References of "Far, Johann"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailPredicting Ion Mobility-Mass Spectrometry Trends of Polymers using the Concept of Apparent Densities
Haler, Jean ULiege; Morsa, Denis ULiege; Lecomte, Philippe ULiege et al

in Methods (in press)

Ion Mobility (IM) coupled to Mass Spectrometry (MS) has been used for several decades, bringing a fast separation dimension to the MS detection. IM-MS is a convenient tool for structural elucidation. The ... [more ▼]

Ion Mobility (IM) coupled to Mass Spectrometry (MS) has been used for several decades, bringing a fast separation dimension to the MS detection. IM-MS is a convenient tool for structural elucidation. The fold- ing of macromolecules is often assessed with the support of computational chemistry. However, this strat- egy is strongly dependent on computational initial guesses. Here, we propose the analysis of the Collision Cross-Section (CCS) trends of synthetic homopolymers based on a fitting method which does not rely on computational chemistry a prioris of the three-dimensional structures. The CCS trends were evaluated as a function of the polymer chain length and the charge state. This method is also applicable to mobility trends. It leads to two parameters containing all information available through IM(-MS) measurements. One parameter can be interpreted as an apparent density. The second parameter is related to the shape of the ions and leads us to introduce the concept of trends with constant apparent density. Based on the two fitting parameters, a method for IM trend predictions is elaborated. Experimental deviations from the predictions facilitate detect- ing structural rearrangements and three-dimensional structure differences of the cationized polymer ions. This leads for instance to an easy identification and prediction of the presence of different polymer topologies in complex polymer mixtures. The classification of predicted trends could as well allow for software-assisted data processing. Finally, we suggest the link between the CCS trends of homopolymers and those obtained from (monodisperse) biomolecules to interpret potential folding differences during IM-MS studies. [less ▲]

Detailed reference viewed: 47 (16 ULiège)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 29 (20 ULiège)
Full Text
See detailEvaluation of capillary electrophoresis separation of cyclic lipopeptides
Mc Cann, Andréa ULiege; Far, Johann ULiege; De Pauw, Edwin ULiege et al

Poster (2018, March 29)

Detailed reference viewed: 27 (15 ULiège)
See detailIon Mobility-Mass Spectrometry of Synthetic Polymers: Interpretation Models & Calibration Strategies
Haler, Jean ULiege; Far, Johann ULiege; de la Rosa, Victor R. et al

Conference (2018, March 11)

Detailed reference viewed: 38 (3 ULiège)
Full Text
See detailEmerging mass spectrometry techniques for lipopeptide understanding
Mc Cann, Andréa ULiege; Far, Johann ULiege; Delvaux, Cédric ULiege et al

Scientific conference (2018, March 05)

Detailed reference viewed: 27 (15 ULiège)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 64 (20 ULiège)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 69 (20 ULiège)
Peer Reviewed
See detailGoing Inside Structural and Physicochemical Properties of Polymers using Ion Mobility-Mass Spectrometry
Haler, Jean ULiege; de la Rosa, Victor R.; Far, Johann ULiege et al

Conference (2017, September 06)

Detailed reference viewed: 59 (9 ULiège)
Peer Reviewed
See detailComprehensive Ion Mobility Calibration Strategies based on Synthetic Polymers
Haler, Jean ULiege; Kune, Christopher ULiege; Chirot, Fabien et al

Conference (2017, July 24)

Detailed reference viewed: 48 (10 ULiège)
See detailIon Mobility-Mass Spectrometry: Going beyond the numbers
Haler, Jean ULiege; Far, Johann ULiege; Béchet, Eric ULiege et al

Scientific conference (2017, July 03)

Detailed reference viewed: 38 (9 ULiège)
Peer Reviewed
See detailSeparation, identification and quantification of peptidoglycan fragments by zwitterionic hydrophilic interaction chromatography and capillary electrophoresis coupled to mass spectrometry
Boulanger, Madeleine ULiege; Delvaux, Cédric ULiege; Raymackers, Alice ULiege et al

Poster (2017, June 05)

Bacterial peptidoglycan-derived muropeptides and peptides are soluble fragments acting as messengers in diverse cell-signalling events. As the peptidoglycan wall is a key target of antibiotics, bacteria ... [more ▼]

