title: Speeding up protein folding: mutations that increase the rate at which Rop folds and unfolds by over four orders of magnitude.
abstract: BACKGROUND
  The dimeric four-helix-bundle protein Rop folds and unfolds extremely slowly. To understand the molecular basis for the slow kinetics, we have studied the folding and unfolding of wild-type Rop and a series of hydrophobic core mutants.
  
  
  RESULTS
  Mutation of the hydrophobic core creates stable, dimeric, and wild-type-like proteins with dramatically increased rates of both folding and unfolding. The increases in rates are dependent upon the number and position of repacked residues within the hydrophobic core.
  
  
  CONCLUSIONS
  Rop folds by a rapid collision of monomers to form a dimeric intermediate with substantial helical content, followed by a slow rearrangement to the final native structure. Rop unfolding is a single extremely slow kinetic phase. The slow steps of both folding and unfolding are dramatically increased by hydrophobic core replacements, suggesting that their main effect is to substantially decrease the energy of the transition state.
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
authors.forename: M
authors.initials: M
authors.lastname: Munson
authors.forename: K S
authors.initials: KS
authors.lastname: Anderson
authors.forename: L
authors.initials: L
authors.lastname: Regan
mesh_terms: D000595:Amino Acid Sequence; D002942:Circular Dichroism; D003001:Cloning, Molecular; D004224:Diterpenes / Q000737:chemistry; D007700:Kinetics; D008956:Models, Chemical; D008961:Models, Structural; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011487:Protein Conformation; D015202:Protein Engineering; D017510:Protein Folding
chemical_list: D004224:Diterpenes; C011309:mezerein