Thèses sur le sujet « Cristallographie RMN »
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Bouchevreau, Boris. « Détermination structurale de matériaux inorganiques par cristallographie RMN ». Versailles-St Quentin en Yvelines, 2013. http://www.theses.fr/2013VERS0073.
Structure determination of hybrid solids by powder diffraction only is still a great challenge preventing a better understanding of their properties. For nanoporous materials with more and more complex architectures, an additional difficulty arises from the combinatorial explosion of computation time with the increased number of atoms. Therefore, the present Thesis had for objective the development of a strategy based on nuclear magnetic resonance (NMR) data to drive the structure determination from powder diffraction. The tools necessary to apply this strategy (tools for space group selection, for NMR line assignment, for the analysis of the structure topology, new NMR experiments for better resolution…) have been adapted or developed in the context of the structural study of aluminophosphates. The efficiency of the method, in particular the strong decrease in computation time it provides, has been illustrated with the examples of two layered aluminophosphates. Diffraction techniques usually ignore the non-periodic parts of crystals. Solid-state NMR, more sensitive to local order, provides structural information complementary to those extracted from diffraction data. With this in mind, the structure of several aluminophosphates, fluorinated or not, has been re-investigated by NMR Crystallography. The very high-resolution obtained using state-of-the-art NMR experiments has allowed the accurate location of the fluoride ions, hydroxyl groups, water molecules (including dehydration/rehydration processes) and template molecules in these solids. From this ensemble of data, simple rules describing distribution of these species and their potential templating roles have emerged
Dekhil, Myriam. « RMN cristallographique : mesure de distances internucléaires sur des échantillons de poudre par RMN du solide ». Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4734.
Measurment of dipolar coupling provides 3D structural information of powder samples. However, in practice, the high density of spins in organic compounds prevents the measurements of long-range dipolar couplings in solid-state NMR by the so-called dipolar truncation effect. The study of rare spins on natural abundance allows to overcome this problem. In fact, with a natural abundance of 1.1 %, the probability for three 13C to be coupled is negligible. We developed a methodology based either on the dipolar recoupling NMR pulse sequence POST-C7 or on the dramatic increase in sensitivity provided by dynamic nuclear polarization. We demonstrated that its methodology provides a measure of 13C-13C dipolar couplings in natural abundance powder samples and that the so-obtained distance information is sensitive to both molecular conformation and crystal packing of powder samples. Moreover, we show that the recoupling pulse sequence R20_9_2 is more robust to strong chemical shift anisotropy and also to strong 1H-13C heteronuclear dipolar couplings than POST-C7. The second challenge involves 13C signal assignment for natural abundance. In fact, there are only a few examples of 13C-13C correlation spectra obtained for natural abundance samples. Here, we show that 13C-13C correlation spectra sequence based on the reintroduction of 13C−13C dipolar couplings can be obtained with standard MAS probe and within few days using R20_9_2 pulse sequence. Contrary to pulse sequences based on 13C-13C J coupling, our pulse sequence requires shorter DQ excitation time and hence, is more suitable for samples having short T2 relaxation times such as amorphous solids
Dekhil, Myriam. « RMN cristallographique : mesure de distances internucléaires sur des échantillons de poudre par RMN du solide ». Electronic Thesis or Diss., Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4734.
Measurment of dipolar coupling provides 3D structural information of powder samples. However, in practice, the high density of spins in organic compounds prevents the measurements of long-range dipolar couplings in solid-state NMR by the so-called dipolar truncation effect. The study of rare spins on natural abundance allows to overcome this problem. In fact, with a natural abundance of 1.1 %, the probability for three 13C to be coupled is negligible. We developed a methodology based either on the dipolar recoupling NMR pulse sequence POST-C7 or on the dramatic increase in sensitivity provided by dynamic nuclear polarization. We demonstrated that its methodology provides a measure of 13C-13C dipolar couplings in natural abundance powder samples and that the so-obtained distance information is sensitive to both molecular conformation and crystal packing of powder samples. Moreover, we show that the recoupling pulse sequence R20_9_2 is more robust to strong chemical shift anisotropy and also to strong 1H-13C heteronuclear dipolar couplings than POST-C7. The second challenge involves 13C signal assignment for natural abundance. In fact, there are only a few examples of 13C-13C correlation spectra obtained for natural abundance samples. Here, we show that 13C-13C correlation spectra sequence based on the reintroduction of 13C−13C dipolar couplings can be obtained with standard MAS probe and within few days using R20_9_2 pulse sequence. Contrary to pulse sequences based on 13C-13C J coupling, our pulse sequence requires shorter DQ excitation time and hence, is more suitable for samples having short T2 relaxation times such as amorphous solids
Salager, Elodie. « High-resolution solid-state NMR for powder crystallography ». Lyon, Ecole normale supérieure, 2010. http://www.theses.fr/2010ENSL0592.
Knowledge of the three-dimensional structure is an invaluable element for the understanding of the properties of solid materials and towards the development of new materials. While single-crystal X-ray diffraction is established as the best tool to characterise monocrystalline samples, the experimental determination of the structure of polycrystalline powders remains a challenging domain. Many crystalline solids cannot be prepared as single crystals and must be characterized in the powder form. Other compounds are highly subject to polymorphism, and there is a need for structural determination techniques that minimize the risk of structural change during the characterisation. The problem is particularly relevant in the case of drug powders, which need to be accurately characterized in their active pharmaceutical form. This thesis presents new developments relating to powder nuclear magnetic resonance (NMR) crystallography, i. E. Structure determination of powdered samples using high-resolution solid-state NMR at natural isotopic abundance. The first part of the thesis concentrates on the challenging case of protons and illustrates the opportunities offered by the latest generation of commercial NMR probes and new decoupling methods. Protocols are proposed in the second part, which benefit of the high-resolution solid-state NMR spectra accessible for protons and carbons and which make use of the strong dependence of the NMR parameters on crystalline structure details. These techniques are successfully applied to a model compound, thymol, and demonstrate the potential of solid-state NMR for structural determination of powdered compounds
Mifsud, Nicolas. « Détermination Structurale de Solides Ordonnés et Désordonnés par Spectroscopie RMN Haute Résolution ». Phd thesis, Ecole normale supérieure de lyon - ENS LYON, 2007. http://tel.archives-ouvertes.fr/tel-00175539.
