title: Linkage of proton binding to the thermal dissociation of triple helix complex.
abstract: The effects of cytosine protonation on the thermodynamic properties of parallel pyrimidine motif DNA triplex were investigated and characterized by different techniques, such as circular dichroism (CD), ultraviolet spectroscopy (UV) and differential scanning calorimetry (DSC). A thermodynamic model was developed which, by linking the cytosine ionization equilibrium to the dissociation process of the triplex, is able to rationalize the experimental data and to reproduce the pH dependence of the free energy, enthalpy and entropy changes associated with the triplex formation. The results are useful to systematically introduce the effect of pH in a more general model able to predict the stability of DNA triplexes on the basis of the sequence alone.
authors.affiliation: Dipartimento di Scienze Farmaceutiche, Via Ponte Don Melillo, 84084, Fisciano (SA), Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Petraccone
authors.forename: Eva
authors.initials: E
authors.lastname: Erra
authors.forename: Carlo Andrea
authors.initials: CA
authors.lastname: Mattia
authors.forename: Vito
authors.initials: V
authors.lastname: Fedullo
authors.forename: Guido
authors.initials: G
authors.lastname: Barone
authors.forename: Concetta
authors.initials: C
authors.lastname: Giancola
mesh_terms: D002152:Calorimetry, Differential Scanning; D002942:Circular Dichroism; D003596:Cytosine / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D009690:Nucleic Acid Conformation; D009691:Nucleic Acid Denaturation; D011522:Protons; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature; D013816:Thermodynamics
chemical_list: D011522:Protons; C051802:triplex DNA; D003596:Cytosine; D004247:DNA