linear 3,5dioxohexyl group (HDO) efficiently reacted with argininecontaining peptides to form stable pyrimidine-linked conjugates, whereas the branched 2-acetyl-3-oxo-butyl (PDO) group was not reactive. Reaction with Lys or a terminal amino group formed enamine adducts that were prone to hydrolysis. This reactive HDO modification in DNA was used for bioconjugations and cross-linking with Arg-containing peptides or proteins (e.g. histones).

Glyoxal-linked 2'-deoxyuridine 5'-O-mono-and triphosphates were synthesized through a CuAAC click reaction of 4-azidophenylglyoxal or a Sonogashira reaction of 4-bromophenylglyoxal with 5-ethynyl-dUMP or -dUTP. The triphosphates were used as substrates for enzymatic synthesis of modified DNA probes with KOD XL DNA polymerase. The glyoxal-linked nucleotides reacted with arginine-containing peptides to form stable imizadolone-linked conjugates. This reactive glyoxal modification in DNA was used for efficient bioconjugations and crosslinking with Arg-containing peptides or proteins (e. g., histones) and was found to be more reactive than previously reported 1,3-diketone-linked DNA probes.