Spelling suggestions: "subject:"recombinant""
291 |
Ocorrência de anticorpos anti-hantavírus (IgG) em populações humanas na região Amazônica e no estado de São Paulo (Mata Atlântica), utilizando proteína recombinante (nucleocapsídio) do vírus Araraquara. / Detection of antibodies (IgG) against hantavirus in human population of Amazon region and the state of Sao Paulo (Atlantic Forest), using recombinant antigen of Araraquara virus.Felipe Alves Morais 11 November 2010 (has links)
A hantavirose (infecção por Hantavírus) é uma das zoonoses que vem preocupando as autoridades sanitárias de todo o mundo. Sua ocorrência se deve principalmente os distúrbios ecológicos é transmitida ao homem através de inalação de partículas virais contida na excreta de roedores. São conhecidas duas doenças humanas distintas causadas pelo Hantavírus: a Febre Hemorrágica com Síndrome Renal (FHSR) e a Síndrome Pulmonar e Cardiovascular (SPCVH). O objetivo deste estudo foi verificar a ocorrência de anticorpos IgG anti-hantavírus, através do ELISA, em populações da Amazônia e Sudeste brasileiro, que vivem em contato com os roedores silvestres, utilizando a proteína recombinante do vírus Araraquara expressa em Escherichia coli. Do total de estudados 1308 soros humanos estudados, na Amazônia (1078) encontramos 59 soros positivos (5%). Na cidade Machadinho do OesteRO os soros coletados durante o ano 2003, foram analisados 638, onde foram encontrados 20 soros positivos (4,5%); e no Rio Machado RO. foram analisados 435 soros da população ribeirinha onde foram encontrados 39 (5%) soros positivos, respectivamente. Após análise realizada em 151 soros humanos provenientes do Vale do Ribeira, em 2007; e 84 no Pontal do Paranapanema, em 2008, foram observados 14 positivos (9%) e 6 (7%) das amostras, respectivamente. / The genus Hantavirus of the family Bunyaviridae includes a large number of rodent-borne viruses that are distributed worldwide. The occurrence is due mainly to ecological disturbances and it is transmitted to the humans through inhalation of virus particles contained in the excreta of wild rodents. Two different human diseases known to be caused by Hantavirus: are Hemorrhagic Fever with Renal Syndrome (HFRS) and Hantavirus Cardiopulmonary Syndrome (HPS). The main objective of this study was detected antibody against hanatavirus (IgG) by ELISA, in Amazon region and Brazilian Southwest populations who live in contact with the wild rodents, using recombinant protein (antigen) of the Araraquara virus expressed in Escherichia coli. We study 1308 human sera (1078 from Amazon region) and there were found 59 (5%) positive sera. From the city of Machadinho do Oeste RO (2003 year), 633 sera were analysed, where there were found to be 20 positive (4.5%) serums. In Machado river RO (2005 year), 435 sera of the river-dwelling population were analysed where there were found 39 (5%) positive sera, respectively. After analysis was accomplished for 151 human sera coming from the Vale do Ribeira - SP, in 2007, and 84 from the Pontal do Paranapanema - SP, in 2008, 14 (9%) and 6 (7%) of the samples were observed to be positive, respectively.
|
292 |
La morbidité à long terme des enfants traités par hormone de croissance synthétique / Long term morbidity of children treated with synthetic growth hormonePoidvin, Amélie 14 June 2017 (has links)
Les données de la littérature concernant la tolérance à long terme du traitement par hormone de croissance (GH) recombinante sont très réduites. L’objectif du travail rapporté dans cette thèse porte sur l’analyse de la morbidité chez 6874 patients de l’étude SAGhE traités en France dans le cadre d’un déficit idiopathique en GH ou d’une petite taille constitutionnelle, avec les 3 axes de travail suivants : Risque neurovasculaire : Utilisant des données de référence issues de 2 registres de population, nous avons montré une augmentation du risque d’accident vasculaire cérébral (SIR à 3.5 ou 4.4 selon le registre considéré), et plus particulièrement d’hémorragies sous-arachnoïdiennes (SIR 5.7 ou 6.3). Risque de diabète : Utilisant les prescriptions d’antidiabétiques fournies par le SNIIRAM au sein de notre cohorte, nous n’avons pas mis en évidence d’augmentation de la prévalence du diabète traité (SPR 1.0). Risque de cancer : En comparaison au registre de référence du réseau FRANCIM, il n’y a pas de différence significative dans le risque de survenue d’un cancer (SIR 0.7). En revanche, le risque de développer une tumeur osseuse est 3.5 fois plus élevé chez les sujets exposés à l’hormone de croissance dans l’enfance. Les évènements ont été identifiés à partir de trois sources : a) RNIPP et CépiDC pour la connaissance du statut vital et les causes de décès si le sujet est décédé, b) Questionnaire de santé envoyé aux sujets non décédés, c) Données SNIIRAM à partir d’une extraction spécifique basée sur les identifiants des sujets de notre cohorte, permettant d’obtenir les codes CIM-10 des déclarations d’Affection Longue Durée, les codages PMSI entre 2008 et 2010 correspondant aux hospitalisations, et les prescriptions d’antidiabétiques. / The literature is scarce regarding the long term effect of synthetic growth hormone (GH) treatment. The objective of this thesis was to analyse the morbidity of 6874 patients from the French SAGhE study treated by GH for short stature, focusing on three themes: Neurovascular risk: Using two population-based registries, we showed an increase in the risk of stroke (SIR 3.5 to 4.4 according the registry used), more specifically for the subarachnoid hemorrhage (SIR 5.7 or 6.3). Risk of diabetes : Using the antidiabetic drugs deliveries obtained from the French national health insurance database, no difference in the risk of treated diabetes was found (SPR 1.0). Risk of cancer : Compared with the French population-based registries of cancer, no significant difference in the risk of cancer was found (SIR 0.7), but the excess risk for bone tumor is 3.5 . Events were identified from three sources : a) Information on vital status collected from the Répertoire National d’Identification des Personnes Physiques and cause of death as indicated on death certificate, b) Health questionnaire sent to all living patients, c) Data extracted from the French national health insurance information, including the French hospital discharge database, also called Programme de Médicalisation des Systèmes d’Information from 2008 to December 2010, long-lasting affection statements, and antidiabetics drugs deliveries.
