Hierarchical nature of phase transitions

Although much remains to be learned about protein stmcture and evolution, all the available evidence now supports the conclusion that the folds represent a finite natural ensemble of forms, determined by a hierarchic set of physical constmctional mles that arise out of the fundamental properties of linear polymers made up of the twenty proteinaceous amino acids, and assemble into their native forms like a set of crystals through a series of phase transitions (Scheraga, 1963 Florey, 1969). And, like any other set of natural forms, such as atoms or crystals, the folds are genuine universals that are antecedent to biology and thus to Darwinian selection. In short, the universe of protein forms can be accounted for by physical... 

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