Related Experiment Videos
Proton-Assisted Recoupling (PAR) in Peptides and Proteins
Kevin J Donovan1, Sheetal K Jain1, Robert Silvers1
1Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
The Journal of Physical Chemistry. B
|October 19, 2017
Summary
Proton-assisted recoupling (PAR) experiments were optimized using the SUBPAR protocol for efficient magnetization transfer analysis. This method provides valuable structural constraints for proteins like amyloid beta 1-42 fibrils.
Area of Science:
- Solid-state Nuclear Magnetic Resonance (NMR) spectroscopy.
- Biophysical chemistry and structural biology.
Background:
- Proton-assisted recoupling (PAR) is a technique used to study nuclear spin systems.
- Optimizing PAR experimental conditions is crucial for efficient magnetization transfer and structural analysis.
Purpose of the Study:
- To explore optimal experimental conditions and magnetization transfer rates for PAR in various biological systems.
- To introduce and validate a selective PAR protocol, SUBPAR, for efficient assessment of PAR conditions.
- To apply PAR to study the structure of amyloid beta 1-42 (Aβ1-42) fibrils.
Main Methods:
- Development and application of the SUBPAR (setting up better proton assisted recoupling) protocol for 1D PAR spectra.
- Comparison of experimental and simulated PAR data for peptide spin systems.
- Recording and analysis of PAR magnetization transfer trajectories (buildup curves) for peptides and Aβ1-42 fibrils.
- Utilizing optimal Rabi frequencies determined by SUBPAR.
Main Results:
- The SUBPAR protocol enables efficient assessment of optimal PAR conditions, minimizing experiment time.
- Experimental and simulated PAR data for peptides provide insights into interactions influencing magnetization transfer.
- PAR buildup curves for Aβ1-42 fibrils, when modeled biexponentially, offer semiquantitative structural constraints, despite weak correlation to internuclear distances.
Conclusions:
- The SUBPAR protocol offers a complete and efficient method for recording PAR 13C-13C correlation spectra.
- PAR provides valuable semiquantitative structural information for challenging systems like Aβ1-42 fibrils.
- This work facilitates the use of PAR in protein structural studies.