|
293 |
Établissement d’un nouveau modèle de souris pour étudier les cellules valvulaires interstitielles : ADAMTS19-Cre-ert2Comes, Johanna 05 1900 (has links)
Superviseur : Dr. Piet Van Vliet
Collaborateurs: Dr. Alexandre Dubrac, Dr. Martin Smith / Résumé
INTRODUCTION : Les maladies valvulaires du cœur surviennent dans 2% de la population, impliquant souvent un reflux sanguin dû au rétrécissement de la valve. Nous avons récemment identifié deux familles non apparentées étant atteintes par une sténose aortique. Le séquençage exomique des familles a révélé une mutation entrainant une perte de fonction homozygote pour le gène ADAMTS19. La relation entre la perturbation du gène ADAMTS19 et la sténose a été reproduite et donc confirmée grâce à une souris ADAMTS19-LACZ KO/KO. Cette souris montre également que ADAMTS19 est spécifiquement exprimé dans les cellules valvulaires interstitielles (VICs) dans les valves. Le rôle d’ADAMTS19 durant le développement des valves reste inconnu. Pour analyser le patron d’expression d’ADAMTS19 pendant le développement du cœur, nous avons obtenu un modèle de souris transgénique contenant une CRE-tamoxifen inductible (Cre-ERT2) qui est exprimé sous l’influence du promoteur humain ADAMTS19. HYPOTHESE/OBJECTIF : Nous émettons l’hypothèse que le promoteur humain d’ADAMTS19 inséré dans la souris ADAMTS19-Cre-ERT2 contient toutes les séquences régulatrices permettant d’exprimer le gène ADAMTS19 et que ADAMTS19 est principalement exprimé au niveau des cellules valvulaires interstitielles dans les valves. L’objectif est de caractériser le patron d’expression d’ADAMTS19 en analysant sa distribution durant le développement grâce à une souris reportrice tdTomato. Comme ADAMTS19 est spécifiquement exprimé dans les VICs, cet outil transgénique permettrait d’étudier ces cellules durant le développement. METHODE/RESULTAT : Suite à une étude in silico le promoteur ADAMTS19 est apparu comme extrêmement conservé. Par conséquent, pour analyser l’expression d’ADAMTS19 nous avons obtenu une souris BAC ADAMTS19-Cre-ERT2 contenant la séquence conservée que nous avons croisé avec une souris reportrice tdTomato. Le Tamoxifen est administré aux femelles gestantes par gavage aux jours embryonnaires E9,5, E11,5 ainsi que E13,5, et les cœurs sont extrait a E16,5. Des coupes de cœurs embryonnaires vont permettre d’identifier la localisation et la morphologie des cellules marquées. L’expression d’ADMATS19 dans les cellules valvulaires interstitielles est consistant avec le fait qu’ADAMTS19 est connu pour affecter les valves durant le développent et dans le cas de maladie valvulaire. Cependant, le patron des valves n’est pas reproductible au travers des générations. De plus, nous observons qu’ADAMTS19 est marqué dans des cellules des oreillettes et ventricule dans une lignée et dans une sous population de cellules de l’artère pulmonaire dans une autre. CONCLUSION : L’analyse des séquences de chaque lignée par séquençage permettre d’investiguer la raison de ses différents patrons et de mettre en évidence des régulateurs spécifiques. / BACKGROUND: Valvular heart disease (VHD) occurs in ~2% of the general population, often
resulting in reduced or disturbed blood flow. We recently identified two unrelated families with recessive
inheritance patterns of progressive polyvalvular heart disease in absence of any clear syndromic
phenotype. Exome sequencing revealed homozygous, rare, loss of function (LOF) alleles in both families
for the gene ADAMTS19. The relation between ADAMTS19 mutation and aortic stenosis were confirm via
an ADAMTS19-LacZ KO/KO mouse model. This model also shows that ADAMTS19 is specific of VICs
during valve development. The ADAMTS protein family includes 19 proteases that are involved in matrix
remodeling, and tissue homeostasis in development and disease. However, the role of ADAMTS19
specifically during valve development remains unknown. We aim to characterize ADAMTS19 expression
using a BAC transgenic ADMTS19-CRERT2 mouse. HYPOTHESE/OBJECTIVE We hypothesize that
the BAC used to make the ADMTS19-CRERT2 mouse contains all the regulatory elements to express it
and also that its expression will be specific to the VICs. The objective is to establish the ADAMTS19-
CREERT2 and therefore to create a new tool to study VICs in vivo. METHODS/RESULTS: In silico
analysis of the human and mouse ADAMTS19 genomic regions showed a high level of conservation.
Thus, to analyze ADAMTS19 expression patterns during mouse development, we obtained a BAC
transgenic mouse model containing a tamoxifen inducible Cre (CreERT2) that is expressed under the
influence of the human ADAMTS19 promoter and surrounding genomic region. We crossed males from
several lines created in parallel with Rosa-tdTomato reporter females to generate offspring in which
expression of the fluorescent tdTomato reporter is activated in ADAMTS19-expressing cells upon
tamoxifen administration. Surprisingly, whole mount imaging of embryos induced at E13.5 and isolated
at E16.5 revealed strong, but distinct labelling patterns in offspring from different ADAMTS19CreERT2
sublines. Whereas one line exclusively labelled VICs, consistent with ADAMTS19 in situ RNA
expression data from the Eurexpress database, another line specifically labelled cells in atrial and
ventricular, but not VICs. A third line seems to label only a subset of cells in the pulmonary artery.
Labeling of ADAMTS19-positive VICs is consistent with ADAMTS19 affecting valve development and
VHD. In addition, we observed exclusive ADAMTS19-dependent labelling in atrial and ventricular cells
or in a subset of pulmonary artery cells in two different sublines. CONCLUSION: The distinct expression
patterns in offspring from different ADAMTS19-Cre-ERT2 lines indicates that although regulation of
ADAMTS19 is conserved between human and mouse, expression in VICs versus other cells may be
dependent on mutually exclusive regulatory mechanisms.
