References of "Kune, Christopher"
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See detailComputational chemistry and ion mobility – mass spectrometry at high resolving power suggest prototropism of cyclic lipopeptides
Mc Cann, Andréa ULiege; Kune, Christopher ULiege; Far, Johann ULiege et al

Poster (2019, June)

Introduction Cyclic lipopeptides (CLPs) are cyclic hydrophilic peptides with a lipid ramification using a β-hydroxy fatty acid that are produced by bacteria in a ribosome independent manner. Despite CLPs ... [more ▼]

Introduction Cyclic lipopeptides (CLPs) are cyclic hydrophilic peptides with a lipid ramification using a β-hydroxy fatty acid that are produced by bacteria in a ribosome independent manner. Despite CLPs have relatively low molecular weight between 800 and 2,000 Da, the analysis of lipopeptides remains challenging due to the wide variety of synthetized isoforms differing in fatty acid chain length, in methyl group branching position, and in the nature of the amino-acids residues. These isoforms are suspected to have different biological activities requiring development of reliable methods for CLPs characterization. We present here an original approach combining UPLC and ion mobility - mass spectrometry at high resolving powers to separate the different species. Experimentally determined CCS will be compared with theoretical ones. Methods Lipopeptides were separated by UPLC (I-class, Waters, U.K.) on a C18 BEH column and identified by CID MS/MS mass spectrometry. Ion mobility – mass spectrometry (IM-MS) measurements were performed on a traveling wave ion mobility mass spectrometer (Synapt G2 HDMS from Waters, U.K.) and on a trapped Ion Mobility Mass Spectrometer (timsTOF, Bruker Daltonics, U.S.A.) to investigate the 3D structures of the ionized lipopeptides. Accurate Collison Cross Section (CCS) were obtained in both positive and negative mode and compared with theoretical CCS. Density Functional Theory (Gaussian) was used for structure optimizations at the CAM-B3LYP level of theory and 3-21G as basis set. Theoretical CCS have been computed from optimized structures using the trajectory method from IMoS V2. Preliminary data Separation of lipopeptides such as surfactins was successfully performed by reverse phase liquid chromatography. Lipopeptides were separated according to lipidic chain length and the branching position of the methyl group (iso/anteiso/linear). In positive ionization mode, the infusion of each isolated isoforms in the Synapt G2 showed a broad IMS distribution. These ion mobility profiles suggested the presence of different conformers. The higher IMS resolving power of the TIMS allowed the detection of at least three near-resolved peaks for a single isomer. In negative ionization mode however, only one peak was observed in the IM-MS profile on both Synapt G2 and TIMS, corresponding to one CCS. We included prototropic hypotheses where all the potential protonation and deprotonation sites on each lipopeptide had been determined by theoretical calculation. The abundances of the species in the CCS distributions of the resulting structures were obtained based on the Boltzmann distribution. Regarding the surfactin family, preliminary calculations by DFT shows that several protonation sites are energetically favorable and that the proton localization has a significant effect on the resulting CCS (∆CCS = 10Ų). These results are in good agreement with the experimental IMS profiles, obtained in both positive and negative ionization mode. Lipopeptides are then not related to a unique CCS value but a set of IM-MS profile that probably contains additional structural and physicochemical information. Novel aspect Experimental and theoretical approaches for lipopeptides IMS profiles analysis: protonation site determination, peaks intensity prediction and structural information extraction. [less ▲]

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See detailRapid visualization of chemically related compounds using Kendrick mass defect as a filter in mass spectrometry imaging
Kune, Christopher ULiege; Mc Cann, Andréa ULiege; La Rocca, Raphaël ULiege et al

E-print/Working paper (2019)

Kendrick mass defect (KMD) analysis is widely used for helping the detection and identification of chemically related compounds based on exact mass measurements. We report here the use of KMD as a ... [more ▼]

