Photomodification of RNA and DNA fragments by oligonucleotide reagents bearing arylazide groups.

Photomodification of ribo- and deoxyribo-octanucleotides by oligonucleotide reagents (6- and 7-mers) bearing p-azidotetrafluorobenzamido and 2-nitro-5-azidobenzamido groups has been investigated. It is shown that the oligonucleotides with a perfluoroarylazide group were effective modifiers both of deoxyribo- and ribo-targets. Maximum extent of cross-linked product formation (70%) was obtained when the deoxyribo-octanucleotide was modified by a heptanucleotide reagent with a perfluoroarylazide group. Selectivity of the photomodification was also high (50% on the G-residue at a certain position).