|
294 |
Conception et évaluation d’un nouveau système de transfection ciblée, basé sur l’utilisation du système E/KcoilLouvier, Elodie 06 1900 (has links)
Actuellement le polyéthylènimine (PEI) est l’agent de transfection transitoire le plus utilisé par l’industrie pharmaceutique pour la production de protéines recombinantes à grande échelle par les cellules de mammifères. Il permet la condensation de l’ADN plasmidique (ADNp) en formant spontanément des nanoparticules positives appelées polyplexes, lui procurant la possibilité de s’attacher sur la membrane cellulaire afin d’être internalisé, ainsi qu’une protection face aux nucléases intracellulaires. Cependant, alors que les polyplexes s’attachent sur la quasi-totalité des cellules seulement 5 à 10 % de l’ADNp internalisé atteint leur noyau, ce qui indique que la majorité des polyplexes ne participent pas à l’expression du transgène. Ceci contraste avec l’efficacité des vecteurs viraux où une seule particule virale par cellule peut être suffisante. Les virus ont évolués afin d’exploiter les voies d’internalisation et de routage cellulaire pour exprimer efficacement leur matériel génétique. Nous avons donc supposé que l’exploitation des voies d’internalisation et de routage cellulaire d’un récepteur pourrait, de façon similaire à plusieurs virus, permettre d’optimiser le processus de transfection en réduisant les quantités d’ADNp et d’agent de transfection nécessaires. Une alternative au PEI pour transfecter les cellules de mammifèreest l’utilisation de protéines possédant un domaine de liaison à l’ADNp. Toutefois, leur utilisation reste marginale à cause de la grande quantité requise pour atteindre l’expression du transgène. Dans cette étude, nous avons utilisé le système E/Kcoil afin de cibler un récepteur membranaire dans le but de délivrer l’ADNp dans des cellules de mammifères. Le Ecoil et le Kcoil sont des heptapeptides répétés qui peuvent interagir ensemble avec une grande affinité et spécificité afin de former des structures coiled-coil. Nous avons fusionné le Ecoil avec des protéines capables d’interagir avec l’ADNp et le Kcoil avec un récepteur membranaire que nous avons surexprimé dans les cellules HEK293 de manière stable. Nous avons découvert que la réduction de la sulfatation de la surface cellulaire permettait l’attachement ciblé sur les cellules par l’intermédiaire du système E/Kcoil. Nous démontrons dans cette étude comment utiliser le système E/Kcoil et une protéine interagissant avec l’ADNp pour délivrer un transgène de manière ciblée. Cette nouvelle méthode de transfection permet de réduire les quantités de protéines nécessaires pour l’expression du transgène. / Pharmaceutical industry often employs polyethylenimine (PEI) for large scale protein production processes by transient transfection of mammalian cells. PEI condenses plasmid DNA (pDNA) by spontaneously forming positive nanoparticles known as polyplexes. Condensed pDNA is favoured for cell surface binding, internalization and protection from intracellular nucleases. While most of the cells efficiently uptake polyplexes, only 5 to 10% of captured pDNA reaches the nucleus for transgene expression. This suggests that polyplexes are hampered in their ability to route and to translocate to the nucleus necessitating large amounts of polyplexes to achieve high expression levels. By contrast, many viruses can efficiently transduce cells with only one or a few viral genome copies. Viruses have evolved to exploit cellular internalization and routing properties to express their own genetic material. We hypothesized that less pDNA would be used in an optimized transfection process if we exploited the internalization and routing properties that viruses use. DNA binding proteins could be used as an alternative to PEI to transfect mammalian cells. However, their usage is marginal due to the large protein quantities required to bind pDNA for transgene expression. If less pDNA is used less binding protein is needed.
In this study, we used the E/Kcoil system to target a membrane receptor to deliver pDNA in mammalian cells. The Ecoil and Kcoil are two repeated heptapeptides which interact with a high affinity and specificity to form coiled-coil structures. We fused the Ecoil with a recombinant pDNA-binding protein. The Kcoil was fused to a stably-expressed membrane receptor in HEK293 cells.
We discovered that low sulfation of the cell surface reduced non-specific binding of the pDNA:protein complex and permitted targeted binding via the E/Kcoil interaction. We demonstrate how to use recombinant pDNA-binding protein and the E/Kcoil system for targeted transgene delivery. This newly developed system provides a new transfection method, with reduced pDNA-binding protein quantities needed to achieve transgene expression.
|
295 |
Mapeamento dos subsítios de α-amilase de Xanthomonas axonopodis pv citri envolvidos na interação com o substrato / Subsite mapping of Xanthomonas axonopodis pv citri α-amylase involved in substrate bindingPinho, Jean Marcel Rodrigues 20 December 2004 (has links)
Mapeamento dos subsítios de α-amilase de Xanthomonas axonopodis pv. Citri envolvidos na interação com o substrato A família das enzimas α-amilases é um modelo experimental interessante para o estudo das interações entre os aminoácidos e seus ligantes, já que estas enzimas apresentam especificidade variável, são frequentemente alvos de estudos por mutagênese e há estruturas cristalinas disponíveis para alguns membros da família. A proposta deste trabalho foi o mapear subsítios da α-amilase de Xanthomonas axonopodis pv. citri (AXA) envolvidos na interação com substratos, através de comparações estruturais, mutagêneses sítio-dirigidas, análises de parâmetros cinéticos sobre amido e do padrão de clivagem sobre p-nitrofenil malto-oligossacarideos (PNPG7, PNPG5, PNPG4). Foi criado um modelo estrutural para AXA a partir da estrutura tridimensional da α-amilase de Alteromonas haloplanctis (Aghajari et al., 1998). O modelo de AXA foi sobreposto na estrutura da α-amilase pancreática de porco (Qian et al., 1994) e 11 resíduos foram selecionados e mutados para alanina. As α-amilases recombinantes mutantes e selvagem foram secretadas pela levedura Pichia pastoris GS115, apresentando uma massa molecular aparente de 45 kDa. Todos os mutantes analisados reduziram em maior ou menor grau a atividade catalítica da enzima sobre amido e p-nitrofenil maltooligossacarideos. Mutações dos resíduos H88, F136, D196, E223, D295 e N299, deletaram a atividade enzimática, indicando que suas cadeias laterais são essenciais para o desempenho catalítico da enzima. As análises cinéticas e estruturais sugerem fortemente que D196, E223 e D295 são os resíduos catalíticos. Substituições das cadeias laterais de C157, H200, G227, T230 e H294 reduziram a eficiência catalítica (kcat/Km) da α-amilase sobre o substrato amido para, respectivamente, 28%, 41%, 84%, 81% e 51%. As mutações em G227 e T230 foram menos importantes para a atividade da enzima e afinidade pelo amido, entretanto, estes resíduos mostraram-se importantes para a estabilização de complexos com substratos curtos (pNPG4). Os resultados indicam que o sítio ativo de AXA é formado por, no mínimo, seis subsítios. As interações dos anéis de glicose com os subsítios +2 e -2 são favorecidas em relação às interações nos subsítios -3 e +3, respectivamente, e a interação do anel de glicose no subsítio -3 é favorecida em relação à interação no subsítio +3. A enzima selvagem diva preferencialmente a terceira ligação glicosídica de p-nitrofenil maltooligossacarideos. Como produtos de hidrólise a enzima libera maltopentaose, maltotetraose, maltotriose, maltose e glicose. / The α-amylase family is an interesting group for structure/function relationship investigation, as this family exhibits a variable deavage patterm, several crystal structures are available, and its members were studied by mutagenesis. The aim of this study was the mapping of Xanthomonas axonopodis pv. Citri α-amylase (AXA) subsites involved in substrate binding, using structural comparison, site-directed mutagenesis and lcinetics analyses. A structural model for AXA was created from the three-dimensional structure of the α-amylase from Alteromonas haloplanctis (Aghajari et al., 1998). This model was superimposed on the structure ofthe pig pancreatic α-amylase, PPA (Qian et. al., 1994), and 11 residues were selected and changed to alanine. Wild type and mutant AXA were secreted by Pichia pastoris strain GS115 cells and showed apparent molecular mass of 45 kDa. All mutants have reduced α-amylase activity on starch and 4-nitrophenyl maltooligosaccharides (pNPG7, PNPG5 and PNPG4) at different levels. Mutation of residues H88, F136, D196, E223, D295 and N299 indicate their essential role by complete loss of activity. Kinetic and structural analyses strongly suggested that D196, E223 and D295 are the catalytic residues. The substitution of the side chain of C157, H200, G227, T230 and H294 reduced the catalytic efficiency (kcat/Km) of α-amylase on starch to respectively 28%, 41%, 84%, 81% and 51%. Although G227 and T230 were not much important for activity and binding on starch, these residues were important for stabilization of complexes with short substrates (PNPG4). The results indicate that AXA\'s active site is composed of at least six sugar binding subsites. The binding of the glucoses at subsites +2 and -2 are favored against binding at subsites -3 and +3, respectively. The binding of glucose at subsite -3 is favored against binding at subsite +3. The wild type enzyme primarily hydrolyzes the third glucosidic bond in PNPG7, PNPG5 and PNPG4 and the products of hydrolysis were maltopentaose, maltotetraose, maltotriose, maltose and glucose.
