Threshold Collision-Induced Dissociation of Hydrogen-Bonded Dimers of Carboxylic Acids

Jia, Beike; Angel, Laurence A.; Ervin, Kent M.

doi:10.1021/jp7114093

Cited by 26 publications

(27 citation statements)

References 41 publications

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“…In addition, Equation 1 naturally includes competition among parallel reactions with a full statistical treatment [26]. Previous studies have verified the efficacy of this approach in modeling reactions that compete through loose as well as loose versus tight transition states [10,14,[27][28][29][30][31].…”

Section: Thermochemical Analysismentioning

confidence: 99%

Thermodynamics and Mechanisms of Protonated Diglycine Decomposition: A Guided Ion Beam Study

Armentrout

Heaton

2011

J. Am. Soc. Mass Spectrom.

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We present a full molecular description of fragmentation reactions of protonated diglycine (H + GG) by studying their collision-induced dissociation (CID) with Xe using a guided ion beam tandem mass spectrometer (GIBMS). Analysis of the kinetic energy-dependent CID cross sections provides the 0 K barriers for the sequential H 2 O+CO and CO+NH 3 losses from H + GG as well as for the reactions involved in y 1 and a 1 ion formation, after accounting for unimolecular decay rates, internal energy of reactant ions, and multiple ionmolecule collisions. Here, seven energetic barriers are measured for the fragmentation processes of H + GG, including the loss of H 2 O and of CO at~140 and~156 kJ/mol, the combined loss of (H 2 O+CO) and of (CO+NH 3 ) at~233 and~185 kJ/mol, and formation of y 1 and a 1 ions at~191 and~212 kJ/mol, respectively, with a second channel for a 1 formation opening at~326 kJ/mol. Theoretical energies from the preceding paper are compared with our experimental energies and found to be in good agreement. This validates the mechanisms explored computationally, including unambiguous identification of the b 2 ion as protonated 2-aminomethyl-5-oxazolone, thereby allowing a complete characterization of the elementary steps of H + GG decomposition. These results also demonstrate that all reactive species are available from the ground state conformation, as opposed to involving an initial broad distribution of protonated conformers. This result verifies the utility of the "mobile proton" model for understanding the fragmentation of protonated proteins.

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Section: Thermochemical Analysismentioning

confidence: 99%

Thermodynamics and Mechanisms of Protonated Diglycine Decomposition: A Guided Ion Beam Study

Armentrout

Heaton

2011

J. Am. Soc. Mass Spectrom.

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“…The gas-phase acidities of isolated amino acids and simple derivatives have been determined experimentally using different gas-phase techniques. [32][33][34][35][36][37][38][39][40] Recent studies provided conflicting results regarding the relative acidities of the two acidic groups in cysteine. Results from photoelectron spectroscopy and gasphase hydrogen-deuterium exchange experiments show that the thiol group (SH) is more acidic than the carboxyl group (CO 2 H).…”

Section: Introductionmentioning

confidence: 99%

Gas-Phase Acidities of Cysteine-Polyalanine Peptides I: A_3,4CSH and HSCA_3,4

2009

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The gas-phase acidities of four cysteine-polyalanine peptides, A(3,4)CSH and HSCA(3,4), were determined using the extended Cooks kinetic method with full entropy analysis. A triple-quadrupole mass spectrometer with an electrospray interface was employed for the experimental study. The ion activation was achieved via collision-induced dissociation (CID) experiments. The deprotonation enthalpies (Delta(acid)H) of the peptides were determined to be 332.2 +/- 2.0 kcal/mol (A(3)CSH), 325.9 +/- 2.0 kcal/mol (A(4)CSH), 319.3 +/- 3.0 kcal/mol (HSCA(3)), and 319.2 +/- 4.0 kcal/mol (HSCA(4)). The deprotonation entropies (Delta(acid)S) of the peptides were estimated based on the entropy term (Delta(DeltaS)) and the deprotonation entropies of the reference acids. By using the deprotonation enthalpies and entropies, the gas-phase acidities (Delta(acid)G) of the peptides were derived: 325.0 +/- 2.0 kcal/mol (A(3)CSH), 320.2 +/- 2.0 kcal/mol (A(4)CSH), 316.3 +/- 3.0 kcal/mol (HSCA(3)), and 315.4 +/- 4.0 kcal/mol (HSCA(4)). Conformations and energetic information of the peptides were calculated through simulated annealing (Tripos), geometry optimization (AM1), and single-point energy calculations (B3LYP/6-31+G(d)), respectively. The calculated theoretical deprotonation enthalpies (Delta(acid)H) of 334.2 kcal/mol (A(3)CSH), 327.7 kcal/mol (A(4)CSH), 320.6 kcal/mol (HSCA(3)), and 318.6 kcal/mol (HSCA(4)) are in good agreement with the experimentally determined values. Both the experimental and computational studies suggest that the two N-terminal cysteine peptides, HSCA(3,4), are significantly more acidic than the corresponding C-terminal ones, A(3,4)CSH. The high acidities of the former are likely due to the helical conformational effects for which the thiolate anion may be strongly stabilized by the interaction with the helix macrodipole.

