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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

The automatic detection of small molecule binding hotspots on proteins : applying hotspots to structure-based drug design

Radoux, Christopher John January 2017 (has links)
Locating a ligand-binding site is an important first step in structure-guided drug discovery, but current methods typically assess the pocket as a whole, doing little to suggest which regions and interactions are the most important for binding. This thesis introduces Fragment Hotspot Maps, a grid-based method that samples atomic propensities derived from interactions in the Cambridge Structural Database (CSD) with simple molecular probes. These maps specifically highlight fragment-binding sites and their corresponding pharmacophores, offering more precision over other binding site prediction methods. The method is validated by scoring the positions of 21 fragment and lead pairs. Fragment atoms are found in the highest scoring parts of the map corresponding to their atom type, with a median percentage rank of 98%. This is reduced to 72% for lead atoms, showing that the method can differentiate between the hotspots, and the warm spots later used during fragment elaboration. For ligand-bound structures, they provide an intuitive visual guide within the binding site, directing medicinal chemists where to grow the molecule and alerting them to suboptimal interactions within the original hit. These calculations are easily accessible through a simple to use web application, which only requires an input PDB structure or code. High scoring specific interactions predicted by the Fragment Hotspot Maps can be used to guide existing computer aided drug discovery methods. The Hotspots Python API has been created to allow these work flows to be executed programmatically through a single Python script. Two of the functions use scores from the Fragment Hotspot Maps to guide virtual screening methods, docking and field-based ligand screening. Docking virtual screening performance is improved by using a constraint selected from the highest scoring polar interaction. The field-based ligand screener uses modified versions of the Fragment Hotspot Maps directly to predict and score the binding pose. This workflow gave comparable results to docking, and for one target, Glucocorticoid receptor (GCR), showed much better results, highlighting its potential as an orthogonal approach. Fragment Hotspot Maps can be used at multiple stages of the drug discovery process, and research into these applications is ongoing. Their utility in the following areas are currently being explored: to assess ligandability for both individual structures and across proteomes, to aid in library design, to assess pockets throughout a molecular dynamics trajectory, to prioritise crystallographic fragment hits and to guide hit-to-lead development.
92

Planejamento e relação estrutura-atividade de inibidores da MARK3 em câncer de cabeça e pescoço / Design and structure-activity relationship of inhibitors of MARK3 in head and neck cancer

Josiana Garcia de Araujo Volpini 29 September 2010 (has links)
O Projeto Genoma Humano do Câncer (PGHC), financiado pela FAPESP e pelo Instituto Ludwig de Pesquisa sobre o câncer, buscou identificar os genes expressos nos tipos mais comuns de câncer no Brasil. Tal projeto conseguiu identificar aproximadamente um milhão de sequências de genes de tumores frequentes no Brasil. A contribuição brasileira foi maior para tumores de cabeça e pescoço, mama e cólon. Uma das iniciativas mais recentes e estimuladas pelo PGHC é o projeto Genoma Clínico, o qual visa desenvolver novas formas de diagnóstico e tratamento do câncer através do estudo de genes expressos. A partir da análise molecular de tecidos saudáveis e neoplásicos em diferentes estágios, é possível identificar marcadores de prognóstico, permitindo escolhas de terapias mais adequadas e eficientes. A proteína MARK3 foi identificada como um desses marcadores, em neoplasias de tecidos de cabeça e pescoço, sendo o objetivo deste estudo a aplicação de técnicas de bioinformática e modelagem molecular no planejamento baseado em estrutura de candidatos a fármacos antineoplásicos que bloqueiem a atividade da proteína MARK3. Após screening virtual em bases de dados de compostos (1.000.000 aproximadamente) com propriedades drug-like, 20 compostos com potencial de inibidor da MARK3 foram selecionados. Os modos de ligação para cada um dos mesmos no sítio ligante da proteína MARK3 foram sugeridos por simulações de docking e apresentaram um bom encaixe espacial com os sítios receptores virtuais calculados pelos campos de interação molecular (MIF). Simulações de dinâmica molecular foram realizadas com o intuito de avaliar a estabilidade dos compostos selecionados, que também foram avaliados quanto à presença de grupamentos toxicofóricos em sua estrutura. / The Brazilian Project Genoma Câncer (PGHC) supported by FAPESP and the Ludwig Institute for Cancer Research, intended to identify the genes involved in the most common cases of cancer in Brazil. In this project about a million of gene sequences were identified. The major contribution was made in breast, colorectal and head and neck cancers. The results obtained stimulated the creation of another project, called Genoma Clínico, which intend to develop new trends in treatments and diagnosis of cancer based on the study of expressed genes. Analyzing healthy and neoplasic tissues in different stages, it is possible to identify molecular markers related to the prognosis of cancer, allowing the use of more efficient therapies. The MARK3 protein was identified as a molecular marker in head and neck cancer, where the objective of this work lies in the application of bioinformatics and molecular modeling strategies by structure-based drug design to identify potential antineoplasic drug candicates that could act against MARK3 protein. After the virtual screening simulations performed with drug-like compound databases, containing approximately 1.000.000 compounds, 20 were selected as potential ligands of MARK3 protein. The binding modes suggested for these compounds, by docking simulations, presented a good spatial fit when compared with the virtual receptor sites calculated by molecular interaction fields (MIF). Molecular dynamics simulations were performed in order to evaluate de stability of the binding modes suggested. The potential ligands were also evaluated to identify toxicophoric features in its chemical structures.
93