Kendrick mass defect (KMD) analysis is widely used for helping the detection and identification of chemically related compounds based on exact mass measurements. We report here the use of KMD as a criterion for filtering complex mass spectrometry data. The method enables an automated, faster and efficient data processing, enabling the reconstruction of 2D distributions of family of homologous compound in MSI images. We show that the KMD filtering, based on a homemade software, is suitable for low resolution and high resolution MSI data. This method has been successfully applied to two different types of samples, bacteria co-cultures and brain tissue section. [less ▲]

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See detailFrom noise to signal: Kendrick mass filtering for high-resolution mass spectrometry imaging analysis
Mc Cann, Andréa ULiege; Kune, Christopher ULiege; Arguelles Arias, Anthony ULiege et al

Poster (2019, April 14)

Introduction Over the last years, lots of progress have been done in the development of mass spectrometry imaging, making the technique more and more accessible for various applications, such as ... [more ▼]

Introduction Over the last years, lots of progress have been done in the development of mass spectrometry imaging, making the technique more and more accessible for various applications, such as biomarkers discovery or bioactive compounds identification. However, the progresses made in terms of spatial and instrumental resolution has for consequences the dramatic increase of dataset size, shifting the burden from data production to data analysis. We propose here to use a semi-targeted method based on Kendrick mass defect (KMD) analysis to immediately identify the chemistry-related compounds in mass spectrometry imaging applied to microbiology samples. Thanks to an in-house software, we are now able to better understand the bacteria-bacteria interactions. Materials and methods Bacillus velezensis GA1 and Pseudomonas sp. CMR12a were inoculated on a semi-solid agar-based medium and incubated at 30°C. Region of interest was cut directly from the petri dish and transferred to the target ITO plate, previously covered with double sided conductive carbon tape. This assembly was then put in a vacuum desiccator until complete drying (overnight), and covered with HCCA matrix. Mass spectrometry images were obtained using a FT-ICR mass spectrometer (9.4T SolariX, Bruker Daltonics, Bremen, Germany). Data analysis was performed on an in-house software. Results & Discussion Thanks to the KMD analysis, we were able to directly compare and identify the nature of the compounds detected in MSI such as lipids (1) or lipopeptides (2a), without the need of an extensive database search. It was also possible to identify some lipopeptides degradation occurring nearby Pseudomonas (2b). Thanks to our in-house software, the compounds with a similar chemistry can now be filtrated and the image can be reconstructed, removing thus the noise and focusing only on the signal. [less ▲]

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See detailUse of IMMS for the investigation of the effects of shapes, densities and dipole moments on the CCS of small metal complexes
Kune, Christopher ULiege; Haler, Jean ULiege; Rappe, Sophie ULiege et al

Conference (2019, March 31)

Ion mobility mass spectrometry provides the collision cross section (CCS) of ions in the gas phase. The CCS growth of ions sharing similar physicochemical properties such as charge state, geometry, shape ... [more ▼]

Ion mobility mass spectrometry provides the collision cross section (CCS) of ions in the gas phase. The CCS growth of ions sharing similar physicochemical properties such as charge state, geometry, shape, apparent density and dipole moments correlates well with their masses evolution. In this presentation, we study the effect on the CCS/mass correlations after variation of these physicochemical properties using a set of negatively charged iron center complexes with halogens (chloride, bromide and iodide) and carboxylates (linear or branched mono carboxylate) as ligands. Due to the halogen ligands are more compact and denser than the carboxylate ligands, all combinations of these ligands lead to a set of iron center complexes (theoretically superior to 250 complexes) having different CCS growth. Indeed, the number of ligands imposes the geometry (linear, trigonal plan, tetrahedral) while the halogen/carboxylate ligands ratio influences the apparent densities and the shape (spherical or near spherical) of the complex ions. Moreover, theses complex ions also share different dipole moment. These properties have been estimated by computational chemistry (Molecular Mechanism or Density Functional Theory levels) for each complex whereas the CCS and mass values have been measured by traveling wave ion mobility (Water’s Synapt G2). Comparing all the experimental CCS/mass trends in function of the physicochemical properties shows that the apparent density is the main factor influencing these correlations following by the shape and geometry factors. The variations on the dipole moment of theses complexes seems to be insufficient to significantly affect the CCS/mass correlation. This work also highlights the capability of CCS prediction of a given ion based on its mass, apparent density, shape, geometry, and the dipole moment. [less ▲]

