biostudies-literatureVander Meulen KANIGMS NIH HHS9-27https://www.ebi.ac.uk/biostudies/studies/S-EPMC2336898biostudies-literatureUnknown377(1)To characterize driving forces and driven processes in formation of a large-interface, wrapped protein-DNA complex analogous to the nucleosome, we have investigated the thermodynamics of binding the 34-base pair (bp) H' DNA sequence to the Escherichia coli DNA-remodeling protein integration host factor (IHF). Isothermal titration calorimetry and fluorescence resonance energy transfer are applied to determine effects of salt concentration [KCl, KF, K glutamate (KGlu)] and of the excluded solute glycine betaine (GB) on the binding thermodynamics at 20 degrees C. Both the binding constant K(obs) and enthalpy Delta H degrees (obs) depend strongly on [salt] and anion identity. Formation of the wrapped complex is enthalpy driven, especially at low [salt] (e.g., Delta H(o)(obs)=-20.2 kcal x mol(-Journal of molecular biologyFormation of a wrapped DNA-protein interface: experimental characterization and analysis of the large contributions of ions and water to the thermodynamics of binding IHF to H' DNA.PMC2336898R37 GM023467GM 23467Vander Meulen KASaecker RMRecord MTfalseFormation of a wrapped DNA-protein interface: experimental characterization and analysis of the large contributions of ions and water to the thermodynamics of binding IHF to H' DNA.To characterize driving forces and driven processes in formation of a large-interface, wrapped protein-DNA complex analogous to the nucleosome, we have investigated the thermodynamics of binding the 34-base pair (bp) H' DNA sequence to the Escherichia coli DNA-remodeling protein integration host factor (IHF). Isothermal titration calorimetry and fluorescence resonance energy transfer are applied to determine effects of salt concentration [KCl, KF, K glutamate (KGlu)] and of the excluded solute glycine betaine (GB) on the binding thermodynamics at 20 degrees C. Both the binding constant K(obs) and enthalpy Delta H degrees (obs) depend strongly on [salt] and anion identity. Formation of the wrapped complex is enthalpy driven, especially at low [salt] (e.g., Delta H(o)(obs)=-20.2 kcal x mol(-2008-01-01T00:00:00Z2008 Mar2026-04-29T13:07:05.909Z2026-04-07T15:14:17.981ZS-EPMC23368981823774010.1016/j.jmb.2007.11.104