Spécificité et inhibition des interactions protéine-protéine : Exemples d'approches

Lugari, Adrien 08 April 2011 (has links)
L’identification de molécules organiques capables de moduler des interactions protéine-protéine (PPIs) est longtemps restée un domaine peu exploité par la recherche pharmaceutique privée comme académique. Cependant, le développement de méthodologies innovantes pour l’étude des PPIs et la validation récente de ce type d’inhibiteurs dans des essais précliniques, démontrent que les PPIs constituent une nouvelle source de cibles importantes. Les composés capables de moduler ces interactions représentent une nouvelle classe d’outils prometteurs, tant en recherche fondamentale qu’en thérapeutique. Elles peuvent aider à différencier les multiples fonctions portées par une même protéine, à replacer la protéine dans une cascade de réactions, ainsi qu’à disséquer et reconstituer des réseaux de signalisations protéiques. Ces molécules permettront également de faire émerger de nouvelles familles d’agents pharmacologiques actifs dans diverses pathologies.Mon travail de thèse s'est projeté dans l'avenir de la recherche biomédicale, en ciblant les interactions protéine-protéine. J’ai pu durant mon doctorat mettre en œuvre plusieurs méthodologies pour étudier et caractériser des interactions protéiques afin de développer des inhibiteurs de ces interactions. J’ai ainsi pu travailler sur l’optimisation d’un composé inhibiteur de l’interaction de la protéine virale Nef VIH-1 avec les domaines SH3 des Src kinases, le composé DLC27. J’ai également pu mettre en évidence la pertinence biologique de ce composé, qui cible un mode d’interaction unique, ou très rare, au niveau cellulaire en étudiant l’interaction avec les domaines SH3 de deux protéines, ALIX (ALG2-Interacting Protein X) et la sous-unité p85 de la PI3K (phosphatidylinositol 3-kinase).J’ai également pu caractériser la surface et le mode d’interaction de protéines virales impliquées dans le complexe de réplication du virus du SRAS (Syndrome Respiratoire Aigu Sévère). Cette étude tend à montrer que la protéine virale nsp10 agit comme une plateforme de reconnaissance pour ses partenaires, les protéines virales nsp14 et nsp16. Ces interactions permettent l’activation ou l’augmentation des activités respectives de nsp16 et nsp14 et jouent un rôle au niveau de la réplication virale. Suite à l’identification d’un ‘point chaud’ d’interaction, le résidu Tyr96 à la surface de nsp10, nous avons mis en évidence la première famille de molécules inhibitrices du complexe nsp10-nsp14 en couplant des méthodes informatiques (in silico) à des criblages expérimentaux. Ces molécules pourraient être utilisées comme antiviraux ou servir d’outils pour la recherche, en permettant par exemple de mieux comprendre et d’élucider les mécanismes moléculaires impliqués dans la réplication du virus du SRAS et des coronavirus en général. / Protein-protein interactions (PPIs) participate in and regulate almost all essential cellular functions. As a consequence, they are frequently involved in various pathologies (going from cancer development to viral replication and host cell infection) but their study remains a challenge.Thus understanding those interactions as well as finding small drug candidates able to modulate them, a field of research not currently fully developed, appear as the future of the healthcare industry.In this context, I chose to learn different techniques to study PPIs that are usually employed in academic (IMR laboratory, CNRS, France) or corporate environments (Genentech, USA). Moreover, I also worked on the development of small organic inhibitors of PPIs coupling in silico methodologies (chemo-informatics, Drug Design) to biological and structural validations.During my PhD, I could manage and work on different projects involving the study of PPIs involved in cancer signaling pathways as well as the development of potent antiviral drugs targeting the HIV and SARS viruses.My organizational, personal and scientific skills as well as the practical experience I developed on various techniques (from cell biology to biophysics, structural biochemistry and Drug Design), make me feel confident on the management of PPIs drug discovery projects.I am thus able to efficiently work on, and manage, the study of protein-protein interactions in various pathologies as well as the development of potent PPIs inhibitors, that will be a major breakthrough for Biotech/Pharma companies in the coming years.
94

