Gas‐phase study of the stability of α‐substituted cyclic amino nitriles under electron ionization and electrospray ionization and fragmentation peculiarities of cyclic ketimines

2020 ◽  
Vol 34 (13) ◽  
Author(s):  
Anna A. Sosnova ◽  
Dmitrii M. Mazur ◽  
Albert T. Lebedev
Keyword(s):  
Electrospray Ionization ◽  
Gas Phase ◽  
Electron Ionization ◽  
Phase Study ◽  
The Stability

scholarly journals Mass Spectrometric and Bio-Computational Binding Strength Analysis of Multiply Charged RNAse S Gas-Phase Complexes Obtained by Electrospray Ionization from Varying In-Solution Equilibrium Conditions

2021 ◽  
Vol 22 (19) ◽  
pp. 10183
Author(s):  
Cornelia Key ◽  
Kwabena F. M. Opuni ◽  
Bright D. Danquah ◽  
Andrei Neamtu ◽  
Michael O. Glocker
Keyword(s):  
Experimental Data ◽  
Electrospray Ionization ◽  
Gas Phase ◽  
Single Amino Acid ◽  
Strength Analysis ◽  
S Protein ◽  
Solution Equilibrium ◽  
Multiply Charged ◽  
Polar Interactions ◽  
The Stability

We investigated the influence of a solvent’s composition on the stability of desorbed and multiply charged RNAse S ions by analyzing the non-covalent complex’s gas-phase dissociation processes. RNAse S was dissolved in electrospray ionization-compatible buffers with either increasing organic co-solvent content or different pHs. The direct transition of all the ions and the evaporation of the solvent from all the in-solution components of RNAse S under the respective in-solution conditions by electrospray ionization was followed by a collision-induced dissociation of the surviving non-covalent RNAse S complex ions. Both types of changes of solvent conditions yielded in mass spectrometrically observable differences of the in-solution complexation equilibria. Through quantitative analysis of the dissociation products, i.e., from normalized ion abundances of RNAse S, S-protein, and S-peptide, the apparent kinetic and apparent thermodynamic gas-phase complex properties were deduced. From the experimental data, it is concluded that the stability of RNAse S in the gas phase is independent of its in-solution equilibrium but is sensitive to the complexes’ gas-phase charge states. Bio-computational in-silico studies showed that after desolvation and ionization by electrospray, the remaining binding forces kept the S-peptide and S-protein together in the gas phase predominantly by polar interactions, which indirectly stabilized the in-bulk solution predominating non-polar intermolecular interactions. As polar interactions are sensitive to in-solution protonation, bio-computational results provide an explanation of quantitative experimental data with single amino acid residue resolution.

A novel rearrangement in the gas phase under electron ionization for 3-glycosyl-5-aryl-2-isoxazolines

1999 ◽  
Vol 34 (9) ◽  
pp. 915-921 ◽  
Author(s):  
Norma D’Accorso ◽  
Mirta Fascio ◽  
Carlos Gustavo Arabehety ◽  
Alicia M. Seldes
Keyword(s):  
Gas Phase ◽  
Electron Ionization
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