Modified alpha-beta Chimeric OligoDNA as a Unique Class of TFO

A series of novel alpha-beta chimeric oligodeoxynucleotides bearing either an intercalator-conjugated nucleobase located at the internal 4-nt linker region or an anthraquinone-conjugated propionic acid as a non-nucleosidic backbone unit at the internal linker region was synthesized. The UV-melting experiments reveled that the obtained modified chimera TFOs formed remarkably stable alternate-stranded triplex. On the other hand, modified TFOs bearing non-nucleosidic intercalator-conjugate possessed two diastereomers formed substantially stable alternate-stranded triple helix almost regardless of the stereochemistry of the incorporated non-nucleosidic backbone unit. The sequence discrimination ability and thermodynamic stability of some TFOs were also examined.