Intermolecular aromatic acid association of an anthocyanin (petanin) evidenced by two-dimensional nuclear overhauser enhancement nuclear magnetic resonance experiments and distance geometry calculations

1992 ◽  
Vol 3 (4) ◽  
pp. 182-189 ◽  
Author(s):  
Willy Nerdal ◽  
Øyvind M. Andersen
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Distance Geometry ◽  
Aromatic Acid ◽  
Two Dimensional ◽  
Nuclear Overhauser Enhancement ◽  
Nuclear Overhauser ◽  
Nuclear Magnetic

Nuclear magnetic resonance studies of the structure of B50/neuromodulin and its interaction with calmodulin

1994 ◽  
Vol 72 (3-4) ◽  
pp. 109-116 ◽  
Author(s):  
Mingjie Zhang ◽  
Hans J. Vogel ◽  
Henk Zwiers
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Helical Conformation ◽  
Two Dimensional ◽  
Solution Ph ◽  
Nonionic Detergent ◽  
Nuclear Overhauser ◽  
Α Helix ◽  
Nuclear Magnetic

B50/neuromodulin is a neuronal phosphoprotein that is found in association with the inner membrane of nerve cells. In this work, we have studied the structure of bovine B50 in aqueous solution (pH 7.5) by 1H nuclear magnetic resonance (NMR) spectroscopy and our results indicate that B50 is an unstructured protein under these conditions. One-dimensional 1H-NMR titration studies of the interaction between B50 and calmodulin (CaM) have shown that B50 does not interact with (or) interacts very weakly with apo-CaM in solution; neither does B50 interact with Ca2+-CaM. These NMR data are consistent with an earlier observation that B50 is not capable of binding apo-CaM in vitro unless some nonionic detergent is present. We have also detected aromatic NMR peaks for a new posttranslational modification that might involve the His residues of the protein. The interaction of a 14-residue peptide (I38-L51) encompassing the CaM-binding domain of B50 with CaM was also studied by NMR. We have found from two-dimensional transferred nuclear Overhauser enhancement experiments that the B50 peptide binds weakly to apo-CaM in an α-helical conformation; the α-helix appears to be induced by the binding of the peptide to apo-CaM.Key words: calmodulin, protein B50, neuromodulin, two-dimensional NMR, α-helix.

Major saponins from the starfish Asteriasforbesi. Complete structures by nuclear magnetic resonance methods

1987 ◽  
Vol 65 (6) ◽  
pp. 1384-1391 ◽  
Author(s):  
John A. Findlay ◽  
Mahesh Jaseja ◽  
D. Jean Burnell ◽  
Jean-Robert Brisson
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Sodium Sulfate ◽  
Nuclear Overhauser Enhancement ◽  
Nuclear Overhauser ◽  
Nuclear Magnetic

The structures of the two major saponins isolated from the starfish Asteriasforbesi have been deduced totally by nuclear magnetic resonance methods applied to the undegraded molecules. The structure of forbeside A, 6α-O-{β-D-galactopyranosyl-(1 → 3)-β-D-fucopyranosyl-(1 → 2)-β-D-galactopyranosyl-(1 → 4)-[β-D-quinovopyranosyl-(1 → 2)]-β-D-xylopyranosyl-(1 → 3)-β-D-quinovopyranosyl}-20-hydroxy-23-oxo-5α-cholest-9(11)-en-3β-yl sodium sulfate, was deduced principally from 1H 2D-COSY, J-resolved, nuclear Overhauser enhancement and selected decoupling experiments. The structure of forbeside B, 6α-O-{β-D-quinovopyranosyl-(1 → 2)-β-D-galactopyranosyl-(1 → 4)-[β-D-quinovopyranosyl-(1 → 2)]-β-D-xylopyranosyl-(1 → 3)-β-D-quinovopyranosyl}-20-hydroxy-23-oxo-5α-cholest-9(11)-en-3β-yl sodium sulfate, was deduced principally from 2D-COSY, HCORR, RECSY, and NOESY experiments.

4,6-Dinitro-benzofuroxan and -benzofurazan adducts of 1,8-bis(dimethylamino)naphthalene. A conformational study by low temperature nuclear magnetic resonance

1987 ◽  
Vol 65 (2) ◽  
pp. 404-408 ◽  
Author(s):  
Marie-Paule Simonnin ◽  
Jean-Claude Halle ◽  
Marie-José Pouet ◽  
François Terrier ◽  
Daniel Davoust
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Low Temperature ◽  
Proton Sponge ◽  
Conformational Study ◽  
Difference Spectra ◽  
Nuclear Overhauser Enhancement ◽  
Nuclear Magnetic Resonance Spectra ◽  
Nuclear Overhauser ◽  
Nuclear Magnetic

Low temperature 1H nuclear magnetic resonance spectra of the zwitterionic and anionic carbon-bonded adducts resulting from the addition of 4,6-dinitrobenzofuroxan (DNBF) or 4,6-dinitrobenzofurazan (DNBZ) to 1,8-bis(dimethylamino)naphthalene, the proton sponge PS, have been recorded at 500 MHz inDMF-d7. They reveal the presence of two conformers due to restricted rotation around the [Formula: see text] bond between C-4 of PS and the sp3 carbon C-7′ of the negatively charged DNBF− or DNBZ− moiety. The geometry of these conformers was deduced from nuclear Overhauser enhancement difference spectra. The results show that in all systems there is a large preference for the less strained s-trans type of conformation, whose population lies between 80 and 90%. An interesting feature is the dependence of the chemical shift of the peri H5 proton on the conformation. In accordance with previously reported peri effects, a significant deshielding of H5 is observed in the major conformers, where this proton is spatially close to H7′. In contrast, H5 moves upfield in the minor conformers, in which it lies in the vicinity of the DNBF− or DNBZ− moiety.

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