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See detailLigand binding mode to duplex and triplex DNA assessed by combining electrospray tandem mass spectrometry and molecular modeling
Rosu, Frédéric ULg; Nguyen, Chi-Hung; De Pauw, Edwin ULg et al

in Journal of the American Society for Mass Spectrometry (2007), 18(6), 1052-1062

In this paper, we report the analysis of seven benzopyridoindole and benzopyridoquinoxaline drugs binding to different duplex DNA and triple helical DNA, using an approach combining electrospray ... [more ▼]

In this paper, we report the analysis of seven benzopyridoindole and benzopyridoquinoxaline drugs binding to different duplex DNA and triple helical DNA, using an approach combining electrospray ionization mass spectrometry (ESI-MS), tandem mass spectrometry (MS/MS), and molecular modeling. The ligands were ranked according to the collision energy (CE(50)) necessary to dissociate 50% of the complex with the duplex or the triplex in tandem MS. To determine the probable ligand binding site and binding mode, molecular modeling was used to calculate relative ligand binding energies in different binding sites and binding modes. For duplex DNA binding, the ligand-DNA interaction energies are roughly correlated with the experimental CE(50), with the two benzopyridoindole ligands more tightly bound than the benzopyridoquinoxaline ligands. There is, however, no marked AT versus GC base preference in binding, as supported both by the ESI-MS and the calculated ligand binding energies. Product ion spectra of the complexes with triplex DNA show only loss of neutral ligand for the benzopyridoquinoxalines, and loss of the third strand for the benzopyridoindoles, the ligand remaining on the duplex part. This indicates a higher binding energy of the benzopyridoindoles, and also shows that the ligands interact with the triplex via the duplex. The ranking of the ligand interaction energies compared with the CE(50) values obtained by MS/MS on the complexes with the triplex clearly indicates that the ligands intercalate via the minor groove of the Watson-Crick duplex. Regarding triplex versus duplex selectivity, our experiments have demonstrated that the most selective drugs for triplex share the same heteroaromatic core. [less ▲]

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See detailLigand Binding Study of Human PEBP1/RKIP: Interaction with Nucleotides and Raf-1 Peptides Evidenced by NMR and Mass Spectrometry
Tavel, Laurette ULg; Jaquillard, Lucie; Karsisiotis, Andreas et al

in PLoS ONE (2012), 7(4): e36187

Background Human Phosphatidylethanolamine binding protein 1 (hPEBP1) also known as Raf kinase inhibitory protein (RKIP), affects various cellular processes, and is implicated in metastasis formation and ... [more ▼]

Background Human Phosphatidylethanolamine binding protein 1 (hPEBP1) also known as Raf kinase inhibitory protein (RKIP), affects various cellular processes, and is implicated in metastasis formation and Alzheimer's disease. Human PEBP1 has also been shown to inhibit the Raf/MEK/ERK pathway. Numerous reports concern various mammalian PEBP1 binding ligands. However, since PEBP1 proteins from many different species were investigated, drawing general conclusions regarding human PEBP1 binding properties is rather difficult. Moreover, the binding site of Raf-1 on hPEBP1 is still unknown. Methods/Findings In the present study, we investigated human PEBP1 by NMR to determine the binding site of four different ligands: GTP, FMN, and one Raf-1 peptide in tri-phosphorylated and non-phosphorylated forms. The study was carried out by NMR in near physiological conditions, allowing for the identification of the binding site and the determination of the affinity constants KD for different ligands. Native mass spectrometry was used as an alternative method for measuring KD values. Conclusions/Significance Our study demonstrates and/or confirms the binding of hPEBP1 to the four studied ligands. All of them bind to the same region centered on the conserved ligand-binding pocket of hPEBP1. Although the affinities for GTP and FMN decrease as pH, salt concentration and temperature increase from pH 6.5/NaCl 0 mM/20°C to pH 7.5/NaCl 100 mM/30°C, both ligands clearly do bind under conditions similar to what is found in cells regarding pH, salt concentration and temperature. In addition, our work confirms that residues in the vicinity of the pocket rather than those within the pocket seem to be required for interaction with Raf-1. [less ▲]

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See detailLigand binding to tetra-end-linked (TGGGGT)4 G-quadruplexes: an electrospray mass spectroscopy study
Amato, Jussara; Oliviero, Giorgia; Borbone, Nicola et al

in Nucleic Acids Symposium Series (2008), 52

The binding properties of a series of known G-quadruplex ligands have been studied by ESI-MS experiments. The tetramolecular (TG(4)T)(4) quadruplex and its analogues I and II blocked, respectively, at the ... [more ▼]

