Unfolded and partially unfolded proteins participate in a wide range of biological processes from pathological aggregation to the regulation of normal cellular activity. Characterization of nonnative states is critical for the understanding of these processes, yet comparatively little is known about their energetics and their structural propensities under native conditions. We demonstrate that energetically important interactions, which involve multiple residues and which include significant nonnative effects, can form in the denatured state ensemble (DSE) of globular proteins, and can involve residues that are distant in sequence and spatially well separated in the native structure. Mutations that alter the energetics of the DSE can impact the analysis of cooperativity and folding, and could modulate the propensity to aggregate.

Abstract