Understanding the role of water on the binding of protein to substrate provides insight into substrate recognition. Osmotic stress, a technique in which neutral osmolyte modifies the activity of a solvent, is a method by which the role of water can be elucidated. The thermodynamics of binding of UV-p(dT)10 to DNA photolyase under conditions of osmotic stress was studied using the technique of isothermal titration calorimetry (ITC). Titrations of DNA into photolyase solution were carried out under conditions of constant temperature and ionic strength, and thermodynamic data on the binding were obtained from the titration. Equilibrium constants were determined over a range of molal concentrations of glycerol, the neutral osmolyte. The data were used to determine the number of water molecules that were released upon formation of the protein-substrate complex. Release of water molecules as a function of the oxidation state of the protein was also explored.

Osmotic stress analysis of the effects of water on a protein-DNA interaction

243rd National Meeting (2012)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.