title: The stability of a β-hairpin is altered by surface-water interactions under confinement.
abstract: Understanding protein folding and stability in in vivo confined environments is a challenging problem from both experimental and computational points of views. Despite recent insights, an appreciation and complete understanding of how the solvent influences the structure and stability of proteins under complex confined environments is still lacking. Here, using all-atom molecular dynamics simulations in explicit solvent, we report the effects of confinement on the lifetime of a metastable β-hairpin structure in the Aβ(21-30) decapeptide. Our results show that the values of these lifetimes depend on the nature of the confining surface, where smooth and rough hydrophobic confining walls have solvent-mediated stabilizing and destabilizing effects, respectively. The source of the destabilization found inside atomically rough confining walls lies in surface-peptide interactions that break the β-hairpin in this peptide, whereas smooth confining walls stabilize it by forming well-ordered layers of water that keep the decapeptide solvated in the inner part of the pore and away from the surface. In addition, we show that the size of the confining pore can tune the value of the lifetimes where pore sizes comparable to the size of the decapeptide have the largest effects.
authors.affiliation: Department of Physics, Drexel University , 3141 Chestnut Street, Philadelphia, Pennsylvania, 19104, United States.
authors.forename: J Srinivasa
authors.initials: JS
authors.lastname: Rao
authors.forename: Micholas Dean
authors.initials: MD
authors.lastname: Smith
authors.forename: Luis
authors.initials: L
authors.lastname: Cruz
mesh_terms: D016229:Amyloid beta-Peptides / Q000737:chemistry* / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D056004:Molecular Dynamics Simulation; D010446:Peptide Fragments / Q000737:chemistry* / Q000378:metabolism; D017510:Protein Folding; D017433:Protein Structure, Secondary; D012997:Solvents / Q000737:chemistry; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
chemical_list: D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; D012997:Solvents; C501831:amyloid beta-protein (21-30); D014867:Water