Abstract
This chapter discusses the unique information that can be obtained by the application of selected calorimetric techniques to the study of DNA. The chapter demonstrates calorimetry to be a powerful tool in biophysical research, capable of uniquely providing thermodynamic and extrathermodynamic characterizations of DNA structure, conformational transitions, and ligand interactions. A differential scanning calorimeter is an instrument that allows to measure continuously the heat capacity of a system as a function of temperature. Isothermal mixing calorimetry has been used in nucleic acid studies to characterize the influence of metal ion binding; to determine the enthalpy of duplex formation from the mixing of two complementary strands; to measure the energetics of pH-induced changes in nucleic acid structure; and to determine the enthalpy of small ligand-DNA interactions and protein–DNA interactions. Multifrequency calorimetry has been applied to the analysis of membrane phase transitions and to the folding–unfolding transition of the protein cytochrome c.