A study of DNA melting in concentrated water-alcohol solutions.

The DNA melting profiles with high resolution have been studied for conditions corresponding to the B and A conformations of DNA in water-alcohol solutions. The melting profiles of the A-form and B-form DNA, their mean melting temperatures and melting range width were found to differ. DNA was shown to be heterogeneous in respect of the B-A transition, the GC-rich regions more readily converting into the A form than AT-rich ones. The presence of boundaries between the A and B sections within the transition zone did not smooth off the fine structure of melting profiles.