title: Native and unfolded states of phosphoglycerate kinase studied by single-molecule FRET.
abstract: Single-molecule Förster resonance energy transfer (FRET) measurements with phosphoglycerate kinase from yeast were performed at different concentrations of guanidine hydrochloride. From these steady-state measurements we obtained FRET efficiency histograms characterizing structural properties of individual proteins at different stages between the native and the fully unfolded state. Native proteins exhibit a slightly more expanded structure under buffer conditions without denaturant as compared to conditions with denaturant. At 0.5 M GndHCl an unfolded state population that exhibits a significantly expanded structure as compared to the native state, emerges. The unfolded state is characterized by a pronounced broadening of the efficiency distribution, which indicates a large structural and/or dynamical heterogeneity within the population. At high denaturant concentrations, well above the unfolding transition at C(1/2)~0.7 M, we observe a progressive expansion of the protein structure, namely globule-coil transition.
authors.affiliation: Research Centre Jülich, ISB-2: Molecular Biophysics, 52425 Jülich, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Rosenkranz
authors.forename: Ramona
authors.initials: R
authors.lastname: Schlesinger
authors.forename: Matteo
authors.initials: M
authors.lastname: Gabba
authors.forename: Jörg
authors.initials: J
authors.lastname: Fitter
mesh_terms: D031541:Fluorescence Resonance Energy Transfer; D019791:Guanidine / Q000737:chemistry; D010735:Phosphoglycerate Kinase / Q000737:chemistry*; D011489:Protein Denaturation; D017434:Protein Structure, Tertiary; D058767:Protein Unfolding
chemical_list: D010735:Phosphoglycerate Kinase; D019791:Guanidine