Maurice, Frédérique. « Plasticité structurale et émergence d'antibiorésistance à large spectre : étude d'une aminoglycoside acétyltransférase et recherche d'inhibiteurs ». Phd thesis, Université Pierre et Marie Curie - Paris VI, 2007. http://tel.archives-ouvertes.fr/tel-00336237.
Baudin, Antoine. « Études structurales de ligands peptidomimétiques de TRAIL complexés au récepteur de mort DR5 ». Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0424/document.
Apoptosis plays a protective role against the formation of tumor cells. This phenomenon can be regulated by the death receptor pathway, among which the Death Receptor 5 that can be activated by the TRAIL ligand (Tumor necrosis factor-Related Apoptosis Induction Ligand), whose major interest is to induce tumor cell apoptosis, specifically. Our work focuses on peptidomimetic ligands of TRAIL: those 16 amino acid peptides exist as monomers or multimers and show affinity for DR5 protein as up to 5-fold the affinity of TRAIL. Functional assays have shown that not only those ligands induce in vitro apoptosis of tumor cells, but also show selectivity for cancer cells, and can reduce mice tumor volume in vivo. The purpose of this project is to characterize the mechanisms by which those ligands interact with DR5, by using Nuclear Magnetic Resonance (NMR) and X-Ray Crystallography. We have produced the recombinant extracellular domain of DR5 in fusion with the NusA protein, in order to increase the folding of the protein, and we have purified the receptor through a 4-step protocol. We assigned the backbone resonances of 89 % of the protein residues with NMR, and secondary structure calculations showed that DR5 adopts the same β strand folding in solution as from the DR5 crystal structures from the PDB (Protein Data Bank). NMR titrations of DR5 with monomeric and multimeric ligands have allowed us to identify the peptide-protein binding area within the first Cystein Rich Domain (CRD1) of the receptor, but also that the binding with oligomeric peptides lead to protein-protein interactions at the level of the CRD2, suggesting the dimerization of the receptor. This was confirmed par Size Exclusion Chromatography assays that showed an oligomerization of the receptor in the presence of dimeric and trimeric peptides. Ongoing crystallography assays are conducted in order to determine the 3D structure at the atomic level of oligomeric complexes with DR5. Our results show that peptidomimetic ligands of TRAIL display a different mechanism from TRAIL in the activation of apoptosis
Martinez, Denis. « Rôles des phosphoinositides dans l'intéraction membranaire de la protéine Rgd1 et la croissance polarisée des levures : étude structurale et interaction par RMN et cristallographie ». Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0369/document.
Phosphoinositides act as regulatory and signalling molecules at the membrane-cytosol interface in signal transduction, membrane traffic and cytoskeleton organization. These lipids recruit several proteins to specific compartments, but also regulate their activity. In the yeast Saccharomycescerevisiae, they directly bind the Rgd1-RhoGAP domain, that stimulates the GTPase activity of bothRho3p and Rho4p. The GTPase activity of these two Rho proteins, respectively involved in the polarized growth and cytokinesis of the yeast, is enhanced with the presence of Rgd1p and PIPs. The main objective of this thesis is to understand the PIP-RhoGAP interaction at the molecular level. In order to do that, we coupled X-ray structure determination to solution NMR spectroscopy on the isolated RhoGAP domain. Our results show that the domain contains the conserved elements that would usually confer the catalytic GTPase activation. We us e liquid-state NMR spectroscopy to follow the interaction with PI(4)P and PI(4,5)P2, respectively found in secretion vesicles and the plasma membrane. Our study reveals a common binding site for both PIPs in a non-conserved region in the RhoGAP domain family. We measured sub-millimolar binding affinity for PIPs. Such moderate binding affinities are consistent with the biological requirement for reversible complex formation. The selectivity of the interaction could be made in a spatio temporal way, on the secretion vesicles during polarized growth and at the plasma membrane during cytokinesis
Mifsud, Nicolas. « Structure determination in ordered and disordered solids by high-resolution NMR spectroscopy ». Lyon, École normale supérieure (sciences), 2007. http://www.theses.fr/2007ENSL0418.
La résonance magnétique nucléaire du solide est un outil potentiellement puissant pour déterminer la structure et la dynamique d’une large variété de composés. Dans cette thèse, nous montrons tout d’abord comment assigner un échantillon en poudre et en abondance isotopique naturelle à une structure cristalline en utilisant la RMN du solide haute résolution proton et carbone associée à des calculs théoriques. De même, la détermination de la structure tridimensionnelle d’un composé organique en poudre et en abondance isotopique naturelle est présentée. Elle est obtenue par une méthode qui combine modélisation moléculaire et données expérimentales de diffusion de spin proton. Enfin, une étude de la dynamique et du désordre structural a été réalisée sur des matériaux composés de silice par l’intermédiaire de la RMN du silicium. Ainsi, on montre que le temps de déphasage transverse T2’ du silicium peut être utilisé comme une sonde de la dynamique indépendamment du désordre statique
Richet-Tuillière, Nicolas. « Etude biochimique et structurale de deux complexes macromoléculaires à AAA+ ATPases : le protéasome 26S et le réplisome. Mode d’assemblage de la sous-unité Rpt1 du protéasome 26S et rôle secondaire de la sous-unité Mcm2 du réplisome dans le transfert intergénérationnel des histones ». Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066099/document.