The binding properties of a series of known G-quadruplex ligands have been studied by ESI-MS experiments. The tetramolecular (TG(4)T)(4) quadruplex and its analogues I and II blocked, respectively, at the 3' or 5'-end by a tetra-end-linker (TEL) unit were chosen as the ligands targets. The stoichiometries of the obtained complexes as well as the ligand affinity and selectivity to the different quadruplexes were determined to deduce the ligand binding site. The TEL derivatives I and II allowed the probing of the grooves contribution to the binding of ligands to G-quadruplexes, demonstrating that the 3' and 5' quartets are not equivalent binding sites for ligand end-stacking. [less ▲]

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See detailLIGAND-INDEPENDENT IDENTIFICATION OF ORPHAN GPCR ARRESTIN BINDING
Dupuis, Nadine ULg; Gilissen, Julie ULg; Derj, Anouar ULg et al

Poster (2014, June 05)

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See detailLigand-independent Identification of orphan GPCR Signaling pathways
Dupuis, Nadine ULg; Gilissen, Julie; Derj, Anouar ULg et al

Conference (2014, July 16)

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See detailLigands and tracers for PET studies of the 5-HT system--current status.
Crouzel, C.; Guillaume, Marcel ULg; Barre, L. et al

in International Journal of Radiation Applications and Instrumentation. Part B : Nuclear Medicine and Biology (1992), 19(8), 857-70

The status of the radiochemical development and biological evaluation of radioligands and tracers for PET studies of the serotonergic system is reviewed, indicating those agents with present value and ... [more ▼]

The status of the radiochemical development and biological evaluation of radioligands and tracers for PET studies of the serotonergic system is reviewed, indicating those agents with present value and those with future potential. Practical recommendations are given for the preparation of two useful radioligands for PET studies of central 5-HT2 receptors, namely [18F]setoperone and [18F]altanserin. Though, it has not proved possible to recommend tracers or radioligands for the study of other aspects of serotonergic system, prospects for future radiochemical development are indicated, especially for developing radioligands for the 5-HT re-uptake site, and for the 5-HT1 and 5-HT3 receptors. [less ▲]

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See detailLigands playing musical chairs with G-quadruplex DNA: A rapid and simple displacement assay for identifying selective G-quadruplex binders
Monchaud, David; Allain, C.; Bertrand, Hélène et al

in Biochimie (2008), 90(8), 1207-1223

We report here the details of G4-FID (G-quadruplex fluorescent intercalator displacement), a simple method aiming at evaluating quadruplex DNA binding affinity and quadruplex- over duplex-DNA selectivity ... [more ▼]

We report here the details of G4-FID (G-quadruplex fluorescent intercalator displacement), a simple method aiming at evaluating quadruplex DNA binding affinity and quadruplex- over duplex-DNA selectivity of putative ligands. This assay is based on the loss of fluorescence upon displacement of thiazole orange from quadruplex and duplex-DNA matrices. The original protocol was tested using various quadruplex and duplex-DNA targets, and with a wide panel of G-quadruplex ligands belonging to different families (i.e. from quinacridines to metalloorganic ligands) likely to display various binding modes. The reliability of the assay is further supported by comparisons with FRET-melting and ESI-MS assays. [less ▲]

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See detailLigated anionic block copolymerization of methyl methacrylate with n-butyl acrylate and n-nonyl acrylate as promoted by lithium 2-(2-methoxyethoxy) ethoxide/diphenylmethyllithium
Nugay, Nihan; Nugay, Turgut; Jérôme, Robert ULg et al

in Journal of Polymer Science. Part A, Polymer Chemistry (1997), 35(8), 1543-1548

Poly(methyl methacrylate-b-n-butyl acrylate) (PMMA-b-Pn-BuA) and poly(methyl methacrylate-b-n-nonyl acrylate) (PMMA-b-Pn-NonA) diblock copolymers have been successfully synthesized by the sequential ... [more ▼]

Poly(methyl methacrylate-b-n-butyl acrylate) (PMMA-b-Pn-BuA) and poly(methyl methacrylate-b-n-nonyl acrylate) (PMMA-b-Pn-NonA) diblock copolymers have been successfully synthesized by the sequential anionic polymerization of methyl methacrylate (MMA) and the n-alkyl acrylate (n-BuA or n-NonA), in a 90/10 toluene/ tetrahydrofuran (THF) mixture at -78°C. When diphenylmethyllithium (DPMLi) ligated with lithium 2-(2-methoxyethoxy) ethoxide (LiOEEM) is used as the initiator, the polymerization of each block appears to be living. Molecular weight and composition of block copolymers can be predicted from the monomer over initator molar ratio and the molecular weight distribution is narrow. Size exclusion chromatography (SEC) supports that no homo-PMMA contaminates the final copolymer. Although the reverse polymerization sequence Pn-NonA-b-PMMA always results in some contamination by homo-Pn-NonA, it has no really significant effect on the final product characteristics. [less ▲]

