Protein folding cooperativity in the correlated lattice

As it folds onto itself under in vitro renaturation conditions, a protein c reates local solvent environments which affect its pairwise intramolecular interactions. This context dependence of the folding process is modelled by introducing spatially correlated self-avoiding walks in a cubic lattice. I n contrast with the context-insensitive chain, the energy spectrum for the spatially correlated walker is shown to be highly localized, forming a few clusters of kinetically related states. Furthermore, the spatial correlatio ns are shown to account for the cooperativity of the folding process. (C) 2 001 Elsevier Science B.V. All rights reserved.