Investigation of guanine-rich DNA telomeric structure by a covalently linked BODIPY dye

We have investigated the interactions and structures of various guanine-ric h oligonucleotides that are covalently linked by a BODIPY dye at the 5' end . HPLC was used to purify and separate different complexes. A single predom inant complex is collected for BODIPY-modified d(T-10) and d(G(10)), while two major complexes are collected at different retention times for the BODI PY-modified d(CGCGT(4)CGCG) and d(T(2)G(4)T(2)G(4)) in the HPLC chromatogra ms during sample preparation. Distinct nonresonant holes in the satellite h ole spectra allow us to distinguish different conformational structures wit h the same BODIPY-oligonucleotide sequence. In addition, our satellite hole results indicate that the coupling between the BODIPY and the thymine resi dues in the G-rich sequences can affect the yield of the G-rich aggregation . Furthermore, the appearance of new bands in the absorption spectra result ing from BODIPY aggregates may be a useful diagnostic of various G-rich str uctures at room temperature. This is because the BODIPY aggregates are driv en by the association of G-rich sequences.