A novel NMR method characterizes slow motions in proteins by multiple refocusing of double- and zero-quantum coherences of amide protons and nitrogen-15 nuclei. If both nuclei experience changes in their isotropic chemical shifts because of internal motions on slow time scales (mus - ms), this leads to a difference in the relaxation rates of double- and zero-quantum coherences. This is due to CSM/CSM (chemical shift modulation) cross-correlation effects that are related to the well-known chemical exchange contribution Rex to the decay rate R2 = 1/T2 of nitrogen-15 nuclei. The CSM/CSM contributions can be distinguished from other mechanisms through their dependence on the repetition rate of a Carr-Purcell-Meiboom-Gill (CPMG) multiple refocusing sequence. In ubiquitin, motional processes can be identified that could hitherto not be observed by conventional CPMG nitrogen-15 NMR.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/ja0386243 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Homonuclear decoupled INADEQUATE NMR methods with improved sensitivity and resolution in solid-state NMR.
J Magn Reson
January 2025
Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181, UCCS - Unité de Catalyse et Chimie du Solide, F-59000 Lille, France. Electronic address:
The two-dimensional (2D) refocused INADEQUATE NMR experiment, which correlates double-quantum (DQ) and single-quantum (SQ) coherences, is widely used to probe the chemical connectivities in solids. Nevertheless, the multiplets along the F dimension reduce the resolution and sensitivity of this experiment. The Composite-Refocusing (CR) technique with two excitation pulses has been proposed to suppress these multiplets in 2D INADEQUATE spectra of liquids.
View Article and Find Full Text PDFDependence of brain-tissue R on MRI field strength.
Magn Reson Med
December 2024
Advanced MRI Section, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA.
Purpose: To quantify T relaxation in the brain at 3 T and 7 T to study its field dependence and correlation with iron content, and to investigate whether iron can be separated from other sources of T relaxation based on this field dependence.
Methods: Nine subjects were scanned at both field strengths with the same acquisition technique, which used multiple gradient-echo sampling of a spin echo. This allowed for separation of T relaxation from static dephasing by B field inhomogeneities and the effects of radiofrequency refocusing imperfections.
Light field displays reconstruct 3D scenes through integral imaging. However, inefficient light ray acquisition degrades the visual experience, while the fixed position of the exit pupil limits viewer mobility. In this paper, we propose a novel light field acquisition method employing parallax mapping techniques, coupled with adaptive viewport optimization based on eye tracking data.
View Article and Find Full Text PDFIt is Time to Revisit miRNA Therapeutics.
Nucleic Acid Ther
November 2024
Departments of Pharmacology and Biochemistry, UT Southwestern Medical Center, Dallas, Texas, USA.
The recent Nobel Prizes awarded to Ambros and Ruvkun have refocused attention on microRNAs (miRNAs). The importance of miRNAs for basic science has always been clear, but the application to therapy has lagged behind. This delay has been made even more apparent by the accelerating pace of successful programs using duplex RNAs and antisense oligonucleotides to target mRNA.
View Article and Find Full Text PDFRefocusing graduate gross anatomy training: Curating future content experts.
Anat Sci Educ
January 2025
Department of Neuroscience and Cell Biology, Office of Education, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA.
Graduate anatomy courses should be designed based on several needs. These include preparation for how to study in medical school and other healthcare programs, integrating multiple ways of engaging with the material, including repetition for long-term retention, and training of anatomy educators. Our graduate anatomy course presents an example of a balanced course structure that caters to the varying needs of different learners and encourages interest in anatomy education as a profession.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!