Revealing Conformational Variants of Solution‐Phase Intrinsically Disordered Tau Protein at the Single‐Molecule Level

• Published in: Angewandte Chemie International Edition 2017-12, Vol.56 (49), p.15584-15588
• Main Authors: Manger, Lydia H., Foote, Alexander K., Wood, Sharla L., Holden, Michael R., Heylman, Kevin D., Margittai, Martin, Goldsmith, Randall H.
• Format: Article
• Language: English
• Subjects: Anisotropy; biophysics; Chemical compounds; Compaction; Electrokinetics; Fluorescence; Fluorescence Polarization; fluorescence spectroscopy; Fluorophores; Intrinsically Disordered Proteins - chemistry; microfluidics; Protein Conformation; protein structures; Proteins; single-molecule studies; Solutions; Tau protein; tau Proteins - chemistry
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201708242

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. An anti‐Brownian electrokinetic trap was employed to prolong measurements of single tau proteins in solution. Once trapped, the fluorescence anisotropy was recorded to investigate the diversity of conformations sampled by the single molecules. The 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.