Une approche rationnelle de la chimiothérapie : histoire des antimétabolites (1935-1955) / A rational approach to chemotherapy : the history of antimetabolites (1935-1955)

Serviant-Fine, Thibaut 13 December 2016 (has links)
En 1940, le biochimiste anglais Donald Woods propose une explication du mode d'action des nouveaux sulfamides antibactériens : l'inhibition compétitive. Son collègue Paul Fildes fonde sur cette base une nouvelle approche de la chimiothérapie, revendiquée comme rationnelle, un programme pour la recherche de nouveaux médicaments. Cette thèse explore l'impact de la théorie des antimétabolites, comme elle sera appelée, dans la recherche biochimique et pharmaceutique. La première partie retrace son élaboration dans le contexte de l'école de biochimie anglaise, puis sa reprise aux États-Unis à la suite de travaux menés en parallèle sur les vitamines. La seconde partie est consacrée au développement de deux programmes de recherche distincts dédiés aux antimétabolites, illustrant les modalités et fortunes divergentes d'appropriation de cette approche rationnelle. Le premier est une collaboration modeste entre le biochimiste Henry McIlwain et la firme pharmaceutique Glaxo pendant la guerre au Royaume-Uni. Le second consiste en la mise en place du programme de George Hitchings et Gertrude Elion chez Burroughs Wellcome aux États-Unis, souvent considéré comme l'origine du rational drug design actuel. La théorie des antimétabolites correspond aussi bien à l'ambition d'obtenir des chimiothérapies spécifiques qu'à un ensemble de pratiques dans le quotidien du laboratoire / In 1940, the British biochemist Donald Woods put forward an explanation of the mode of action of the new antibacterial sulfa drugs, competitive inhibition. His colleague, Paul Fildes, developed this work into a new approach to chemotherapy, which he qualified as a rational programme for drug discovery. This dissertation explores the impact of the theory of antimetabolites, as it came to be known, in biochemical and pharmaceutical research. The first part traces its development in the context of the British school of biochemistry and its further expansion in the United States following parallel research on vitamins. The second part deals with the construction of two distinct research programmes dedicated to antimetabolites, each one illustrating a different way of following this rational approach and their varying consequences. The first one is a modest collaboration between the biochemist Henry McIlwain and the Glaxo pharmaceutical company during the war in the United Kingdom. The second one corresponds to the establishment of George Hitchings' and Gertrude Elion's programme at Burroughs Wellcome in the United States, often considered as the origin of today's rational drug design. The theory of antimetabolites simultaneously embodied both the ambition of attaining specific chemotherapies, and a set of practices in day-to-day laboratory work
95

Prédiction de la cinétique des inhibiteurs de protéines kinases et de leur affinité par docking flexible / Binding kinetic and affinity prediction of protein kinase inhibitors by flexible docking

