title: Understanding beta-hairpin formation.
abstract: The kinetics of formation of protein structural motifs (e.g., alpha-helices and beta-hairpins) can provide information about the early events in protein folding. A recent study has used fluorescence measurements to monitor the folding thermodynamics and kinetics of a 16-residue beta-hairpin. In the present paper, we obtain the free energy surface and conformations involved in the folding of an atomistic model for the beta-hairpin from multicanonical Monte Carlo simulations. The results suggest that folding proceeds by a collapse that is downhill in free energy, followed by rearrangement to form a structure with part of the hydrophobic cluster; the hairpin hydrogen bonds propagate outwards in both directions from the partial cluster. Such a folding mechanism differs from the published interpretation of the experimental results, which is based on a helix-coil-type phenomenological model.
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA.
authors.forename: A R
authors.initials: AR
authors.lastname: Dinner
authors.forename: T
authors.initials: T
authors.lastname: Lazaridis
authors.forename: M
authors.initials: M
authors.lastname: Karplus
mesh_terms: D000595:Amino Acid Sequence; D002151:Calorimetry; D003196:Computer Graphics; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D011506:Proteins / Q000737:chemistry*; D012984:Software; D013816:Thermodynamics
chemical_list: D010455:Peptides; D011506:Proteins