|
296 |
Avaliação da potência do hormônio da paratireóide humano recombinante por bioensaio, métodos cromatográficos e eletroforético / Recombinant human parathyroid hormone potency evaluation by bioassay, chromatographic and electrophoretic methodsMaldaner, Fernanda Pavani Stamm 24 May 2017 (has links)
Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul - FAPERGS / The human parathyroid hormone (hPTH) is a polypeptide secreted by the parathyroid glands that is essential for the maintenance of the calcium ion homeostasis in the blood. The recombinant DNA technology has enabled the expression of hPTH gene in Escherichia coli, and thus the large-scale production of recombinant human parathyroid hormone (rhPTH 1-34), teriparatide, which contain the active amino-terminal fragment of the full length hPTH. The rhPTH is clinically used to treat osteoporosis at high risk of fractures in postmenopausal women, men with osteoporosis primary or hypogonadal and adults with glucocorticoid-induced osteoporosis (GIO). Cappilary zone electrophoresis (CZE) method was developed and validated for the assessment of rhPTH in biopharmaceutical formulations. The analysis for CZE method was performed on a fused-silica capillary (effective length, 40 cm; 50 μm i.d.), using electrolyte solution consisted of 50 mM dihydrogen phosphate solution at pH 3.0. The capillary was maintained at 25º C, the applied voltage was 20 kV. Injections were performed using a pressure mode at 50 mbar for 45 s, with detection by photodiode array detector set at 200 nm. Separation was obtained with a migration time of 5.3 min, and was linear over the concentration range of 0.25-250 μg mL-1 (r2 = 0.9992). The limits of detection and quantitation were 0.12 and 0.40 μg/mL, respectively. Specificity and stability-indicating capability were established in degradation studies, which also showed that there was no interference of the excipients. The accuracy was 100.28% with bias lower than 0.85%. Moreover, the in vitro cytotoxicity test of acidic, photolytic and thermal degradated forms showed significant differences (p<0.05) compared to intact molecule. The cell proliferation and alkaline phosphatase activity bioassays in UMR-106 cells were developed and applied to assess the biological activity of rhPTH in biopharmaceutical formulations The results of content/potency were correlated to those of the validated reversed-phase liquid chromatography (RP-LC), size-exclusion liquid chromatography (SE-LC) and CZE methods, showing significant correlation (p> 0.05) Thus, the application of the validated physico-chemical methods together with in vitro bioassays, was suggested to improve quality control of rhPTH biotechnology-derived product and to support studies of biosimilars. / O hormônio da paratireóide humano (hPTH) é um polipeptídeo produzido e secretado pelas glândulas paratireóides, e é fundamental para a manutenção da homeostase dos íons cálcio no sangue. A tecnologia do DNA recombinante possibilitou a expressão do gene do hPTH em Escherichia coli, e a produção em grande escala do hormônio da paratireóide humano recombinante (rhPTH 1-34), também denominado Teriparatida, o qual apresenta a sequência de aminoácidos responsável pela porção biologicamente ativa do paratôrmonio natural. O rhPTH é clinicamente indicado para o tratamento da osteoporose de alto risco de fraturas em mulheres pós-menopausa, de homens com osteoporose primária ou hipogonadal, e da osteoporose associada à terapia sistêmica com glicocorticóides. Neste trabalho foi desenvolvido e validado método por eletroforese capilar de zona (ECZ) para a avaliação de rhPTH em produtos biofarmacêuticos. No método por ECZ, utilizou-se capilar de sílica fundida (40 cm de comprimento efetivo x 50 μm d.i.) e solução eletrolítica composta de fosfato de sódio dihidrogenado 50 mM, pH 3,0. O capilar foi mantido a temperatura de 25ºC, e a tensão aplicada foi de 20 kV. O tempo de injeção foi de 45 s, com pressão de 50 mBar, e detecção por arranjo de diodos (DAD), em 200 nm. A separação eletroforética foi obtida com tempo de migração de 5,3 min, sendo linear na faixa de concentração de 0,25-250 μg/mL (r2 = 0,9992). Os limites de detecção e quantificação foram de 0,12 e 0,40 μg/mL, respectivamente. A especificidade foi avaliada através de análises com os excipientes da formulação biofarmacêutica e estudos de degradação, demonstrando a seletividade do método. A exatidão foi 100,28% com bias inferior a 0,85%. Além disso, realizou-se o teste de citotoxicidade in vitro das formas degradadas, apresentando, para as amostras submetidas às condições ácida, fotolítica e térmica, diferença significativa (p< 0,05) em relação à molécula íntegra. Os bioensaios de proliferação celular e da atividade da fosfatase alcalina em células UMR-106 foram desenvolvidos e aplicados para avaliação da atividade biológica de rhPTH em formulações biofarmacêuticas. Os resultados de teor/potência foram correlacionados com os métodos já validados por cromatografia líquida em fase reversa (CL-FR), cromatografia líquida por exclusão molecular (CL-EM) e ECZ, apresentando correlação significativa (p> 0,05). Assim, sugere-se que o métodos físico-químicos validados sejam aplicados paralelamente aos bioensaios in vitro para aprimorar o controle da qualidade do produto biotecnológico de rhPTH, e para avaliação da biossimilaridade de rhPTH.