Braka, Abdennour 28 March 2018 (has links)
Dans le cadre d’un projet de drug design, l’amélioration de la prédiction de l’affinité représente toujours un défi malgré les nombreux efforts déployés dans ce sens. De plus, les constantes cinétiques d’association et de dissociation sont d'un intérêt majeur pour la découverte de nouveaux médicaments, notamment au stade précoce de l'optimisation des molécules afin de mieux évaluer leurs tolérances et efficacités. De par la récente émergence des études de constantes cinétiques, il existe peu de méthodes de prédiction de ces dernières et aucune approche efficace n'a encore été développée pour estimer correctement ces paramètres cinétiques.En relevant ces deux défis, le premier volet de cette thèse consiste au développement de nouvelles méthodes qui permettent dans un premier temps d’améliorer la prédiction de l’affinité par docking flexible et dans un deuxième temps la prédiction des constantes cinétiques d’association et de dissociations (kon et koff) grâce à des simulations de dynamique moléculaire accélérées.Dans le second volet de cette thèse, nous avons conçu de nouveaux inhibiteurs des LIM kinases, cibles émergentes impliquées dans plusieurs physiopathologies incluant la neurofibromatose et le cancer. Nos composés ont de bonnes affinités et sélectivités in vitro, et d’excellentes activités et tolérances évaluées sur des tests cellulaires. / In a drug design project, improving the prediction of affinity is still an issue despite the considerable efforts made in this direction. In addition, binding kinetic constants are of major interest for the discovery of new drugs, in particular at the early stage of molecules optimization to better evaluate their tolerance and efficacy. Due to the recent emergence of the importance of binding kinetics, methods of kinetic rates prediction remain scarce and no efficient computational approach has still been developed to correctly estimate kinetic parameters.In order to challenge these two problematics, the first part of this thesis consists in the development of new methods that allow, first, to improve the prediction of affinity by a flexible docking and, second, to predict the ligand binding/unbinding pathways and binding kinetic rates (kon and koff) by enhanced molecular dynamics simulations.In the second part of this thesis, we have designed novel inhibitors of LIM kinases, emerging targets involved in several pathophysiologies including neurofibromatosis and cancer. Our compounds have good affinities and selectivities in vitro, and excellent activities and tolerances evaluated on cellular tests.
96

Synthèse de dérivés de la phénothiazine et étude de leur rôle d'inhibiteurs de la résistance aux antibiotiques chez les Burkholderiaceae / Synthesis of phenothiazine derivatives and study of their role as inhibitors of antibiotic resistance against Burkholderiaceae

Stutzmann, Aurélien 14 December 2017 (has links)
Si les antibiotiques ont amélioré le pronostic des maladies infectieuses, l’apparition de résistances importantes et les manipulations génétiques volontaires peuvent faire craindre l’émergence de pathogènes très virulents et résistants aux antibiotiques recommandés. Aussi, la multidrug résistance (MDR) est devenue un problème majeur pour traiter des infections impliquant des bactéries à Gram-négatif. La surexpression des mécanismes d’efflux contribue largement au phénotype de multi-résistance aux antibiotiques et l’inhibition de ces mécanismes intéresse donc de plus en plus le monde de la recherche.Les phénothiazines font partie des molécules les plus prometteuses du 20e siècle. La présence d’un substituant en position C-2 sur le noyau tricyclique et celle d’une chaine alkyl aminée en position N-10 se sont révélées être critiques pour des activités de type neuroleptique, antihistaminique et anthelminthique. Une activité anti-MDR a également été mise en évidence, notamment contre les cancers et la tuberculose. Le mécanisme par lequel ces molécules inhiberaient l’efflux est cependant encore mal connu. Différents dérivés de la phénothiazine ont été synthétisés afin de comprendre ce mécanisme et de dégager les propriétés physico-chimiques mises en jeu chez Burkholderia pseudomallei. Cette bactérie à Gram-négatif, responsable de la mélioïdose, est classée parmi les agents potentiels du bioterrorisme. Elle est en effet extrêmement pathogène et présente une sensibilité très réduite à une majorité de classes d’antibiotiques. L’activité des phénothiazines a été évaluée par la technique Etest® sur Burkholderia thailandensis, modèle d’étude non-pathogène. / If antibiotic drugs improved the prognosis of infectious diseases, the appearance of antimicrobial resistance and deliberate genetic modifications could be followed by the worrying emergence of highly virulent pathogens resistant to usual antibiotics. Thus, Multi-Drug Resistance (MDR) became a major problem to treat infections involving Gram negative bacteria. The overexpression of efflux mechanisms contributes to a great extent to antibiotic resistance and the inhibition of these mechanisms increasingly interest research areas.Phenothiazines are the most promising molecules of the 20th century. The presence of substituent in C-2 position on the tricyclic structure and the one of alkyl amino chain in N-10 position proved their critical activity as neuroleptic, antihistaminic and antihelmintic drugs. An anti-MDR activity has also been put into evidence against cancers and tuberculosis, but the mechanism by which molecules would inhibit efflux is not well known yet. Different phenothiazine derivatives have been synthesized in order to better understand this mechanism and to draw the physicochemical properties involved in Burkholderia pseudomallei. This Gram negative bacterium is responsible of melioidosis and classified as potential bioterrorism infectious agent. This bacterium is indeed extremely pathogenic and has a very low susceptibility to most classes of antibiotics. The activity of phenothiazine derivatives was evaluated using the Etest® method in Burkholderia thailandensis, the non-pathogenic study model.
97