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See detailLight absorption in conical silicon particles
Bogdanowicz, J; Gilbert, M; Innocenti, N et al

in Optics Express (2013), 21(3), 3891

The problem of the absorption of light by a nanoscale dielectric cone is discussed. A simplified solution based on the analytical Mie theory of scattering and absorption by cylindrical objects is proposed ... [more ▼]

The problem of the absorption of light by a nanoscale dielectric cone is discussed. A simplified solution based on the analytical Mie theory of scattering and absorption by cylindrical objects is proposed and supported by the experimental observation of sharply localized holes in conical silicon tips after high-fluence irradiation. This study reveals that light couples with tapered objects dominantly at specific locations, where the local radius corresponds to one of the resonant radii of a cylindrical object, as predicted by Mie theory. [less ▲]

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See detailLight and Electron microscopic immunolocalization of Bovine pregnancy-associated glycoprotein in the Bovine Placentome
Demez, Pierre ULg; Zolli, A. P.; Beckers, Jean-François ULg et al

in 1st Joint meeting of the Royal Microscopical society and the Belgian Societies for Cell biology, clinical cytology, Electron Microscopy and pathology-Abstract book (1993)

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See detailLight and electron microscopic immunolocalization of bovine pregnancy-associated glycoprotein in the bovine placentome.
Zoli, A.; Demez, Pierre ULg; Beckers, Jean-François ULg et al

in Biology of Reproduction (1992), 46(4), 623-9

A bovine pregnancy-associated glycoprotein (bPAG) of 67 kDa has previously been isolated from bovine fetal cotyledons. The objective of this study was to determine the cytological localization of that ... [more ▼]

A bovine pregnancy-associated glycoprotein (bPAG) of 67 kDa has previously been isolated from bovine fetal cotyledons. The objective of this study was to determine the cytological localization of that protein in the placentomes and possibly the cells responsible for its production. Highly specific antisera raised against pure bPAG were used to demonstrate the cellular localization of the protein in bovine placentomes by light and electron microscopic techniques. Strong immunostaining was observed exclusively in the cytoplasm of large binucleate cells present predominantly in fetal cotyledonary tissue (villi). Some smaller weakly immunostained cells were also present in caruncular epithelium. By ultrastructural immunogold procedures, the protein was detected only within amorphous cytoplasmic granules. Granules of identical size, but weakly labeled, were found on the maternal side. All cells containing labeled granules were binucleate. These results suggest that bPAG is probably synthesized by trophoblast binucleate cells and stored in granules prior to delivery into the maternal circulation after cell migration. [less ▲]

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See detailLight and electron microscopical localization of structural lipids with Sudan Black B and osmium tetroxide
Compère, Philippe ULg; Lhoas, Marie-Laure; Goffinet, Gerhard ULg

in Micron and Microscopica Acta (1989), 20(2), 119-120

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See detailLight as a modulator of cognitive brain function
Vandewalle, Gilles ULg; Maquet, Pierre ULg; Dijk, D. J.

in Trends in Cognitive Sciences (2009), 13(10), 429-38

Humans are a diurnal species usually exposed to light while engaged in cognitive tasks. Light not only guides performance on these tasks through vision but also exerts non-visual effects that are mediated ... [more ▼]

Humans are a diurnal species usually exposed to light while engaged in cognitive tasks. Light not only guides performance on these tasks through vision but also exerts non-visual effects that are mediated in part by recently discovered retinal ganglion cells maximally sensitive to blue light. We review recent neuroimaging studies which demonstrate that the wavelength, duration and intensity of light exposure modulate brain responses to (non-visual) cognitive tasks. These responses to light are initially observed in alertness-related subcortical structures (hypothalamus, brainstem, thalamus) and limbic areas (amygdala and hippocampus), followed by modulations of activity in cortical areas, which can ultimately affect behaviour. Light emerges as an important modulator of brain function and cognition. [less ▲]

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See detailLight as a modulator of cognitive brain functions
Vandewalle, Gilles ULg

Conference (2012, December)

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See detailLight as a modulator of cognitive brain functions
Vandewalle, Gilles ULg

Conference (2013, May 24)

Detailed reference viewed: 11 (1 ULg)
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See detailLight as a modulator of cognitive brain functions
Vandewalle, Gilles ULg

Conference (2012, April)

Detailed reference viewed: 30 (1 ULg)
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See detailLight as a modulator of cognitive brain functions
Vandewalle, Gilles ULg

Conference (2012, September)

Detailed reference viewed: 23 (2 ULg)