References of "Feller, Georges"
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See detailA nondetergent sulfobetaine prevents protein aggregation in microcalorimetric studies
Collins, T.; D'Amico, Salvino ULg; Georlette, D. et al

in Analytical Biochemistry (2006), 352(2), 299-301

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See detailOligosaccharide binding in family 8 glycosidases: Crystal structures of active-site mutants of the beta-1,4-xylanase pXyl from Pseudoaltermonas haloplanktis TAH3a in complex with substrate and product
De Vos, D.; Collins, T.; Nerinckx, W. et al

in Biochemistry (2006), 45(15), 4797-4807

The structures of inactive mutants D144A and E78Q of the glycoside hydrolase family 8 (GH-8) endo-beta-1,4-D-Xylanase (pXyl) from the Antarctic bacterium Pseudoalteromonas haloplanktis TAH3a in complex ... [more ▼]

The structures of inactive mutants D144A and E78Q of the glycoside hydrolase family 8 (GH-8) endo-beta-1,4-D-Xylanase (pXyl) from the Antarctic bacterium Pseudoalteromonas haloplanktis TAH3a in complex with its substrate xylopentaose (at 1.95 angstrom resolution) and product xylotriose (at 1.9 angstrom resolution) have been determined by X-ray crystallography. A detailed comparative analysis of these with the apoenzyme and with other GH-8 structures indicates an induced fit mechanism upon ligand binding whereby a number of conformational changes and, in particular, a repositioning of the proton donor into a more catalytically competent position Occurs. This has also allowed for the description of protein-ligand interactions in this enzyme and for the demarcation of subsites -3 to +3. An in-depth analysis of each of these subsites gives an insight into the structure-function relationship of this enzyme and the basis of xylose/glucose discrimination in family 8 glycoside hydrolases. Furthermore, the structure of the -1/+1 subsite spanning complex reveals that the substrate is distorted from its ground state conformation. Indeed, structural analysis and in silico docking Studies indicate that substrate hydrolysis in GH-8 members is preceded by a conformational change, away from the substrate ground-state chair conformation, to a pretransition state local minimum S-2(O) conformation. [less ▲]

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See detailPsychrophilic microorganisms: challenges for life
D'Amico, Salvino ULg; Collins, T.; Marx, J. C. et al

in EMBO Reports (2006), 7(4), 385-389

The ability of psychrophiles to survive and proliferate at low temperatures implies that they have overcome key barriers inherent to permanently cold environments. These challenges include: reduced enzyme ... [more ▼]

The ability of psychrophiles to survive and proliferate at low temperatures implies that they have overcome key barriers inherent to permanently cold environments. These challenges include: reduced enzyme activity; decreased membrane fluidity; altered transport of nutrients and waste products; decreased rates of transcription, translation and cell division; protein cold- denaturation; inappropriate protein folding; and intracellular ice formation. Cold- adapted organisms have successfully evolved features, genotypic and/ or phenotypic, to surmount the negative effects of low temperatures and to enable growth in these extreme environments. In this review, we discuss the current knowledge of these adaptations as gained from extensive biochemical and biophysical studies and also from genomics and proteomics. [less ▲]

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See detailUse of glycoside hydrolase family 8 xylanases in baking
Collins, T.; Hoyoux, A.; Dutron, A. et al

in Journal of Cereal Science (2006), 43(1), 79-84

Xylanases have long been used in the baking industry for improving dough stability and flexibility and for increasing bread volume and crumb structure. Only xylanases from glycoside hydrolase families 10 ... [more ▼]

Xylanases have long been used in the baking industry for improving dough stability and flexibility and for increasing bread volume and crumb structure. Only xylanases from glycoside hydrolase families 10 and I I appear to have been tested in this application and only those from the latter family have as yet found application. Interestingly, enzymes with a putative xylanase activity are also found in glycoside hydrolase families 5, 7, 8 and 43, but apparently these have not, as yet, been tested in baking. Baking trials were used to determine the effectiveness of a psychrophilic and a mesophilic family 8 xylanolytic enzyme as well as a psychrophilic family 10 xylanase and a currently used family 11 commercial mesophilic xylanase. The potential of family 8 xylanases as technological aids in baking was clearly demonstrated as both the psychrophilic enzyme from Pseudoalteromonas haloplanktis TAH3a and the mesophilic enzyme from Bacillus halodurans C-125 had a positive effect on loaf volume. In contrast, the psychrophilic family 10 enzyme from Cryptococcus adeliae TAE85 was found to be ineffective. (c) 2005 Elsevier Ltd. All rights reserved. [less ▲]

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See detailA novel family 8 psychrophilic xylanase: fundamentals and applications.
Collins, Tony; Gerday, Charles ULg; Feller, Georges ULg

Poster (2006)

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See detailBiocatalysis at low temperatures: a challenge for life.
Feller, Georges ULg

Conference (2006)

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See detailProteomics of marine microorganisms
Voigt, B.; Hieu, C.X.; Wilmes, B. et al

Conference (2006)

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See detailSurvival in the cold: proteome analysis of the psychrophilic marine bacterium Pseudoalteromonas haloplanktis TAC125
Wilmes, B.; Glagla, S.; Albrecht, D. et al

Poster (2006)

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See detailProtein folding is a rate limiting step for bacterial growth at low temperatures.
Piette, Florence; D'Amico, Salvino; Leprince, Pierre ULg et al

Poster (2006)

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See detailAnalysis of Ser-His-Glu triad in alpha-amylases
Marx, Jean Claude; Feller, Georges ULg

Poster (2006)

