DNA photo-cross-linking using 3-cyanovinylcarbazole modified oligonucleotide with threoninol linker

3-Cyanovinylcarbazole modified D-threoninol ((CNV)D) was incorporated in oligodeoxyribonucleotide and tested for a photo-cross-linking reaction with complementary oligodeoxyribonucleotide. The photoreactivity was 1.8- to 8-fold greater than that of 3-cyanovinylcarbazole modified deoxyribose ((CNV)K) previously reported. From the results of melting analysis and circular dichroism spectroscopy of the duplexes, the relatively flexible structure of (CNV)D compared with (CNV)K might be advantageous for [2 + 2] photocycloaddition between the cyanovinyl group on the (CNV)D and pyrimidine base in the complementary strand.