AAA+ ATPases are involved in numerous molecular complexes. These proteins form homomeric or heteromeric hexamers and constitute molecular motors. During my Ph. D., I focused my work on two macromolecular complexes composed of AAA+ ATPases: the 26S proteasome regulatory particle and the Mcm2-7 helicase of the replisome. These complexes are implicated in the development of cancers and constitute interesting therapeutic targets. The 26S proteasome is the main machinery responsible for the regulated degradation of poly-ubiquitinated proteins and the helicase Mcm2-7 is responsible for the unwinding of the DNA during replication. These two complexes are composed of a heterohexameric ring of six AAA+ ATPases called Rpt1 to 6 for the 26S proteasome regulatory particle and Mcm2 to 7 for the replisome. I have studied the role of Hsm3/S5b in the assembly mechanism of the proteasome and the specific role of the subunit Mcm2 in the intergenerational transfer of the epigenetic information. X-ray structures of the complexes Hsm3-Rpt1 and S5b-Rpt1 allowed us to elucidate the dual functions of the assembly chaperone Hsm3/S5b which mediates the assembly of the subcomplex Rpt1-Rpt2-Rpn1 during the assembly of the regulatory particle. In addition, hsm3/S5b inhibits the association of a premature regulatory particle onto the core particle and protects the HbYX motif of Rpt1. Other AAA+ ATPases, like the replisome subunits, possess additional domains which confer specific roles. I also studied the interaction between the N-terminal domain of Mcm2 and the tetrameric form of histones H3-H4 by several methods like X-ray crystallography, NMR and SEC-MALS. I propose a model of the intergenerational transfer of histones H3-H4 in which Mcm2 plays a crucial role of molecular histones chaperone directly integrated in the replication machinery
Samson, Camille. « Une représentation en trois dimensions de l'interface entre l'enveloppe nucléaire et la chromatine ». Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS048/document.
The nucleus is an organelle characteristic of eukaryotic cells and its mechanical properties play an essential role in the behavior of the cell, in particular its motility, polarity and survival. It is surrounded by an envelope comprising an inner membrane and an outer membrane, as well as a large number of proteins. These proteins are either anchored at the nuclear membrane, as emerin, or form a filament meshwork lining the inner nuclear membrane, as lamins. My thesis objectives were to understand molecular mechanisms deficient in two types of genetic diseases caused by mutations in inner nuclear envelope proteins: Emery-Dreifuss muscular dystrophy, associated to mutations in emerin and A-type lamins, and progeroid syndromes caused by mutations in A-type lamins.First, we showed that the emerin protein self-assembles in vitro and in cells (Herrada, Samson et al., ACS Chem. Biol., 2015). I then studied the structure of emerin oligomers, determined the minimal protein fragment necessary for the formation of these oligomers, identify residues forming the structural core of these oligomers by solid-state NMR in collaboration with the group of Prof A. Lange (FMP Berlin), and described the impact of emerin mutations causing Emery-Dreifuss muscular dystrophy on emerin self-assembly (Samson et al., Biomol. NMR Assign. 2016, Samson et al., FEBS J. 2017). Then, I observed, mainly using solution-state NMR, that only the self-assembled form of emerin is able to interact with A-type lamin tail, and that mutants causing Emery-Dreifuss muscular dystrophy and unable to self-assemble are also defective in A-type lamin binding. I also obtained preliminary data showing that phosphorylation of emerin by the Src kinase, observed after a mechanical stress in purified nuclei, regulates the interaction between self-assembled emerin and A-type lamins.Finally, I showed that the monomeric form of emerin is able to form a ternary complex with A-type lamin tail through the chromatin-associated protein Barrier-to-Autointegration Factor (BAF). After having measured the protein-protein affinities within this complex, identified the minimal protein fragments involved in the complex and developed a robust protocol for purification of this complex, I was able to obtain crystals under several conditions. Subsequently, I solved the 3D structure of this complex by molecular replacement at a resolution of 2 Å. Finally, I showed that mutations in A-type lamins causing autosomal recessive progeroid syndromes impair interaction with BAF in vitro, and our collaborators at Univ. Paris Diderot, the team of Dr B. Buendia, showed that these same mutations induce a significant decrease in the proximity between lamin A and BAF in HeLa cells. An article with me as a first author is in preparation that reports all these new data
Richet-Tuillière, Nicolas. « Etude biochimique et structurale de deux complexes macromoléculaires à AAA+ ATPases : le protéasome 26S et le réplisome. Mode d’assemblage de la sous-unité Rpt1 du protéasome 26S et rôle secondaire de la sous-unité Mcm2 du réplisome dans le transfert intergénérationnel des histones ». Electronic Thesis or Diss., Paris 6, 2015. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2015PA066099.pdf.
AAA+ ATPases are involved in numerous molecular complexes. These proteins form homomeric or heteromeric hexamers and constitute molecular motors. During my Ph. D., I focused my work on two macromolecular complexes composed of AAA+ ATPases: the 26S proteasome regulatory particle and the Mcm2-7 helicase of the replisome. These complexes are implicated in the development of cancers and constitute interesting therapeutic targets. The 26S proteasome is the main machinery responsible for the regulated degradation of poly-ubiquitinated proteins and the helicase Mcm2-7 is responsible for the unwinding of the DNA during replication. These two complexes are composed of a heterohexameric ring of six AAA+ ATPases called Rpt1 to 6 for the 26S proteasome regulatory particle and Mcm2 to 7 for the replisome. I have studied the role of Hsm3/S5b in the assembly mechanism of the proteasome and the specific role of the subunit Mcm2 in the intergenerational transfer of the epigenetic information. X-ray structures of the complexes Hsm3-Rpt1 and S5b-Rpt1 allowed us to elucidate the dual functions of the assembly chaperone Hsm3/S5b which mediates the assembly of the subcomplex Rpt1-Rpt2-Rpn1 during the assembly of the regulatory particle. In addition, hsm3/S5b inhibits the association of a premature regulatory particle onto the core particle and protects the HbYX motif of Rpt1. Other AAA+ ATPases, like the replisome subunits, possess additional domains which confer specific roles. I also studied the interaction between the N-terminal domain of Mcm2 and the tetrameric form of histones H3-H4 by several methods like X-ray crystallography, NMR and SEC-MALS. I propose a model of the intergenerational transfer of histones H3-H4 in which Mcm2 plays a crucial role of molecular histones chaperone directly integrated in the replication machinery
Raval, Parth. « Insights into structure-stability-property relationships in hybrid perovskites using solid-state NMR spectroscopy ». Electronic Thesis or Diss., Université de Lille (2022-....), 2022. http://www.theses.fr/2022ULILR081.
