Determination of the residence time of water molecules hydrating B ′ -DNA and B -DNA, by one-dimensional zero-enhancement nuclear overhauser effect spectroscopy 1 1Edited by I. Tinoco

1999 ◽  
Vol 286 (2) ◽  
pp. 505-519 ◽  
Author(s):  
Anh Tuân Phan ◽  
Jean-Louis Leroy ◽  
Maurice Guéron
Keyword(s):  
Residence Time ◽  
Nuclear Overhauser Effect ◽  
Water Molecules ◽  
One Dimensional ◽  
Overhauser Effect ◽  
Nuclear Overhauser

scholarly journals Benderamide A, a Cyclic Depsipeptide from a Singapore Collection of Marine Cyanobacterium cf. Lyngbya sp.

Marine Drugs ◽  
2018 ◽  
Vol 16 (11) ◽  
pp. 409 ◽  
Author(s):  
Chi Ding ◽  
Ji Ong ◽  
Hui Goh ◽  
Cynthia Coffill ◽  
Lik Tan
Keyword(s):  
Breast Cancer Cells ◽  
Nuclear Overhauser Effect ◽  
2D Nmr ◽  
Marine Cyanobacterium ◽  
One Dimensional ◽  
Mechanistic Pathway ◽  
Overhauser Effect ◽  
Cyclic Depsipeptide ◽  
Nuclear Overhauser ◽  
Related Compounds

Benderamide A (1), a (S)-2,2-dimethyl-3-hydroxy-7-octynoic acid (S-Dhoya)-containing cyclic depsipeptide that belongs to the kulolide superfamily, was isolated from a Singapore collection of cf. Lyngbya sp. marine cyanobacterium using a bioassay-guided approach. While the planar structure of 1 was elucidated using a combination of 1D and 2D NMR experiments and MS analysis, the absolute configuration was subsequently achieved using the results obtained from Marfey’s analysis, comparative analysis of nuclear overhauser effect spectroscopy (NOESY) with the known compound 3, and one dimensional-nuclear overhauser effect (1D-NOE). Although 1 did not display antiproliferative activity against MCF7 breast cancer cells, the presence of an Ala instead of Gly suggests a possible mechanistic pathway to explain the consequential decrease in cytotoxicity compared to the closely related 2. In addition, results obtained from an LC–MS/MS-based molecular networking algorithm revealed two other closely related compounds encouraging further identification and isolation from the same marine cyanobacterium extract.

scholarly journals In Silico Modeling of Spirolides and Gymnodimines: Determination of S Configuration at Butenolide Ring Carbon C-4

Toxins ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 685
Author(s):  
Christian Zurhelle ◽  
Tilmann Harder ◽  
Urban Tillmann ◽  
Jan Tebben
Keyword(s):  
In Silico ◽  
Density Functional ◽  
Nuclear Overhauser Effect ◽  
Resonance Spectroscopy ◽  
Functional Theory ◽  
Relative Configuration ◽  
Overhauser Effect ◽  
In Silico Modeling ◽  
Nuclear Overhauser

Only few naturally occurring cyclic imines have been fully structurally elucidated or synthesized to date. The configuration at the C-4 carbon plays a pivotal role in the neurotoxicity of many of these metabolites, for example, gymnodomines (GYMs) and spirolides (SPXs). However, the stereochemistry at this position is not accessible by nuclear Overhauser effect—nuclear magnetic resonance spectroscopy (NOE-NMR) due to unconstrained rotation of the single carbon bond between C-4 and C-5. Consequently, the relative configuration of GYMs and SPXs at C-4 and its role in protein binding remains elusive. Here, we determined the stereochemical configuration at carbon C-4 in the butenolide ring of spirolide- and gymnodimine-phycotoxins by comparison of measured 13C NMR shifts with values obtained in silico using force field, semiempirical and density functional theory methods. This comparison demonstrated that modeled data support S configuration at C-4 for all studied SPXs and GYMs, suggesting a biosynthetically conserved relative configuration at carbon C-4 among these toxins.

Determination of configuration and conformation of isoxazolidines by nuclear Overhauser effect difference spectroscopy

1982 ◽  
Vol 47 (23) ◽  
pp. 4397-4403 ◽  
Author(s):  
Philip DeShong ◽  
C. Michael Dicken ◽  
Ronald R. Staib ◽  
Alan J. Freyer ◽  
Steven M. Weinreb
Keyword(s):  
Nuclear Overhauser Effect ◽  
Difference Spectroscopy ◽  
Overhauser Effect ◽  
Effect Difference ◽  
Nuclear Overhauser ◽  
Configuration And Conformation

Applications of the intermolecular nuclear Overhauser effect. I. Determination of differential solvent effects: the hydration of pyridine

1983 ◽  
Vol 36 (3) ◽  
pp. 493 ◽  
Author(s):  
GR Smith ◽  
B Ternai
Keyword(s):  
Nuclear Overhauser Effect ◽  
Water System ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Alternative Methods ◽  
Relaxation Rates ◽  
Overhauser Effect ◽  
Nuclear Overhauser ◽  
Intermolecular Relaxation

The intermolecular relaxation rates of the pyridine-water system have been obtained by the measurement of the total spin lattice relaxation rate and the intermolecular nuclear Overhauser effect between pyridine and water, for each pyridine proton. The advantages of this method for the determination of the intermolecular relaxation rates are discussed, and the method is compared with alternative methods. The results indicate that there is a varying degree of hydration about the pyridine molecule, with the nitrogen being the preferred site of water interaction. It is necessary to interpret the results in terms of solute-solute as well as solute-solvent interactions. A model is proposed which takes account of both types of interaction, and is considered in terms of previously proposed models of pyridine-water interactions.

Sign in / Sign up

Export Citation Format

Share Document