title: Effect of sulphur crosslinking on the stability and transition of triple helical DNA.
abstract: In continuation to our work on order-order and order-disorder transition in triple stranded DNA when it is bounded to netropsin, we report in this communication the stabilizing/destabilizing effect of disulphide linkage on the phase dynamics of the triplex using the amended Zimm-Bragg theory. It is observed that in contrast to the sequential triplex-->duplex -->single strand melting of the uncrosslinked triplex, crosslinking causes the triplex state to melt directly to the single stranded state, with no apparent intermediary of a duplex state. Since there is no overall difference in the enthalpy of crosslinked and uncrosslinked triplexes, the transition is entropy driven.
authors.affiliation: Division of Biopolymers, Central Drug Research Institute, Lucknow, India.
authors.forename: S
authors.initials: S
authors.lastname: Srivastava
authors.forename: V D
authors.initials: VD
authors.lastname: Gupta
authors.forename: S
authors.initials: S
authors.lastname: Singh
mesh_terms: D001483:Base Sequence; D003432:Cross-Linking Reagents / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D004220:Disulfides / Q000737:chemistry*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D013816:Thermodynamics
chemical_list: D003432:Cross-Linking Reagents; D004220:Disulfides; C051802:triplex DNA; D004247:DNA