scholarly journals Tuning the 1H NMR Paramagnetic Relaxation Enhancement and Local Order of [Aliquat]+-Based Systems Mixed with DMSO

2021 ◽  
Vol 22 (2) ◽  
pp. 706
Author(s):  
Rui Cordeiro ◽  
Maria J. Beira ◽  
Carlos Cruz ◽  
João L. Figueirinhas ◽  
Marta C. Corvo ◽  
...  
Keyword(s):  
1H Nmr ◽  
Molecular Level ◽  
Outer Sphere ◽  
Paramagnetic Relaxation ◽  
Paramagnetic Relaxation Enhancement ◽  
Local Order ◽  
Large Set ◽  
X Ray ◽  
Nmr Relaxometry ◽  
Ionic Systems

Understanding the behavior of a chemical compound at a molecular level is fundamental, not only to explain its macroscopic properties, but also to enable the control and optimization of these properties. The present work aims to characterize a set of systems based on the ionic liquids [Aliquat][Cl] and [Aliquat][FeCl4] and on mixtures of these with different concentrations of DMSO by means of 1H NMR relaxometry, diffusometry and X-ray diffractometry. Without DMSO, the compounds reveal locally ordered domains, which are large enough to induce order fluctuation as a significant relaxation pathway, and present paramagnetic relaxation enhancement for the [Aliquat][Cl] and [Aliquat][FeCl4] mixture. The addition of DMSO provides a way of tuning both the local order of these systems and the relaxation enhancement produced by the tetrachloroferrate anion. Very small DMSO volume concentrations (at least up to 1%) lead to enhanced paramagnetic relaxation without compromising the locally ordered domains. Larger DMSO concentrations gradually destroy these domains and reduce the effect of paramagnetic relaxation, while solvating the ions present in the mixtures. The paramagnetic relaxation was explained as a correlated combination of inner and outer-sphere mechanisms, in line with the size and structure differences between cation and anion. This study presents a robust method of characterizing paramagnetic ionic systems and obtaining a consistent analysis for a large set of samples having different co-solvent concentrations.

scholarly journals 1H NMR relaxometry and X-ray study of PCL/nevirapine hybrids

2013 ◽  
Vol 32 (3) ◽  
pp. 553-566 ◽  
Author(s):  
Mariana S.S.B. Monteiro ◽  
Fabián Vaca Chávez ◽  
Pedro. J. Sebastião ◽  
Maria Inês Bruno Tavares
Keyword(s):  
1H Nmr ◽  
X Ray ◽  
Nmr Relaxometry ◽  
1H Nmr Relaxometry

scholarly journals NMR Study of Repair Mechanism of DNA Photolyase by FAD-induced Paramagnetic Relaxation Enhancement

2004 ◽  
Vol 279 (50) ◽  
pp. 52574-52579 ◽  
Author(s):  
Takumi Ueda ◽  
Akira Kato ◽  
Yuuta Ogawa ◽  
Takuya Torizawa ◽  
Seiki Kuramitsu ◽  
...  
Keyword(s):  
Thermus Thermophilus ◽  
Paramagnetic Relaxation ◽  
Paramagnetic Relaxation Enhancement ◽  
Pyrimidine Dimer ◽  
Dna Photolyase ◽  
X Ray ◽  
Double Stranded Dna ◽  
Nmr Study ◽  
Tryptophan Residues ◽  
Dna Complex

Cyclobutane pyrimidine dimer (CPD) photolyases, which contain FAD as a cofactor, use light to repair CPDs. We performed structural analyses of the catalytic site of theThermus thermophilusCPD photolyase-DNA complex, using FAD-induced paramagnetic relaxation enhancement (PRE). The distances between the tryptophan residues and the FAD calculated from the PRE agree well with those observed in the x-ray structure (with an error of <3 Å). Subsequently, a single-stranded DNA containing13C-labeled CPD was prepared, and the FAD-induced PRE of the NMR resonances from the CPD lesion in complex with the CPD photolyase was investigated. The distance between the FAD and the CPD calculated from the PRE is 16 ± 3 Å. The FAD-induced PRE was also observed in the CPD photolyase-double-stranded DNA complex. Based on these results, a model of the CPD photolyase-DNA complex was constructed, and the roles of Arg-201, Lys-240, Trp-247, and Trp-353 in the CPD-repair reaction are discussed.

RNA polymerase: Preparation and structural analysis of helical polymers

1984 ◽  
Vol 42 ◽  
pp. 152-153
Author(s):  
E. Loren Buhle ◽  
Pamela Rew ◽  
Ueli Aebi
Keyword(s):  
Structural Analysis ◽  
Rna Polymerase ◽  
Molecular Level ◽  
X Ray Diffraction ◽  
Helical Polymers ◽  
X Ray ◽  
E Coli ◽  
The Past ◽  
Ordered Arrays ◽  
Low Ionic Strength

While DNA-dependent RNA polymerase represents one of the key enzymes involved in transcription and ultimately in gene expression in procaryotic and eucaryotic cells, little progress has been made towards elucidation of its 3-D structure at the molecular level over the past few years. This is mainly because to date no 3-D crystals suitable for X-ray diffraction analysis have been obtained with this rather large (MW ~500 kd) multi-subunit (α2ββ'ζ). As an alternative, we have been trying to form ordered arrays of RNA polymerase from E. coli suitable for structural analysis in the electron microscope combined with image processing. Here we report about helical polymers induced from holoenzyme (α2ββ'ζ) at low ionic strength with 5-7 mM MnCl2 (see Fig. 1a). The presence of the ζ-subunit (MW 86 kd) is required to form these polymers, since the core enzyme (α2ββ') does fail to assemble into such structures under these conditions.

