References of "Damblon, Christian"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailReinforced poly(hydroxyurethane) thermosets as high performance adhesives for aluminum substrates
Panchireddy, Satyannarayana ULiege; Thomassin, Jean-Michel ULiege; Grignard, Bruno ULiege et al

in Polymer Chemistry (2017), 8(38), 5897-5909

Poly(hydroxyurethane) (PHU) thermosets reinforced with (functional) nanofillers were developed to design high performance adhesives for bare aluminum. Solvent-free cyclic carbonate/amine/PDMS formulations ... [more ▼]

Poly(hydroxyurethane) (PHU) thermosets reinforced with (functional) nanofillers were developed to design high performance adhesives for bare aluminum. Solvent-free cyclic carbonate/amine/PDMS formulations loaded with native, epoxy- or cyclic carbonate-functionalized ZnO nanofillers were premixed before deposition and thermal curing onto Al. The results highlight that the addition of PDMS prevents PHUs from delamination of the Al surface by increasing the adhesive hydrophobicity and thus limiting the water uptake. The dispersion of functional fillers within PHUs improves their thermal and mechanical properties. Benchmarking of the adhesive performances of the reinforced PHU glues with existing PHU formulations attests for the benefits of dispersing functional fillers and PDMS within the resin and evidences a 270% increase of the shear strength of reinforced PHUs adhesives compared to formulations reported in the literature. [less ▲]

Detailed reference viewed: 62 (28 ULiège)
Full Text
Peer Reviewed
See detail1H, 13C and 15N backbone resonance assignments of the β-lactamase BlaP from Bacillus licheniformis 749/C and two mutational variants
Kay, Jennifer ULiege; Thorn, David; Rhazi, Noureddine ULiege et al

in Biomolecular NMR Assignments (2017)

Class A β-lactamases have been widely used as versatile scaffolds to create hybrid (or chimeric) proteins for a series of applications ranging from basic research to medicine. We have, in particular, used ... [more ▼]

Class A β-lactamases have been widely used as versatile scaffolds to create hybrid (or chimeric) proteins for a series of applications ranging from basic research to medicine. We have, in particular, used the β-lactamase BlaP from Bacillus licheniformis 749/C (BlaP) as a protein scaffold to create model polyglutamine (polyQ) proteins in order to better understand the mechanism(s) by which an expanded polyQ sequence triggers the formation of amyloid fibrils. The model chimeras were designed by inserting a polyQ sequence of various lengths at two different locations within BlaP (i.e. position 197 or position 216) allowing a detailed comparison of the effects of subtle differences in the environment of the polyQ sequence on its ability to trigger protein aggregation. In order to investigate the effects of the polyQ insertion at both positions on the structure, stability and dynamics of BlaP, a series of NMR experiments including H/D exchange are foreseen. Accordingly, as necessitated by these studies, here we report the NMR assignment of the wild-type BlaP (BlaP-WT) and of the two reference proteins BlaP197Q0 and BlaP216Q0, wherein a dipeptide Pro-Gly has been introduced at position 197 and 216, respectively; this dipeptide originates from the addition of the Sma1 restriction site at the genetic level to allow further polyQ sequence insertion. [less ▲]

Detailed reference viewed: 17 (3 ULiège)
Full Text
Peer Reviewed
See detailVisible-light TiO2 photocatalyst doped with silylated porphyrin
Mahy, Julien ULiege; Pàez Martinez, Carlos ULiege; Léonard, Géraldine ULiege et al

Conference (2017, August 15)

Detailed reference viewed: 39 (6 ULiège)
Full Text
Peer Reviewed
See detailIdentification and characterization of EYK1, a key gene for erythritol catabolism in Yarrowia lipolytica
Carly, Frédéric; Gamboa-Melendez, Heber; Vandermies, Marie ULiege et al

in Applied Microbiology and Biotechnology (2017), 101

Erythritol is a four-carbon sugar alcohol synthesized by osmophilic yeasts, such as Yarrowia lipolytica, in response to osmotic stress. This metabolite has application as food additive due to its ... [more ▼]

Erythritol is a four-carbon sugar alcohol synthesized by osmophilic yeasts, such as Yarrowia lipolytica, in response to osmotic stress. This metabolite has application as food additive due to its sweetening properties. Although Y. lipolytica can produce erythritol at a high level from glycerol, it is also able to consume it as carbon source. This ability negatively affects erythritol productivity and represents a serious drawback for the development of an efficient erythritol production process. In this study, we have isolated by insertion mutagenesis a Y. lipolytica mutant unable to grow on erythritol. Genomic characterization of the latter highlighted that the mutant phenotype is directly related to the disruption of the YALI0F01606g gene. Several experimental evidences suggested that the identified gene, renamed EYK1, encodes an erythrulose kinase. The mutant strain showed an enhanced capacity to produce erythritol as compared to the wild-type strain. Moreover, in specific experimental conditions, it is also able to convert erythritol to erythrulose, another compound of biotechnological interest. [less ▲]

