Fast Ultra-Selective ¹H-¹⁵N 1D NMR Spectroscopy Unlocks Atom-Resolved Dynamics of Low-Complexity Protein Regions

Area of Science:

• Structural Biology
• Biophysics
• Nuclear Magnetic Resonance (NMR) Spectroscopy

Background:

• Understanding protein conformational dynamics is key to molecular function.
• NMR relaxation rates quantify atomic motions but require resolved spectral signals.
• Standard 2D ¹H-¹⁵N NMR is time-consuming for congested spectra, hindering studies of intrinsically disordered proteins (IDPs).

Purpose of the Study:

• To develop a fast, ultra-selective 1D NMR method for measuring ¹⁵N spin-relaxation constants.
• To overcome limitations of 2D NMR for proteins with dense ¹H-¹⁵N spectra.
• To enable characterization of protein dynamics in challenging systems like IDPs.

Main Methods:

• Development of a novel fast, ultra-selective 1D ¹H-¹⁵N NMR experiment.
• Measurement of individual ¹⁵N spin-relaxation constants with high precision.
• Application to study pico- to nanosecond dynamics and millisecond conformational exchange.

Main Results:

• High-quality ¹⁵N spin-relaxation constants were measured for resonances as close as 6-8 Hz apart.
• Pico- to nanosecond dynamics of a polyglutamine stretch in huntingtin were characterized.
• Millisecond conformational exchange in the SH3GL3 protein was successfully analyzed.

Conclusions:

• The new 1D NMR method significantly enhances the study of protein dynamics, especially for IDPs.
• It provides a powerful tool for analyzing conformational dynamics in biomacromolecules with dense spectra.
• This technique offers broad applicability in structural biology and disease research.