|
297 |
Vacinas recombinantes contra erisipela suína: desenvolvimento integrado de bioprocesso, da biologia molecular ao biorreatorSilva, Adilson José da 11 October 2011 (has links)
Made available in DSpace on 2016-06-02T19:02:40Z (GMT). No. of bitstreams: 1
3950.pdf: 2965296 bytes, checksum: 1e00d517bd464f272b8c1a2c9f67ca9c (MD5)
Previous issue date: 2011-10-11 / Valée S.A. / Swine erysipelas is among the diseases that causes great economic losses in swine cultures worldwide. The disease is caused by the bacterium Erysipelothrix rhusiopathiae, and the surface protein SpaA is one of its main antigens. Herein, we report studies concerning the development of recombinant vaccines against swine erysipelas based on the SpaA antigen. Protein production for a subunit vaccine formulation was studied in shaken flasks and 5.0 L bioreactors. For this propose, a 1026 bp fragment of the spaA gene was cloned in Escherichia coli cells under the lac promoter control. The recombinant organism (E. coli BL21(DE3) pET28a_spaA) was cultivated in fed batch using complex medium with glycerol as carbon source. Nonconventional induction strategies were evaluated and high protein yield (198 mgprot/gDCW) and productivity values (0.4 gprot/L.h) were reached. The same antigen was cloned for expression and secretion in attenuated Salmonella typhimurium cells to obtain a live bacterial vector for the SpaA antigen. The recombinant lineage was able to express and secrete the SpaA fragment fused to the alpha-hemolysin secretion signal both in vitro and in vivo. High plasmid maintenance was observed in both conditions. The vaccinal vehicle showed to be able to colonize the Peyer patches and to invade the gut epithelial barrier in the inoculated animals. Immunization tests in murine model showed that the recombinant antigen delivered by Salmonella cells inoculated by oral route induced the production of seric IgG antibodies anti-SpaA. According to the literature, these antibodies must be able to promote pathogen opsonization in case of infection, contributing to confer a protective immunity against swine erysipelas to the vaccinated animals. In summary, this work presents contributions to development of subunit vaccines against swine erysipelas, in the form of recombinant protein formulations, or SpaA antigen delivery by attenuated S. typhimurium cells. / A erisipela suína é uma das enfermidades que causam grandes prejuízos na suinocultura em todo o mundo. A doença é causada pela bactéria Erysipelothrix rhusiopathiae, e a proteína de superfície SpaA desse microrganismo é um de seus principais antígenos. Neste trabalho, estudou-se o desenvolvimento de vacinas recombinantes contra a erisipela suína a partir do antígeno SpaA. Avaliou-se a produção de uma vacina de subunidade composta pelo antígeno recombinante, a qual foi estudada em frascos agitados e em biorretores de bancada de 5,0 L. Para isso, um fragmento de 1026 pb do gene spaA foi clonado em células de Escherichia coli sob controle do promotor lac e o organismo recombinante (E. coli BL21(DE3) pET28a_spaA) foi cultivado em batelada alimentada, utilizando-se meio complexo contendo glicerol como fonte de carbono. Estratégias não convencionais de indução foram avaliadas e altos valores de rendimento (198 mgprot/gDCW) e produtividade (0,4 gprot/L.h) da proteína recombinante foram alcançados. O mesmo antígeno foi clonado em um plasmídeo que possibilita a expressão e secreção da proteína recombinante em Salmonella typhimurium atenuada, a fim de se obter um vetor bacteriano vivo para o antígeno em questão. A linhagem recombinante foi capaz de expressar e secretar o fragmento da proteína SpaA fusionado ao sinal de secreção da alfa-hemolisina tanto in vitro quanto in vivo, apresentando alta taxa de manutenção plasmidial nas duas condições. Além disso, o veículo vacinal se mostrou capaz de colonizar as placas de Peyer e de invadir a barreira epitelial do intestino dos animais inoculados. Ensaios de imunização em modelo murino mostraram que a veiculação do antígeno pelas células de Salmonella inoculadas por via oral induziu a produção de anticorpos IgG séricos anti-SpaA, que de acordo com a literatura, devem ser capazes de promover a opsonização do patógeno em caso de infecção, contribuindo para conferir uma imunidade protetora contra a erisipela suína aos animais vacinados. Em suma, este trabalho apresenta contribuições para o desenvolvimento de vacinas de subunidade contra a erisipela suína na forma de uma vacina de proteína recombinante, ou por veiculação do antígeno SpaA por linhagens atenuadas de S. typhimurium.