1H NMR Relaxometry and ATR-FT-IR Spectrosopy Used for the Assesment of Wastewater Treatment in Slaughterhouse

2018 ◽  
Vol 63 (1-2) ◽  
pp. 49-60
Author(s):  
R. Crainic ◽  
◽  
L. R. Drăgan ◽  
R. Fechete ◽  
◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
1H Nmr ◽  
Nmr Relaxometry ◽  
Ft Ir ◽  
1H Nmr Relaxometry

The Electron Effect of Aromatic Group: Control Conformation of 2-Aromatic Cyclododecanone Derivatives

2020 ◽  
Vol 24 (10) ◽  
pp. 1139-1147
Author(s):  
Yang Mingyan ◽  
Wang Daoquan ◽  
Wang Mingan
Keyword(s):  
1H Nmr ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Coupling Constants ◽  
The Other ◽  
Repulsive Interaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electron Effect ◽  
Group Control

2-Phenylcyclododecanone and 2-cyclohexylcyclododecanone derivatives were synthesized and characterized by 1H NMR, 13C NMR, HR-ESI-MS and X-ray diffraction. Their preferred conformations were analyzed by the coupling constants in the 1H NMR spectra and X-ray diffraction, which showed the skeleton ring of these derivatives containing [3333]-2-one conformation, and the phenyl groups were located at the side-exo position of [3333]-2-one conformation due to the strong π-π repulsive interaction between the π- electron of benzene ring and π-electron of carbonyl group. The cyclohexyl groups were located at the corner-syn or the side-exo position of [3333]-2-one conformation depending on the hindrance of the other substituted groups. The π-π electron effect played a crucial role in efficiently controlling the preferred conformation of 2-aromatic cyclododecanone and the other 2-aromatic macrocyclic derivatives with the similar preferred square and rectangular conformations.

scholarly journals Structure-Free Validation of Residual Dipolar Coupling and Paramagnetic Relaxation Enhancement Measurements of Disordered Proteins

Biochemistry ◽  
2015 ◽  
Vol 54 (46) ◽  
pp. 6876-6886 ◽  
Author(s):  
Francisco N. Newby ◽  
Alfonso De Simone ◽  
Maho Yagi-Utsumi ◽  
Xavier Salvatella ◽  
Christopher M. Dobson ◽  
...  
Keyword(s):  
Dipolar Coupling ◽  
Residual Dipolar Coupling ◽  
Paramagnetic Relaxation ◽  
Paramagnetic Relaxation Enhancement ◽  
Disordered Proteins

Water Dynamics in NH2-MIL-125: Insights from a Combined 1H NMR Relaxometry and Computational Investigation

2021 ◽  
Author(s):  
Silvia Pizzanelli ◽  
Angelo Freni ◽  
Amir H. Farmahini ◽  
Larisa G. Gordeeva ◽  
Lev Sarkisov ◽  
...  
Keyword(s):  
1H Nmr ◽  
Water Dynamics ◽  
Computational Investigation ◽  
Nmr Relaxometry ◽  
1H Nmr Relaxometry

scholarly journals Physical and chemical imaging of adhesive interfaces with soft X-rays

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Hiroyuki Yamane ◽  
Masaki Oura ◽  
Osamu Takahashi ◽  
Tomoko Ishihara ◽  
Noriko Yamazaki ◽  
...  
Keyword(s):  
Molecular Level ◽  
Covalent Bond ◽  
Chemical Imaging ◽  
Diglycidyl Ether ◽  
X Rays ◽  
X Ray ◽  
Covalent Bond Formation ◽  
Chemical States ◽  
The Individual ◽  
Physical And Chemical

AbstractAdhesion is an interfacial phenomenon that is critical for assembling carbon structural composites for next-generation aircraft and automobiles. However, there is limited understanding of adhesion on the molecular level because of the difficulty in revealing the individual bonding factors. Here, using soft X-ray spectromicroscopy we show the physical and chemical states of an adhesive interface composed of a thermosetting polymer of 4,4’-diaminodiphenylsulfone-cured bisphenol A diglycidyl ether adhered to a thermoplastic polymer of plasma-treated polyetheretherketone. We observe multiscale phenomena in the adhesion mechanisms, including sub-mm complex interface structure, sub-μm distribution of the functional groups, and molecular-level covalent-bond formation. These results provide a benchmark for further research to examine how physical and chemical states correlate with adhesion, and demonstrate that soft X-ray imaging is a promising approach for visualizing the physical and chemical states at adhesive interfaces from the sub-mm level to the molecular level.

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