Detailed Investigation of the Immunodominant Role of O-Antigen Stoichiometric O-Acetylation as Revealed by Chemical Synthesis, Immunochemistry, Solution Conformation and STD-NMR Spectroscopy forShigella flexneri 3a

2016 ◽  
Vol 22 (31) ◽  
pp. 10892-10911 ◽  
Author(s):  
Julien Boutet ◽  
Pilar Blasco ◽  
Catherine Guerreiro ◽  
Françoise Thouron ◽  
Sylvie Dartevelle ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Chemical Synthesis ◽  
Solution Conformation ◽  
O Antigen ◽  
Std Nmr

Controlling Gas Selectivity in Molecular Porous Liquids by Tuning the Cage Window Size

2019 ◽  
Author(s):  
Benjamin Egleston ◽  
Konstantin V. Luzyanin ◽  
Michael C. Brand ◽  
Rob Clowes ◽  
Michael E. Briggs ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Chemical Synthesis ◽  
Field Gradient ◽  
Window Size ◽  
Standard Approach ◽  
Porous Solids ◽  
Pulsed Field Gradient Nmr ◽  
Pulsed Field ◽  
Cage Molecules ◽  
Gas Selectivity

Control of pore window size is the standard approach for tuning gas selectivity in porous solids. Here, we present the first example where this is translated into a molecular porous liquid formed from organic cage molecules. Reduction of the cage window size by chemical synthesis switches the selectivity from Xe-selective to CH<sub>4</sub>-selective, which is understood using <sup>129</sup>Xe, <sup>1</sup>H, and pulsed-field gradient NMR spectroscopy.

Controlling Gas Selectivity in Molecular Porous Liquids by Tuning the Cage Window Size

2019 ◽  
Author(s):  
Benjamin Egleston ◽  
Konstantin V. Luzyanin ◽  
Michael C. Brand ◽  
Rob Clowes ◽  
Michael E. Briggs ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Chemical Synthesis ◽  
Field Gradient ◽  
Window Size ◽  
Standard Approach ◽  
Porous Solids ◽  
Pulsed Field Gradient Nmr ◽  
Pulsed Field ◽  
Cage Molecules ◽  
Gas Selectivity

Control of pore window size is the standard approach for tuning gas selectivity in porous solids. Here, we present the first example where this is translated into a molecular porous liquid formed from organic cage molecules. Reduction of the cage window size by chemical synthesis switches the selectivity from Xe-selective to CH<sub>4</sub>-selective, which is understood using <sup>129</sup>Xe, <sup>1</sup>H, and pulsed-field gradient NMR spectroscopy.

Discovery and Study of the Binding Epitopes of Novel Urease Inhibitors by STD-NMR Spectroscopy and Biochemical Analyses

2013 ◽  
Vol 10 (6) ◽  
pp. 515-521 ◽  
Author(s):  
Atia-tul- Wahab ◽  
Ajmal Khan ◽  
Bishnu P. Marasini ◽  
M. Arif Lodhi ◽  
Atta-ur- Rahman ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Urease Inhibitors ◽  
Std Nmr ◽  
Biochemical Analyses

scholarly journals Dissecting the contribution of O-Antigen and proteins to the immunogenicity of Shigella sonnei generalized modules for membrane antigens (GMMA)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Francesca Mancini ◽  
Gianmarco Gasperini ◽  
Omar Rossi ◽  
Maria Grazia Aruta ◽  
Maria Michelina Raso ◽  
...  
Keyword(s):  
Protective Immunity ◽  
Critical Role ◽  
Shigella Sonnei ◽  
Added Value ◽  
Protein Antigens ◽  
Outer Membranes ◽  
O Antigen ◽  
Membrane Antigens ◽  
Specific Igg

AbstractGMMA are exosomes released from engineered Gram-negative bacteria resembling the composition of outer membranes. We applied the GMMA technology for the development of an O-Antigen (OAg) based vaccine against Shigella sonnei, the most epidemiologically relevant cause of shigellosis. S. sonnei OAg has been identified as a key antigen for protective immunity, and GMMA are able to induce anti-OAg-specific IgG response in animal models and healthy adults. The contribution of protein-specific antibodies induced upon vaccination with GMMA has never been fully elucidated. Anti-protein antibodies are induced in mice upon immunization with either OAg-negative and OAg-positive GMMA. Here we demonstrated that OAg chains shield the bacteria from anti-protein antibody binding and therefore anti-OAg antibodies were the main drivers of bactericidal activity against OAg-positive bacteria. Interestingly, antibodies that are not targeting the OAg are functional against OAg-negative bacteria. The immunodominant protein antigens were identified by proteomic analysis. Our study confirms a critical role of the OAg on the immune response induced by S. sonnei GMMA. However, little is known about OAg length and density regulation during infection and, therefore, protein exposure. Hence, the presence of protein antigens on S. sonnei GMMA represents an added value for GMMA vaccines compared to other OAg-based formulations.

