Linkage of proton binding to the thermal dissociation of triple helix complex.
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.
Petraccone
Luigi
L
Dipartimento di Scienze Farmaceutiche, Via Ponte Don Melillo, 84084, Fisciano (SA), Italy.
Erra
Eva
E
Mattia
Carlo Andrea
CA
Fedullo
Vito
V
Barone
Guido
G
Giancola
Concetta
C
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
D011522:Protons; C051802:triplex DNA; D003596:Cytosine; D004247:DNA