A study of thermal denaturation/renaturation in DNA using laser light scattering: a new approach.

The thermal denaturation/renaturation processes in E. coli and eukaryotic DNAs have been studied using the laser light scattering (LS) technique. The differential scattering intensity curve has been utilized to determine the transition temperature T(m). The effect of solution pH on DNA thermal denaturation has been examined. It has been shown clearly that LS is an extremely sensitive method (more than the UV absorption method) and reveals even the subtler effects such as the pre-transition fluctuations, and that the DNA denaturation is prominently affected by pH. The dependence of melting temperature (T(m)) on composition of DNA, number of base pairs and base sequences has also been investigated. It has been observed that depending upon its base sequence, the T(m) decreases in the case of renatured DNAs. The results have been compared with the UV absorption studies.