Frustration in the energy landscapes of multidomain protein misfolding

Proc Natl Acad Sci U S A. 2013 Jan 29;110(5):1680-5. doi: 10.1073/pnas.1222130110. Epub 2013 Jan 14.

Abstract

Frustration from strong interdomain interactions can make misfolding a more severe problem in multidomain proteins than in single-domain 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. Domain-swapped 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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Connectin
  • Humans
  • Hydrophobic and Hydrophilic Interactions
  • Models, Molecular
  • Muscle Proteins / chemistry
  • Muscle Proteins / metabolism
  • Protein Folding*
  • Protein Kinases / chemistry
  • Protein Kinases / metabolism
  • Protein Multimerization
  • Protein Structure, Secondary
  • Protein Structure, Tertiary*
  • Proteins / chemistry*
  • Proteins / metabolism
  • Thermodynamics
  • src Homology Domains

Substances

  • Connectin
  • Muscle Proteins
  • Proteins
  • TTN protein, human
  • Protein Kinases