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See detailIon mobility mass spectrometry for lipopeptides analysis
Mc Cann, Andréa ULiege; Kune, Christopher ULiege; Far, Johann ULiege et al

Poster (2019, March 31)

Cyclic lipopeptides (CLPs) are produced by bacteria in a ribosome independent manner and consists in a hydrophilic peptide linked to a B-hydroxy fatty acid chain. Despite CLPs have relatively low ... [more ▼]

Cyclic lipopeptides (CLPs) are produced by bacteria in a ribosome independent manner and consists in a hydrophilic peptide linked to a B-hydroxy fatty acid chain. Despite CLPs have relatively low molecular weight (between 800 and 2,000 Da), the analysis of lipopeptides remains challenging due to the wide variety of synthetized isoforms differing in fatty acid chain length, in methyl group branching position, and in the nature of the amino-acids residues. These isoforms are suspected to have different biological activities requiring development of reliable methods for CLPs identification and characterization. In this work, we present an original approach combining UPLC and ion mobility - mass spectrometry at high resolving powers to separate and identify the different species. Lipopeptides were separated by UPLC (I-class, Waters, U.K.) on a C18 BEH column and identified by CID MS/MS mass spectrometry. Ion mobility – mass spectrometry (IM-MS) measurements were performed on a trapped Ion Mobility Mass Spectrometer (TimsTOF, Bruker Daltonics, U.S.A.). Accurate Collison Cross Section (CCS) were obtained in both positive and negative mode and compared with theoretical CCS obtained by the trajectory method from IMoS V2. Separation of lipopeptides such as surfactins, iturins, or mycosubtilins was successfully performed by reverse phase liquid chromatography. Lipopeptides were separated according to lipid chain length and according to the branching position of the methyl group (iso/anteiso/linear). Ion mobility analysis with computational chemistry support gave additional information on the lipopeptides structure and family. Structural information are obtained by experimental and theoretical CCS comparison while the lipopeptides family could be determined with CCS/mass trends. These results pave the way to a new strategy for fast lipopeptides identification and could potentially contribute to lipopeptides structure elucidation. [less ▲]

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See detailAnalytical tool for lipopeptide identification
Mc Cann, Andréa ULiege; Kune, Christopher ULiege; Far, Johann ULiege et al

Conference (2018, November 30)

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See detailCombination of Capillary Electrophoresis and Ion mobility coupled to Mass Spectrometry and Theoretical Calculations for cysteine connectivity identification in peptides bearing two intra-molecular disulfide bonds
Delvaux, Cédric ULiege; Massonnet, Philippe ULiege; Kune, Christopher ULiege et al

Conference (2018, November 06)

Disulfide bonds are post translational modification playing essential roles in the biological activity and stability of numerous peptides and proteins. Intra-molecular disulfide bonds are found in various ... [more ▼]

Disulfide bonds are post translational modification playing essential roles in the biological activity and stability of numerous peptides and proteins. Intra-molecular disulfide bonds are found in various natural-occurring peptides such as animal venoms. In such peptides, the appropriate cysteine connectivity provides the required conformation for efficient binding to their molecular targets, which ensures their bioactivity. The characterization of cysteine pairing is still a challenging issue in the analysis of peptides targeting pharmaceutical or pharmacological utilizations. Thus, the use of sensitive, robust and efficient characterization techniques to access the cysteine pairing is crucial. In our workflow,the separation of the disulfide isomers of three peptides bearing two intra-molecular disulfide bonds but different cysteine connectivities have been tested using Capillary Zone Electrophoresis (CZE) and Ion Mobility (IM) coupled to Mass Spectrometry (MS). Results show that CZE-MS and IM-MS act as complementary techniques to unambiguously determine the cysteine connectivity of a given peptide. Indeed, the combination of the relative migration time to a reference peptide in CZE-MS, the drift time in IM-MS and the generation of fragments by Collision Induced Dissociation (CID) led to the attribution of the disulfide connectivities in all studied cases. Finally, theoretical calculations were performed to model the different structures in gas phase and solution, supporting the experimental observations on the basis of the predicted physicochemical properties. [less ▲]

