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Dvores MP, Çarçabal P, Gerber RB. Selective reactivity of glycosyl cation stereoisomers: the role of intramolecular hydrogen bonding. Phys Chem Chem Phys 2023; 25:26737-26747. [PMID: 37779496 DOI: 10.1039/d3cp03326k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
The impact of the stereochemistry of the glycosyl cation species upon its dynamic properties is examined together with their vibrational spectra in order to gain insight into the effects of configurational isomerism on conformer dynamics and proton mobility. Ab initio molecular dynamics (AIMD) simulations and infrared multiple photon dissociation (IRMPD) spectroscopy explore the conformational and reactive dynamics of two pairs of glycosyl cation isomers: (1) protonated α- and β- anomers of methyl-D-galactopyranoside and (2) the oxocarbenium ions of the D-aldohexose C2 epimers galactose and talose. Analysis of these simulations together with experimental spectroscopy, interpreted by anharmonic calculations, points to the key role played by the intramolecular hydrogen bonds which are present in a unique pattern and extent in each isomer. We find that the reactivity of galactoside stereoisomers toward acid-catalyzed nucleophilic substitution, as gauged by the ability to form free oxocarbenium ions, differs markedly in a way that agrees with experimental measurements in the condensed phase. Other properties such as conformer stability and vibrational transitions were also found to reflect the characteristic hydrogen bonding interactions present in each isomer. In both systems, the stereochemistry is shown to determine the strength of intramolecular hydrogen bonding as well as between which substituents proton transfer is possible. We expect that the critical impact of non-covalent interactions on stereoisomer selectivity may be a widely found phenomenon whose effects should be further investigated.
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Affiliation(s)
- M P Dvores
- Fritz Haber Centre for Molecular Dynamics, The Institute of Chemistry, The Hebrew University, Jerusalem 91904, Israel.
| | - P Çarçabal
- Insitut des Sciences Moléculaires d'Orsay, ISMO, Univ Paris-Sud, CNRS, bat 210, Univ Paris-Sud, 91405 Orsay Cedex, France
| | - R B Gerber
- Fritz Haber Centre for Molecular Dynamics, The Institute of Chemistry, The Hebrew University, Jerusalem 91904, Israel.
- Department of Chemistry, University of California Irvine, CA, 92697, USA
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Abikhodr AH, Yatsyna V, Ben Faleh A, Warnke S, Rizzo TR. Identifying Mixtures of Isomeric Human Milk Oligosaccharides by the Decomposition of IR Spectral Fingerprints. Anal Chem 2021; 93:14730-14736. [PMID: 34704745 PMCID: PMC8581968 DOI: 10.1021/acs.analchem.1c03190] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 10/19/2021] [Indexed: 12/17/2022]
Abstract
The analysis of glycans presents a significant challenge that arises from their isomeric heterogeneity. While high-resolution ion mobility spectrometry (IMS) has shown the ability to resolve subtly different glycan isomers, their unambiguous assignment remains difficult. Here, we demonstrate an infrared (IR) spectroscopic approach for identifying isomers in a glycan mixture. To display the feasibility of this approach, we have constructed a small database of cryogenic spectra of five lacto-N-fucopentaose (LNFP) and six disaccharide isomers and demonstrated that in the cases where they cannot be separated by IMS, we can use a cryogenic IR spectrum to identify the isomeric components of a mixture.
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Affiliation(s)
- Ali H. Abikhodr
- Laboratoire
de Chimie Physique Moléculaire, École Polytechnique
Fédérale de Lausanne, EPFL SB ISIC LCPM, Station 6, CH-1015 Lausanne, Switzerland
| | - Vasyl Yatsyna
- Laboratoire
de Chimie Physique Moléculaire, École Polytechnique
Fédérale de Lausanne, EPFL SB ISIC LCPM, Station 6, CH-1015 Lausanne, Switzerland
- Department
of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden
| | - Ahmed Ben Faleh
- Laboratoire
de Chimie Physique Moléculaire, École Polytechnique
Fédérale de Lausanne, EPFL SB ISIC LCPM, Station 6, CH-1015 Lausanne, Switzerland
| | - Stephan Warnke
- Laboratoire
de Chimie Physique Moléculaire, École Polytechnique
Fédérale de Lausanne, EPFL SB ISIC LCPM, Station 6, CH-1015 Lausanne, Switzerland
| | - Thomas R. Rizzo
- Laboratoire
de Chimie Physique Moléculaire, École Polytechnique
Fédérale de Lausanne, EPFL SB ISIC LCPM, Station 6, CH-1015 Lausanne, Switzerland
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Fraschetti C, Letzel MC, Paletta M, Mattay J, Crestoni ME, Chiavarino B, Filippi A. Unprotected Galactosamine as a Dynamic Key for a Cyclochiral Lock. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:736-743. [PMID: 33499589 PMCID: PMC7944569 DOI: 10.1021/jasms.0c00437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 01/13/2021] [Accepted: 01/13/2021] [Indexed: 06/12/2023]
Abstract
The discrimination of d-galactosamine (G), representative of the amino-sugar class of compounds, has been probed through nano-ESI-FT-ICR mass spectrometry by isolating the relevant [C·H·G]+ proton-bound complexes with the enantiomers of the cyclochiral resorcin[4]arene C and allowing them to react toward three primary amines (B = EtNH2, iPrNH2, and (R)- and (S)-sBuNH2). The system under investigation presents several features that help to unveil the behavior of unprotected G in such a supramolecular architecture: (i) the hydrophobic derivatization of the C convex side forces the polar guest G to be coordinated by the cyclochiral concave region; (ii) protonated d-galactosamine exists as an anomeric mixture, dynamically interconverting throughout the experimental time-window; and (iii) different basicities of B allow the experiment to subtly tune the reactivity of the [C·H·G]+ complexes. Three [C·H·G]+ aggregate-types were found to exist, differing in both their origin and reactivity. The most reactive adducts ([C·H·G]ESI+), generated in the electrospray environment, undergo a G-to-B ligand exchange in competition with a partial isomerization to the unreactive [C·H·G]GAS+-type complexes. Finally, the poorly reactive [C·H·G]SOL+ aggregates are formed in solution over an hours-long time scale. A cyclochirality effect on the reactivity was found to depend on the considered [C·H·G]+ aggregate-type.
