References of "De Pauw, Edwin"
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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 (in press)

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 detailThe Arabidopsis frd3 mutant phenotype: a new level of complexity
Scheepers, Maxime ULiege; Spielmann, Julien ULiege; Boulanger, Madeleine ULiege et al

Poster (2017, December 07)

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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 detailWhere Ion Mobility and Molecular Dynamics Meet to Unravel the (Un)Folding Mechanisms of an Oligorotaxane Molecular Switch
Hanozin, Emeline ULiege; Mignolet, Benoît ULiege; Morsa, Denis ULiege et al

in ACS Nano (2017), 11(10), 10253-10263

At the interface between foldamers and mechanically interlocked molecules, oligorotaxanes exhibit a spring-like folded secondary structure with remarkable mechanical and physicochemical properties. Among ... [more ▼]

At the interface between foldamers and mechanically interlocked molecules, oligorotaxanes exhibit a spring-like folded secondary structure with remarkable mechanical and physicochemical properties. Among these properties, the ability of oligorotaxanes to act as molecular switches through controlled modulations of their spatial extension over (un)folding dynamics is of particular interest. The present study aims to assess and further characterize this remarkable feature in the gas phase using mass spectrometry tools. In this context, we focused on the [4]5NPR+12 oligorotaxane molecule complexed with PF6 - counterion and probed its co-conformational states as a function of the in-source-generated charge states. Data were interpreted in light of electronic secondary structure computations at the PM6 and DFT levels. Our results highlight two major co-conformational groups associated either with folded compact structures, notably stabilized by intramolecular π-π interactions and predominant for low charge states or with fully stretched structures resulting from significant Coulombic repulsions at high charge states. Between, the oligorotaxane adopts intermediate folded co-conformations, suggesting a stepwise unfolding pathway under increasing repulsive Coulombic constraints. The reversibility of this superstructural transition was next interrogated under electron-driven (nondissociative electron transfer) and heat-driven (collision-induced unfolding) activation stimuli. The outcomes support the feasibility to either unfold or (partially) refold the oligorotaxane foldamer on purpose in the gas phase. Our results show that the balance between the stabilizing π-π interactions and the versatile Coulomb interactions dictates the elongation state of the foldamer in the gas phase and emphasizes the adequacy of mass spectrometry tools for the superstructural characterization of desolvated prototypical artificial molecular machines. © 2017 American Chemical Society. [less ▲]

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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)

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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 detailIon Mobility-Mass Spectrometry: Going beyond the numbers
Haler, Jean ULiege; Far, Johann ULiege; Béchet, Eric ULiege et al

Scientific conference (2017, July 03)

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See detailComparative Proteomics Analysis Provides New Candidates for Zinc Homeostasis Regulation in Arabidopsis
Amini, Sahand ULiege; Arsova, Borjana ULiege; Scheepers, Maxime ULiege et al

Poster (2017, July 03)

Zinc (Zn) is an essential micronutrient for plants and around two billion people are depending on grains and legumes as their main Zn source. On the other hand, this transition metal is toxic for plants ... [more ▼]

Zinc (Zn) is an essential micronutrient for plants and around two billion people are depending on grains and legumes as their main Zn source. On the other hand, this transition metal is toxic for plants at high concentrations in soils. This calls for a better unravelling of Zn homeostasis regulation mechanisms, including sensing and signaling in plants. In order to fulfill this aim, we are testing for novel proteins involved in Zn homeostasis in the model plant Arabidopsis thaliana. First, quantitative proteomics was performed on root and shoot samples obtained upon Zn starvation and re-supply in different spatio-temporal conditions. Inductively coupled plasma atomic emission spectroscopy (ICP-AES) analysis was also performed for those treatments to measure the Zn concentration in tissues. It showed very rapid Zn uptake in root upon re-supply. Moreover, quantitative expression studies of known players of Zn homeostasis confirmed our large-scale proteomic results, although for a few genes lack of correlation between transcript and protein regulation was observed. Using clustering, statistical and gene ontology analyses, we selected candidate genes for further studies. Among more than 5000 detected proteins in roots by shotgun proteomics, 75 genes were selected for targeted analyses. In general, our results show that comparative proteomics study can be useful to reveal new players in the Zn regulatory network in plants, which can lead to new Zn biofortification and phytoremediation strategies. [less ▲]

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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 ▲]

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See detailMass spectrometry imaging of small xenobiotics on Danio rerio : influence of molecular profiles modification as potential localization asset
Tiquet, Mathieu ULiege; Muller, Marc ULiege; De Pauw, Edwin ULiege

Poster (2017, June 02)

MALDI Mass spectrometry often fail to locate small xenobiotics present in low concentration in tissues due to ion suppression effect. This new method compare tissues of contaminated zebrafish to controles ... [more ▼]

MALDI Mass spectrometry often fail to locate small xenobiotics present in low concentration in tissues due to ion suppression effect. This new method compare tissues of contaminated zebrafish to controles with the statistical tool called receiver operating characteristic. Results cannot directly locate the xenobiotic but can indicate which tissues are affected by the contamination and thus give a hint on the biolocalization. [less ▲]

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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 ▲]

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See detailGreen mamba peptide targets type-2 vasopressin receptor against polycystic kidney disease
Ciolek, Justyna; Reinfrank, Helen; Quinton, Loïc ULiege et al

in Proceedings of the National Academy of Sciences of the United States of America (2017)

Polycystic kidney diseases (PKDs) are genetic disorders that can cause renal failure and death in children and adults. Lowering cAMP in cystic tissues through the inhibition of the type-2 vasopressin ... [more ▼]

Polycystic kidney diseases (PKDs) are genetic disorders that can cause renal failure and death in children and adults. Lowering cAMP in cystic tissues through the inhibition of the type-2 vasopressin receptor (V2R) constitutes a validated strategy to reduce disease progression. We identified a peptide from green mamba venom that exhibits nanomolar affinity for the V2R without any activity on 155 other G-protein–coupled receptors or on 15 ionic channels. Mambaquaretin-1 is a full antagonist of the V2R activation pathways studied: cAMP production, beta-arrestin interaction, and MAP kinase activity. This peptide adopts the Kunitz fold known to mostly act on potassium channels and serine proteases. Mambaquaretin-1 interacts selectively with the V2R through its first loop, in the same manner that aprotinin inhibits trypsin. Injected in mice, mambaquaretin-1 increases in a dose-dependent manner urine outflow with concomitant reduction of urine osmolality, indicating a purely aquaretic effect associated with the in vivo blockade of V2R. CD1-pcy/pcy mice, a juvenile model of PKD, daily treated with 13 μ𝝁g of mambaquaretin-1 for 99 d, developed less abundant (by 33%) and smaller (by 47%) cysts than control mice. Neither tachyphylaxis nor apparent toxicity has been noted. Mambaquaretin-1 represents a promising therapeutic agent against PKDs. [less ▲]

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