|
298 |
Mapeamento dos subsítios de α-amilase de Xanthomonas axonopodis pv citri envolvidos na interação com o substrato / Subsite mapping of Xanthomonas axonopodis pv citri α-amylase involved in substrate bindingJean Marcel Rodrigues Pinho 20 December 2004 (has links)
Mapeamento dos subsítios de α-amilase de Xanthomonas axonopodis pv. Citri envolvidos na interação com o substrato A família das enzimas α-amilases é um modelo experimental interessante para o estudo das interações entre os aminoácidos e seus ligantes, já que estas enzimas apresentam especificidade variável, são frequentemente alvos de estudos por mutagênese e há estruturas cristalinas disponíveis para alguns membros da família. A proposta deste trabalho foi o mapear subsítios da α-amilase de Xanthomonas axonopodis pv. citri (AXA) envolvidos na interação com substratos, através de comparações estruturais, mutagêneses sítio-dirigidas, análises de parâmetros cinéticos sobre amido e do padrão de clivagem sobre p-nitrofenil malto-oligossacarideos (PNPG7, PNPG5, PNPG4). Foi criado um modelo estrutural para AXA a partir da estrutura tridimensional da α-amilase de Alteromonas haloplanctis (Aghajari et al., 1998). O modelo de AXA foi sobreposto na estrutura da α-amilase pancreática de porco (Qian et al., 1994) e 11 resíduos foram selecionados e mutados para alanina. As α-amilases recombinantes mutantes e selvagem foram secretadas pela levedura Pichia pastoris GS115, apresentando uma massa molecular aparente de 45 kDa. Todos os mutantes analisados reduziram em maior ou menor grau a atividade catalítica da enzima sobre amido e p-nitrofenil maltooligossacarideos. Mutações dos resíduos H88, F136, D196, E223, D295 e N299, deletaram a atividade enzimática, indicando que suas cadeias laterais são essenciais para o desempenho catalítico da enzima. As análises cinéticas e estruturais sugerem fortemente que D196, E223 e D295 são os resíduos catalíticos. Substituições das cadeias laterais de C157, H200, G227, T230 e H294 reduziram a eficiência catalítica (kcat/Km) da α-amilase sobre o substrato amido para, respectivamente, 28%, 41%, 84%, 81% e 51%. As mutações em G227 e T230 foram menos importantes para a atividade da enzima e afinidade pelo amido, entretanto, estes resíduos mostraram-se importantes para a estabilização de complexos com substratos curtos (pNPG4). Os resultados indicam que o sítio ativo de AXA é formado por, no mínimo, seis subsítios. As interações dos anéis de glicose com os subsítios +2 e -2 são favorecidas em relação às interações nos subsítios -3 e +3, respectivamente, e a interação do anel de glicose no subsítio -3 é favorecida em relação à interação no subsítio +3. A enzima selvagem diva preferencialmente a terceira ligação glicosídica de p-nitrofenil maltooligossacarideos. Como produtos de hidrólise a enzima libera maltopentaose, maltotetraose, maltotriose, maltose e glicose. / The α-amylase family is an interesting group for structure/function relationship investigation, as this family exhibits a variable deavage patterm, several crystal structures are available, and its members were studied by mutagenesis. The aim of this study was the mapping of Xanthomonas axonopodis pv. Citri α-amylase (AXA) subsites involved in substrate binding, using structural comparison, site-directed mutagenesis and lcinetics analyses. A structural model for AXA was created from the three-dimensional structure of the α-amylase from Alteromonas haloplanctis (Aghajari et al., 1998). This model was superimposed on the structure ofthe pig pancreatic α-amylase, PPA (Qian et. al., 1994), and 11 residues were selected and changed to alanine. Wild type and mutant AXA were secreted by Pichia pastoris strain GS115 cells and showed apparent molecular mass of 45 kDa. All mutants have reduced α-amylase activity on starch and 4-nitrophenyl maltooligosaccharides (pNPG7, PNPG5 and PNPG4) at different levels. Mutation of residues H88, F136, D196, E223, D295 and N299 indicate their essential role by complete loss of activity. Kinetic and structural analyses strongly suggested that D196, E223 and D295 are the catalytic residues. The substitution of the side chain of C157, H200, G227, T230 and H294 reduced the catalytic efficiency (kcat/Km) of α-amylase on starch to respectively 28%, 41%, 84%, 81% and 51%. Although G227 and T230 were not much important for activity and binding on starch, these residues were important for stabilization of complexes with short substrates (PNPG4). The results indicate that AXA\'s active site is composed of at least six sugar binding subsites. The binding of the glucoses at subsites +2 and -2 are favored against binding at subsites -3 and +3, respectively. The binding of glucose at subsite -3 is favored against binding at subsite +3. The wild type enzyme primarily hydrolyzes the third glucosidic bond in PNPG7, PNPG5 and PNPG4 and the products of hydrolysis were maltopentaose, maltotetraose, maltotriose, maltose and glucose.
|
299 |
VALIDAÇÃO DE MÉTODO POR ELETROFORESE CAPILAR PARA AVALIAÇÃO DE FILGRASTIMA. ESTUDOS DE CORRELAÇÃO ENTRE MÉTODOS FÍSICO-QUÍMICOS E BIOLÓGICO. / VALIDATION OF CAPILLARY ELECTROPHORESIS METHOD FOR THE EVALUATION OF FILGRASTIM. CORRELATION STUDY BETWEEN PHYSICO-CHEMICAL AND BIOLOGICAL METHODS.D'avila, Felipe Bianchini 24 September 2010 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The granulocyte-colony stimulating factor (G-CSF) is a hematopoietic cytokine that stimulates and regulates the proliferation and differentiation of neutrophils precursors cells of the bone marrow. The recombinant hormone (rhG-CSF) non-glycosylated, filgrastim, is used to treat the neutropenia induced by chemotherapy and bone marrow transplantation. The hydrophobic protein is a 175
aminoacids chain which contains an extra methionine at its N-terminus, and molecular weight of 18.8 kDa. In the present study, a capillary zone electrophoresis (CZE) method was developed and validated for the analysis of filgrastim in pharmaceuticals. The analyses were performed on a fused-silica capillary (75 μm i.d.; effective length, 72 cm) and background electrolyte consisted of 50 mM sodium
tetraborate solution at pH 9.0. The capillary temperature was maintained at 15 °C and the applied voltage was 15 kV. The injection was performed using the hydrodynamic mode at 50 mbar for 6 s, with detection at 195 nm using a PDA detector. The electrophoretic separation was obtained with
migration time of 21.8 and 15.8 minutes for the filgrastim and leuprorrelin acetate (internal standard), respectively, and with run time of 30 minutes. The procedure was validated by the parameters of specificity, linearity, precision, accuracy, robustness, limit of quantitation and limit of detection. The method was linear in the concentration range of 1 200 μg/mL (r2 = 0.9978) and the limit of quantitation (LOQ) was 1 μg/mL, with acceptable validation parameters. The method was applied for the analysis of pharmaceutical formulations, and the results were correlated to the reversed-phase HPLC method (RP-HPLC), size-exclusion HPLC method (SE-HPLC) and in vitro bioassay method. Therefore, the procedures represent valid alternatives which can improve the quality control, assuring the safety and therapeutic efficacy of the biological product. / O fator estimulador da colônia de granulócitos humanos é uma citocina hematopoiética que estimula e regula a proliferação e diferenciação de células precursoras de neutrófilos da medula óssea. O hormônio recombinante (rhG-CSF) sob a forma não-glicosilada, filgrastima, é usado para o tratamento de neutropenia induzida por quimioterapia e transplante de medula óssea. A proteína hidrofóbica é constituída por uma cadeia de 175 aminoácidos com uma metionina N-terminal, e massa molecular de 18,8 kDa. No presente estudo, foi desenvolvido e validado método por eletroforese capilar de zona (CZE) para determinação de filgrastima em formulações farmacêuticas. As análises foram realizadas em capilar de sílica fundida (comprimento efetivo de 72 cm e diâmetro interno de 75 μm) e solução eletrolítica composta de tetraborato de sódio 50 mM, pH 9,0. O capilar foi mantido a
temperatura de 15 °C, e a tensão aplicada foi de 15 kV. O tempo de injeção foi de 6 s, com pressão de 50 mbar, e detecção por arranjo de diodos (DAD) a 195 nm. A separação eletroforética foi obtida com tempo de migração de 21,8 e 15,8 minutos para filgrastima e acetato de leuprorrelina (padrão interno), respectivamente, e tempo total de corrida de 30 minutos. O procedimento foi validado, avaliando-se os
parâmetros de especificidade, linearidade, precisão, exatidão, robustez, limite de quantificação e limite de detecção. Demonstrou-se linearidade na faixa de concentração de 1 200 μg/mL (r2 = 0,9978) e limite de quantificação (LQ) de 1 μg/mL, com os demais parâmetros de validação aceitáveis. O
método foi aplicado para análise de formulações farmacêuticas, e os resultados foram correlacionados
com os obtidos por cromatografia líquida em fase reversa (CL-FR) e por exclusão molecular (CLEM), e pelo bioensaio in vitro. Deste modo, os procedimentos pesquisados contribuem para o
estabelecimento de alternativas que aprimoram o controle da qualidade, garantindo a segurança e eficácia terapêutica do produto biológico.
