Related Experiment Video
Updated: Aug 29, 2026

In Vitro Aggregation Assays Using Hyperphosphorylated Tau Protein
Published on: January 2, 2015
Different associational and conformational behaviors between the second and third repeat fragments in the tau
Katsuhiko Minoura1, Tian-Ming Yao, Koji Tomoo
1Osaka University of Pharmaceutical Sciences, Takatsuki, Osaka, Japan. minoura@gly.oups.ac.jp
Abstract:
The third repeat fragment (R3) in the four-repeat microtubule-binding domain of the water-soluble tau protein has been considered to play an essential role in the protein's filamentous assembly. To clarify the associational and conformational features that differentiate R3 from the second repeat, R2, the heparin-induced assembly profiles of these peptide fragments were monitored by the thioflavin fluorescence method and electron microscopy. The trifluoroethanol-induced reversible conformational change from a random structure to an alpha-helical structure, in an aqueous solution, was monitored by CD measurement, and the structure of R2 in trifluoroethanol solution was analyzed by a combination of two-dimensional 1H-NMR measurements and molecular modeling calculations to facilitate comparison with the structure of R3. The speed of R3 assembly was remarkably faster than that of R2, in spite of their similar amino acid sequences. The averaged NMR conformers of R2 exhibited the whole-spanning alpha-helical structure. Similar features observed in R2 and R3 conformers in trifluoroethanol were that the Leu10-Leu20/Lys20 sequence takes a helical structure with the amphipathic-like distribution of the respective side-chains, whereas the C-terminal moieties are both flexible. In contrast, a notable difference was observed at the N-terminal Val1-Lys6 sequence, namely, a helical conformation for R2 and an extended conformation for R3. These conformational behaviors would be associated with the different self-aggregation speeds and seeding reactions between R2 and R3.
More Related Videos
08:44Visualizing Actin and Microtubule Coupling Dynamics In Vitro by Total Internal Reflection Fluorescence (TIRF) Microscopy
Published on: July 20, 2022
12:55Assay for Phosphorylation and Microtubule Binding Along with Localization of Tau Protein in Colorectal Cancer Cells
Published on: October 10, 2017
Related Concept Videos
Assembly of Complex Microtubule Structures
Assembly of Cytoskeletal Filaments
Microtubule Associated Proteins (MAPs)
Conserved Binding Sites
Binding sites are often located in large pockets, and if their location on a protein’s surface is unknown, it can be predicted using various approaches. The energetic method computationally analyses the...
Destabilization of Microtubules
Tail-anchoring of Proteins in the ER Membrane