Improving the analysis of NMR spectra tracking pH-induced conformational changes: Removing artefacts of the electric field on the NMR chemical shift

2009 ◽  
Vol 78 (4) ◽  
pp. 971-984 ◽  
Author(s):  
Predrag Kukić ◽  
Damien Farrell ◽  
Chresten R. Søndergaard ◽  
Una Bjarnadottir ◽  
John Bradley ◽  
...  
Keyword(s):  
Chemical Shift ◽  
Electric Field ◽  
Conformational Changes ◽  
Nmr Spectra ◽  
Nmr Chemical Shift

scholarly journals Interactions between Human Liver Fatty Acid Binding Protein and Peroxisome Proliferator Activated Receptor Selective Drugs

PPAR Research ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Tony Velkov
Keyword(s):  
Fatty Acid ◽  
Chemical Shift ◽  
Conformational Changes ◽  
Gene Activation ◽  
Chemical Shift Perturbation ◽  
Peroxisome Proliferator ◽  
Nmr Chemical Shift ◽  
Fatty Acid Binding ◽  
Regulatory Pathways ◽  
Subtype Selective

Fatty acid binding proteins (FABPs) act as intracellular shuttles for fatty acids as well as lipophilic xenobiotics to the nucleus, where these ligands are released to a group of nuclear receptors called the peroxisome proliferator activated receptors (PPARs). PPAR mediated gene activation is ultimately involved in maintenance of cellular homeostasis through the transcriptional regulation of metabolic enzymes and transporters that target the activating ligand. Here we show that liver- (L-) FABP displays a high binding affinity for PPAR subtype selective drugs. NMR chemical shift perturbation mapping and proteolytic protection experiments show that the binding of the PPAR subtype selective drugs produces conformational changes that stabilize the portal region of L-FABP. NMR chemical shift perturbation studies also revealed that L-FABP can form a complex with the PPAR ligand binding domain (LBD) of PPARα. This protein-protein interaction may represent a mechanism for facilitating the activation of PPAR transcriptional activity via the direct channeling of ligands between the binding pocket of L-FABP and the PPARαLBD. The role of L-FABP in the delivery of ligands directly to PPARαvia this channeling mechanism has important implications for regulatory pathways that mediate xenobiotic responses and host protection in tissues such as the small intestine and the liver where L-FABP is highly expressed.

Incorporation of Chlorinated Anilines into Lignin

1981 ◽  
Vol 36 (9-10) ◽  
pp. 714-720 ◽  
Author(s):  
K. T. v. d. Trenck ◽  
D. Hunkier ◽  
H. Sandermann
Keyword(s):  
Chemical Shift ◽  
1H Nmr ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Chain Structure ◽  
Coniferyl Alcohol ◽  
13C Nmr Spectra ◽  
Nmr Chemical Shift ◽  
Phenyl Propanoid

Abstract Coniferyl Alcohol, Peroxidase, Lignin, 4-Chloroaniline, 3,4-Dichloroaniline Lignin was formed in vitro by the peroxidase/hydrogen peroxide mediated polymerization of coniferyl alcohol. In the presence of [14C]4-chloroaniline or [14C]3,4-dichloroaniline copolymeri­ zation occurred with incorporation rates of about 45 mol%. Co-elution of UV-absorbing material (reflecting lignin) and of incorporated radioactivity was observed on a calibrated column of Sephadex LH-60. This method indicated a broad molecular weight distribution of the copolymers with values of between about 20000 and 1000. Most of the copolymer products had apparent molecular weights near 1000.The 1H-NMR and 13C-NMR spectra of the copolymers were compared with those of in vitro lignin. The copolymer spectra showed a relative increase in aromatic peaks and a relative decrease in most of the typical lignin peaks. Three peaks indicative of a new type of phenyl-propanoid side-chain structure were detected in the 'H-NMR and 13C-NMR spectra of the copolymers. The corresponding 1H-NMR chemical shift values were 4.75 ppm (a-C-H), 4.40 ppm (β-C-H) and 3.70/3.50 ppm (y-C-H2). The 13C-NMR chemical shift values were 56.9 ppm (a-C), 84.3 ppm (β-C) and 60.0 ppm (y-C). These peaks were attributed to a 3-aryl-3-anilino-2-aryloxy-propanol-1 structure in the copolymers by analysis of coupling patterns and by comparison with spectral reference data.The NMR-results and experiments with catalase and inhibitors suggested that a major mechanism of copolymerization consisted of a nucleophilic addition of the anilines to the benzylic ar-carbon of lignol quinone-methide intermediates.