Detailed reference viewed: 41 (1 ULiège)
Full Text
Peer Reviewed
See detailInteraction of Avibactam with Class B Metallo-β-Lactamases.
Abboud, MI; Damblon, Christian ULiege; Brem, J et al

in Antimicrobial Agents and Chemotherapy (2016), 60

Detailed reference viewed: 25 (4 ULiège)
Full Text
Peer Reviewed
See detailInvestigation of a suitable in vitro dissolution test for itraconazole-based solid dispersions
Thiry, Justine ULiege; Broze, Guy ULiege; Pestieau, Aude ULiege et al

in European Journal of Pharmaceutical Sciences (2016)

Detailed reference viewed: 133 (50 ULiège)
Full Text
Peer Reviewed
See detailThe role of active site flexible loops in catalysis and of zinc in conformational stability of Bacillus cereus 569/H/9 beta-lactamase.
Montagner, Caroline ULiege; Nigen, Michaël; Jacquin, Olivier et al

in Journal of Biological Chemistry (2016), 291(31), 16124-16137

Metallo-beta-lactamases catalyse the hydrolysis of most beta-lactam antibiotics and hence represent a major clinical concern. The development of inhibitors for these enzymes is complicated by the ... [more ▼]

Metallo-beta-lactamases catalyse the hydrolysis of most beta-lactam antibiotics and hence represent a major clinical concern. The development of inhibitors for these enzymes is complicated by the diversity and flexibility of their substrate binding sites, motivating research into their structure and function. In this study, we examined the conformational properties of the Bacillus cereus beta-lactamase II in the presence of chemical denaturants using a variety of biochemical and biophysical techniques. The apoenzyme was found to unfold cooperatively, with a Gibbs free energy of stabilization (DeltaG degrees ) of 32 +/- 2 kJ.mol11. For holoBcII, a first non-cooperative transition leads to multiple interconverting native-like states, in which both zinc atoms remain bound in an apparently unaltered active site and the protein displays a well-organized compact hydrophobic core with structural changes confined to the enzyme surface, but with no catalytic activity. 2D NMR data revealed that the loss of activity occurs concomitantly with perturbations in two loops that border the enzyme active site. A second cooperative transition, corresponding to global unfolding, is observed at higher denaturant concentrations, with DeltaG degrees value of 65 +/- 1.4 kJ.mol11. These combined data highlight the importance of the two zinc ions in maintaining structure as well as a relatively well-defined conformation for both active site loops in order to maintain enzymatic activity. [less ▲]

Detailed reference viewed: 53 (14 ULiège)
Full Text
Peer Reviewed
See detailMetal binding to the N-terminal cytoplasmic domain of the PIB ATPase HMA4 is required for metal transport in Arabidopsis.
Laurent, Clémentine ULiege; Lekeux, Gilles ULiege; Ukuwela, Ashwinie A et al

in Plant Molecular Biology (2016), 90

PIB ATPases are metal cation pumps that transport metals across membranes. These proteins possess N- and C-terminal cytoplasmic extensions that contain Cys- and His-rich high affinity metal binding ... [more ▼]

PIB ATPases are metal cation pumps that transport metals across membranes. These proteins possess N- and C-terminal cytoplasmic extensions that contain Cys- and His-rich high affinity metal binding domains, which may be involved in metal sensing, metal ion selectivity and/or in regulation of the pump activity. The PIB ATPase HMA4 (Heavy Metal ATPase 4) plays a central role in metal homeostasis in Arabidopsis thaliana and has a key function in zinc and cadmium hypertolerance and hyperaccumulation in the extremophile plant species Arabidopsis halleri. <br />Here, we examined the function and structure of the N-terminal cytoplasmic metal-binding domain of HMA4. We mutagenized a conserved CCTSE metal-binding motif in the domain and assessed the impact of the mutations on protein function and localization in planta, on metal-binding properties in vitro and on protein structure by Nuclear Magnetic Resonance spectroscopy. <br />The two Cys residues of the motif are essential for the function, but not for localization, of HMA4 in planta, whereas the Glu residue is important but not essential. These residues also determine zinc coordination and affinity. Zinc binding to the N-terminal domain is thus crucial for HMA4 protein function, whereas it is not required to maintain the protein structure. <br />Altogether, combining in vivo and in vitro approaches in our study provides insights towards the molecular understanding of metal transport and specificity of metal P-type ATPases. [less ▲]