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Affiliation(s)
- Caterina Fraschetti
- Dipartimento
di Chimica e Tecnologie del Farmaco, Sapienza-Università
di Roma, Piazzale Aldo Moro 5, I-00185 Rome, Italy
| | - Matthias C. Letzel
- Organisch-Chemisches
Institut der Westf. Wilhelms Abt. Massenspektrometrie, Westfälische Wilhelms-Universität Münster, Room 252a, Corrensstraße 40, 48149 Münster, Germany
| | - Marlene Paletta
- Department
of Chemistry, Bielefeld University, P. O. Box 100131, D-33501 Bielefeld, Germany
| | - Jochen Mattay
- Department
of Chemistry, Bielefeld University, P. O. Box 100131, D-33501 Bielefeld, Germany
| | - Maria Elisa Crestoni
- Dipartimento
di Chimica e Tecnologie del Farmaco, Sapienza-Università
di Roma, Piazzale Aldo Moro 5, I-00185 Rome, Italy
| | - Barbara Chiavarino
- Dipartimento
di Chimica e Tecnologie del Farmaco, Sapienza-Università
di Roma, Piazzale Aldo Moro 5, I-00185 Rome, Italy
| | - Antonello Filippi
- Dipartimento
di Chimica e Tecnologie del Farmaco, Sapienza-Università
di Roma, Piazzale Aldo Moro 5, I-00185 Rome, Italy
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Dvores MP, Çarçabal P, Maître P, Simons JP, Gerber RB. Gas phase dynamics, conformational transitions and spectroscopy of charged saccharides: the oxocarbenium ion, protonated anhydrogalactose and protonated methyl galactopyranoside. Phys Chem Chem Phys 2020; 22:4144-4157. [PMID: 32039431 DOI: 10.1039/c9cp06572e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Protonated intermediates are postulated to be involved in the rate determining step of many sugar reactions. This paper presents a study of protonated sugar species, isolated in the gas phase, using a combination of infrared multiple photon dissociation (IRMPD) spectroscopy, classical ab initio molecular dynamics (AIMD) and quantum mechanical vibrational self-consistent field (VSCF) calculations. It provides a likely identification of the reactive intermediate oxocarbenium ion structure in a d-galactosyl system as well as the saccharide pyrolysis product anhydrogalactose (that suggests oxocarbenium ion stabilization), along with the spectrum of the protonated parent species: methyl d-galactopyranoside-H+. Its vibrational fingerprint indicates intramolecular proton sharing. Classical AIMD simulations for galactosyl oxocarbenium ions, conducted in the temperature range ∼300-350 K (using B3LYP potentials on-the-fly) reveal efficient transitions on the picosecond timescale. Multiple conformers are likely to exist under the experimental conditions and along with static VSCF calculations, they have facilitated the identification of the individual structural motifs of the galactosyl oxocarbenium ion and protonated anhydrogalactose ion conformers that contribute to the observed experimental spectra. These results demonstrate the power of experimental IRMPD spectroscopy combined with dynamics simulations and with computational spectroscopy at the anharmonic level to unravel conformer structures of protonated saccharides, and to provide information on their lifetimes.
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Affiliation(s)
- M P Dvores
- Institute of Chemistry and the Fritz Haber Research Center, The Hebrew University, Jerusalem 91904, Israel.
| | - P Çarçabal
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405, Orsay, France
| | - P Maître
- Université Paris-Saclay, CNRS, Institut de Chimie Physique, 91405, Orsay, France
| | - J P Simons
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford OX1 3QZ, UK
| | - R B Gerber
- Institute of Chemistry and the Fritz Haber Research Center, The Hebrew University, Jerusalem 91904, Israel. and Department of Chemistry, University of California Irvine, CA 92697, USA
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