References of "Teller, Nathalie"
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See detailSynthesis of two new alkyne-bearing liners used for the preparation of siRNA for labeling by click chemistry with fluorine-18
Flagothier, Jessica ULg; Kaisin, Geoffroy ULg; Mercier, Frederic et al

in Applied Radiation & Isotopes (2012), 70(8), 1549-1557

Oligonucleotides (ONs) and more particularly siRNAs are promising drugs but their pharmacokinetics and biodistribution are widely unknown. Positron Emission Tomography (PET) using fluorine-18 is a ... [more ▼]

Oligonucleotides (ONs) and more particularly siRNAs are promising drugs but their pharmacokinetics and biodistribution are widely unknown. Positron Emission Tomography (PET) using fluorine-18 is a suitable technique to quantify these biological processes. Click chemistry (Huisgen cycloaddition) is the current method for labeling siRNA. In order to study the influence of a linker bearing by [18F]labeled ONs, on the in vivo pharmacokinetic and metabolism, we have developed two modified ONs by two news linkers. Here we report the synthesis of two alkyne-bearing linkers, the incorporation onto a ONs and the conjugation by click chemistry with a [18F]prosthetic group. [less ▲]

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See detailA peptidoglycan fragment triggers beta-lactam resistance in Bacillus licheniformis.
Amoroso, Ana Maria ULg; Boudet, Julien; Berzigotti, Stephanie et al

in PLoS Pathogens (2012), 8(3), 1002571

To resist to beta-lactam antibiotics Eubacteria either constitutively synthesize a beta-lactamase or a low affinity penicillin-binding protein target, or induce its synthesis in response to the presence ... [more ▼]

To resist to beta-lactam antibiotics Eubacteria either constitutively synthesize a beta-lactamase or a low affinity penicillin-binding protein target, or induce its synthesis in response to the presence of antibiotic outside the cell. In Bacillus licheniformis and Staphylococcus aureus, a membrane-bound penicillin receptor (BlaR/MecR) detects the presence of beta-lactam and launches a cytoplasmic signal leading to the inactivation of BlaI/MecI repressor, and the synthesis of a beta-lactamase or a low affinity target. We identified a dipeptide, resulting from the peptidoglycan turnover and present in bacterial cytoplasm, which is able to directly bind to the BlaI/MecI repressor and to destabilize the BlaI/MecI-DNA complex. We propose a general model, in which the acylation of BlaR/MecR receptor and the cellular stress induced by the antibiotic, are both necessary to generate a cell wall-derived coactivator responsible for the expression of an inducible beta-lactam-resistance factor. The new model proposed confirms and emphasizes the role of peptidoglycan degradation fragments in bacterial cell regulation. [less ▲]

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See detailRadiolabeling of modified siRNA by click chemistry with fluorine-18 for PET studies
Flagothier, Jessica ULg; Mercier, Frédéric; Kaisin, Geoffroy ULg et al

in Journal of Labelled Compounds and Radiopharmaceuticals (2011)

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See detailGeneral Method for Labeling siRNA by Click Chemistry with Fluorine-18 for the Purpose of PET Imaging
Mercier, Frédéric; Paris, Jérôme ULg; Kaisin, Geoffroy ULg et al

in Bioconjugate Chemistry (2011), 22(1), 108-114

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See detail1,6-AnhMurNAc derivatives for assay development of amidase AmiD.
Mercier, Frédéric ULg; Zervosen, Astrid ULg; Teller, Nathalie et al

in Bioorganic & Medicinal Chemistry (2010), 18(21), 7422-31

Various peptidoglycan fragments were synthesized from two anhydro-muramic acid derivatives protected with a Bn or a PMB group at the 4th position, in homogenate phase or on a solid support. In order to ... [more ▼]

Various peptidoglycan fragments were synthesized from two anhydro-muramic acid derivatives protected with a Bn or a PMB group at the 4th position, in homogenate phase or on a solid support. In order to facilitate HPLC detection, a chromophoric group was attached to the peptide chain. The periplasmic amidase sAmiD of Escherichia coli was used to cleave the amide bond between the lactyl group of the MurNAc and the alpha-amino group of L-Ala where the peptide chain was at least a dipeptide (L-Ala-gamma-D-Glu) amidated by benzylamine on the gamma-carboxyl group of D-Glu. In the presence of a tripeptide chain (L-Ala-gamma-D-Glu-L-Lys) or a tetrapeptide chain (L-Ala-gamma-D-Glu-m-A(2)pm-D-Ala) higher hydrolysis rates were observed. We have also demonstrated that the presence of TNB on the epsilon-amino group of L-Lys only has a small influence on the hydrolysis capacity of sAmiD. [less ▲]