In the last decade, there has been a progressive increase in the performance of solution-processed hybrid lead halide perovskite solar cells (PSCs), which has been enabled by means of compositional tailoring and interfacial engineering of the perovskite absorber layer and the charge transport layers. However, the long-term operational stability of these materials, including state-of-the-art perovskite formulations, is a major bottleneck in commercializing these materials. In this context, the main objective of this thesis is to understand the different degradation reactions and kinetics aspects of these reactions in hybrid perovskite layers and charge transport layers, especially in the presence of moisture. The degradation reactions in methylammonium (MA) and formamidinium (FA)-based perovskite formulation, in particular, MAPbI3, FAPbI3, and CsMAFAPbIxBr3-x, which are among the high-performing perovskite formulations in PSCs, are studied, analyzed, and compared. In doing so, these materials in crystalline and thin film forms are exposed to low (40% relative humidity, RH) and high (85% RH) water-vapor concentrations. However, the coexistence of the different organic/inorganic and hybrid byproducts and dilute concentrations of different phases formed during the degradation reactions raise challenges in terms of structural characterization. A multi-technique approach involving XRD, microscopy, and solid-state (ss)NMR spectroscopy has been employed to characterize the different degradation products. As a quantitative local characterization technique, ssNMR spectroscopy has notably the ability to probe dilute concentrations of organic byproducts formed upon degradation, which are challenging to detect using other structure-determining techniques. In particular, insights into the moisture-induced phase transformation reactions of FAPbI3 as a function of water vapor concentration, particle size, and light illumination have been obtained by this multi-technique approach. This concept has been later extended to investigate the cascading degradation reactions in MAPbI3-based perovskites with and without surface passivating agents. Our studies indicate that the stability of the perovskite can be adjusted from a few days to several months, depending on the moisture-exposure conditions. Finally, a combination of ssNMR, ssEPR, and computational modelling (NMR crystallography) has been employed to gain insight into the structure-stability-property relationship in a hole-transporting layer spiro-OMeTAD. A detailed study of degradation reactions using multiscale characterization techniques described in this thesis has wider implications for the molecular-level understanding of structure-processing-stability-property relationships in hybrid perovskites and charge transport layers
Baptiste, Benoît. « Foldamères d’oligoamides aromatiques : des doubles hélices artificielles aux ligands de G-quadruplex ». Thesis, Bordeaux 2, 2009. http://www.theses.fr/2009BOR21679/document.
Oligopyridine-dicarboxamides and oligoquinoline-carboxamides are synthetic oligomers able to fold into stable and well defined helical conformations. The first ones are comparable to molecular springs which can extend then associate to form artificial double helices. A structural study of oligopyridines of various sizes by X-ray diffraction and NMR provided a better understanding of the hybridization process. For example, we noticed that the stability of the duplex is all the higher as the oligomer is long but the kinetics of hybridization decrease with length. These properties depend on diverse parameters such as the solvent or the substituants of pyridine rings. The second family forms stable single helices in organic solvents and also in water. We adapted their synthesis on solid support to promote accessibility to a variety of sequences, just like for alphas-peptides. NMR studies suggested that the introduction of aminomethylpyridine units within a hydrophilic oligoquinoline strand brings some flexibility without disrupting its helical structure, showing the high stability of these secondary structures in protic solvents. Besides, some of these peptidomimetics turn out to be capable of recognizing and stabilizing a particular DNA motif: G-quadruplex structure. Given that these architectures form in critical places of the genome involved in cancers, these molecular helices may represent a new class of potential antitumoral agents
Gavriluta, Anatolie. « Complexes osmium nitrosyle avec des ligands bioactifs : synthèse, structure, réactivité et activité antiproliférative in vitro ». Phd thesis, Université Claude Bernard - Lyon I, 2013. http://tel.archives-ouvertes.fr/tel-00903651.
Liu, Danni. « Rôle des chaperons d’histones dans la réplication et la réparation de l’ADN ». Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS044.
In eukaryotes, chromatin carries both, the genetic and epigenetic information. Mechanisms implicated in maintenance of these information during cell division or DNA repair remain poorly understood and they constitute the main issue of this thesis project. More specifically, the goal of the project is to understand how histone chaperones coordinate their action with partners associated with the replication fork to recognize and preserve the epigenetic marks carried by parental histones and to copy on the newly synthesized histones. The work unravels how ASF1 (Anti-Silencing Function 1) cooperates with the CAF-1 complex (Chromatin Assembly Factor 1) and with the replicative helicase subunit MCM2 (Mini Chromosome Maintenance 2), for the management of H3-H4 histones in DNA replication and repair.Moreover, this thesis investigates the regulation of histone chaperones activities by kinases activated after a replicative stress or DNA damage. In particular, we analyzed the consequences of ASF1 phosphorylation by the enzyme called TLK (Tousled like kinase). The activity of TLK is modulated during the cell cycle and after DNA damage. Characterization of the importance of phosphorylated sites on the chaperone binding properties, allows a better understanding of the role played by different forms of ASF1 in the assembly of histones on DNA and maintenance of epigenetic information. The thesis work included biochemical and structural analysis with a combination of different techniques (SEC-MALS, AUC, ITC, NMR, X-ray crystallography) and functional analysis in cellular models
Communie, Guillaume. « Ordre et désordre, bases structurales de la reconnaissance moléculaire chez les paramyxovirus ». Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENV065.