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See detailEffectiveness and limitations of computational chemistry and mass spectrometry in the rational design of target‐specific shift reagents for ion mobility spectrometry
Kune, Christopher ULiege; Haler, Jean ULiege; Far, Johann ULiege et al

in Chemphyschem: A European Journal of Chemical Physics and Physical Chemistry (2018)

Ion mobility spectrometry (IMS) is a gas‐phase separation technique based on ion mobility differences in an electric field. It is largely used for the detection of specific ions such as small molecule ... [more ▼]

Ion mobility spectrometry (IMS) is a gas‐phase separation technique based on ion mobility differences in an electric field. It is largely used for the detection of specific ions such as small molecule explosives. IMS detection system includes the use of e.g. a Faraday plate or mass spectrometry (MS). The presence of interfering ion signals in standalone IMS may lead to the detection of false positives or negatives due to e.g. lacking resolving power. In this case, selective mobility shifts obtained using shift reagents (SR), i.e. ligands complexing a specific target, can bring help. The effectiveness of an SR strategy relies on the SR‐target ion selectivity. The crucial step lies in the SR design. The aim of this paper is to present an efficient interplay of experimental ion mobility mass spectrometry (IMMS) and predictive computational chemistry using various levels of computational efforts for rationally designing target‐specific SR. Mass spectrometry is used to evaluate the efficiency of the SR selectivity with identification and semi‐quantification of free and complexed ions. Minimal computational efforts allow the design of the SR, predict the SR‐target ion relative stabilities, and prediction of ion mobility shifts. We demonstrate our approach using crown ethers and β‐cyclodextrin to selectively shift interfering perchlorate, amino acids and diaminonaphthalene isomers. We also release the software ParsIMoS for straightforward use of ion mobility calculator IMoS. [less ▲]

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See detailRevisiting protomers of aniline by high-resolution ion mobility spectrometry, capillary electrophoresis-mass spectrometry, and abinitio calculations
Kune, Christopher ULiege; Delvaux, Cédric ULiege; Haler, Jean ULiege et al

Poster (2018, June 05)

The detection of two stable tautomers of protonated aniline, the amino-protonated and the protonated carbone in para position (“Cpara-protonated”), are already reported in the literature. The use of ... [more ▼]

The detection of two stable tautomers of protonated aniline, the amino-protonated and the protonated carbone in para position (“Cpara-protonated”), are already reported in the literature. The use of traveling wave ion mobility spectrometry (TWIMS) spotlights a possible conversion between both of these tautomers. Moreover, the presence of phenol strongly suggests that water adduct(s) is/are involved during this tautomerisation. The use of high resolution ion mobility - mass spectrometry also suggests tautomers conversion and the presence of other metastable species of protonated aniline than the Cpara-protonated and amino-protonated aniline. These observations support that the measurement of protomers ratio should be affect by gas phase reactions. Aqueous and non-aqueous capillary electrophoresis results show the effect of the solvents. The rate of tautomers conversion seems to be higher in protic solvent (water) than aprotic solvent (acetonitrile). [less ▲]

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See detailRevisiting protomers of aniline by high-resolution ion mobility spectrometry, capillary electrophoresis-mass spectrometry, and abinitio calculations
Kune, Christopher ULiege; Delvaux, Cédric ULiege; Haler, Jean ULiege et al

Poster (2018, March 29)