Detailed reference viewed: 151 (35 ULiège)
Full Text
Peer Reviewed
See detailInfluences of the aqueous synthesis way and organosilane nature on the physico-chemical properties of porous alumina
Claude, Vincent ULiege; Vilaseca, Miriam; Tatton, Andrew ULiege et al

in European Journal of Inorganic Chemistry (2016), 2016(11), 1678-1689

The aqueous sol-gel synthesis of γ-Al2O3 modified with different silicon precursors {trimethoxysilane, triethoxysilane and N-[3-(trimethoxysilyl)propyl]ethylene diamine} has been investigated. Two ... [more ▼]

The aqueous sol-gel synthesis of γ-Al2O3 modified with different silicon precursors {trimethoxysilane, triethoxysilane and N-[3-(trimethoxysilyl)propyl]ethylene diamine} has been investigated. Two parameters have been studied: the silicon addition step and the type of silicon alkoxide. A first observation was that adding a silicon alkoxide either before or just after the precipitation step influences both the crystallinity and structure, whereas adding the alkoxide after a long agitation time only slightly modifies the support properties. It was also highlighted that due to their higher reactivity, silicon precursors with methoxy groups interact more strongly with the bulk alumina than the silicon precursors with ethoxy groups. This difference of Si location in the alumina structure permitted not only their resistance toward phase transition to be increased at high temperature, but also to stabilize them more efficiently against sintering under normal and steam conditions. Among the different silicon alkoxides tested, samples prepared with N-[3-(trimethoxysilyl)propyl]ethylene diamine showed very unusual properties. The alumina supports modified with this precursor showed grain-shaped nanocrystallites, whereas all other samples were platelet-like. As a result, this sample presented a very narrow pore diameter distribution of around 5 nm and a remarkably high specific surface area (530 m2/g). [less ▲]

Detailed reference viewed: 36 (3 ULiège)
Full Text
Peer Reviewed
See detailThe unexpected structure of the designed protein Octarellin V.1 forms a challenge for protein structure prediction tools.
Figueroa Yévenes, Maximiliano ULiege; Sleutel, Mike; Vandevenne, Marylène ULiege et al

in Journal of structural biology (2016)

Despite impressive successes in protein design, designing a well-folded protein of more 100 amino acids de novo remains a formidable challenge. Exploiting the promising biophysical features of the ... [more ▼]

Despite impressive successes in protein design, designing a well-folded protein of more 100 amino acids de novo remains a formidable challenge. Exploiting the promising biophysical features of the artificial protein Octarellin V, we improved this protein by directed evolution, thus creating a more stable and soluble protein: Octarellin V.1. Next, we obtained crystals of Octarellin V.1 in complex with crystallization chaperons and determined the tertiary structure. The experimental structure of Octarellin V.1 differs from its in silico design: the (alphabetaalpha) sandwich architecture bears some resemblance to a Rossman-like fold instead of the intended TIM-barrel fold. This surprising result gave us a unique and attractive opportunity to test the state of the art in protein structure prediction, using this artificial protein free of any natural selection. We tested 13 automated webservers for protein structure prediction and found none of them to predict the actual structure. More than 50% of them predicted a TIM-barrel fold, i.e. the structure we set out to design more than 10years ago. In addition, local software runs that are human operated can sample a structure similar to the experimental one but fail in selecting it, suggesting that the scoring and ranking functions should be improved. We propose that artificial proteins could be used as tools to test the accuracy of protein structure prediction algorithms, because their lack of evolutionary pressure and unique sequences features. [less ▲]

Detailed reference viewed: 42 (5 ULiège)
Full Text
See detailProtein structure modeling using backbone chemical shifts
Wanko Nembot, Alexis Marius ULiege; Damblon, Christian ULiege

Poster (2015, December 01)

The knowledge of the tridimensional structure of a protein is essential to study its interactions and understand its mode of action. The Purpose of our work is to quickly and easily determine the ... [more ▼]

The knowledge of the tridimensional structure of a protein is essential to study its interactions and understand its mode of action. The Purpose of our work is to quickly and easily determine the structure of proteins using the backbone chemical shifts. Backbone chemical shifts data are NMR parameters that can be rapidly, easily and accurately measured. This parameter is very sensitive to the conformation of amino acids and is used to deduct the secondary structure (TALOS, RCI,...). We therefore plan to use backbone chemical shifts as constraints on dihedral angles to quickly and easily determine protein structure. Several « de novo » methods like CS-Rosetta , CS23D et CHESHIRE have been recently developed in this purpose. We will use proteins of different sizes for which, the structure (X-ray or NMR structure) and chemical shifts backbone are available for testing the three softwares. Knowing that each of these softwares predicted a large number of low energy models on the one hand, and that the deployment and use of these tools constitutes obstacles for users who are not experts in computer science on the other hand, our goal will be to develop a platform that can easily compare these three methods based on quality of the structure produced. [less ▲]

