Energetics of folding of a lysozyme β-bend

The forces directing the “β-fold” at residues 52–59 in hen egg-white lysozyme have been explored by theoretical conformational analysis, which includes solvent interaction. It is shown that, whereas the conformation is in its most favorable free-energy state for a folded form, the fold is actually a destabilizing influence which is overcome only by long range interactions. The concept is introduced that nucleation of the tertiary structure initiates the folding process which is localized by the specific sequence. Thus, long range forces “drive” the fold and short range forces “localize” it.