Protomers are ions which displays tautomerism due to the position change of a proton. Recent papers show that two stable protomers of aniline were observed using ion mobility spectrometry. Protonation of ... [more ▼]

Protomers are ions which displays tautomerism due to the position change of a proton. Recent papers show that two stable protomers of aniline were observed using ion mobility spectrometry. Protonation of the amine functional group and the carbon in “para” position were identified [Lalli, 2012 and Attygalle, 2017]. Tautomerization was also observed for other amine functional group containing in aromatic compounds. We present here the use of capillary electrophoresis and high-resolution ion mobility spectrometry to detect other stable or metastable protomers predicted by ab-initio calculations such as protonation of the carbon in “ortho” and “meta” position of aniline. These data should allow the refinement of the energy landscape during the protomer formation and tautomerization. For this reason, it is required to characterize all the ions that can be implicated during protomers formation. High resolution ion mobility(TIMS) allowed the detection of more ions related to aniline than those presented by the stateof-the-art. In addition, benzenium (C6H7+) and phenol (C6H7O+) cations can also be formed according to the electrospray ion source settings from the mass spectrometer. All of these ions must be taken in account to refine the energy landscape during the protomer formation and tautomerization. Ab-initio computation was used to support the identification of these ions in regard of the experimental data. Preliminary calculations by Density Functional Theory show that the protonation in the carbon in “ortho” position should be almost as stable as the amine protonation and should be observed during IMS experiments using the appropriate ion mobility resolving power. Calculations using polarizable continuum model also predict that the ratio of protomers is affected in presence of solvents and especially its dielectric constant. The protonation of the amine functional group is the most predominant species when aniline is solubilized in protic solvents. To the contrary both protonations of the amine functional group and the carbon in “para” should be significantly present in aprotic solvents. Aqueous and non-aqueous capillary zone electrophoresis (CZE) coupled to mass spectrometry are then consider to confirm these hypotheses. [less ▲]

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See detailComparison of Different Ion Mobility Setups using Poly(ethylene oxide) PEO Polymers: Drift Tube, TIMS and T-Wave
Haler, Jean ULiege; Massonnet, Philippe ULiege; Chirot, Fabien et al

in Journal of the American Society for Mass Spectrometry (2018), 29(1), 114-120

Over the years, polymer analyses using ion mobility-mass spectrometry (IM-MS) measurements have been performed on different ion mobility spectrometry (IMS) setups. In order to be able to compare ... [more ▼]

Over the years, polymer analyses using ion mobility-mass spectrometry (IM-MS) measurements have been performed on different ion mobility spectrometry (IMS) setups. In order to be able to compare literature data taken on different IM(-MS) instruments, ion heating and ion temperature evaluations have already been explored. Nevertheless, extrapolations to other analytes are difficult and thus straightforward same-sample instrument comparisons seem to be the only reliable way to make sure that the different IM(-MS) setups do not greatly change the gas phase behavior. We used a large range of degrees of polymerization (DP) of poly(ethylene oxide) PEO homopolymers to measure IMS drift times on three different IM-MS setups: a homemade drift tube (DT), a trapped (TIMS) and a travelling wave (T-Wave) IMS setup. The drift time evolutions were followed for increasing polymer DPs (masses) and charge states and they are found to be comparable and reproducible on the three instruments. [less ▲]

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See detailExploitation de la plateforme e-Campus pour l’apprentissage de la Chimie de Première année pour les étudiants non acquis à la matière
Kune, Christopher ULiege; Quinton, Loïc ULiege

Scientific conference (2017, November 23)

De nos jours, les étudiants sont de plus en plus ouverts à l’e-Learning. La plateforme e-Campus, de par sa facilité à rendre disponible des contenus et des activés en ligne, permet à tout corps enseignant ... [more ▼]

