scholarly journals Evaluation of the supramolecular interaction of Congo red with cucurbiturils using mass spectrometry and spectroscopic methods

2020 ◽  
Vol 44 (6) ◽  
pp. 2587-2596 ◽  
Author(s):  
Ana L. Costa ◽  
Ana C. Gomes ◽  
André D. Lopes ◽  
José P. Da Silva ◽  
Martyn Pillinger ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Aqueous Solutions ◽  
Gas Phase ◽  
Outer Surface ◽  
Congo Red ◽  
Spectroscopic Methods ◽  
Supramolecular Interaction ◽  
Esi Ms

Cucurbit[n]urils decolourise aqueous solutions of Congo red by forming outer-surface adducts, which are also detected in gas-phase ESI-MS studies.

Do electrospray mass spectra reflect the ligand binding state of proteins in solution?

2005 ◽  
Vol 83 (11) ◽  
pp. 1953-1960 ◽  
Author(s):  
Belal M Hossain ◽  
Douglas A Simmons ◽  
Lars Konermann
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Protein Interactions ◽  
Noncovalent Complex ◽  
Deuterium Exchange ◽  
Solution Phase ◽  
Hydrogen Deuterium Exchange ◽  
Esi Ms ◽  
Protein Ions ◽  
Hydrogen Deuterium

Electrospray ionization (ESI) mass spectrometry (MS) has become a popular tool for monitoring ligand–protein and protein–protein interactions. Due to the "gentle" nature of the ionization process, it is often possible to transfer weakly bound complexes into the gas phase, thus making them amenable to MS detection. One problem with this technique is the potential occurrence of fragmentation events during ESI. Also, some analytes tend to cluster together during ionization, thus forming nonspecific gas-phase assemblies that do not represent solution-phase complexes. In this work, we implemented a hydrogen–deuterium exchange (HDX) approach that can reveal whether or not the free and (or) bound constituents of a complex observed in ESI-MS reflect the binding situation in solution. Proteins are subjected to ESI immediately following an isotopic labeling pulse; only ligand-free and ligand-bound protein ions that were formed directly from the corresponding solution-phase species showed different HDX levels. Using myoglobin as a model system, it is demonstrated that this approach can readily distinguish scenarios where the heme–protein interactions were disrupted in solution from those where dissociation of the complex occurred in the gas phase. Experiments on cytochrome c strongly suggest that dimeric protein ions observed in ESI-MS reflect aggregates that were formed in solution.Key words: electrospray mass spectrometry, ligand–protein interaction, noncovalent complex, hydrogen–deuterium exchange, protein folding.

scholarly journals Photodegradation of Riboflavin under Alkaline Conditions: What can Gas-Phase Photolysis Tell Us About What Happens in Solution?

2021 ◽  
Author(s):  
Natalie G.K. Wong ◽  
Chris Rhodes ◽  
Caroline E.H. Dessent
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Direct Method ◽  
Photochemical Reactions ◽  
Solution Phase ◽  
Ionization Mass ◽  
Phase Reaction ◽  
Esi Ms ◽  
Alkaline Conditions ◽  
On Line

The application of electrospray ionization mass spectrometry (ESI-MS) as a direct method for detecting reactive intermediates is a technique of developing importance in the routine monitoring of solution-phase reaction pathways. Here, we utilize a novel on-line photolysis ESI-MS approach to detect the photoproducts of riboflavin in aqueous solution under mildly alkaline conditions. Riboflavin is a constituent of many food products, so its breakdown processes are of wide interest. Our on-line photolysis setup allows for solution-phase photolysis to occur within a syringe using UVA LEDs, immediately prior to being introduced into the mass spectrometer via ESI. Gas-phase photofragmentation studies via laser-interfaced mass spectrometry of deprotonated riboflavin, [RFH], the dominant solution-phase species under the conditions of our study, are presented alongside the solution-phase photolysis. The results obtained illustrate the extent to which gas-phase photolysis methods can inform our understanding of the corresponding solution-phase photochemistry. We determine that the solution-phase photofragmentation observed for [RFH] closely mirrors the gas-phase photochemistry, with the m/z 241 ion being the only major condensed-phase photoproduct. Further gas-phase photoproducts are observed at m/z 255, 212, and 145. The value of exploring both the gas- and solution-phase photochemistry to characterize photochemical reactions is discussed.

scholarly journals New Triterpenoid Saponins from the Roots of Saponaria officinalis

