Research Centre Jülich, ISB-2: Molecular Biophysics, 52425 Jülich, Germany.
Chemphyschem. 2011 Feb 25;12(3):704-10. doi: 10.1002/cphc.201000701. Epub 2010 Nov 5.
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.
对酵母磷酸甘油酸激酶进行了不同浓度盐酸胍的单分子荧光能量转移（FRET）测量。从这些稳态测量中，我们获得了 FRET 效率直方图，这些直方图描述了在天然状态和完全展开状态之间的不同阶段中单个蛋白质的结构特性。与有变性剂的条件相比，在没有变性剂的缓冲条件下，天然蛋白质的结构稍微更加展开。在 0.5 M GndHCl 下，出现了一种与天然状态相比结构明显展开的展开状态群体。展开状态的特征是效率分布明显变宽，这表明群体内存在较大的结构和/或动力学异质性。在高变性剂浓度下，远高于 C(1/2)~0.7 M 的展开转变，我们观察到蛋白质结构的逐渐扩展，即球-线圈转变。
