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Native and unfolded states of phosphoglycerate kinase studied by single molecule FRET


Structure of double labeled PGK and FRET with efficiency histograms for different denaturant conecentrations

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 exhibits 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 shows up which exhibits a significantly expanded structure as compared to the native state. 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, we observe a progressive expansion of the protein structure, a so-called globule-coil transition. (T. Rosenkanz et al., ChemPhysChem 2011, 12, 704-710)

Contact: Prof. Dr. Jörg Fitter