What is the origin of "melting" in molecular genetics?

Question

I'm reading some papers about prokaryotic transcription mechanisms, and I've come across a term I haven't heard before: *DNA melting* or *promoter melting*. After reading a bit, it's pretty clear that they're referring to the separation of DNA from the double stranded form to single strands.Maybe it's just because chemistry isn't my thing, but when I think of *melting* I think of a solid gaining enough energy to become a liquid. How did the term *melting* come to apply to DNA in this way? Does the term *melting* have a more general definition in terms of thermal chemistry?

Answer 1

In order for the double-stranded DNA to separate and become two single strands, the forces holding the two strands together have to be overcome. The two strands are held together by hydrogen bonds, which are relatively weak interactions, but there are many of them.



Just like transitioning from a solid to a liquid requires the addition of enough energy to break the interactions holding the molecules together, melting DNA (transitioning from double to single strands) requires the addition of enough energy to overcome the forces holding the strands together.