کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
216530 | 1426275 | 2011 | 8 صفحه PDF | دانلود رایگان |
Binding of the phenothaizinium dye thionine with four sequence specific deoxyribopolynucleotides, poly(dG-dC).poly(dG-dC), poly(dG).poly(dC), poly(dA-dT).poly(dA-dT), and poly(dA).poly(dT) has been investigated by means of thermal helix melting, isothermal titration calorimetry, and differential scanning calorimetry experiments. The binding affinity values evaluated from isothermal titration calorimetry suggests that thionine exhibits the highest binding affinity to poly(dG-dC).poly(dG-dC). The binding to poly(dG-dC).poly(dG-dC), poly(dA-dT).poly(dA-dT), and poly(dG).poly(dC) is exothermic and favoured by negative enthalpy changes while binding to poly(dA).poly(dT) is endothermic and anomalous. The values of heat capacity changes of the interaction are negative and in the range (−0.4 to −0.5) kJ · K−1 · mol−1. The binding is characterized by strong stabilization of the polynucleotides against thermal strand separation. The binding affinity values derived from thermal melting data are in excellent agreement with those obtained from isothermal titration calorimetry data. Insights into the energetic aspects and guanine–cytosine selectivity of the DNA interaction of thionine have been obtained from these studies.
Research highlights
► Thionine binds to DNA exhibiting alternating guanine-cytosine sequence selectivity.
► Exothermic bindings were favoured by negative enthalpy and positive entropy changes.
► The binding was characterized by strong thermal stabilization of the polynucleotides.
► Complete energetics revealed from the salt and temperature dependent data.
Journal: The Journal of Chemical Thermodynamics - Volume 43, Issue 7, July 2011, Pages 1036–1043