Développement et validation du logiciel S4MPLE : application au docking moléculaire et à l'optimisation de fragments assistée par ordinateur dans le cadre du fragment-based drug design / Development and validation of molecular modeling tool S4MPLE : application to in silico fragment-based drug design, using molecular docking and virtual optimisation of fragment-like compounds

Hoffer, Laurent 03 June 2013 (has links)
Cette thèse a pour but de développer le pendant in silico des étapes clés du Fragment-Based Drug Design (FBDD), et ce dans le cadre plus général du développement de l'outil S4MPLE. Le FBDD génère des ligands drug-like à partir de petites molécules (fragments). Après une étape de validation de S4MPLE et de sa fonction d’énergie, un recentrage autour du FBDD est réalisé, à travers le docking puis l'optimisation virtuelle de fragments par growing ou linking (G/L). Cette stratégie reposesur 1) la création d’une chimiothèque focalisée en connectant un ou deux fragment(s) avec des linkers pré-générés, et 2) l’échantillonnage avec S4MPLE des composés chimères dans le site avec des contraintes. Des simulations de G/L plus ou moins ambitieuses (site flexible, ajout de H2O libres) permettent de valider cette approche avec des études rétrospectives basées sur des données expérimentales. La dernière phase de la thèse a consisté à appliquer ce protocole in silico à un projet de l’entreprise. / This work aims to develop in silico methods targeting the key stages of Fragment-Based Drug Design (FBDD), participating to the development of the molecular modeling tool S4MPLE. Briefly, FBDD generates ıdrug-likeı ligands from small organic molecules called fragments. After a validation step of S4MPLE and its energy function, the work focused on FBDD: molecular docking of fragments and their subsequent virtual optimization. The latter mimics standard evolution strategies in FBDD(growing and linking). This in silico approach involves among other two key stages 1) building of a focused library by plugging in pre-generated linkers into reference fragments using rules and 2) sampling of these new compounds under atomic and binding site constraints. Validation simulations, relying on known experimental data, included ıclassicalı growing / linking and more challenging ones (site flexibility, free waters). Finally, this strategy is applied to one project of the company.
98

Caractérisation structurale de la CTP : phosphocholine cytidylyltransférase de Plasmodium falciparum et identification de composés inhibiteurs basée sur la structure visant à cibler la voie de biosynthèse des phospholipides / Structural characterization of Plasmodium falciparum CTP : phosphocholine cytidylyltransferase and fragment-based drug design approach for targeting phospholipid biosynthesis pathway