About 40 percent of the human proteome contains large disordered regions. These intrinsically disordered proteins (IDPs) do not adopt stable secondary and tertiary structures, but sample a large conformational space. In spite of that, they are now known to be involved in many physiological as well as pathological processes. Following the example of eukaryotes, viruses -- especially RNA viruses -- benefit from the particular features of IDPs in their replication machinery. Paramyxoviruses, that includes Measles virus, are single stranded, negative sense RNA viruses and about 10 percent of their 15 to 18 kilobase RNA genome is known to encode for disordered regions. This thesis focuses on the study of two different proteins of paramyxoviruses, namely the nucleoprotein and the phosphoprotein that are directly involved in the replication of the viral genome. They interact with each other and are composed of folded and disordered domains. Atomic resolution information is obtained about the structure and dynamics of these proteins using a combination of Nuclear Magnetic Resonance (NMR) spectroscopy measurements for the disordered parts and X-ray crystallography for the folded domains. The results provide novel insight into the role of conformational disorder in transcription and replication of paramyxoviruses
Lautrette, Guillaume. « Capsules hélicoïdales auto-organisées par repliement d'oligoamides aromatiques pour la reconnaissance moléculaire ». Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-00908000.
Barraud, Pierre. « Etudes structurales de différents processus biologiques impliquant les ARN de transfert ». Phd thesis, Université René Descartes - Paris V, 2007. http://tel.archives-ouvertes.fr/tel-00364789.
Wang, Xiang. « Orchestration de l'auto-assemblage et des mouvements moléculaires de pseudo-rotaxanes helicoïdaux ». Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0076/document.
The directional motion orchestration of supramolecular architectures is crucial for the construction of artificial molecular machines. Aromatic amide oligomers (i.e. foldamers) can adopt stable helical conformations able to wind around dumbbell-like guests to form (pseudo)-rotaxanes. A fine control of the association-dissociation kinetics allows the oligomers to slide along the rods without dissociation. In this thesis, based on the segregation of the kinetics of association-dissociation and sliding, helical oligomer motions were orchestrated to form complex self-assemblies and to perform directional motion. NMR and crystallographic studies showed that multistation rod guests can template the formation of well-defined multi-helical supramolecular polymers with high fidelity. Each station possessing a defined length and chirality can induce the complexation of oligomers presenting matching length and chirality. Directional sliding of a double helical oligomer along linear multistation rod guests was investigated. Placing a bulky spacer on the rod prohibits the sliding process, forcing the oligomer to dissociate and reassociate onto the thermodynamically favored station. An asymmetrical oligomer was prepared showing highly selective binding toward asymmetrical rod guests. The threading of this oligomer onto linear asymmetrical guests was investigated. Kinetic data indicated that the threading orientation of this asymmetrical oligomer was polarized by its passage along guest molecules
Le, Meur Rémy. « Etude structurale du mécanisme d'échange de chaînes des dimères de la protéine HU d'E. coli ». Thesis, Orléans, 2015. http://www.theses.fr/2015ORLE2004/document.
HU is a histone like protein of bacteria involved in numerous biological functions such as DNA compaction, transcription, replication and repair. In E. coli, three HU dimers types are present (HUα2, HUβ2 et HUαβ) and show distinct biological roles. The heterodimer is formed from homodimers through a peptidic chain exchange. A model of this mechanism has been proposed by Ramstein and coworkers (J.M.B. 331, 101-121 2003) and was used as a starting point for this study. In this model, homodimers undergo a conformationnal change from a native state (N2) toward an intermediate state (I2). Then, I2 homodimers associate to form a transient heterotetramer which then dissociate into heterodimers. The main aim of this work was to characterize the structure and kinetic of each step of this mechanism. Major results of this work include the elucidation of two original crystal structures : HUβ2 from E. coli and HU from L. lactis in N2 states. A model of the partially disordered I2 state has also been proposed for HUβ2 and HUα2, and is consistent with results obtained from both NMR and molecular dynamics experiments. In addition, the existence of a low concentration tetrameric conformation has been evidenced by native mass spectrometry experiments. A protocol of production/purification/oxydation as been developped for the introduction of disulfide bridges in order to stabilize this conformation and characterize its structure. Together, results obtained from these different biophysical means refine our understanding of the chain exchange mechanism at the molecular level and highlight the role of the I2 conformation in controlling HU dimers composition
Hu, Xiaobo. « Synthèse, analyses structurales et assemblage de foldamères oligoamide hydrosolubles à base de quinolines ». Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0611/document.
Foldamer chemistry is a rapidly expanding research field where chemists explore the construction of various artificial architectures that mimic the folded structures of biopolymers found in nature. Quinoline oligoamide foldamers, as an important branch of foldamers, have been shown to possess many desirable features, including stability and predictability of their folded conformations, and are promising candidates to achieve biological applications. Up to now, most investigations of quinoline oligoamide foldamers have been carried out in organic solvents. This thesis is aimed to expand their scope in aqueous medium and presents several methodologies to achieve solubility, folding, side-chain variation, aggregation and crystal growth ability in water.First, a solid phase synthesis method was developed to enable the fast access to α-amino acid/quinoline (X/Q) hybrid oligoamide foldamers. The study of these hybrid foldamers in water showed that contrary to (XQ)n-type foldamers the (XQ2)n-type foldamers could adopt aromatic helical conformations with α-amino acid side chains aligned in space. Then, several short side chains were identified to endow aromatic foldamers with both solubility in, and crystal growth ability from water. Six quinoline oligoamides displaying these side chains were synthesized as a case study. Crystals were obtained from aqueous medium in all cases but one, exceedingly soluble in water. At last, efforts were made to construct self-assembled aromatic helix bundles in water based on hydrophobic effects and electrostatic interactions. NMR and crystallographic studies indicated that hydrophobic effects are weaker than expected and not strongly conducive of aggregation
Belaissaoui, Abdelhak. « ETUDE DE LA REACTIVITE DE LA N-ETHOXYCARBONYL-N-(2,2,2-TRICHLOROETHYLIDENE)AMINE AVEC QUELQUES DIPOLES-1,3 ». Phd thesis, Université de Franche-Comté, 1995. http://tel.archives-ouvertes.fr/tel-00923089.