scholarly journals Radical Dehalogenation and Purine Nucleoside Phosphorylase E. coli: How Does an Admixture of 2′,3′-Anhydroinosine Hinder 2-fluoro-cordycepin Synthesis

Biomolecules ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 539
Author(s):  
Alexey L. Kayushin ◽  
Julia A. Tokunova ◽  
Ilja V. Fateev ◽  
Alexandra O. Arnautova ◽  
Maria Ya. Berzina ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Chemical Synthesis ◽  
Purine Nucleoside Phosphorylase ◽  
Purine Nucleoside ◽  
Preparative Synthesis ◽  
Nucleoside Phosphorylase ◽  
E Coli ◽  
First Time

During the preparative synthesis of 2-fluorocordycepin from 2-fluoroadenosine and 3′-deoxyinosine catalyzed by E. coli purine nucleoside phosphorylase, a slowdown of the reaction and decrease of yield down to 5% were encountered. An unknown nucleoside was found in the reaction mixture and its structure was established. This nucleoside is formed from the admixture of 2′,3′-anhydroinosine, a byproduct in the preparation of 3-′deoxyinosine. Moreover, 2′,3′-anhydroinosine forms during radical dehalogenation of 9-(2′,5′-di-O-acetyl-3′-bromo- -3′-deoxyxylofuranosyl)hypoxanthine, a precursor of 3′-deoxyinosine in chemical synthesis. The products of 2′,3′-anhydroinosine hydrolysis inhibit the formation of 1-phospho-3-deoxyribose during the synthesis of 2-fluorocordycepin. The progress of 2′,3′-anhydroinosine hydrolysis was investigated. The reactions were performed in D2O instead of H2O; this allowed accumulating intermediate substances in sufficient quantities. Two intermediates were isolated and their structures were confirmed by mass and NMR spectroscopy. A mechanism of 2′,3′-anhydroinosine hydrolysis in D2O is fully determined for the first time.

Role of Barium(II) in the Determination of the Absolute Configuration of Chiral Amines by1H NMR Spectroscopy

2006 ◽  
Vol 71 (3) ◽  
pp. 1119-1130 ◽  
Author(s):  
Rosa García ◽  
José M. Seco ◽  
Saulo A. Vázquez ◽  
Emilio Quiñoá ◽  
Ricardo Riguera
Keyword(s):  
Nmr Spectroscopy ◽  
Absolute Configuration ◽  
Chiral Amines ◽  
The Absolute

CERAMICS BASED ON ORGANOSILICON POLYMERS-PRECURSORS: MICROSTRUCTURE AND PROPERTIES (review). Part 2

2021 ◽  
pp. 22-32
Author(s):  
A.M. Shestakov ◽  
Keyword(s):  
Electron Microscopy ◽  
Nmr Spectroscopy ◽  
Material Properties ◽  
Structural Organization ◽  
Ceramic Materials ◽  
Special Role ◽  
Correct Interpretation ◽  
Instrumental Methods ◽  
Organosilicon Polymers

Shows the scientific approaches of various authors to the study of the microstructure of ceramics, the purpose of which is to elucidate its structural organization at the micro- and nanoscale, as well as the influence of the microstructure on the complex of material properties. Various instrumental methods for studying ceramics (NMR spectroscopy, electron microscopy, х-ray structural analysis, etc.) are considered, the permissible capabilities of research methods and analysis of the results obtained with their correct interpretation are shown. The special role of theoretical modeling in understanding the structure of the considered ceramic materials is noted.

Structural studies of digitoxin and related cardenolides by two-dimensional NMR

1990 ◽  
Vol 68 (2) ◽  
pp. 272-277 ◽  
Author(s):  
Torbjörn Drakenberg ◽  
Peter Brodelius ◽  
Deane D. McIntyre ◽  
Hans J Vogel
Keyword(s):  
Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Chair Conformation ◽  
Coupling Constants ◽  
Two Dimensional ◽  
Structural Studies ◽  
Solution Conformation ◽  
Phase Sensitive ◽  
Multiple Relay ◽  
C Nmr

The 1H and 13C NMR spectra of the cardenolides digitoxigenin, digoxigenin, digitoxin, and mono- and bis-digitoxigenin digitoxosides have been completely assigned by two-dimensional NMR spectroscopy. The techniques used include phase-sensitive COSY, multiple relay COSY, and carbon–proton correlation (HETCOR and HMQC) spectra. Various aspects of the solution conformation of the steroid moiety of digitoxin and digoxigenin could be determined from coupling constants and NOE difference experiments and they are indicative of an all-chair conformation. The carbohydrate rings in digitoxin and the mono- and bis-digitoxigenin digitoxosides are also in the chair conformation. Keywords: cardenolides, digitoxigenin, digitoxin, 2-dimensional NMR, conformational analysis.

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