Bacterial peptidoglycan-derived muropeptides and peptides are soluble fragments acting as messengers in diverse cell-signalling events. As the peptidoglycan wall is a key target of antibiotics, bacteria have developed specific resistance mechanisms based on the detection of these fragments inside their cytoplasm. In our model strain, Bacillus licheniformis, the peptidoglycan dipeptide m-A2pm-D-Glu triggers a beta-lactamase induction. However, the nature and the concentration of cytoplasmic peptidoglycan fragments leading to the dipeptide formation are unknown. Additionally, the muropeptides sensing is involved in the innate immune response toward bacterial invasion and is therefore of considerable importance in eukaryotes self-defence functions. In this context, the development of reliable analytical methods aiming to identify and quantify those fragments in complex samples are of major interest. [less ▲]

Detailed reference viewed: 133 (12 ULiège)
Full Text
Peer Reviewed
See detailN-Glycosylation of an IgG antibody secreted by Nicotiana tabacum BY-2 cells can be modulated through co-expression of human β-1,4-galactosyltransferase
Navarre, Catherine; Smargiasso, Nicolas ULiege; Duvivier, Laurent et al

in Transgenic Research (2017), 26(3), 375-384

Nicotiana tabacum BY-2 suspension cells have several advantages that make them suitable for the production of full-size monoclonal antibodies which can be purified directly from the culture medium ... [more ▼]

Nicotiana tabacum BY-2 suspension cells have several advantages that make them suitable for the production of full-size monoclonal antibodies which can be purified directly from the culture medium. Carbohydrate characterization of an antibody (Lo-BM2) expressed in N. tabacum BY-2 cells showed that the purified Lo-BM2 displays N-glycan homogeneity with a high proportion (>70%) of the complex GnGnXF glycoform. The stable co-expression of a human β-1,4-galactosyltransferase targeted to different Golgi sub-compartments altered Lo-BM2N-glycosylation and resulted in the production of an antibody that exhibited either hybrid structures containing a low abundance of the plant epitopes (α-1,3-fucose and β-1,2-xylose), or a large amount of galactose-extended N-glycan structures. These results demonstrate the suitability of stable N-glycoengineered N. tabacum BY-2 cell lines for the production of human-like antibodies. © 2017, Springer International Publishing Switzerland. [less ▲]

Detailed reference viewed: 33 (3 ULiège)
Peer Reviewed
See detailComprehensive Ion Mobility Calibration Strategies based on Synthetic Polymers
Haler, Jean ULiege; Kune, Christopher ULiege; Chirot, Fabien et al

Conference (2017, May 09)

Detailed reference viewed: 35 (7 ULiège)
Peer Reviewed
See detailComprehensive Ion Mobility Calibration Strategies based on Synthetic Polymers
Haler, Jean ULiege; Kune, Christopher ULiege; Chirot, Fabien et al

Conference (2017, March 21)

Detailed reference viewed: 33 (4 ULiège)
Peer Reviewed
See detailPeptidoglycan fragments separation and identification by zwitterionic hydrophilic interaction chromatography and capillary electrophoresis coupled to mass spectrometry
Boulanger, Madeleine ULiege; Raymackers, Alice ULiege; Delvaux, Cédric ULiege et al

Poster (2017, February 08)

Bacterial peptidoglycan-derived peptides and muropeptides are soluble unique fragments acting as messengers in diverse cell-signalling events. As the bacterial peptidoglycan wall is a major target of ... [more ▼]

Bacterial peptidoglycan-derived peptides and muropeptides are soluble unique fragments acting as messengers in diverse cell-signalling events. As the bacterial peptidoglycan wall is a major target of antibiotics, bacteria have developed specific resistance mechanisms based on the detection of such fragments. In addition, the muropeptides sensing is involved in the innate immune response toward bacterial invasion and is therefore of major importance in the eukaryotes self-defence functions. In Bacillus licheniformis 749/I, the peptidoglycan dipeptide m-A2pm-D-Glu triggers beta-lactam resistance via the induction of a beta-lactamase, BlaP. This induction process relies on a complex regulation system for which the nature and the concentration of peptidoglycan fragments leading to the formation of dipeptide moiety inside the cytoplasm are unknown. In this context, the development and the validation of a reliable method to identify and quantify those cytoplasmic fragments is of major interest. Conventionally, the peptidoglycan is first digested by mutanolysin in order to generate muropeptides which are subsequently analyzed by reversed-phase liquid chromatography (RP-LC, C18). However, this technique is not effective enough to separate the peptides that, as a result, are eluted in the flow through . In this work, we developed two novel analytical separation methods, namely capillary electrophoresis (CE) and zwitterionic hydrophilic interaction liquid chromatography (ZIC-HILIC) both coupled to mass spectrometry (MS), aiming at overcoming the drawbacks encountered in traditional separation techniques. Both methods show great results in the identification of peptidoglycan fragments in complex samples. CE analysis lead to muropeptides and peptides separation whereas ZIC-HILIC only retains peptides. Nevertheless, the latter has been optimized and validated for the cytoplasmic peptidoglycan peptides identification and quantification. Althogether, ZIC-HILIC-MS and CE-MS have proved to be powerful analytical tools for the identification and quantification of peptidoglycan fragments in complex matrix samples. Further optimizations are still ongoing for the analysis of muropeptides, which hopefully will lead to the identification and quantification of cytoplasmic peptidoglycan fragments composition during the Bacillus licheniformis 749/I BlaP beta-lactamase induction process. [less ▲]