Nars, Guillaume. « Dynamique fonctionnelle des protéines : études d'une lipase et d'une protéine A de la membrane externe de bactérie ». Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30111/document.
Understanding the function of proteins and biological systems requires an accurate knowledge of the underlying molecular mechanisms. Crystallography and nuclear magnetic resonance provide a detailed description of these mechanisms, with an atomic resolution, by providing data on both structures and motions. We investigated two proteins, the lip2 lipase from the yeast Yarrowia lipolytica and the membrane protein OmpA from the bacteria Klebsiella pneumoniae. We tried to produce lip2 with uniform and amino-acid specific stable isotope labelling on its functional loop (the lid) for NMR experiments. The homologous recombinant expression in Yarrowia lipolytica turned out to be the most efficient for uniform labelling but failed for specific labelling due to extensive isotope scrambling. We solved the structure of OmpA C-terminal domain by X-ray crystallography, and analyzed its dynamics in solution by NMR (15N relaxation techniques). We characterized its transmembrane N-terminal domain in proteoliposomes by solid state NMR: using state of the art ultra-fast MAS (60 kHz), 1H detection and a 1 GHz spectrometer, we could assign most ?-barrel resonances and establish a NH order parameter profile. In a complementary approach, we used proteolysis to reveal a unique trypsin cleavage site on the extracellular loop 3. Finally, a first characterization of the full-length protein expressed in the outer membrane of Escherichia coli was initiated by solid state NMR on intact outer membranes
Genera, Mariano. « Structural and functional study of the human phosphatase PTPN3 and its interaction with oncogenic viruses ». Electronic Thesis or Diss., Sorbonne université, 2019. http://www.theses.fr/2019SORUS112.
The human protein tyrosine phosphatase non-receptor type 3 (PTPN3) is a PDZ (PSD-95/Dlg/ZO-1) domain-containing phosphatase with a tumor-suppressive or a tumor-promoting role in many cancers, although its role in cell signalling is still unclear. Interestingly, the high-risk genital human papillomavirus (HPV) types 16 and 18 and the hepatitis B virus (HBV) target the PDZ domain of PTPN3 through PDZ-binding motifs (PBMs) in their E6 and HBc proteins. Here, I report a detailed study of the interactions between the PDZ domain of PTPN3 and its cellular and viral ligands. First, we combined biophysical, NMR and X-ray experiments to investigate the structural and functional properties of the PDZ domain of PTPN3 and its interaction with the E6 PBM. We then extended our structural study of PTPN3-PDZ to other cellular and viral partners, and gained insights into the main structural determinants of recognition of PBMs. We then focused on the HBV HBc protein. We screened a library of human PDZ-containing proteins for HBc binders and identified 28 cellular HBc-interacting partners, most of which are involved in cell polarity. We confirmed that PTPN3 can bind the HBc PBM in the context of the viral capsid, and we showed that viral PBMs interact with PTPN3-PDZ with similar affinities to endogenous PTPN3 ligands. Using HBV-infected hepatocytes we observed that overexpression of PTPN3 has multiple effects on HBV infection. Finally, we investigated the interactome of PTPN3-PDZ to gain insights into the role of this protein in cell signalling and the disruptive effects of HBV
Gupta, Kapil. « Dissection de TFIID, un facteur de transcription général humain : Études structurales etfonctionnelles des sous-ensembles du TFIID human ». Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAV051/document.
Eukaryotic genomes are highly complex and can be very large. For example, the human genome contains approximately 20,000-25,000 protein coding genes. Expression of these genes needs to be tightly regulated at many levels, including chromatin organization, gene transcription, mRNA processing and export and translation, for proper functioning of cellular machinery. Many proteins and protein complexes are involved in these essential regulatory processes, examples include chromatin remodelers, transcriptional activators and coactivators, transcriptional repressors and notably the general transcription machinery. Transcription of protein coding genes in eukaryotes is called Class II gene transcription, and is catalyzed by RNA polymerase II (Pol II). Gene transcription by Pol II requires the cooperative interaction of multiple proteins and protein complexes to facilitate the assembly of a preinitiation complex (PIC) at the core promoter. The PIC comprises Pol II and the General Transcription Factors (GTFs)- TFIIA, TFIIB, TFIID, TFIIE, TFIIF, and TFIIH, together with the Mediator complex and a large variety of transcriptional coactivators.A fundamental step in PIC assembly is recognition of the core promoter by GTF TFIID, a magdalton sized multiprotein complex. In humans, TFIID comprises about twenty subunits made up of 14 different proteins – the TATA box binding protein (TBP) and its associated factors (TAFs, numbered 1 to 13). A range of studies on human TFIID and its subassemblies have been carried out since its discovery more than two decades ago, to understand the structure and mechanism of this essential GTF, but the architecture of TFIID, its activities, its functions, its inner workings and the mechanisms of its cellular assembly have eluded detailed understanding to date.This thesis describes biochemical, biophysical, structural and functional studies carried out on three distinct human TFIID subassemblies. We used a number of structural biology techniques, including crystallization, nuclear magnetic resonance (NMR) spectroscopy and small angle X-ray scattering (SAXS) to analyse a complex formed by the human TBP associated factors TAF1 and TAF7. These structural studies provide detailed insights into the intricate interaction interface formed by TAF1 and TAF7, and, together with other data available from the literature, highlight the dynamic nature of the TAF1/TAF7 interaction in the human TFIID complex.In a second study, we analyzed a novel complex formed by TAF11, TAF13 and TBP using a range of biophysical and biochemical methods including electrophoretic mobility shift assay (EMSA), analytical ultracentrifugation (AUC), size exclusion chromatography (SEC) analysis, pull-down assay, native mass-spectroscopy and chemical cross-linking mass spectroscopy (CLMS). This complex is reminiscent of a so-called TATA-box mimicry discovered previously in a TAF1/TBP complex.As part of the ongoing efforts in the Berger laboratory to determine the structure of human holo-TFIID, we furthermore produced and purified a large (~900 kDa) TFIID subassembly called 9TAF, which is composed of nine different TBP associated factors. We carried out negative stain EM studies and random conical tilt (RCT) analysis on 9TAF to obtain low resolution structural information. These studies set the stage for future cryo-EM studies of this 9TAF complex to obtain a high(er) resolution model to decipher the inner workings of human TFIID
Gonthier, Sabine. « Systèmes modèles du réseau carré frustré : synthèses, caractérisations structurales et propriétés magnétiques : étude en fonction de la température ». Toulouse 3, 2005. http://www.theses.fr/2005TOU30096.