2013 ◽  
Vol 8 (12) ◽  
pp. 1934578X1300801 ◽  
Author(s):  
Barbara Moniuszko-Szajwaj ◽  
Łukasz Pecio ◽  
Mariusz Kowalczyk ◽  
Ana M. Simonet ◽  
Francisco A. Macias ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Electrospray Ionization ◽  
2D Nmr ◽  
Ionization Mass ◽  
Spectroscopic Methods ◽  
Triterpenoid Saponins ◽  
Esi Ms ◽  
Gypsogenic Acid ◽  
Saponaria Officinalis

Three new triterpenoid saponins (1–3), along with nine known saponins, were isolated from the roots of Saponaria officinalis L. Two of them: vaccaroside D (4) and dianchinenoside B (5) are known, but not previously reported for S. officinalis, and seven others: saponarioside C (6), D (7), F (8), G (9), I (10), K (11), and L (12) have been previously isolated from this plant. The structures of the new saponins were established as 3- O-β-D-xylopyranosyl-16α-hydroxygypsogenic acid-28- O-[β-D-glucopyranosyl-(1→6)]-β-D-glucopyranoside (1), 3- O-β-D-xylopyranosyl-16α-hydroxygypsogenic acid-28- O-[β-D-glucopyranosyl-(1→3)]-[α-D-galactopyranosyl-(1→6)-α-D-galactopyranosyl-(1→6)-β-D-glucopyranosyl-(1→6)]-β-D-glucopyranoside (2) and 3- O-β-D-xylopyranosyl-gypsogenic acid-28- O-[β-D-glucopyranosyl-(1→3)]-[6- O-(3-hydroxy-3-methylglutaryl)-β-D-glucopyranosyl-(1→6)]-β-D-glucopyranoside (3). Their structures were elucidated by extensive spectroscopic methods, including 1D- (1H, 13C) and 2D-NMR (D QF-COSY, TOCSY, ROESY, HSQC and HMBC) experiments, as well as high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), ESI-MS/MS and acid hydrolysis.

scholarly journals Photodegradation of Riboflavin under Alkaline Conditions: What Can Gas-Phase Photolysis Tell Us about What Happens in Solution?

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 6009
Author(s):  
Natalie G. K. Wong ◽  
Chris Rhodes ◽  
Caroline E. H. Dessent
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Direct Method ◽  
Photochemical Reactions ◽  
Solution Phase ◽  
Phase Reaction ◽  
Esi Ms ◽  
Routine Monitoring ◽  
Alkaline Conditions ◽  
On Line

The application of electrospray ionisation mass spectrometry (ESI-MS) as a direct method for detecting reactive intermediates is a technique of developing importance in the routine monitoring of solution-phase reaction pathways. Here, we utilise a novel on-line photolysis ESI-MS approach to detect the photoproducts of riboflavin in aqueous solution under mildly alkaline conditions. Riboflavin is a constituent of many food products, so its breakdown processes are of wide interest. Our on-line photolysis setup allows for solution-phase photolysis to occur within a syringe using UVA LEDs, immediately prior to being introduced into the mass spectrometer via ESI. Gas-phase photofragmentation studies via laser-interfaced mass spectrometry of deprotonated riboflavin, [RF − H]−, the dominant solution-phase species under the conditions of our study, are presented alongside the solution-phase photolysis. The results obtained illustrate the extent to which gas-phase photolysis methods can inform our understanding of the corresponding solution-phase photochemistry. We determine that the solution-phase photofragmentation observed for [RF − H]− closely mirrors the gas-phase photochemistry, with the dominant m/z 241 condensed-phase photoproduct also being observed in gas-phase photodissociation. Further gas-phase photoproducts are observed at m/z 255, 212, and 145. The value of exploring both the gas- and solution-phase photochemistry to characterise photochemical reactions is discussed.

Evaluating the cation binding strength and selectivity of calix[4]pyrroles: a computational and ESI-MS/MS study

2014 ◽  
Vol 16 (32) ◽  
pp. 17266-17271 ◽  
Author(s):  
Chinthapalli Dinesh Kumar ◽  
Bhaskar Sharma ◽  
Yarasi Soujanya ◽  
Vadla Naresh Chary ◽  
Santhosh Reddy Patpi ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Cation Binding ◽  
Computational Studies ◽  
Binding Strength ◽  
Esi Ms ◽  
Esi Mass Spectrometry

The cation binding strength of calix[4]pyrroles in the gas phase has been evaluated by computational studies and further substantiated by ESI mass spectrometry experiments.

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