Folding pathway of a lattice model for proteins

The folding of a protein-like heteropolymer is studied by using direct simu lation of a lattice model that folds rapidly to a well-defined "native" str ucture. The details of each molecular folding event depend on the random in itial conformation as well as the random thermal fluctuations of the polyme r. By analyzing the statistical properties of hundreds of folding events, a classical folding "pathway" for such a polymer is found that includes part ially folded, on-pathway intermediates that are shown to be metastable equi librium states of the polymer. These results are discussed in the context o f the "classical" and "new" views of folding.