A critical comparison of coarse-grained structure-based approaches and atomic models of protein folding

Phys Chem Chem Phys. 2017 May 31;19(21):13629-13639. doi: 10.1039/c7cp01532a.

Abstract

Structure-based coarse-grained Gō-like models have been used extensively in deciphering protein folding mechanisms because of their simplicity and tractability. Meanwhile, explicit-solvent molecular dynamics (MD) simulations with physics-based all-atom force fields have been applied successfully to simulate folding/unfolding transitions for several small, fast-folding proteins. To explore the degree to which coarse-grained Gō-like models and their extensions to incorporate nonnative interactions are capable of producing folding processes similar to those in all-atom MD simulations, here we systematically compare the computed unfolded states, transition states, and transition paths obtained using coarse-grained models and all-atom explicit-solvent MD simulations. The conformations in the unfolded state in common Gō models are more extended, and are thus more in line with experiment, than those from all-atom MD simulations. Nevertheless, the structural features of transition states obtained by the two types of models are largely similar. In contrast, the folding transition paths are significantly more sensitive to modeling details. In particular, when common Gō-like models are augmented with nonnative interactions, the predicted dimensions of the unfolded conformations become similar to those computed using all-atom MD. With this connection, the large deviations of all-atom MD from simple diffusion theory are likely caused in part by the presence of significant nonnative effects in folding processes modelled by current atomic force fields. The ramifications of our findings to the application of coarse-grained modeling to more complex biomolecular systems are discussed.

Publication types

  • Comparative Study

MeSH terms

  • Bacterial Outer Membrane Proteins / chemistry
  • Humans
  • Models, Chemical
  • Molecular Dynamics Simulation
  • NIMA-Interacting Peptidylprolyl Isomerase / chemistry
  • Phospholipases A1 / chemistry
  • Protein Conformation
  • Protein Folding*
  • Repressor Proteins / chemistry
  • Ribosomal Proteins / chemistry
  • Viral Regulatory and Accessory Proteins / chemistry

Substances

  • Bacterial Outer Membrane Proteins
  • NIMA-Interacting Peptidylprolyl Isomerase
  • Repressor Proteins
  • Ribosomal Proteins
  • Viral Regulatory and Accessory Proteins
  • phage repressor proteins
  • ribosomal protein L9
  • Phospholipases A1
  • outer membrane phospholipase A
  • PIN1 protein, human