CYCLIC OLIGONUCLEOTIDES - III - ABILITY TO FORM TRIPLEXES WITH AN OLIGODEOXYRIBONUCLEOTIDE CONSISTING OF ADJACENT PYRIMIDINE AND PURINE TRACTS

Formation of triplexes wherein the (G,T)-containing strand passes over from one purine strand of DNA duplex to the other was studied by chem ical ligation and electrophoresis under nondenaturing conditions. Olig odeoxyribonucleotides with adjacent purine and pyrimidine regions were shown to be capable of forming stable bimolecular triplexes with cycl ic oligonucleotides as well as with Linear ones that form a triple hel ix by both Watson-Crick and Hoogsteen base pairing.