Noe Effect
Noe Effect - Related Videos
01:06
Nuclear Overhauser Enhancement (NOE)
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2025
Irradiation of a spin-active nucleus causes an increase or decrease in the signal intensity of neighboring nuclei that are not necessarily chemically bonded or involved in J-coupling. This phenomenon, called the nuclear Overhauser enhancement (NOE), results from through-space interactions between the nuclear spins. The NOE effect decreases with increasing internuclear distance and is generally not observed beyond 4 angstroms. In NOE, dipole-dipole interactions between neighboring spin-active...
14:44
Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR
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Cited by 4 •
2013
The NMR-solution structure of a metallochaperone model peptide with Cu (I) was determined, and a detailed protocol from sample preparation and 1D and 2D data collection to a three-dimensional structure is described.
10:59
Artificial RNA Polymerase II Elongation Complexes for Dissecting Co-transcriptional RNA Processing Events
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Cited by 1 •
2019
Here, we describe the assembly of RNA polymerase II (Pol II) elongation complexes requiring only short synthetic DNA and RNA oligonucleotides and purified Pol II. These complexes are useful for studying mechanisms underlying co-transcriptional processing of transcripts associated with the Pol II elongation complex.
10:42
Flow Cytometric Analysis of Particle-bound Bet v 1 Allergen in PM10
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Cited by 8 •
2016
Here, we present a protocol to quantify allergen-loaded particles by flow cytometry. Ambient particulate matter particles may act as carriers of adsorbed allergens. We show here that flow cytometry, a method widely used to characterize suspended solids >0.5 µm in diameter, can be used to measure these allergen-loaded particles.
10:24
Quantitation of Endothelial Cell Adhesiveness In Vitro
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Cited by 10 •
2015
We report an in vitro method that allows the quantitation of the actual number of adhesive cells within an endothelial cell monolayer.
FAQs
Cross-relaxation transfers relaxation effects between nuclear spins through their through-space dipole–dipole interaction. Irradiating one spin therefore alters the relaxation behavior and observed signal intensity of another nearby spin. Because this interaction depends on internuclear separation, the resulting change provides structural information that complements resonance assignments in chemical analysis.
Irradiation does not produce a single universal response: the affected resonance may become more intense or less intense. The direction and magnitude of the change depend on cross-relaxation, molecular motion, internuclear distance, and spectrometer operating conditions. Consequently, an NOE observation must be interpreted in the context of the molecule and measurement conditions rather than as a simple proximity label.
The distance sensitivity of an NOE is moderated by molecular motion and by the operating conditions of the spectrometer. These factors influence how strongly cross-relaxation affects the observed intensity change, so identical spatial relationships may not produce identical responses in every measurement. Accounting for these variables improves interpretation during conformational and three-dimensional structural analysis.
A researcher irradiates a selected nuclear spin and monitors the signal intensity of another resonance for enhancement or attenuation. The observed change is then evaluated in relation to internuclear distance, molecular motion, and spectrometer conditions. This workflow converts a spin-response measurement into evidence that supports resonance assignment, stereochemical analysis, or structural modeling.
Spatially informative intensity changes can reveal whether nuclei occupy nearby positions in a molecular structure. Comparing these proximity relationships helps distinguish stereoisomers and evaluate relative configurations, even when the alternatives share the same chemical composition. In organic chemistry, this makes NOE measurements useful for testing structural assignments and identifying the arrangement of groups in three dimensions.
The method is particularly valuable when chemists need spatial or conformational information that supports resonance assignments. Applications include structural elucidation of organic compounds, conformational analysis, and investigation of biomolecules in solution. Its distance-sensitive response can contribute to three-dimensional molecular structure determination, while intensity enhancement or attenuation provides the experimental observation used for interpretation.