Detailed reference viewed: 47 (4 ULiège)
See detailRecyclable shape-memory materials based on photo or thermo-reversible crosslinking
Defize, Thomas ULiege; Riva, Raphaël ULiege; Wauters, Céline et al

Poster (2014, November 11)

Shape memory polymers (SMPs) are remarkable materials able to switch from a stressed deformed state (temporary shape) to their initial relaxed state (permanent shape) by the application of a stimulus ... [more ▼]

Shape memory polymers (SMPs) are remarkable materials able to switch from a stressed deformed state (temporary shape) to their initial relaxed state (permanent shape) by the application of a stimulus, such as heat or light. Typically, the shape memory property is generally observed for chemically or physically cross-linked polymers that exhibit an elastomeric behavior above a phase transition, e.g. glass or melting transition. Cross-linked semi-crystalline poly(ε-caprolactone) (PCL) is already widely studied for the development of SMPs. However, the tensile strength of standard PCL-based SMPs remains quite low, limiting their use in some applications. A convenient way to enhance the strength of SMPs relies on the introduction of nanofillers, such as silica nanoparticles, leading to an enhancement of mechanical strength. Moreover, silica nanoparticles can be advantageously used as multifunctional crosslinking nodes, with the purpose to increase the cross-linking density of the material. As most of SMPs are irreversibly cross-linked material, their reprocessing is impossible preventing any recycling. Thereby, reversible reactions, allowing the formation/cleavage of the network, raise tremendous interest in macromolecular engineering. Recently, a reversibly cross-linked 4-arm star-shaped PCL-based SMP was prepared using the Diels-Alder (DA) reaction between furan and maleimide moieties, well-known to create reversible bonds. This shape memory material demonstrated to be implementable, and so recyclable, and was characterized by excellent fixity and recovery before and after recycling experiments. However, the relatively low retro-DA temperature of the furan- maleimide adducts led to an inelastic deformation during shape memory tensile cycles. In order to get rid of this drawback, two alternative approaches were investigated. Firstly, the substitution of the DA reaction by a photo-reversible reaction, typically the photo- induced (2+2) cycloaddition of coumarins, was proposed to crosslink the PCL matrix. The second approach is based on the use of surface functionalized silica nanoparticles as crosslinking nodes with the purpose to increase the crosslinking density of the material. The network formation and cleavage were studied by solid-state NMR and rheology.4 The resulting shape memory materials were characterized by excellent one-way and two-way shape memory properties as demonstrated by dynamical mechanical analysis. [less ▲]

Detailed reference viewed: 87 (5 ULiège)
See detailStructural and functional analysis of the HMA4 protein
Lekeux, Gilles ULiege; Laurent, Clémentine ULiege; Damblon, Christian ULiege et al

Poster (2014, September 09)

Detailed reference viewed: 17 (1 ULiège)
Full Text
Peer Reviewed
See detailA variety of roles for versatile zinc in metallo-b-lactamases
Karsisiotis, Andreas Ioannis; Damblon, Christian ULiege; Roberts, Gordon C K

in Metallomics (2014)

Metallo-b-lactamases are important as a major source of resistance of pathogenic bacteria to the widely used b-lactam antibiotics. They show considerable diversity in terms of sequence and are grouped ... [more ▼]

Metallo-b-lactamases are important as a major source of resistance of pathogenic bacteria to the widely used b-lactam antibiotics. They show considerable diversity in terms of sequence and are grouped into three subclasses, B1, B2 and B3, which share a common overall fold. In each case the active enzyme has binding sites for two zinc ions in close proximity, although the amino-acid residues which coordinate the metals vary from one subclass to another. In subclasses B1 and B3, there has been controversy about whether both zinc ions are required for activity, but the most recent evidence indicates that there is positive cooperativity in zinc binding and that the catalytically relevant species is the di-zinc enzyme. Subclass B2 enzymes, on the other hand, are active in the mono-zinc state and are inhibited by the binding of a second zinc ion. Evidence for the importance of the zinc ions in substrate binding has come from structures of product complexes which indicate that the b-lactam core binds to subclass B1 and B3 enzymes in a rather consistent fashion, interactions with the zinc ions being centrally important. The zinc ions play key roles in the catalytic mechanism, including facilitating nucleophilic attack on the amide carbonyl by the zinc-bound hydroxide ion, stabilising the anionic tetrahedral intermediate and coordinating the departing amine nitrogen. [less ▲]

Detailed reference viewed: 39 (1 ULiège)