De nos jours, les étudiants sont de plus en plus ouverts à l’e-Learning. La plateforme e-Campus, de par sa facilité à rendre disponible des contenus et des activés en ligne, permet à tout corps enseignant de répondre à cette demande grandissante. Pour les étudiants en première année de kinésithérapie et sciences de la motricité, l’e-Learning est devenu un complément incontournable du cours de Chimie. Lors de cette présentation, nous aborderons le développement de ce projet E-Learning pour le cours de chimie, de l’idée à la réalisation, en découvrant les outils offerts par la plateforme E-Campus, tels les questionnaires en ligne, les forums, les médiathèques… [less ▲]

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See detailExploitation de la plateforme e-Campus pour l’apprentissage de la Chimie de Première année pour les étudiants non acquis à la matière
Kune, Christopher ULiege; Quinton, Loïc ULiege

Conference (2017, November 23)

De nos jours, les étudiants sont de plus en plus ouverts à l’e-Learning. La plateforme e-Campus, de par sa facilité à rendre disponible des contenus et des activés en ligne, permet à tout corps enseignant ... [more ▼]

De nos jours, les étudiants sont de plus en plus ouverts à l’e-Learning. La plateforme e-Campus, de par sa facilité à rendre disponible des contenus et des activés en ligne, permet à tout corps enseignant de répondre à cette demande grandissante. Pour les étudiants en première année de kinésithérapie et sciences de la motricité, l’e-Learning est devenu un complément incontournable du cours de Chimie. Lors de cette présentation, nous aborderons le développement de ce projet E-Learning pour le cours de chimie, de l’idée à la réalisation, en découvrant les outils offerts par la plateforme E-Campus, tels les questionnaires en ligne, les forums, les médiathèques… [less ▲]

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See detailComprehensive Ion Mobility Calibration: Poly(ethylene oxide) Polymer Calibrants and General Strategies
Haler, Jean ULiege; Kune, Christopher ULiege; Massonnet, Philippe ULiege et al

in Analytical Chemistry (2017), 89(22), 1207612086

Ion Mobility (IM) is now a well-established and fast analytical technique. The IM hardware is constantly being improved, especially in terms of the resolving power. The Drift Tube (DTIMS), the Traveling ... [more ▼]

Ion Mobility (IM) is now a well-established and fast analytical technique. The IM hardware is constantly being improved, especially in terms of the resolving power. The Drift Tube (DTIMS), the Traveling Wave (TWIMS), and the Trapped Ion Mobility Spectrometry (TIMS) coupled to mass spectrometry are used to determine the Collision Cross-Sections (CCS) of ions. In analytical chemistry, the CCS is approached as a descriptor for ion identification and it is also used in physical chemistry for 3D structure elucidation with computational chemistry support. The CCS is a physical descriptor extracted from the reduced mobility (K0) measurements obtainable only from the DTIMS. TWIMS and TIMS routinely require a calibration procedure to convert measured physical quantities (drift time for TWIMS and elution voltage for TIMS) into CCS values. This calibration is a critical step to allow inter-instrument comparisons. The previous calibrating substances lead to large prediction bands and introduced rather large uncertainties during the CCS determination. In this paper, we introduce a new IM calibrant (CCS and K0) using singly charged sodium adducts of poly(ethylene oxide) monomethyl ether (CH3O-PEO-H) for positive ionization in both helium and nitrogen as drift gas. These singly charged calibrating ions make it possible to determine the CCS/K0 of ions having higher charge states. The fitted calibration plots exhibit larger coverage with less data scattering and significantly improved prediction bands and uncertainties. The reasons for the improved CCS/K0 accuracy, advantages and limitations of the calibration procedures are also discussed. A generalized IM calibration strategy is suggested. [less ▲]

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See detailComprehensive Ion Mobility Calibration Strategies based on Synthetic Polymers
Haler, Jean ULiege; Kune, Christopher ULiege; Chirot, Fabien et al

Conference (2017, July 24)

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See detailComprehensive Ion Mobility Calibration Strategies based on Synthetic Polymers
Haler, Jean ULiege; Kune, Christopher ULiege; Chirot, Fabien et al

Conference (2017, May 09)

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