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See detailProtein folding is a rate limiting step for bacterial growth at low temperatures
Piette, Florence; D'Amico, Salvino; Leprince, Pierre ULg et al

Poster (2006)

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See detailFundamentals and biotechnological aspects of cold-adapted enzymes
Gerday, Charles ULg; Collins, Tony; D'Amico, Salvino et al

Conference (2006)

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See detailAnalysis of Ser-His-Glu triad in alpha-amylases
Marx, Jean Claude; Feller, Georges ULg

Poster (2006)

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See detailCold-adapted xylanases: from Antarctica to the table.
Collins, Tony; Georis, Jacques; Dauvrin, Thierry et al

Poster (2006)

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See detailProtein folding is a rate limiting step for bacterial growth at low temperatures
D'Amico, Salvino; Piette, Florence; Leprince, Pierre ULg et al

Poster (2006)

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See detailOutils de biorestauration des sols sub-antarctiques exposés aux hydrocarbures pétroliers
Delille, D.; Pelletier, E.; Coulon, F. et al

in carn (2006), 21

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See detailStability domains, substrate-induced conformational changes, and hinge-bending motions in a psychrophilic phosphoglycerate kinase: A microcalorimetric study
Zecchinon, Laurent ULg; Oriol, A.; Netzel, U. et al

in Journal of Biological Chemistry (2005), 280(50), 41307-41314

The cold-active phosphoglycerate kinase from the Antarctic bacterium Pseudomonas sp. TACII18 exhibits two distinct stability domains in the free, open conformation. It is shown that these stability ... [more ▼]

The cold-active phosphoglycerate kinase from the Antarctic bacterium Pseudomonas sp. TACII18 exhibits two distinct stability domains in the free, open conformation. It is shown that these stability domains do not match the structural N- and C-domains as the heat-stable domain corresponds to about 80 residues of the C-domain, including the nucleotide binding site, whereas the remaining of the protein contributes to the main heat-labile domain. This was demonstrated by spectroscopic and microcalorimetric analyses of the native enzyme, of its mutants, and of the isolated recombinant structural domains. It is proposed that the heat-stable domain provides a compact structure improving the binding affinity of the nucleotide, therefore increasing the catalytic efficiency at low temperatures. Upon substrate binding, the enzyme adopts a uniformly more stable closed conformation. Substrate-induced stability changes suggest that the free energy of ligand binding is converted into an increased conformational stability used to drive the hinge-bending motions and domain closure. [less ▲]

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See detailStudy of the active site residues of a glycoside hydrolase family 8 xylanase
Collins, T.; De Vos, D.; Hoyoux, A. et al

in Journal of Molecular Biology (2005), 354(2), 425-435

Site-directed mutagenesis and a comparative characterisation of the kinetic parameters, pH dependency of activity and thermal stability of mutant and wild-type enzymes have been used in association with ... [more ▼]

Site-directed mutagenesis and a comparative characterisation of the kinetic parameters, pH dependency of activity and thermal stability of mutant and wild-type enzymes have been used in association with crystallographic analysis to delineate the functions of several active site residues in a novel glycoside hydrolase family 8 xylanase. Each of the residues investigated plays an essential role in this enzyme: E78 as the general acid, D281 as the general base and in orientating the nucleophilic water molecule, Y203 in maintaining the position of the nucleophilic water molecule and in structural integrity and D144 in sugar ring distortion and transition state stabilization. Interestingly, although crystal structure analyses and the pH-activity profiles clearly identify the functions of E78 and D281, substitution of these residues with their amide derivatives results in only a 250-fold and 700-fold reduction in their apparent k(cat) values, respectively. This, in addition to the observation that the proposed general base is not conserved in all glycoside hydrolase family 8 enzymes, indicates that the mechanistic architecture in this family of inverting enzymes is more complex than is conventionally believed and points to a diversity in the identity of the mechanistically important residues as well as in the arrangement of the intricate microenvironment of the active site among members of this family. (c) 2005 Elsevier Ltd. All rights reserved. [less ▲]

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See detailCoping with cold: The genome of the versatile marine Antarctica bacterium Pseudoalteromonas haloplanktis TAC125
Medigue, C.; Krin, E.; Pascal, G. et al

in Genome Research (2005), 15(10), 1325-1335

A considerable fraction of life develops in the sea at temperatures lower than 15 degrees C. Little is known about the adaptive features selected under those conditions. We present the analysis of the ... [more ▼]

A considerable fraction of life develops in the sea at temperatures lower than 15 degrees C. Little is known about the adaptive features selected under those conditions. We present the analysis of the genome Sequence of the fast growing Antarctica bacterium Pseudoalteromonas haloplanktis TAC125. We find that it copes with the increased Solubility of oxygen at low temperature by multiplying dioxygen scavenging while deleting whole pathways producing reactive oxygen species. Dioxygen-consuming lipid desaturases achieve both protection against oxygen and synthesis of lipids making the membrane fluid. A remarkable strategy for avoidance of reactive oxygen species generation is developed by A haloplanktis, with elimination of the ubiquitous molybdopterin-dependent metabolism. The A haloplanktis proteome reveals a concerted amino acid usage bias specific to psychrophiles, consistently appearing apt to accommodate asparagine, a residue prone to make proteins age. Adding to its originality, A haloplanktis further differs from its marine Counterparts with recruitment of a plasmid origin of replication for its second chromosome. [less ▲]

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See detailNovel xylanases and their use
Georis, Jacques; Dauvrin, Thierry; Hoyoux, Anne et al

Patent (2005)

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