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See detailSynthesis and Evaluation of 3-(Dihydroxyboryl)benzoic Acids as d,d-Carboxypeptidase R39 Inhibitors.
Inglis, Steven R.; Zervosen, Astrid ULg; Woon, Esther C.Y. et al

in Journal of Medicinal Chemistry (2009)

Penicillin binding proteins (PBPs) catalyze steps in the biosynthesis of bacterial cell walls and are the targets for the beta-lactam antibiotics. Non-beta-lactam based antibiotics that target PBPs are of ... [more ▼]

Penicillin binding proteins (PBPs) catalyze steps in the biosynthesis of bacterial cell walls and are the targets for the beta-lactam antibiotics. Non-beta-lactam based antibiotics that target PBPs are of interest because bacteria have evolved resistance to the beta-lactam antibiotics. Boronic acids have been developed as inhibitors of the mechanistically related serine beta-lactamases and serine proteases; however, they have not been explored extensively as PBP inhibitors. Here we report aromatic boronic acid inhibitors of the d,d-carboxypeptidase R39 from Actinomadura sp. strain. Analogues of an initially identified inhibitor [3-(dihydroxyboryl)benzoic acid 1, IC(50) 400 muM] were prepared via routes involving pinacol boronate esters, which were deprotected via a two-stage procedure involving intermediate trifluorborate salts that were hydrolyzed to provide the free boronic acids. 3-(Dihydroxyboryl)benzoic acid analogues containing an amide substituent in the meta, but not ortho position were up to 17-fold more potent inhibitors of the R39 PBP and displayed some activity against other PBPs. These compounds may be useful for the development of even more potent boronic acid based PBP inhibitors with a broad spectrum of antibacterial activity. [less ▲]

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See detailCharacterization of the proteins encoded by the Bacillus subtilis yoxA-dacC operon.
Duez, Colette ULg; Zervosen, Astrid ULg; Teller, Nathalie et al

in FEMS Microbiology Letters (2009), 300

Abstract In Bacillus subtilis, the yoxA and dacC genes were proposed to form an operon. The yoxA gene was overexpressed in Escherichia coli and its product fused to a polyhistidine tag was purified. An ... [more ▼]

Abstract In Bacillus subtilis, the yoxA and dacC genes were proposed to form an operon. The yoxA gene was overexpressed in Escherichia coli and its product fused to a polyhistidine tag was purified. An aldose-1-epimerase or mutarotase activity was measured with the YoxA protein that we propose to rename as GalM by analogy with its counterpart in E. coli. The peptide d-Glu-delta-m-A(2)pm-d-Ala-m-A(2)pm-d-Ala mimicking the B. subtilis and E. coli interpeptide bridge was synthesized and incubated with the purified dacC product, the PBP4a. A clear dd-endopeptidase activity was obtained with this penicillin-binding protein, or PBP. The possible role of this class of PBP, present in almost all bacteria, is discussed. [less ▲]

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See detailActivation mechanism of recombinant Der p 3 allergen zymogen - Contribution of cysteine protease Der p 1 and effect of propeptide glycosylation
Dumez, Marie-Eve ULg; Teller, Nathalie; Mercier, Frédéric ULg et al

in Journal of Biological Chemistry (2008), 283(45), 30606-30617

The trypsin-like protease Der p 3, a major allergen of the house dust mite Dermatophagoides pteronyssinus, is synthesized as a zymogen, termed proDer p 3. No recombinant source of Der p 3 has been ... [more ▼]

The trypsin-like protease Der p 3, a major allergen of the house dust mite Dermatophagoides pteronyssinus, is synthesized as a zymogen, termed proDer p 3. No recombinant source of Der p 3 has been described yet, and the zymogen maturation mechanism remains to be elucidated. The Der p 3 zymogen was produced in Pichia pastoris. We demonstrated that the recombinant zymogen is glycosylated at the level of its propeptide. We showed that the activation mechanism of proDer p 3 is intermolecular and is mediated by the house dust mite cysteine protease Der p 1. The primary structure of the proDer p 3 propeptide is associated with a unique zymogen activation mechanism, which is different from those described for the trypsin-like family and relies on the house dust mite papain-like protease Der p 1. This is the first report of a recombinant source of Der p 3, with the same enzymatic activity as the natural enzyme and trypsin. Glycosylation of the propeptide was found to decrease the rate of maturation. Finally, we showed that recombinant Der p 3 is inhibited by the free modified prosequence TP1R. [less ▲]

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