Detailed reference viewed: 172 (5 ULiège)
Full Text
Peer Reviewed
See detailMultiple Gas-Phase Conformations of a Synthetic Linear Poly(acrylamide) Polymer Observed Using Ion Mobility-Mass Spectrometry
Haler, Jean ULiege; Far, Johann ULiege; Aqil, Abdelhafid ULiege et al

in Journal of the American Society for Mass Spectrometry (2017), 28(11), 24922499

Ion mobility-mass spectrometry (IM-MS) has emerged as a powerful separation and identification tool to characterize synthetic polymer mixtures and topologies (linear, cyclic, star-shaped ... [more ▼]

Ion mobility-mass spectrometry (IM-MS) has emerged as a powerful separation and identification tool to characterize synthetic polymer mixtures and topologies (linear, cyclic, star-shaped,...). Electrospray coupled to IM-MS already revealed the coexistence of several charge state-dependent conformations for a single charge state of biomolecules with strong intramolecular interactions, even when limited resolving power IM-MS instruments were used. For synthetic polymers, the sample's polydispersity allows the observation of several chain lengths. A unique collision cross-section (CCS) trend is usually observed when increasing the degree of polymerization (DP) at constant charge state, allowing the deciphering of different polymer topologies. In this paper, we report multiple coexisting CCS trends when increasing the DP at constant charge state for linear poly(acrylamide) PAAm in the gas phase. This is similar to observations on peptides and proteins. Biomolecules show in addition population changes when collisionally heating the ions. In the case of synthetic PAAm, fragmentation occurred before reaching the energy for conformation conversion. These observations, which were made on two different IM-MS instruments (SYNAPT G2 HDMS and high resolution multi-pass cyclic T-Wave prototype from Waters), limit the use of ion mobility for synthetic polymer topology interpretations to polymers where unique CCS values are observed for each DP at constant charge state. [less ▲]

Detailed reference viewed: 95 (47 ULiège)
Full Text
Peer Reviewed
See detailAccurate drift time determination by traveling wave ion mobility spectrometry: The concept of the diffusion calibration
Kune, Christopher ULiege; Far, Johann ULiege; De Pauw, Edwin ULiege

in Analytical Chemistry (2016), 88

Ion mobility spectrometry (IMS) is a gas phase separation technique which relies on differences in collision cross section (CCS) of ions. Ionic clouds of unresolved conformers overlap if the CCS ... [more ▼]

Ion mobility spectrometry (IMS) is a gas phase separation technique which relies on differences in collision cross section (CCS) of ions. Ionic clouds of unresolved conformers overlap if the CCS difference is below the instrumental resolution expressed as CCS/ΔCCS. The experimental arrival time distribution (ATD) peak is then a superimposition of the various contributions weighted by their relative intensities. This paper introduces a strategy for accurate drift time determination using traveling wave ion mobility spectrometry (TWIMS) of poorly resolved or unresolved conformers. This method implements through a calibration procedure the link between the peak full width at half maximum (FWHM) and the drift time of model compounds for wide range of settings for wave heights and velocities. We modified a Gaussian equation which achieves the deconvolution of ATD peaks where the FWHM is fixed according to our calibration procedure. The new fitting Gaussian equation only depends on two parameters: The apex of the peak (A) and the mean drift time value (μ). The standard deviation parameter (correlated to FWHM) becomes a function of the drift time. This correlation function between μ and FWHM is obtained using the TWIMS calibration procedure which determines the maximum instrumental ion beam diffusion under limited and controlled space charge effect using ionic compounds which are detected as single conformers in the gas phase. This deconvolution process has been used to highlight the presence of poorly resolved conformers of crown ether complexes and peptides leading to more accurate CCS determinations in better agreement with quantum chemistry predictions [less ▲]

Detailed reference viewed: 35 (7 ULiège)