Isothermal calorimetry studies of DNA condensation under osmotic pressure.

Abstract

The physics behind DNA condensation has been a subject of research for many years. Despite this, the exact mechanism under the condensed process is still not fully understood. Isothermal calorimetry introduces a unique perspective by providing the full thermodynamics parameter that drives the condensation process. Here we report on isothermal calorimetry studies of DNA condensation by trivalent ions. We investigate this process while altering the osmotic pressure through the addition of polyethylene glycol. We use a home-built Python script to fit the two-peek signal and obtain the full thermodynamics parameter. We find a shift in the condensation peak as a function of osmotic pressure indicating osmotic pressure enhances condensation. These results are key to understanding the basic process of DNA condensation and specifically with the surrounding by osmotic pressure.