Search results for "nmr"
showing 10 items of 1575 documents
Biocatalytic hydrogenation of the C=C bond in the enone unit of hydroxylated chalcones-process arising from cyanobacterial adaptations.
2018
To verify the hypothesis that cyanobacteria naturally biosynthesising polyphenolic compounds possess an active enzymatic system that enables them to transform these substances, such an ability of the biocatalytic systems of whole cells of these biota was assessed for the first time. One halophilic strain and seven freshwater strains of cyanobacteria representing four of the five taxonomic orders of Cyanophyta were examined to determine the following: (i) whether they contain polyphenols, including flavonoids; (ii) the resistance of their cultures when suppressed by the presence of exogenous hydroxychalcones—precursors of flavonoid biosynthesis and (iii) whether these photoautotrophs can tra…
Skeletal Dysplasia Mutations Effect on Human Filamins’ Structure and Mechanosensing
2016
AbstractCells’ ability to sense mechanical cues in their environment is crucial for fundamental cellular processes, leading defects in mechanosensing to be linked to many diseases. The actin cross-linking protein Filamin has an important role in the conversion of mechanical forces into biochemical signals. Here, we reveal how mutations in Filamin genes known to cause Larsen syndrome and Frontometaphyseal dysplasia can affect the structure and therefore function of Filamin domains 16 and 17. Employing X-ray crystallography, the structure of these domains was first solved for the human Filamin B. The interaction seen between domains 16 and 17 is broken by shear force as revealed by steered mo…
The Complete Structure of the Core Oligosaccharide from Edwardsiella tarda EIB 202 Lipopolysaccharide
2017
The chemical structure and genomics of the lipopolysaccharide (LPS) core oligosaccharide of pathogenic Edwardsiella tarda strain EIB 202 were studied for the first time. The complete gene assignment for all LPS core biosynthesis gene functions was acquired. The complete structure of core oligosaccharide was investigated by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, electrospray ionization mass spectrometry MSn, and matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry. The following structure of the undecasaccharide was established: The heterogeneous appearance of the core oligosaccharide structure was due to the partial lack of β-d-Galp and the replace…
The New Structure of Core Oligosaccharide Presented by Proteus penneri 40A and 41 Lipopolysaccharides
2018
The new type of core oligosaccharide in Proteus penneri 40A and 41 lipopolysaccharides has been investigated by 1H and 13C NMR spectroscopy, electrospray ionization mass spectrometry and chemical methods. Core oligosaccharides of both strains were chosen for structural analysis based on the reactivity of LPSs with serum against P. penneri 40A core oligosaccharide–diphtheria toxoid conjugate. Structural analyses revealed that P. penneri 40A and 41 LPSs possess an identical core oligosaccharide.
The impact of cooking on meat microstructure studied by low field NMR and Neutron Tomography
2017
International audience; We studied the impact of temperature of cooking on meat microstructure. The cooking temperature was verified by calorimetry, showing the disappearance of endothermic peaks when cooking temperature was increased. These observations correspond to the denaturation of different protein fractions at specific temperatures. 1H-low field NMR and neutron tomography were used to further understand the relationship between the observed protein denaturation and changes in meat microstructure after heating. Hahn’s echo and solid echo NMR sequences were applied to observe fast relaxation time corresponding to rigid protons. These protons were found to be associated with pools of p…
19F NMR as a versatile tool to study membrane protein structure and dynamics.
2019
Abstract To elucidate the structures and dynamics of membrane proteins, highly advanced biophysical methods have been developed that often require significant resources, both for sample preparation and experimental analyses. For very complex systems, such as membrane transporters, ion channels or G-protein coupled receptors (GPCRs), the incorporation of a single reporter at a select site can significantly simplify the observables and the measurement/analysis requirements. Here we present examples using 19F nuclear magnetic resonance (NMR) spectroscopy as a powerful, yet relatively straightforward tool to study (membrane) protein structure, dynamics and ligand interactions. We summarize meth…
Zero-field nuclear magnetic resonance of chemically exchanging systems.
2019
Zero- to ultralow-field (ZULF) nuclear magnetic resonance (NMR) is an emerging tool for precision chemical analysis. In this work, we study dynamic processes and investigate the influence of chemical exchange on ZULF NMR J-spectra. We develop a computational approach that allows quantitative calculation of J-spectra in the presence of chemical exchange and apply it to study aqueous solutions of [15N]ammonium (15N\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\mathrm{H}}_4^ +$$\end{document}H4+) as a model syst…
The O-antigen of Plesiomonas shigelloides serotype O36 containing pseudaminic acid
2016
The structure of the repeating unit of O-antigen of Plesiomonas shigelloides serotype O36 has been investigated by 1H and 13C NMR spectroscopy, matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry and chemical methods. The new structure of trisaccharide has been established: →4)-β-Pse5Ac7(R3Hb)-(2 → 4)-β-D-Galp-(1 → 3)-β-D-GlcpNAc-(1→ These trisaccharide O-antigen units substitute the core undecasaccharide at C-4 of the β-D-GlcpNAc residue. The core oligosaccharide and lipid A are identical with these of the serotype O17 (PCM 2231) (Maciejewska, A., Lukasiewicz, J., Kaszowska, M., Jachymek, W., Man-Kupisinska, A.; Lugowski, C. Mar. Drugs.2013, 11 (2), 440–454; Lukasi…
Structural Basis of the High Affinity Interaction between the Alphavirus Nonstructural Protein-3 (nsP3) and the SH3 Domain of Amphiphysin-2
2016
We show that a peptide from Chikungunya virus nsP3 protein spanning residues 1728–1744 binds the amphiphysin-2 (BIN1) Src homology-3 (SH3) domain with an unusually high affinity (Kd 24 nM). Our NMR solution complex structure together with isothermal titration calorimetry data on several related viral and cellular peptide ligands reveal that this exceptional affinity originates from interactions between multiple basic residues in the target peptide and the extensive negatively charged binding surface of amphiphysin-2 SH3. Remarkably, these arginines show no fixed conformation in the complex structure, indicating that a transient or fluctuating polyelectrostatic interaction accounts for this …
Structural and functional insights into lysostaphin–substrate interaction
2018
Lysostaphin from Staphylococcus simulans and its family enzymes rapidly acquire prominence as the next generation agents in treatment of S. aureus infections. The specificity of lysostaphin is promoted by its C-terminal cell wall targeting domain selectivity towards pentaglycine bridges in S. aureus cell wall. Scission of these cross-links is carried out by its N-terminal catalytic domain, a zinc-dependent endopeptidase. Understanding the determinants affecting the efficiency of catalysis and strength and specificity of interactions lies at the heart of all lysostaphin family enzyme applications. To this end, we have used NMR, SAXS and molecular dynamics simulations to characterize lysostap…