Spatiotemporal Resolution of Conformational Changes in Biomolecules by Combining Pulsed Electron-Electron Double...

Area of Science:

• Biophysics
• Structural Biology
• Molecular Dynamics

Background:

• Protein function is intrinsically tied to their dynamic conformational states.
• Resolving protein conformations is crucial, but capturing transient intermediates and their temporal order remains challenging with existing high-resolution methods.
• Current techniques often have limitations in providing both spatial and temporal resolution simultaneously.

Purpose of the Study:

• To develop and validate a novel methodology for high-resolution spatiotemporal analysis of biomolecular conformational changes.
• To investigate the dynamics of the Cα-helix in the cyclic nucleotide-binding domain of the Mesorhizobium loti potassium channel.
• To achieve angstrom-level spatial precision and microsecond-level temporal resolution in observing these dynamic events.

Main Methods:

• Integration of pulsed electron-electron double resonance (PELDOR) spectroscopy with a microsecond freeze-hyperquenching setup.
• Application of the combined technique to study the conformational dynamics of a specific protein domain.
• Utilizing PELDOR to measure distances between electron spins, providing structural information.

Main Results:

• The study successfully achieved spatiotemporal resolution in the angstrom range and down to the microsecond timescale.
• The conformational change of the Cα-helix in the target protein was observed to occur within approximately 150 microseconds.
• Angstrom precision was achieved in resolving these rapid molecular movements.

Conclusions:

• The combined PELDOR and freeze-hyperquenching approach offers unprecedented capabilities for studying biomolecular dynamics.
• This methodology provides a powerful tool for generating four-dimensional (4D) landscapes of conformational changes in proteins.
• The findings pave the way for detailed investigations into the mechanisms of protein function and dynamics.