Related Experiment Video
Updated: Jul 12, 2025
08:04
Measuring Sensitivity to Viewpoint Change with and without Stereoscopic Cues
Published on: December 4, 2013
4.5K
Relaxation-induced dipolar exchange with recoupling (RIDER) distortions in CODEX experiments
Alexey Krushelnitsky1, Kay Saalwächter1
1Institute of Physics, Martin-Luther-University Halle-Wittenberg, 06120 Halle, Germany.
Magnetic Resonance (Gottingen, Germany)
|October 31, 2023
Summary
Chemical shift anisotropy (CSA) and dipolar CODEX experiments can be challenging due to RIDER effects. New methods using a filter and cosine signal component eliminate RIDER distortions, revealing proteins lack millisecond-scale global motion.
Area of Science:
- Solid-state Nuclear Magnetic Resonance (NMR) spectroscopy.
- Protein dynamics and molecular motion analysis.
Background:
- Chemical shift anisotropy (CSA) and dipolar CODEX experiments provide insights into molecular reorientation on millisecond-second timescales.
- These experiments are susceptible to RIDER (relaxation-induced dipolar exchange with recoupling) effects, which can lead to misinterpretation of molecular mobility.
Purpose of the Study:
- To investigate the origins of RIDER distortions in CSA and dipolar CODEX experiments, even under decoupling conditions.
- To propose and validate methods for eliminating RIDER effects to enable accurate analysis of molecular motion.
Main Methods:
- Implementation of an additional filter to suppress anti-phase coherence responsible for C-H RIDER.
- Recording only the cosine component of the CODEX signal, which is less susceptible to RIDER distortions.
- Conducting experiments on model substances and microcrystalline 13C/15N-enriched proteins (GB1 and SH3).
Main Results:
- Standard CSA and dipolar CODEX experiments on proteins showed a misleading fast-decaying signal component, misinterpreted as slow global motion.
- The RIDER-free experimental setup resulted in flat mixing time dependences.
- This indicates that the studied proteins do not exhibit global motions on the millisecond timescale.
Conclusions:
- RIDER distortions can significantly hamper the accurate determination of molecular mobility parameters from CODEX experiments.
- The proposed methods effectively eliminate RIDER artifacts, allowing for reliable assessment of molecular dynamics.
- Proteins GB1 and SH3 do not undergo global motions on the millisecond timescale.
Related Concept Videos
01:16Crossover Experiments
2.9K
Crossover experiments, also called the repeated-measurements design, is a study design in which all experimental units are exposed to all treatments in different periods. Crossover experiments are generally used in psychology, the pharmaceutical industry, agriculture, and medicine.
Crossover designs are performed even with smaller sample sizes since the samples can act as their controls. These are better than simple randomized trials since patients are exposed to all the treatments.
Crossover designs are performed even with smaller sample sizes since the samples can act as their controls. These are better than simple randomized trials since patients are exposed to all the treatments.
2.9K
01:25Transformers with Off-Nominal Turns Ratios
162
In scenarios involving parallel transformers with disparate ratings, developing per-unit models requires accommodating off-nominal turns ratios. This situation arises when the selected base voltages are not proportional to the transformer’s voltage ratings. Consider a transformer where the rated voltages are related by the term a. If the chosen voltage bases satisfy a relationship involving term b, term c is defined as the ratio of these bases. This ratio is then substituted into the...
162
01:25Effects of Creep
161
Creep in concrete, the gradual deformation under prolonged stress, significantly impacts the integrity of structures. For reinforced concrete beams, it can be a vital design consideration, as it increases deflection, sometimes necessitating additional design measures. In columns, especially slender ones under eccentric loads, creep can cause buckling, compromising their stability. However, creep can be beneficial in indeterminate structures by mitigating stresses that arise from shrinkage,...
161
01:17Magnetic Damping
469
Eddy currents can produce significant drag on motion, called magnetic damping. For instance, when a metallic pendulum bob swings between the poles of a strong magnet, significant drag acts on the bob as it enters and leaves the field, quickly damping the motion.
If, however, the bob is a slotted metal plate, the magnet produces a much smaller effect. When a slotted metal plate enters the field, an emf is induced by the change in flux; however, it is less effective because the slots limit the...
If, however, the bob is a slotted metal plate, the magnet produces a much smaller effect. When a slotted metal plate enters the field, an emf is induced by the change in flux; however, it is less effective because the slots limit the...
469
01:10Deformation in a Circular Shaft
301
One of the distinctive characteristics of circular shafts is their ability to maintain their cross-sectional integrity under torsion. In other words, each cross-section continues to exist as a flat, unaltered entity, simply rotating like a solid, rigid slab. To understand the distribution of shearing stress within such a shaft, consider a cylindrical section inside this circular shaft. This section has a length of L and a radius of R, with one end fixed. The radius of the cylindrical section is...
301
01:05Doppler Effect - II
3.4K
The Doppler effect has several practical, real-world applications. For instance, meteorologists use Doppler radars to interpret weather events based on the Doppler effect. Typically, a transmitter emits radio waves at a specific frequency toward the sky from a weather station. The radio waves bounce off the clouds and precipitation and travel back to the weather station. The radio frequency of the waves reflected back to the station appears to decrease if the clouds or precipitation are moving...
3.4K