|
300 |
USING RECOMBINANT HUMAN CARBAMOYL PHOSPHATE SYNTHETASE 1 (CPS1) FOR STUDYING THIS ENZYME'S FUNCTION, REGULATION, PATHOLOGY AND STRUCTUREDíez Fernández, Carmen 09 July 2015 (has links)
Tesis por compendio / [EN] Carbamoyl phosphate synthetase 1 (CPS1), a 1462-residue mitochondrial enzyme, catalyzes the entry of ammonia into the urea cycle, which converts ammonia, the neurotoxic waste product of protein catabolism, into barely toxic urea. The urea cycle inborn error and rare disease CPS1 deficiency (CPS1D) is inherited with mendelian autosomal recessive inheritance, being due to CPS1 gene mutations (>200 mutations reported), and causing life-threatening hyperammonemia.
We have produced recombinantly human CPS1 (hCPS1) in a baculovirus/insect cell expression system, isolating the enzyme in active and highly purified form, in massive amounts. This has allowed enzyme crystallization for structural studies by X-ray diffraction (an off-shoot of the present studies). This hCPS1 production system allows site-directed mutagenesis and enzyme characterization as catalyst (activity, kinetics) and as protein (stability, aggregation state, domain composition). We have revealed previously unexplored traits of hCPS1 such as its domain composition, the ability of glycerol to replace the natural and essential CPS1 activator N-acetyl-L-glutamate (NAG), and the hCPS1 protection (chemical chaperoning) by NAG and by its pharmacological analog N-carbamyl-L-glutamate (NCG).
We have exploited this system to explore the effects on the activity, kinetic parameters and stability/folding of the enzyme, and to test the disease-causing nature, of mutations identified in patients with CPS1 deficiency (CPS1D). These results, supplemented with those obtained with other non-clinical mutations, have provided novel information on the functions of three non-catalytic domains of CPS1.
We have introduced three CPS1D-associated mutations and one trivial polymorphism in the glutaminase-like domain of CPS1, supporting a stabilizing and an activity-enhancing function of this non-catalytic domain. Two mutations introduced into the bicarbonate phosphorylation domain have shed light on bicarbonate binding and have directly confirmed the importance of this domain for NAG binding to the distant (in the sequence) C-terminal CPS1 domain. The introduction of 18 CPS1D-associated missense mutations mapping in a clinically highly eloquent central non-catalytic domain have proven the disease-causing nature of most of these mutations while showing that in most of the cases they trigger enzyme misfolding and/or destabilization. These results, by proving an important role of this domain in the structural integration of the multidomain CPS1 protein, have led us to call this domain the Integrating Domain.
Finally, we have examined the effects of eight CPS1D-associated mutations, of one trivial polymorphism and of five non-clinical mutations, all of them mapping in the C-terminal domain of the enzyme where NAG binds, whereas we have re-analyzed prior results with another four clinical and five non-clinical mutations affecting this domain. We have largely confirmed the pathogenic nature of the clinical mutations, predominantly because of decreased activity, in many cases due to hampered NAG binding. A few mutations had substantial negative effects on CPS1 stability/folding. Our analysis reveals that NAG activation begins with a movement of the final part of the ß4-¿4 loop of the NAG site. Transmission of the activating signal to the phosphorylation domains involves helix ¿4 from this domain and is possibly transmitted by the mutually homologous loops 1313-1332 and 778-787 (figures are residue numbers) belonging, respectively, to the carbamate and bicarbonate phosphorylation domains. These two homologous loops are called from here on Signal Transmission Loops. / [ES] La carbamil fosfato sintetasa 1 (CPS1), una enzima mitocondrial, cataliza la entrada del amonio en el ciclo de la urea, que convierte esta neurotoxina derivada del catabolismo de las proteínas en urea, mucho menos tóxica. El déficit de CPS1 (CPS1D) es un error innato del ciclo de la urea, una enfermedad rara autosómica recesiva, que se debe a mutaciones en el gen CPS1 (>200 mutaciones descritas) y que cursa con hiperamonemia.
Hemos producido CPS1 humana recombinante (hCPS1) en un sistema de expresión de células de insecto y baculovirus, y la hemos aislado en forma activa, muy pura y en cantidad elevada. Este sistema de producción de hCPS1 permite la realización de mutagénesis dirigida y la caracterización de la enzima como catalizador (actividad, cinética) y como proteína (estabilidad, estado de agregación y composición de dominios). Hemos revelado características de la hCPS1 antes no exploradas como es la composición de dominios, la capacidad que tiene el glicerol para reemplazar al activador natural y esencial de la CPS1, N-acetil-L-glutamato (NAG), y la protección de la hCPS1 por NAG y por su análogo farmacológico N-carbamil-L-glutamato (NCG) (chaperonas químicas).
Hemos utilizado este sistema para explorar los efectos en actividad, parámetros cinéticos y estabilidad/plegamiento de la enzima, y para comprobar la naturaleza patogénica de mutaciones identificadas en pacientes con CPS1D. Estos resultados, junto con los obtenidos con otras mutaciones no clínicas, han aportado información novedosa sobre tres de los dominios no catalíticos de CPS1.
