Reducing bias in the analysis of solution-state NMR data with dynamics detectors

Area of Science:

• Biophysics
• Chemical Physics
• Structural Biology

Background:

• Nuclear magnetic resonance (NMR) spectroscopy is sensitive to molecular dynamics.
• Traditional analysis of NMR relaxation rates can be biased by limited experimental sensitivity to specific correlation time ranges.
• This bias was previously observed in solid-state NMR and is now shown to affect solution-state NMR analysis as well.

Purpose of the Study:

• To adapt the detector approach, originally developed for solid-state NMR, to solution-state NMR.
• To address potential biases in characterizing molecular motion from solution-state NMR relaxation data.
• To separate overall molecular tumbling from internal motions and account for chemical exchange effects.

Main Methods:

• Application of the detector approach to analyze solution-state NMR relaxation data.
• Separation of overall tumbling and internal motions assuming statistical independence.
• Inclusion of chemical exchange contributions to transverse relaxation.
• Analysis of ubiquitin relaxation data at single and multiple magnetic field strengths.

Main Results:

• The detector approach effectively characterizes molecular motion in solution-state NMR, reducing bias compared to traditional methods.
• Internal protein motions can be accurately described using detectors when independent of overall tumbling.
• The methodology was validated using ubiquitin datasets and compared against model-free analysis and LeMaster's method.

Conclusions:

• The detector approach offers a more robust method for analyzing molecular dynamics in solution-state NMR.
• This technique provides a more accurate characterization of internal protein motions and accounts for complex relaxation contributions.
• The findings suggest broader applicability of the detector method for NMR dynamics studies.