title: Chemical synthesis of oligodeoxynucleotide dumbbells.
abstract: The chemical synthesis of DNA dumbbells is investigated by using two sequences, cyclo-d(GCG-T4-CGCCGC-T4-GCG) and cyclo-d(TTCC-T4-GGAATTCC-T4-GGAA). This method readily and inexpensively yields multimicromole quantities of circular DNA, allowing detailed structural and physical studies to be carried out. Linear oligomers of sequence d(GCG-T4-CGCCGC-T4-GCG) having either 3'- or 5'-phosphates were cyclized in 40% and 67% isolated yield, respectively, by using 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide. Formation of the circular product is confirmed by a 28 degrees C increase in the optical melting temperature, anomalously rapid electrophoretic migration, sequential nuclear Overhauser enhancements between protons of G1 and G20, and observed nuclear coupling between the ligated phosphorus and protons of both G1 and G20. cyclo-d(TTCC-T4-GGAATTCC-T4-GGCC) was synthesized from the corresponding linear 3'-phosphate in 80% yield by the same procedure. Chemical ligation is most effective for 3'-phosphorylated nick sites flanked by two purine bases.
authors.affiliation: Department of Chemistry, Northwestern University, Evanston, Illinois 60208.
authors.forename: G W
authors.initials: GW
authors.lastname: Ashley
authors.forename: D M
authors.initials: DM
authors.lastname: Kushlan
mesh_terms: D001482:Base Composition; D001483:Base Sequence; D004247:DNA / Q000138:chemical synthesis* / Q000737:chemistry; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009691:Nucleic Acid Denaturation; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis* / Q000737:chemistry; D013816:Thermodynamics
chemical_list: D007202:Indicators and Reagents; D009838:Oligodeoxyribonucleotides; D004247:DNA