1,3‐Diketone‐Modified Nucleotides and DNA for Cross‐Linking with Arginine‐Containing Peptides and Proteins.

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 3,5‐dioxohexyl group (HDO) efficiently reacted with arginine‐containing 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). [ABSTRACT FROM AUTHOR]