Related Experiment Video
Updated: May 12, 2026
14:55
Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy
Published on: September 17, 2017
Designing dipolar recoupling and decoupling experiments for biological solid-state NMR using interleaved continuous
Morten Bjerring1, Sheetal Jain, Berit Paaske
1Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University , Denmark.
Accounts of Chemical Research
|April 6, 2013
Summary
Researchers developed new solid-state NMR pulse sequences by combining continuous wave (CW) irradiation with short pulses. These methods improve radiofrequency (rf) pulse performance, polarization transfer, and spectral resolution for structural biology.
Area of Science:
- Solid-state Nuclear Magnetic Resonance (NMR) spectroscopy
- Structural Biology
- Biophysical Chemistry
Background:
- Solid-state NMR is a powerful tool for structural biology, with advances driven by new radiofrequency (rf) pulse sequences and hardware.
- Developing these sequences often involves analytical tools like average Hamiltonian theory or numerical methods such as optimal control theory.
- Challenges arise from using deuterated proteins, where deuterium (2H) nuclei complicate standard NMR operations due to strong quadrupolar couplings.
Purpose of the Study:
- To systematically develop simple pulse sequences combining continuous wave (CW) irradiation with short pulses for improved NMR performance.
- To exploit deuterium (2H) polarization for enhanced structural information and sensitivity in solid-state NMR.
- To design efficient polarization transfer and decoupling methods for biological solid-state NMR experiments.
Main Methods:
- Utilized optimal control theory and analytical adaptations to design rotor-synchronized short pulse sequences for ideal rf pulse performance.
- Developed (2)H to (13)C polarization transfer experiments with significantly enhanced efficiency over standard cross-polarization.
- Translated optimal control waveforms into interleaved CW and rf pulse methods for cross-polarization and decoupling.
Main Results:
- Demonstrated ideal rf pulse performance using rotor-synchronized short pulses.
- Achieved one order of magnitude increase in (2)H to (13)C polarization transfer efficiency.
- Developed new cross-polarization experiments that significantly improve (1)H-(15)N and (15)N-(13)C transfers.
- Enhanced spectral sensitivity by exploiting polarization from both (1)H and (2)H nuclei.
- Improved (1)H decoupling methods that enhance spectral resolution and remove residual cross terms.
Conclusions:
- The combination of CW irradiation and short pulses offers a versatile strategy for developing advanced solid-state NMR pulse sequences.
- These new methods significantly enhance efficiency, sensitivity, and spectral resolution in biological solid-state NMR.
- The developed techniques provide powerful tools for high-resolution structural analysis of biomolecules using solid-state NMR.
Related Concept Videos
01:12Double Resonance Techniques: Overview
Double resonance techniques in Nuclear Magnetic Resonance (NMR) spectroscopy involve the simultaneous application of two different frequencies or radiofrequency pulses to manipulate and observe two distinct nuclear spins. One important application of double resonance is spin decoupling, which selectively suppresses coupling with one type of nucleus while observing the NMR signal from another nucleus, simplifying the spectrum and enhancing resolution.
Spin decoupling is usually achieved by...
Spin decoupling is usually achieved by...
01:04¹³C NMR: ¹H–¹³C Decoupling
The probability of having two carbon-13 atoms next to each other is negligible because of the low natural abundance of carbon-13. Consequently, peak splitting due to carbon-carbon spin-spin coupling is not observed in spectra. However, protons up to three sigma bonds away split the carbon signal according to the n+1 rule, resulting in complicated spectra.
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
01:17NMR Spectrometers: Radiofrequency Pulses and Pulse Sequences
A pulse is a short burst of radio waves distributed over a range of frequencies that simultaneously excites all the nuclei in the sample. Upon passing a radio frequency pulse along the x-axis, the nuclei absorb energy corresponding to their Larmor frequencies and achieve resonance. This shifts the net magnetization vector from the z-axis toward the transverse plane. This angle of rotation of the magnetization vector, or the flip angle, is proportional to the duration and intensity of the pulse.
01:12Two-Dimensional (2D) NMR: Overview
The 1D NMR spectrum of large and complex molecules like natural products has complicated splitting patterns and overlapping signals, which can be easily interpreted using 2-dimensional (2D) NMR. Unlike 1D NMR, 2D NMR has two frequency axes that provide the coupling information between the nucleus A and nucleus B in a molecule. The process from which 2D spectra are obtained has four steps.
The first step is the preparation period, during which nucleus A is excited with a radiofrequency pulse.
The first step is the preparation period, during which nucleus A is excited with a radiofrequency pulse.
01:02¹H NMR: Interpreting Distorted and Overlapping Signals
Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...
01:162D NMR: Overview of Homonuclear Correlation Techniques
Homonuclear correlation spectroscopy (COSY) is a powerful technique used in Nuclear Magnetic Resonance (NMR) spectroscopy to study the correlations between nuclei of the same type within a molecule. It provides information about scalar couplings between adjacent nuclei, which helps determine connectivity and structural information. There are several COSY variants, each with its unique strengths and experimental parameters.
COSY90 is the standard two-dimensional (2D) COSY experiment that...
COSY90 is the standard two-dimensional (2D) COSY experiment that...