We present synthesis, structural and magnetic characterizations of two frustrated systems on a square lattice : VMoO5 and Li2V1-xTixSiO5. The first part is related to the VMoO5 phase. After introducing its elaboration, its magnetic properties are correlated with neutron and synchrotron powder diffraction results at low temperature. These investigations are motivated by the presence of a structural instability, which occurs concomitantly with apparition of magnetic short-range correlations. VMoO5 is shown to be a frustrated 2D antiferromagnet. Moreover, neutron diffraction experiments allow the determination of the magnetic order below 40K. The study of the Li2V1-xTixSiO5 phases shows that magnetic dilution of Li2VSiO5 allows to modulate exchange interactions values. It is particularly interesting because it emphasizes the possibility to investigate the whole magnetic phase diagram of frustrated systems on a square lattice by means of well-chosen substitutions
Lefebvre, Dominique. « Hexagallates de lanthanide pour matrices laser et substrats d'épitaxie : élaboration, étude cristallographique et spectroscopique ». Paris 6, 1986. http://www.theses.fr/1986PA066415.
Lautrette, Guillaume. « Capsules hélicoïdales auto-organisées par repliement d’oligoamides aromatiques pour la reconnaissance moléculaire ». Thesis, Bordeaux 1, 2013. http://www.theses.fr/2013BOR14850/document.
Molecular recognition is one of the major challenges of supramolecular chemistry. Here, we present the design, synthesis and study of helical capsules properties self-organised by aromatic oligoamide folding. These receptors consist of oligomeric chains that fold into a helical conformation and comprise of a sequence of units which code for different diameters. Oligomeric folding defines a cavity which can recognize guests. The great modularity of the sequences has allowed a controlled evolution of foldamer structure resulting in the selective and predict recognition of biological substrates. The phenomenon of encapsulation was demonstrated in solution by NMR and CD spectroscopy and in the solid state by X-ray diffraction
Pitard, Irène. « Analyse du mécanisme d'action d'inhibiteurs ciblant l'activation allostérique du facteur œdématogène de Bacillus anthracis ». Electronic Thesis or Diss., Sorbonne université, 2020. http://www.theses.fr/2020SORUS420.
Edema factor (EF), a major Bacillus anthracis toxin, is activated by host calmodulin (CaM) to produce supraphysiological concentrations of cyclic AMP (cAMP) thus perturbing intracellular signaling. The EF-CaM interaction induces conformational changes in an allosteric switch region of EF that lead to the formation of the catalytic site. Previous in silico studies targeting this switch region, complemented with experimental data, showed that thiophen ureidoacids (TUA) inhibit the enzyme catalytic activity. However, knowledge of the binding site and inhibition mode of TUA compounds are still lacking. Here, we characterize the interaction of the most active TUA compound (TUA-diCl) with EF, CaM and EF-CaM using biochemical assays coupled to biophysical methods and molecular modeling. We show that TUA-diCl interacts with EF, EF-CaM and unexpectedly with CaM. Mapping of the binding site by NMR, showed that TUA-diCl binds to the exposed hydrophobic patches of calcium loaded CaM, causing the compaction and changes in internal dynamics of the protein. Importantly, enzymatic, fluorescence and NMR data show that EF inhibition is due to the interaction of the compound with EF and is CaM-independent. Furthermore, competition experiments between TUA-diCl and the EF catalytic-site inhibitor 2’-MANT-3’-dATP, indicate that TUA-diCl is an allosteric inhibitor of EF. HDX-MS identifies a putative binding site of TUA-diCl on the helical domain of EF, a critical region for CaM insertion. Several possible binding pockets in the helical domain are analyzed in silico. TUA-diCl represents a new class of EF inhibitors with an allosteric mechanism, opening the way towards the design of innovative therapeutic compounds
Issaoui, Fatma. « Etude des propriétés magnétiques des matériaux à bases des métaux de transition sous forme de poudre (AúBO¤) et monocristaux (RMX¥) ». Thesis, Grenoble, 2012. http://www.theses.fr/2012GRENY118/document.
The manuscript presents the work on the structural, electrical and magnetic materials manganites poly-crystalline manganites that have a growing industrial interest due to its many applications and the complexity of fundamental point of view, these materials are systems which electrons are strongly correlated with the presence of several competing interactions. The main objectives of the thesis were to better understand the effect of random substitution on the A site of the perovskite structure twice (family Ruddlesden - Popper A2MnO4 derived from perovskite AMnO3), mainly on the magnetic properties. This study was conducted over the entire temperature range, ie, the study of phenomena Spin Glass at very low temperatures, the study of critical phenomena at the transition point and the study of the magnetic susceptibility at high temperature. Finally, a study of other materials having physical and crystallographic properties very interesting type RMX5
Renault, Louis. « Structure tridimensionnelle de RCC1, le régulateur de la condensation chromosomique par cristallographie aux rayons X ». Université Joseph Fourier (Grenoble ; 1971-2015), 1998. http://www.theses.fr/1998GRE10104.
