title: Unfolding of a branched double-helical DNA three-way junction with triple-helical ends.
abstract: We have designed three oligonucleotides (33 mers) which when mixed in a 1:1:1 ratio form double-helical DNA three-way junctions with triple helical ends in the pH interval pH 4 to 5.5. The triplex to coil transition is initiated by raising the temperature and was recorded by temperature gradient gel electrophoresis, uv melting, and differential scanning calorimetry. The transitions can be deconvoluted into three subtransitions representing the independent thermal denaturation of each of the arms. We have proposed a model for the unfolding pathway and give the thermodynamic parameters for each step as calculated using the formalism outlined in the appendix.
authors.affiliation: Department of Biochemistry, University of Cape Town, Private Bag, Republic of South Africa.
authors.forename: P L
authors.initials: PL
authors.lastname: Hüsler
authors.forename: H H
authors.initials: HH
authors.lastname: Klump
mesh_terms: D001483:Base Sequence; D002152:Calorimetry, Differential Scanning; D004247:DNA / Q000737:chemistry*; D004587:Electrophoresis, Agar Gel; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics
chemical_list: D009838:Oligodeoxyribonucleotides; D004247:DNA