Convergent views on disordered protein dynamics from NMR and computational approaches

Area of Science:

• Biophysics
• Structural Biology
• Protein Dynamics

Background:

• Intrinsically disordered proteins (IDPs) lack a defined structure and are crucial in biological processes.
• Their conformational flexibility and electrostatic interactions are key to function.
• Understanding IDP dynamics is essential for a complete description.

Purpose of the Study:

• To investigate the picosecond-nanosecond (ps-ns) backbone dynamics of the C-terminal domain of Bacillus subtilis RNA polymerase delta subunit.
• To analyze the role of transient electrostatic contacts in the function of this disordered protein region.

Main Methods:

• Nuclear Magnetic Resonance (NMR) spectroscopy, specifically 15N NMR relaxation data.
• Molecular dynamics (MD) simulations.
• High-resolution relaxometry across 12 magnetic fields to capture slower motions.

Main Results:

• The combined NMR and MD approach provided a consistent description of protein dynamics.
• The analysis confirmed the validity of established protocols for studying IDP dynamics.
• Relaxometry data revealed detailed motions on the tens of nanoseconds timescale.

Conclusions:

• The study validates current methodologies for analyzing intrinsically disordered protein dynamics.
• Transient electrostatic contacts within the disordered region, crucial for function, were characterized.
• The findings underscore the utility of multi-field relaxometry for probing slow dynamics in IDPs.