References of "Lamotte-Brasseur, Josette"
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See detailOn the way of understanding the adaptation to extreme pH of family 11 xylanases: Structural comparison and mutational analysis
De Lemos Esteves, Frédéric ULg; Ruelle, Virginie; Gouders, Thierry et al

Poster (2004, December)

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See detailAcidophilic adaptation of family 11 endo--1,4-xylanases: Modeling and mutational analysis
De Lemos Esteves, Frédéric ULg; Ruelle, Virginie; Lamotte-Brasseur, Josette ULg et al

in Protein Science : A Publication of the Protein Society (2004), 13(5), 12091218

Xyl1 from Streptomyces sp. S38 belongs to the low molecular mass family 11 of endo--1,4-xylanases. Its three-dimensional structure has been solved at 2.0 Å and its optimum temperature and pH for enzymatic ... [more ▼]

Xyl1 from Streptomyces sp. S38 belongs to the low molecular mass family 11 of endo--1,4-xylanases. Its three-dimensional structure has been solved at 2.0 Å and its optimum temperature and pH for enzymatic activity are 60°C and 6.0, respectively. Aspergillus kawachii xylanase XynC belongs to the same family but is an acidophilic enzyme with an optimum pH of 2.0. Structural comparison of Xyl1 and XynC showed differences in residues surrounding the two glutamic acid side chains involved in the catalysis that could be responsible for the acidophilic adaptation of XynC. Mutations W20Y, N48D, A134E, and Y193W were introduced by site-directed mutagenesis and combined in multiple mutants. Trp 20 and Tyr 193 are involved in substrate binding. The Y193W mutation inactivated Xyl1 whereas W20Y decreased the optimum pH of Xyl1 to 5.0 and slightly increased its specific activity. The N48D mutation also decreased the optimum pH of Xyl1 by one unit. The A134E substitution did not induce any change, but when combined with N48D, a synergistic effect was observed with a 1.4 unit decrease in the optimum pH. Modeling showed that the orientations of residue 193 and of the fully conserved Arg 131 are different in acidophilic and alkaline xylanases whereas the introduced Tyr 20 probably modifies the pKa of the acid-base catalyst via residue Asn 48. Docking of a substrate analog in the catalytic site highlighted striking differences between Xyl1 and XynC in substrate binding. Hydrophobicity calculations showed a correlation between acidophilic adaptation and a decreased hydrophobicity around the two glutamic acid side chains involved in catalysis. [less ▲]

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See detailRésistance bactérienne aux beta-lactamines
Charlier, Paulette ULg; Coyette, Jacques ULg; Dehareng, Dominique ULg et al

in Medecine Sciences : M/S (1998), 14(5), 544-555

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See detailComparison of the Sequences of Class a β-lactamase and of the Secondary Structure Elements of Penicillin-Recognizing Proteins
Joris, Bernard ULg; Ledent, P.; Dideberg, O. et al

in Antimicrobial Agents and Chemotherapy (1991), 35(11), 2294-2301

The sequences of class A beta-lactamases were compared. Four main groups of enzymes were distinguished: those from the gram-negative organisms and bacilli and two distinct groups of Streptomyces spp. The ... [more ▼]

The sequences of class A beta-lactamases were compared. Four main groups of enzymes were distinguished: those from the gram-negative organisms and bacilli and two distinct groups of Streptomyces spp. The Staphylococcus aureus PC1 enzyme, although somewhat closer to the enzyme from the Bacillus group, did not belong to any of the groups of beta-lactamases. The similarities between the secondary structure elements of these enzymes and those of the class C beta-lactamases and of the Streptomyces sp. strain R61 DD-peptidase were also analyzed and tentatively extended to the class D beta-lactamases. A unified nomenclature of secondary structure elements is proposed for all the penicillin-recognizing enzymes. [less ▲]

