Deuterated peptides and proteins: structure and dynamics studies by MAS solid-state NMR

Area of Science:

• Solid-state Nuclear Magnetic Resonance (NMR) spectroscopy
• Protein structural biology
• Biophysics

Background:

• Nuclear Magnetic Resonance (NMR) spectroscopy is a powerful tool for studying protein structure and dynamics.
• Dipolar interactions between protons can complicate solid-state NMR spectra, limiting resolution and interpretation.
• Effective methods are needed to reduce these interactions for enhanced structural and dynamic analysis.

Purpose of the Study:

• To develop and validate a protein labeling strategy to minimize proton-proton dipolar interactions in microcrystalline proteins.
• To enable high-resolution solid-state NMR studies of protein structure and dynamics.
• To overcome limitations imposed by dipolar truncation artifacts in spectral analysis.

Main Methods:

• Perdeuteration of proteins to remove exchangeable protons.
• Back-substitution of amide protons using Deuterium (D2O)-containing buffers.
• Recrystallization of proteins from D2O-containing buffers.
• Selective protonation of aliphatic protons via specific precursors or controlled H2O incorporation during bacterial growth.

Main Results:

• Achieved significant reduction in (1)H-(1)H dipolar interactions.
• Obtained amide proton line widths on the order of 20 Hz.
• Established methods for accessing both amide and aliphatic proton signals.
• Demonstrated the capability to characterize solid-state protein structure and dynamics without dipolar truncation artifacts.

Conclusions:

• The developed protein labeling scheme effectively reduces proton-proton dipolar couplings in solid-state NMR.
• This approach significantly enhances spectral resolution, enabling detailed structural and dynamic studies.
• The method provides a robust strategy for analyzing protein structure and dynamics in the solid state, overcoming previous limitations.