Hamani, David. « Cristallochimie de matériaux à base de dioxyde de tellure : vers un modèle structural pour l’étude des composés vitreux ». Limoges, 2010. https://aurore.unilim.fr/theses/nxfile/default/9e1f604f-6d30-467b-b4ee-a37147dc6194/blobholder:0/2010LIMO4064.pdf.
This work aims at improving the short range structural description of tellurite materials in order to better understand the structural organization of TeO2-based glasses. We have shown that the local structure of numerous crystallized compounds can be reproduced by considering (i) the modelling of the TeIV atom lone pair with a sphere of 1,15 Å in radius localized at about 1 Å from the atom core and (ii) the bond valence concept. Through a theoretical study about this concept, we have shown that the usual expression is valid in the case of lone pair elements. The structural study of the TeO2 glass and its evolution with the Tl2O addition have been carried out with the use of the total scattering technique and the Reverse Monte Carlo (RMC) modelling. Important similarities are revealed with TeO2‑γ not only at short range but also at medium range order
Lachgar, Abdessadek. « Etude cristallographique et spectroscopique de quelques phases nouvelles du systeme k : :(2)o-sb ::(2)o ::(5)-p ::(2)o ::(5) ». Nantes, 1987. http://www.theses.fr/1987NANT2015.
André, Isabelle. « Études structurales et dynamiques de l'inuline et de sophoranes cycliques et linéaires ». Université Joseph Fourier (Grenoble ; 1971-2015), 1995. http://www.theses.fr/1995GRE10104.
Chable, Johann. « Électrolytes solides fluorés pour batteries tout solide à ions F- ». Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0276/document.
This work deals with the synthesis, shaping and characterization of RE1-xMxF3-x (RE = La, Sm, Ce et M = Ba, Ca, Sr) tysonite-type solid solutions. In a first part, onemeticulous approach has been set up for La1-xBaxF3-x solid solution, chosen as a reference.The solid-state synthesis of these materials led to a better knowledge of their chemicalcomposition (Vegard’s laws) and of the structure-ionic mobility correlations. The impact ofthe sintering process on the ionic conductivity is also highlighted. In a second part, the effectsof the nanostructuration conducted by ball-milling of the microcrystalline samples areevaluated. The use of the Design of Experiments methodology led to identify the optimummilling conditions. It appears that the synthesis of electrolytes can be sped- and scaled-up,while keeping high ionic conductivity properties. At last, this approach is applied on othertysonite-type solid solutions, to look for the best electrolyte. The Ce/Sr and Sm/Casubstitutions generate very promising ionic conductors but not really (electro)chemicallystable compounds. A compromise has been found with the choice of the La1-xSrxF3-x solidsolution as the FIB electrolyte for the electrochemical performances tests, regarding its higherchemical stability
Pecqueur, Ludovic. « Etude du rôle du zinc et des cystéines dans la dimérisation de la protéine FUR (Ferric Uptake Regulator) d'E.coli : une approche structurale par RMN ». Phd thesis, 2005. http://tel.archives-ouvertes.fr/tel-00011629.
Sharifahmadian, Mahzad. « Structural and Biochemical Characterization of VirB8 Protein in Type IV Secretion Systems ». Thèse, 2017. http://hdl.handle.net/1866/19323.
La sécrétion est le passage de macromolécules à travers les membranes cellulaires. Chez les bactéries, la sécrétion est essentielle pour la virulence et la survie. Les bactéries à Gramnégatif utilisent le système de sécrétion de type IV (SST4) pour la sécrétion de toxines et de nucléoprotéines. Les SST4 contribuent notamment à la propagation des gènes de résistance aux antibiotiques. Pour cette raison, les composants du SST4 sont des cibles potentielles pour le développement de médicaments antivirulence. Le SST4 est un complexe protéique qui s’étend entre la double membrane de la bactérie à Gram-négatif. Les protéines qui le composent sont insérées dans les membranes cellulaires ou solubles. Bien que la structure du pore central du SST4 ait été résolue récemment, les détails de l'assemblage et la structure de ce complexe ne sont pas connus. VirB8 est une protéine de la membrane interne qui interagit avec de nombreuses autres sous-unités du SST4. Il s’agit d’un acteur central de l'assemblage du SST4. Des études biophysiques, et notamment des expériences de RMN ont ainsi été réalisées pour caractériser les aspects structuraux des interactions avec VirB8. Des regions dynamiques dans la structure de VirB8 ont été identifiées par spectroscopie RMN lors de la transition entre la forme monomérique et dimérique. Les analyses de cristallographie et de RMN ont révélé des différences structurales dans les régions hélicoïdales (α1 et α4) de VirB8 wild-type et du variant monomérique VirB8M102R. Le criblage de fragments a permis d’identifier de petites molécules capables de se lier à VirB8 ainsi qu’au variant monomérique. Les analyses d’arrimage moléculaire in silico suggèrent que la rainure de surface dans la structure VirB8 est importante pour laliaison de ces petites molécules. Les expériences de RMN et les essais biochimiques révèlent que le feuillet β (β1 en particulier) constitue l'interface d’interaction entre VirB8 et VirB10. Cette interface d’interaction est d’ailleurs importante pour la conjugaison du SST4. De plus, j'ai identifié des changements dans la structure de VirB8 lors de l'interaction avec VirB5. Les études sur la protéine VirB8 nous ont permis de caractériser la séquence d'événements entre VirB8 et d'autres protéines VirB, régulant l'assemblage et la fonction du SST4.