Fast Motions Dominate Dynamics of Intrinsically Disordered Tau Protein at High Temperatures

Area of Science:

• Biophysics
• Structural Biology
• Protein Dynamics

Background:

• Intrinsically disordered proteins (IDPs) exhibit complex, multi-timescale dynamics.
• Previous studies primarily used Nuclear Magnetic Resonance (NMR) at low temperatures, limiting understanding at physiological conditions.
• The dynamic behavior of IDPs at higher temperatures remains less understood.

Purpose of the Study:

• To investigate the temperature-dependent reorientational dynamics of the tau protein, a large intrinsically disordered protein.
• To explore how protein dynamics change across a physiological temperature range (0-25°C).
• To elucidate the interplay between different motional modes in IDPs at varying temperatures.

Main Methods:

• Utilized 15N NMR relaxation rate measurements.
• Performed spectral density analysis on the tau protein.
• Studied protein dynamics across a temperature range of 0-25°C.

Main Results:

• Observed that protein dynamics at 0-25°C are primarily characterized by amide group librations, local backbone fluctuations, and chain segmental motions.
• Spectral density trends suggest that fast backbone and slow chain motions may become indistinguishable at elevated temperatures.
• Demonstrated the dynamic plasticity of the tau protein.

Conclusions:

• The study highlights the dynamic plasticity of intrinsically disordered proteins like tau.
• Findings suggest that distinct motional modes in IDPs may converge at physiological temperatures.
• Emphasizes the necessity of multi-temperature studies for a comprehensive understanding of IDP dynamics.