Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, WI, 53706, USA.
Department of Chemistry & Biochemistry, University of Denver, 2190 East Iliff Ave., Denver, CO, 80208, USA.
Angew Chem Int Ed Engl. 2017 Dec 4;56(49):15584-15588. doi: 10.1002/anie.201708242. Epub 2017 Nov 14.
Intrinsically disordered proteins, such as tau protein, adopt a variety of conformations in solution, complicating solution-phase structural studies. We employed an anti-Brownian electrokinetic (ABEL) trap to prolong measurements of single tau proteins in solution. Once trapped, we recorded the fluorescence anisotropy to investigate the diversity of conformations sampled by the single molecules. A distribution of anisotropy values obtained from trapped tau protein is conspicuously bimodal while those obtained by trapping a globular protein or individual fluorophores are not. Time-resolved fluorescence anisotropy measurements were used to provide an explanation of the bimodal distribution as originating from a shift in the compaction of the two different families of conformations.
无规卷曲蛋白（例如 tau 蛋白）在溶液中会采取多种构象，这使得溶液相结构研究变得复杂。我们采用反布朗运动电泳（ABEL）阱来延长溶液中单 tau 蛋白的测量时间。一旦被捕获，我们就记录荧光各向异性，以研究单分子所采用的构象多样性。从被捕获的 tau 蛋白获得的各向异性值分布明显呈双峰分布，而通过捕获球状蛋白或单个荧光团获得的各向异性值分布则不是双峰分布。时间分辨荧光各向异性测量被用来解释双峰分布源于两种不同构象家族的紧凑度的变化。
