Reproducible protein folding with the stochastic tunneling method.

We report the reproducible folding of the 20 amino-acid protein trp cage using a novel version of the stochastic tunneling method and a recently developed all-atom protein free-energy force field. Six of 25 simulations reached an energy within 1 kcal/mol of the best energy, all of which correctly predicted the native experimental structure of the protein, in total eight simulations converged to the native structure. We find a strong correlation between energy and root-mean-square deviation to the native structure for all simulations.