Las observaciones realizadas tras introducir en el dominio de tipo glutaminasa de la enzima tres mutaciones asociadas a CPS1D y un polimorfismo trivial, apoyan la contribución de este dominio no catalítico a la estabilidad y a aumentar la actividad de la enzima. Dos mutaciones introducidas en el dominio de fosforilación de bicarbonato han arrojado luz sobre el modo de unión del bicarbonato (un sustrato). Los resultados de estas mutaciones también han confirmado la contribución de este dominio para la unión de NAG, cuyo sitio de unión se encuentra en el dominio C-terminal de CPS1, bastante alejado (en la secuencia) del dominio de fosforilación de bicarbonato. Además, hemos introducido 18 mutaciones de cambio de sentido asociadas a CPS1D, las cuales están localizadas en un dominio no catalítico, central y de elevada elocuencia clínica. Estos resultados han demostrado la naturaleza patogénica de estas mutaciones, ya que en la mayoría de los casos estas mutaciones producen un mal plegamiento o/y desestabilización de la enzima. Debido a que estos resultados han puesto de manifiesto el importante papel de este dominio en la integración estructural de la proteína multidominio CPS1, lo hemos llamado Dominio Integrador.
Finalmente, hemos examinado los efectos de 8 mutaciones asociadas a CPS1D, de un polimorfismo trivial y de 5 mutaciones no clínicas, todas localizadas en el dominio C-terminal de la enzima, donde se une NAG. Además, hemos reanalizado resultados anteriores con otras 4 mutaciones clínicas y 5 no clínicas afectando a este dominio. Hemos confirmado el carácter patogénico de las mutaciones clínicas, las cuales predominantemente causan una disminución en la actividad enzimática, en muchos casos debida a que la unión de NAG se encuentra obstaculizada. Unas pocas mutaciones mostraron efectos negativos en la estabilidad/plegamiento de CPS1. Nuestros análisis revelan que la activación por el NAG empieza con un movimiento de la parte final del bucle ß4-¿4 del sitio de NAG. La transmisión de la señal activadora a los dominios de fosforilación implica a la hélice ¿4 de este dominio y posiblemente se transmite a través de los bucles homólogos 1313-1332 y 778-787 (numeración de residuos) pertenecientes, respectivamente, a los dominios de fosforilación de carbamato y bicarbonato. Por ello, hemos llamado a ambos bucles Bucles de / [CA] La carbamil fosfat sintetasa 1 (CPS1), un enzim mitocondrial, catalitza l'entrada d'amoni en el cicle de la urea, que convertix l'amoni, producte neurotòxic del catabolisme de les proteïnes, en urea, una molècula molt poc tòxica. El dèficit de CPS1 (CPS1D) és un error innat del cicle de la urea, una malaltia rara autosòmica recessiva, que es deu a mutacions en el gen CPS1 (>200 mutacions descrites) i que cursa amb hiperamonièmia.
Hem produït CPS1 humana recombinant (hCPS1) en un sistema d'expressió de cèl·lules d'insecte i baculovirus, i l'hem aïllada en forma activa, molt pura i en gran quantitat. Això ha permés la cristal·lització de l'enzim per a estudis estructurals amb difracció de raios-X (treball no inclòs en esta tesi Aquest sistema de producció de hCPS1 permet la realització de mutagènesi dirigida i la caracterització de l'enzim com a catalitzador (activitat, cinètica) i com a proteïna (estabilitat, estat d'agregació i composició de dominis). Hem revelat característiques de la hCPS1 no explorades abans com és la composició de dominis, la capacitat que té el glicerol per a reemplaçar l'activador natural i essencial de CPS1, N-acetil-L-glutamat (NAG), i la protecció de la hCPS1 per NAG i pel seu anàleg farmacològic N-carbamil-L-glutamat (NCG) (xaperones químiques) .
Hem utilitzat aquest sistema per a explorar els efectes en l'activitat, els paràmetres cinètics i l'estabilitat/plegament de l'enzim, i per a comprovar la naturalesa patogènica de mutacions identificades en pacients amb CPS1D. Aquestos resultats, junt amb els obtinguts amb altres mutacions no clíniques, han aportat informació nova sobre tres dels dominis no catalítics de la CPS1.
Les observacions, després d'introduir tres mutacions associades a CPS1D i un polimorfisme trivial en el domini tipus glutaminasa de CPS1, recolzen la contribució d'aquest domini no catalític a l'estabilitat i a l'optimització de l'activitat enzimàtica. Dues mutacions introduïdes en el domini de fosforilació de bicarbonat han esclarit el mode d'unió de bicarbonat. Els resultats d'aquestes mutacions també han confirmat la contribució d'aquest domini per a la unió de NAG, el lloc d'unió de la qual es troba en el domini C-terminal de CPS1, prou allunyat (en la seqüència) del domini de fosforilació de bicarbonat. A més, hem introduït 18 mutacions de canvi de sentit associades a CPS1D, les quals estan localitzades en un domini no catalític, central i d'elevada eloqüència clínica. Aquestos resultats han demostrat la naturalesa patogènica d'aquestes mutacions, ja que, en la majoria dels casos produïxen un mal plegament o/i desestabilització de l'enzim. Pel fet que aquestos resultats han posat de manifest l'important paper d'aquest domini en la integració estructural de la proteïna multidomini CPS1, l'hem anomenat Domini Integrador.
Finalment, hem examinat els efectes de huit mutacions associades a CPS1D, un polimorfisme trivial i cinc mutacions no clíniques, totes elles localitzades en el domini C-terminal de l'enzim, on s'unix NAG. A més, hem reanalitzat resultats anteriors amb altres quatre mutacions clíniques i cinc no clíniques que afecten aquest domini. Hem confirmat el caràcter patogènic de les mutacions clíniques, les quals predominantment causen una disminució en l'activitat enzimàtica, en molts casos pel fet que la unió de NAG es troba obstaculitzada. Unes poques mutacions van mostrar efectes negatius substancials en l'estabilitat/plegament de CPS1. Les nostres anàlisis revelen que l'activació de NAG comença amb un moviment de la part final del bucle ß4-¿4 del lloc de NAG. La transmissió del senyal activadora als dominis de fosforilació involucra l'hèlix ¿4 d'aquest domini i es transmet, possiblement, a través dels bucles homòlegs 1313-1332 i 778-787 (numeració dels residus), pertanyents, respectivament, als dominis de fosforilació de carbamato i bicarbonat. Per això, hem anomenat a ambd / Díez Fernández, C. (2015). USING RECOMBINANT HUMAN CARBAMOYL PHOSPHATE SYNTHETASE 1 (CPS1) FOR STUDYING THIS ENZYME'S FUNCTION, REGULATION, PATHOLOGY AND STRUCTURE [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/52855 / Compendio
|
Page generated in 0.0907 seconds