Guca, Ewelina 18 February 2016 (has links)
À l’heure actuelle, le paludisme reste un problème de santé majeur et demeure une des maladies parasitaires les plus menaçantes. Parmi les cinq espèces de malaria infectant l’homme, Plasmodium falciparum est la forme la plus mortelle. Lors de la phase érythrocytaire de son cycle de vie, causant tous les symptômes du paludisme, P.falciparum utilise les phospholipides pour créer les membranes nécessaires au développement de cellules filles. Chez P. falciparum, la phosphatidylcholine est principalement obtenue grâce à la voie de synthèse de novo, dite voie de Kennedy. Dans cette voie de biosynthèse, la seconde étape catalysée par la CTP:phosphocholine cytidylyltransferase [EC 2.7.7.15] est limitante et apparait essentielle pour la survie du parasite murin P. berghei lors de la phase sanguine. Les objectifs de mon travail de thèse ont été de caractériser structuralement cette enzyme et d’identifier des effecteurs, principalement grâce à des approches de « fragment-based drug design » (FBDD). Ainsi, la première structure cristalline du domaine catalytique de l’enzyme (PfCCT) a été déterminée avec une résolution de 2.2 Å. De plus, les structures de trois complexes enzyme-substrat (en présence de CMP, de phosphocholine ou de choline) et d’un complexe enzyme-produit (CDP-Choline) ont été déterminées. Ces structures cristallographiques apportent des informations détaillées sur la poche de liaison de l’enzyme et elles ont révélé des informations sur le mécanisme de la réaction catalytique à l’échelle atomique. La seconde partie de ma thèse présente les méthodes développées pour identifier des inhibiteurs potentiels de la PfCCT. Une approche de FBDD a été utilisée pour identifier et sélectionner de petites molécules (fragments, PM<300 Da) se liant à la PfCCT. Diverses techniques biophysiques (fluorescence-based thermal shift assay, différence de transfert de saturation par RMN, dénaturation chimique isotherme) ont permis la sélection de 23 fragments à partir du criblage d’une bibliothèque (~ 300 molécules). En parallèle, un criblage in silico de plus grandes bibliothèques de fragments (environ 15 000 composés) a permis d’identifier 100 fragments “hits”. Enfin, 5 composés déjà connus pour inhiber la croissance parasitaire (Malaria Box fournit par Medecines for Malaria Venture) ont été sélectionnés pour leur inhibition de l’activité de la PfCCT recombinante. L’ensemble de ces données ouvre la voie pour l’élaboration de futurs composés ciblant la PfCCT et inhibant la biosynthèse de phosphatidylcholine chez P. falciparum. / Malaria remains a major global health problem and the most threatening parasitic disease. Among the 5 malaria species that affect humans, Plasmodium falciparum is the most deadly form. During its life cycle, in erythrocytic stage, which causes all the malaria symptoms, P. falciparum relies on phospholipids to build the membranes necessary for daughter cell development. Approximately 85% of parasite phospholipids consist of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) synthesized by the parasite through the de novo Kennedy pathways. In the pathway of phosphatidylcholine biosynthesis, the second step catalyzed by CTP:phosphocholine cytidylyltransferase [EC 2.7.7.15] is rate limiting and appears essential for the parasite survival at its blood stage. In this PhD thesis I focus on the structural characterization of this enzyme and the identification of effectors mainly by fragment-based drug design approach (FBDD). The first reported crystal structure of the catalytic domain of the enzyme target (PfCCT) has been solved at resolution 2.2 Å. Four other crystal structures of PfCCT in complex with substrates (CMP, phosphocholine and choline) or product (CDP-choline) have been determined. These structural data give detailed images of the binding pocket and reveal the enzyme structures at all catalytic steps that provide crucial information on the catalytic mechanism at atomic level. The second part of the project present the methods developed to identify potential PfCCT inhibitors. A FBDD approach was used in order to identify and select small molecules (fragments, MW< 300 Da) binding to the PfCCT. A combination of biophysical techniques (fluorescence-based thermal shift assay, saturation transfer difference NMR and isothermal chemical denaturation) allowed the selection of 23 fragment hits from the screenings of fragment library (~ 300 molecules). In parallel in silico screening of larger fragment libraries (~15,000 compounds) resulted in 100 selected hits. Finally, 5 compounds already known to inhibit parasite growth (Malaria Box from Medicines for Malaria Venture) were selected for their inhibition of the recombinant PfCCT activity. The results obtained within this thesis brought important knowledge and structural insights on the catalytic mechanism of PfCCT. Taken together, these results pave the way for future structure-based drug design to target PfCCT and to inhibit the essential phosphatidylcholine biosynthesis in P. falciparum.
99

