The entropic tension of protein loops.

A large survey of reliably known structures supports the hypothesis that protein loops can behave like elastic strings, and has enabled a parameter describing the entropically generated tensions to be determined. Such tensions may be of major importance in the folding process; here they are discussed mainly in the context of the final collapse of a molten globule into the native structure, though they must also play a dominant rôle in the earlier development of the tertiary fold.