title: Hydration and conformational mechanics of single, end-tethered elastin-like polypeptides.
abstract: We investigated the effect of temperature, ionic strength, solvent polarity, and type of guest residue on the force-extension behavior of single, end-tethered elastin-like polypeptides (ELPs), using single molecule force spectroscopy (SMFS). ELPs are stimulus-responsive polypeptides that contain repeats of the five amino acids Val-Pro-Gly-Xaa-Gly (VPGXG), where Xaa is a guest residue that can be any amino acid with the exception of proline. We fitted the force-extension data with a freely jointed chain (FJC) model which allowed us to resolve small differences in the effective Kuhn segment length distributions that largely arise from differences in the hydrophobic hydration behavior of ELP. Our results agree qualitatively with predictions from recent molecular dynamics simulations and demonstrate that hydrophobic hydration modulates the molecular elasticity for ELPs. Furthermore, our results show that SMFS, when combined with our approach for data analysis, can be used to study the subtleties of polypeptide-water interactions and thus provides a basis for the study of hydrophobic hydration in intrinsically unstructured biomacromolecules.
authors.affiliation: Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708, USA.
authors.forename: Alexei
authors.initials: A
authors.lastname: Valiaev
authors.forename: Dong Woo
authors.initials: DW
authors.lastname: Lim
authors.forename: Scott
authors.initials: S
authors.lastname: Schmidler
authors.forename: Robert L
authors.initials: RL
authors.lastname: Clark
authors.forename: Ashutosh
authors.initials: A
authors.lastname: Chilkoti
authors.forename: Stefan
authors.initials: S
authors.lastname: Zauscher
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D003198:Computer Simulation; D004548:Elasticity; D057927:Hydrophobic and Hydrophilic Interactions; D018625:Microscopy, Atomic Force; D008956:Models, Chemical; D008970:Molecular Weight; D009994:Osmolar Concentration; D010455:Peptides / Q000737:chemistry*; D011487:Protein Conformation; D012997:Solvents / Q000737:chemistry; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D000596:Amino Acids; D010455:Peptides; D012997:Solvents; D014867:Water