Conception, synthèse et activité de nouveaux agents anti-infectieux ciblant l'histidinol deshydrogénase de bactéries à développement intracellulaire / Design, synthesis and activity of new anti-infectious agents targeting histidinol dehydrogenase of intracellular bacteria

Turtaut, François 09 December 2011 (has links)
L'accentuation des phénomènes de résistance aux antibiotiques augmente la difficulté d'enrayer les infections bactériennes. Afin de palier ce problème, la mise au point de nouvelles stratégies, telle la stratégie antivirulence, est essentielle. Ainsi, ce manuscrit propose une nouvelle approche thérapeutique contre les bactéries à développement intracellulaire. Les analyses génomiques ont permis de mettre en évidence l'histidinol déshydrogénase (HDH, EC 1.1.1.23), enzyme impliquée dans la biosynthèse de l'histidine, comme cible biologique pour la conception de nouveaux agents antibactériens. L'étude de l'inhibition de cette dernière permet une validation de l'approche sur Brucella suis, agent responsable de la brucellose, et un élargissement du spectre d'action des composés mis au point est envisagé par l'inhibition de HDH de Mycobacterium tuberculosis. Les travaux préliminaires nécessaires a cet élargissement sont présentés dans ce manuscrit. / The raise of antibiotic resistances increases the difficulty to eradicate bacterial infections. The development of new therapeutic approaches, such as the antivirulence strategy, is essential to limitate the impact of this phenomenon. This manuscript details a new therapeutic approach against intracellular pathogens. Genomic analyses allowed to discover new targets. The histidinol dehydrogenase (HDH, EC 1.1.1.23), which is an enzyme involved in histidine biosynthesis, has therefore be chosen for the conception of new antibacterial compounds. Inhibition studies of HDH of Brucella suis allows a validation of the strategy. In order to confirm the width of the therapeutic spectrum of synthesised compounds, the inhibition of HDH from Mycobacterium tuberculosis is envisaged and preliminary experiments are presented.
100

Massively-Parallel Computational Identification of Novel Broad Spectrum Antivirals to Combat Coronavirus Infection

Berry, Michael January 2015 (has links)
Philosophiae Doctor - PhD / Given the significant disease burden caused by human coronaviruses, the discovery of an effective antiviral strategy is paramount, however there is still no effective therapy to combat infection. This thesis details the in silica exploration of ligand libraries to identify candidate lead compounds that, based on multiple criteria, have a high probability of inhibiting the 3 chymotrypsin-like protease (3CUro) of human coronaviruses. Atomistic models of the 3CUro were obtained from the Protein Data Bank or theoretical models were successfully generated by homology modelling. These structures served the basis of both structure- and ligand-based drug design studies. Consensus molecular docking and pharmacophore modelling protocols were adapted to explore the ZINC Drugs-Now dataset in a high throughput virtual screening strategy to identify ligands which computationally bound to the active site of the 3CUro . Molecular dynamics was further utilized to confirm the binding mode and interactions observed in the static structure- and ligand-based techniques were correct via analysis of various parameters in a IOns simulation. Molecular docking and pharmacophore models identified a total of 19 ligands which displayed the potential to computationally bind to all 3CUro included in the study. Strategies employed to identify these lead compounds also indicated that a known inhibitor of the SARS-Co V 3CUro also has potential as a broad spectrum lead compound. Further analysis by molecular dynamic simulations largely confirmed the binding mode and ligand orientations identified by the former techniques. The comprehensive approach used in this study improves the probability of identifying experimental actives and represents a cost effective pipeline for the often expensive and time consuming process of lead discovery. These identified lead compounds represent an ideal starting point for assays to confirm in vitro activity, where experimentally confirmed actives will be proceeded to subsequent studies on lead optimization.

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