Practical methods for solid-state NMR distance measurements on large biomolecules: constant-time rotational resonance

Area of Science:

• Biophysical Chemistry
• Structural Biology
• Nuclear Magnetic Resonance (NMR) Spectroscopy

Background:

• Measuring internuclear distances in large biomolecules is crucial for understanding their structure and function.
• Rotational resonance (RR) experiments are valuable for determining these distances but can be time-consuming and prone to artifacts.
• Existing methods require complex corrections for radiofrequency (RF) heating and intensity variations.

Purpose of the Study:

• To introduce modifications to the rotational resonance experiment to reduce experimental time and improve accuracy.
• To eliminate the need for control spectra to correct for RF heating effects.
• To address issues with peak intensity oscillations and lineshape variations.

Main Methods:

• Implementation of a constant-time rotational resonance experiment.
• Utilizing a selective inversion delay instead of a weak RF pulse.
• Employing a single background subtraction spectrum for all time points.

Main Results:

• Experimental time is reduced by up to a factor of two.
• Elimination of oscillations in peak intensities at short mixing times.
• Consistent lineshapes across different mixing times, simplifying background subtraction.
• Improved accuracy and efficiency in internuclear distance measurements.

Conclusions:

• Modified rotational resonance experiments offer a more efficient and accurate method for distance measurements in large biomolecules.
• The new approach simplifies data processing and reduces potential sources of error.
• These improvements facilitate routine internuclear distance measurements in complex biological systems.