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“…Note that protonation or deprotonation of salts may also occur in a similar way as described above for molecules to give rise to specific ionized species that will be developed later on. Adduct ion formation: by sharing of a proton between two partners via hydrogen bonding . In positive mode, it means that a protonated agent shares one proton with a basic site of M .…”

Section: Definitions and Considerationsmentioning

confidence: 99%

“…Adduct ion formation: by sharing of a proton between two partners via hydrogen bonding . In positive mode, it means that a protonated agent shares one proton with a basic site of M .…”

Section: Definitions and Considerationsmentioning

confidence: 99%

Proposal for a chemically consistent way to annotate ions arising from the analysis of reference compounds under ESI conditions: A prerequisite to proper mass spectral database constitution in metabolomics

et al. 2019

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Nowadays, high‐resolution mass spectrometry is widely used for metabolomic studies. Thanks to its high sensitivity, it enables the detection of a large range of metabolites. In metabolomics, the continuous quest for a metabolite identification as complete and accurate as possible has led during the last decade to an ever increasing development of public MS databases (including LC‐MS data) concomitantly with bioinformatic tool expansion. To facilitate the annotation process of MS profiles obtained from biological samples, but also to ease data sharing, exchange, and exploitation, the standardization and harmonization of the way to describe and annotate mass spectra seemed crucial to us. Indeed, under electrospray (ESI) conditions, a single metabolite does not produce a unique ion corresponding to its protonated or deprotonated form but could lead to a complex mixture of signals. These MS signals result from the existence of different natural isotopologues of the same compound and also to the potential formation of adduct ions, homomultimeric and heteromultimeric ions, fragment ions resulting from “prompt” in‐source dissociations. As a joint reflection process within the French Infrastructure for Metabolomics and Fluxomics (MetaboHUB) and with the purpose of developing a robust and exchangeable annotated MS database made from pure reference compounds (chemical standards) analysis, it appeared to us that giving the metabolomics community some clues to standardize and unambiguously annotate each MS feature was a prerequisite to data entry and further efficient querying of the mass spectral database. The use of a harmonized notation is also mandatory for interlaboratory MS data exchange. Additionally, thorough description of the variety of MS signals arising from the analysis of a unique metabolite might provide greater confidence on its annotation.

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Threshold Collision-Induced Dissociation of Hydrogen-Bonded Dimers of Carboxylic Acids

Cited by 26 publications

References 41 publications

Thermodynamics and Mechanisms of Protonated Diglycine Decomposition: A Guided Ion Beam Study

Thermodynamics and Mechanisms of Protonated Diglycine Decomposition: A Guided Ion Beam Study

Gas-Phase Acidities of Cysteine-Polyalanine Peptides I: A_3,4CSH and HSCA_3,4

Proposal for a chemically consistent way to annotate ions arising from the analysis of reference compounds under ESI conditions: A prerequisite to proper mass spectral database constitution in metabolomics

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Threshold Collision-Induced Dissociation of Hydrogen-Bonded Dimers of Carboxylic Acids

Cited by 26 publications

References 41 publications

Thermodynamics and Mechanisms of Protonated Diglycine Decomposition: A Guided Ion Beam Study

Thermodynamics and Mechanisms of Protonated Diglycine Decomposition: A Guided Ion Beam Study

Gas-Phase Acidities of Cysteine-Polyalanine Peptides I: A3,4CSH and HSCA3,4

Proposal for a chemically consistent way to annotate ions arising from the analysis of reference compounds under ESI conditions: A prerequisite to proper mass spectral database constitution in metabolomics

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Product

Resources

About

Gas-Phase Acidities of Cysteine-Polyalanine Peptides I: A_3,4CSH and HSCA_3,4