DNA TRIPLE-HELIX FORMATION AT PYRIMIDINE-PURINE INVERSION SITES

A systematic investigation of a series of triplex forming oligonucleotides (TFOs) containing α-, and β- thymidine, α- and β-N7-hypoxanthine, and α- and β- N7 and N9 aminopurine nucleosides, designed to bind to T-A inversion sites in DNA target sequences was performed. Data obtained from gel mobility assays indicate that T-A recognition in the antiparallel triple-helical binding motif is possible if the nucleoside αN9-aminopurine is used opposite to the inversion site in the TFO.