Syntheses and properties of fluorescent labeled oligonucleotides containing deoxyethenoadenosine at 5' end.

The fluorescent labeled oligodeoxyribonucleotides which contain deoxyethenoadenosione (d epsilon A) at their 5' end were prepared by treating CPG bound oligonucleotides with 5'-DMTr-deoxyethenoadenosine-3'-H-phosphonate. The hybrid formation of d epsilon A-oligonucleotide with its complementary DNA was studied by fluorescence spectroscopy. The fluorescence of d epsilon A in a single strand was largely quenched by stacking interaction with the base at 3' position. When d epsilon A-oligonucleotides hybridized with their complementary strands, relative fluorescence quantum yields (Qrel) against d epsilon A changed in specific manners. These results suggest that d epsilon A-oligonucleotides are applicable to study the local structure of DNA in solution.