Protein functional dynamics from the rigorous global analysis of DEER data: Conditions, components, and conformations

Area of Science:

• Biophysics
• Structural Biology
• Biochemistry

Background:

• Spin labeling has long offered insights into macromolecular dynamics since the 1960s.
• Advancements in pulsed electron paramagnetic resonance spectroscopy and instrumentation have enabled sophisticated applications.
• Double electron-electron resonance (DEER) spectroscopy is now widely used for studying biological macromolecules.

Purpose of the Study:

• To describe a model-based approach for analyzing DEER spectroscopic data.
• To determine the minimum set of components representing functionally relevant protein conformations.
• To define the equilibrium between these conformations using fractional amplitudes.

Main Methods:

• Utilizing Double electron-electron resonance (DEER) spectroscopy to measure distance distributions between spin labels.
• Applying a model-based approach for rigorous analysis of DEER data.
• Integrating distance distributions into structural models of macromolecules.

Main Results:

• DEER spectroscopy provides distance distributions reflecting conformational states of channels, transporters, and receptors.
• The model-based approach identifies key protein conformations and their relative populations.
• Error analysis is crucial for the accurate structural interpretation of DEER data.

Conclusions:

• DEER spectroscopy is a powerful tool for elucidating the dynamic and functional aspects of macromolecules.
• The presented model-based analysis facilitates a deeper understanding of protein conformational landscapes.
• Rigorous error analysis ensures the reliability of structural interpretations derived from DEER experiments.