Thermal stability and renaturation of DNA in dimethyl sulfoxide solutions: Acceleration of the renaturation rate

Abstract The thermal stability and renaturation kinetics of DNA have been studied as a function of dimethyl sulfoxide (DMSO) concentration. Increasing the concentration of DMSO lowers the melting temperature of DNA but results in an increased second‐order renaturation rate. For example, in a DNA solution containing 0.20 M NaCl, 0.01 M Tris (pH 8.0), and 0.001 M EDTA, the addition of 40% DMSO lowers the melting temperature of the DNA by 27°C and approximately doubles the optimal renaturation rate. The effect of DMSO on the renaturation rate is shown to be at least partially due to its effect on the solution dielectric constant and to be consistent with the polyelectrolyte counterion condensation theory of Manning (1976) Biopolymers 15 , 1333–1343.