Qualitative Applications of the NMR Spectra of Alkylpyridines: Part I. Chemical Shifts of the Ring Protons

1968 ◽  
Vol 22 (4) ◽  
pp. 325-329 ◽  
Author(s):  
F. R. McDonald ◽  
A. W. Decora ◽  
G. L. Cook
Keyword(s):  
Chemical Shift ◽  
Nmr Spectra ◽  
Pyridine Ring ◽  
Structural Information ◽  
Chemical Shifts ◽  
Shale Oil ◽  
Nmr Chemical Shift ◽  
Chemical Shift Data ◽  
Spectroscopic Identification ◽  
Shift Data

Spectroscopic identification of pyridine compounds isolated from complex substances such as shale oil is greatly aided by NMR chemical-shift data on the pyridine-ring protons. Chemical shifts of the ring protons in CCl4 and C6H6 solution and the differential shift of the protons in these two solvents are reported. A paramagnetic shift is observed in the directional character of the proton alpha to the nitrogen in the pyridine ring. These data are used to determine structural information from the spectrum of a mixture of pyridine homologs.

Halogen Bonds of 4-Iodosydnones in Solution Deduced from 13C-NMR Spectra

2018 ◽  
Vol 69 (4) ◽  
pp. 843-845 ◽  
Author(s):  
Constantin Draghici ◽  
Mino R. Caira ◽  
Denisa E. Dumitrescu ◽  
Florea Dumitrascu
Keyword(s):  
Chemical Shift ◽  
Carbon Atom ◽  
13C Nmr ◽  
Nmr Spectra ◽  
13C Nmr Spectra ◽  
Halogen Bonds ◽  
Nmr Chemical Shift ◽  
Lewis Bases

The ability of 4-iodosydnones to form halogen bonds with Lewis bases in solution was deduced from significant changes in the 13C-NMR chemical shift of the carbon atom of the sydnone ring which is bonded to iodine.

Development of 19F-NMR chemical shift detection of DNA B–Z equilibrium using 19F-NMR

2017 ◽  
Vol 15 (24) ◽  
pp. 5109-5111 ◽  
Author(s):  
S. Nakamura ◽  
H. Yang ◽  
C. Hirata ◽  
F. Kersaudy ◽  
K. Fujimoto
Keyword(s):  
Chemical Shift ◽  
Conformational Changes ◽  
19F Nmr ◽  
Nmr Chemical Shift ◽  
Single Stranded Dna ◽  
Shift Detection ◽  
Dna Conformational Changes

The DNA conformational changes such as B-formed, Z-formed, and single stranded DNA, were detected in one of 19F-NMR measurements using a fluorine-labeled nucleobase.

13C NMR chemical shift trends and conformational changes in alkali metal cation complexes of a series of naphthalene crown ethers

1988 ◽  
Vol 26 (3) ◽  
pp. 197-203 ◽  
Author(s):  
Mark R. Johnson ◽  
Christopher A. Colburn ◽  
Susan J. Ganion ◽  
Byungki Son ◽  
John A. Mosbo ◽  
...  
Keyword(s):  
Chemical Shift ◽  
Alkali Metal ◽  
Crown Ethers ◽  
Conformational Changes ◽  
13C Nmr ◽  
Metal Cation ◽  
Alkali Metal Cation ◽  
Nmr Chemical Shift ◽  
Cation Complexes
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