A search for the most stable folds of protein chains.

It is generally believed that it is not sensible to search for a thermodynamically stable structure of a protein because neither a molecule nor a computer can look through all the 3(100) possible (for 100 residues) chain conformations. Here we show that the use of a molecular field theory for the long-range interactions, the use of one-dimensional statistical mechanics for the short-range ones and the discovery that there are and there must be only a small discrete set of folding patterns, make it possible to examine all the variety of 'potentially stable' structures. The general approach and its application is demonstrated here by calculation of stable folds for some beta domains. The most stable of these folds correspond to the observed structures.