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See detailNumerical computation of the electrostatic interaction energy between methanol and the dyad water-imidazole
Dehareng, Dominique ULg; Dive, Georges ULg; Lamotte-Brasseur, Josette ULg et al

in Theoretica Chimica Acta (1989), 76(2), 85-94

The electrostatic interaction energy between methanol and the dyad water-imidazole has been computed numerically at three levels of approximation from 3D grids of the charge density of one partner and the ... [more ▼]

The electrostatic interaction energy between methanol and the dyad water-imidazole has been computed numerically at three levels of approximation from 3D grids of the charge density of one partner and the electrostatic potential of the other. The minimum positions and energy values thus obtained compare well with those calculated analytically. The numerical procedure is especially interesting for the prediction of the stable conformers. [less ▲]

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See detailBacterial wall peptidoglycan, DD-peptidases and beta-lactam antibiotics
Ghuysen, Jean-Marie ULg; Frère, Jean-Marie ULg; Leyh-Bouille, Mélina et al

in Scandinavian Journal of Infectious Diseases (1984), 42

Wall peptidoglycan expansion in bacteria rests upon a cytoplasmic D-Ala: D-Ala ligase (ADP) which catalyses synthesis of a D-Ala-D-Ala dipeptide (with accompanying hydrolysis of one molecule of ATP) and a ... [more ▼]

Wall peptidoglycan expansion in bacteria rests upon a cytoplasmic D-Ala: D-Ala ligase (ADP) which catalyses synthesis of a D-Ala-D-Ala dipeptide (with accompanying hydrolysis of one molecule of ATP) and a set of DD-peptidases which utilize this D-Ala-D-Ala dipeptide--once it has been translocated at the outer face of the plasma membrane as the C-terminal portion of a disaccharide peptide unit--as carbonyl donor for transpeptidation and carboxypeptidation reactions (without additional energy expenditure). Four DD-peptidases have been selected which differ from each other with respect to the effects that amino compounds exert on the fate and rate of consumption of a D-Ala-D-Ala terminated amide carbonyl donor analogue. They serve as models to understand the different mechanisms by which the DD-peptidases perform catalysis and show widely varying responses to the action of beta-lactams, from extreme sensitivity to very high resistance. [less ▲]

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See detailThe active sites of the D-alanyl-D-alanine-cleaving peptidases
Charlier, Paulette ULg; Dideberg, Otto; Dive, Georges ULg et al

in Hakenbeck, Regine; Höltje, Joachim-Volker; Labischinski, Harald (Eds.) The Target Penicillin : the Murein Sacculus of Bacterial Cell Walls Architecture and Growth : Proceedings (1983)

The active site structures of D-alanyl-D-alanine-cleaving peptidases G, R61, R39, and K15 from Streptomyces and Actinomadura are discussed in relation to their substrate specificities and kinetic ... [more ▼]

The active site structures of D-alanyl-D-alanine-cleaving peptidases G, R61, R39, and K15 from Streptomyces and Actinomadura are discussed in relation to their substrate specificities and kinetic mechanisms. [less ▲]

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See detailStructure cristalline et moléculaire d'un nouvel alclaoïde bisindolique: complexe moléculaire 1:2 Strychnofoline-Ethanol
Dideberg, otto; Lamotte-Brasseur, Josette ULg; Dupont, Léon et al

in Acta Crystallographica. Section B-Structural Crystallography and Crystal Chemistry (1977), B33

Strychnofoline is a phenolic alkaloid isolated from leaves of Strychnos usambarensis. The crystals of the complex Strychnofoline-Ethanol are monoclinic. the crystal structure has been solvad by direct ... [more ▼]

Strychnofoline is a phenolic alkaloid isolated from leaves of Strychnos usambarensis. The crystals of the complex Strychnofoline-Ethanol are monoclinic. the crystal structure has been solvad by direct methods. The configuration determined by biogenetic arguments is 3S?4R?7S?15S?17S?20R. This is the first oxindole alkaloid found in a Strychnos species. [less ▲]

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