Frustration from strong interdomain interactions can make misfolding a more severe problem in multidomain proteins than in singledomain proteins. On the basis of bioinformatic surveys, it has been suggested that lowering the sequence identity between neighboring domains is one of nature's solutions to the multidomain misfolding problem. We investigate folding of multidomain proteins using the associative-memory, water-mediated, structure and energy model (AWSEM), a predictive coarse-grained protein force field. We find that reducing sequence identity not only decreases the formation of domain-swapped contacts but also decreases the formation of strong self-recognition contacts between β-strands with high hydrophobic content. The ensembles of misfolded structures that result from forming these amyloid-like interactions are energetically disfavored compared with the native state, but entropically favored. Therefore, these ensembles are more stable than the native ensemble under denaturing conditions, such as high temperature. Domainswapped contacts compete with self-recognition contacts in forming various trapped states, and point mutations can shift the balance between the two types of interaction. We predict that multidomain proteins that lack these specific strong interdomain interactions should fold reliably.aggregation | funnel P rotein misfolding and productive protein folding bear a yinyang relationship in the energy landscape theory of biomolecular self-organization (1). Only by comparing the strengths of the forces leading to proper structure to those that might, by chance, stabilize alternative structure can we quantitatively understand how proteins kinetically access their thermodynamically stable ordered states (1). In vivo and at low concentrations in vitro, unfolded small proteins avoid kinetic traps and generally find their way easily to their native state. Nevertheless, diseases caused by the misfolding of several specific proteins plague mankind (2, 3). Despite much effort, the patterns of interactions that allow pathological misfolding remain incompletely understood. Known pathological misfolding entails aggregation of specific proteins and thus the interactions of protein molecules with other copies of themselves. Energy landscape theory provides one natural explanation of this specificity in misfolding through the funneled nature of the monomeric protein energy landscape: Native-like interactions between different protein molecules like those found within a single protein are stronger than alternate nonnative interactions in the same molecule or interactions between peptide sequences chosen at random in the two molecules. Because of this intrinsic self-stickiness of foldable molecules, runaway domain swapping, in which native-like interactions are made between different copies of the same protein, provides a natural mechanism for aggregation (4-7). Indeed, transient protein aggregation during refolding at moderately high concentration does appear to be universal (8). Nevertheless this aggregati...