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Jimenez, Rosales Angelica. « Methyltransferases as bioorthogonal labelling tools for proteins ». Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/methyltransferases-as-bioorthogonal-labelling-tools-for-proteins(27231f93-7cdd-4c2d-9f31-0adc3f38b147).html.
Texte intégralRésumé :
Development of enzymatic labelling methods has been driven by the importance of studying molecular structures and interactions to comprehend cellular processes. Methyltransferases (MTases), which regulate genetic expression by transferring a methyl group from the cofactor S-adenosyl-L-methionine (SAM) to DNA, histones and various proteins, have been shown to accept SAM analogues with an alternative alkyl group on the sulfonium centre. These alkyl groups can be transferred to the substrate, and with a further reaction can be selectively functionalized. Thus, MTases together with SAM analogues have emerged as novel labelling tools. The project aims to use MTases to obtain an orthogonal system that can selectively use a SAM cofactor analogue to transfer functional chains to proteins with a specific motif. To achieve selectivity of the system, the SAM analogue cofactor was modified on the ribose ring; to obtain a new transferase activity of the system, the transferable methyl on the sulfonium centre was changed to a different substituent. SAM analogues were produced enzymatically with hMAT2A by using 3'-deoxy-ATP and methionine or ethionine. Mutants of SET8 and novel substrates were designed to have modifications at residues in the active site, within the vicinity of the ribose ring of SAM, and were assessed for selective activity with the new analogue cofactor. The results showed that the new cofactor 3'-deoxy-S-adenosyl-L-methionine (3'dSAM) was efficient in the mono-methylation of the substrate peptide RFRKVL, and that the mutant SET8 C270V exhibited over 13 fold MTase activity in presence of 3'dSAM and the RFRKVL substrate, in comparison with the activity with the WT sequence RHRKVL and the SAM cofactor. In addition, glutathione S-transferase (GST) was used as a model protein to express the motif RFRKVL, to transform it into a potential substrate for SET8. Assessment of the MTase activity of SET8, 3'dSAM and the novel GST substrate indicated mono-methylation of the substrate. Moreover, the motif showed no interference with GST native activity. Based on the observations, a new enzymatic system shows higher selectivity with a new analogue cofactor over SAM to effectively methylate proteins expressing the consensus RFRKVL. Work on substrates, enzymes and cofactors should continue to obtain a functional-chain transferase activity of the enzymatic system.
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Allsebrook, Andrew M. « QPRTase : quinolinic acid analogue synthesis and non-enzymic decarboxylation of N-alkylquinolinic acids ». Thesis, University of St Andrews, 1998. http://hdl.handle.net/10023/14376.
Texte intégralRésumé :
Quinolinate phosphoribosyltransferase (QPRTase, E.C. 2.4.2.19) is considered to be a unique enzyme in that it is thought to catalyse two distinct chemical reactions. Both the transfer of a phosphoribosyl group from 5-phosphoribosyl-1- pyrophosphate onto the nitrogen of quinolinic acid and the subsequent decarboxylation of the intermediate to form nicotinic acid mononucleotide are thought to be catalysed by the QPRTase system. Analogues of quinolinic acid were designed as potential inhibitors of QPRTase. These contain acidic groups at the 2- and 3- positions but are unable to decarboxylate. However, such compounds may be able to undergo the phosphoribosyl transfer reaction, potentially increasing their inhibitory potency. These compounds may be useful as "biological tools" allowing the neurological effects of an increase in quinolinic acid levels to be investigated. The compounds may show anti-fungal activity blocking the kynurenine pathway for NAD production. 2-Sulfonicotinic acid was synthesised by the oxidation of 2-mercaptonicotinic acid by either basic potassium permanganate, or iodine, with the structure was confirmed by X-ray crystallography. In biological testing the acid was shown to be neither an agonist nor antagonist of the NMDA receptor, or to be neurotoxic. A number of synthetic routes towards 2-phosphononicotinic acid, an alternative quinolinic acid analogue, were attempted though none were successful. These included orthometallation strategies and palladium coupling reactions to incorporate the phosphonic acid group at the 2- position. Nucleophilic addition routes, methods of building up the pyridine ring and including non-selective phosphonic acid addition were also examined. However, a related derivative, 2-(phosphonomethyl)nicotinic acid, was successfully synthesised. The non-enzymic decarboxylation of N-alkyl quinolinic acids was investigated, for comparison with the decarboxylation reaction catalysed by QPRTase. Both N- methyl and N-ethylquinolinic acid were synthesised, and the pH versus rate profiles measured. The rate maximum for both compounds was at pH 1.5, with the rate decreasing both above and below the maximum. N-Methylquinolinic acid was 10 times faster than quinolinic acid itself, demonstrating the effect of the nitrogen substituent. The N-ethyl derivative decarboxylated a further 1.5 times faster, showing the effect of increasing the size of the substituent. An Arrhenius plot was also carried out, giving an activation energy for the reaction of 153 kJ mol-1. Attempts to prepare the N-propyl derivative were unsuccessful, as decarboxylation occurred very readily to give N- propylnicotinic acid.
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Anderson, Gordon James. « Molecular characterisation of the PRP8 protein on Saccharomyces cerevisiae and identification of an analogue in HeLa cells ». Thesis, University of Edinburgh, 1989. http://hdl.handle.net/1842/11287.
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Schmiele, Marcio 1979. « Interações físicas e químicas entre isolado protéico de soja e glúten vital durante a extrusão termoplástica a alta e baixa umidade para a obtenção de análogo de carne = Physical and chemical interactions between isolated soy protein and vital gluten during thermoplastic extrusion at high and low moisture content to obtain meat analogue ». [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/255892.
Texte intégralRésumé :
Orientador: Yoon Kil ChangTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-08-24T06:53:45Z (GMT). No. of bitstreams: 1 Schmiele_Marcio_D.pdf: 9722936 bytes, checksum: 95d9146270f349c5f3e7ad761ac0d266 (MD5) Previous issue date: 2014
Resumo: Os análogos de carne obtidos por extrusão termoplástica de proteínas vegetais são caracterizados pelo seu elevado teor proteico e estrutura semelhante às fibras da carne, envolvendo diversos tipos de ligações e/ou interações químicas entre as proteínas. O objetivo deste trabalho foi avaliar as características tecnológicas e físico-químicas de análogos de carne, à base de isolado proteico de soja, obtidos por processo de extrusão termoplástica a alta umidade (AU) e baixa umidade (BU). Para cada condição de umidade foi utilizado um Delineamento Composto Central Rotacional de três variáveis independentes (glúten vital, umidade de condicionamento e temperatura de extrusão). As variáveis dependentes avaliadas foram a textura instrumental, cor instrumental, capacidade de absorção de água, índice de solubilidade em água, capacidade de absorção de óleo, índice de dispersibilidade de proteína, energia mecânica específica e o tipo de interações proteicas. Estas interações foram avaliadas através de sete tipos de solventes específicos: (i) tampão fosfato para as proteínas no estado nativo; (ii) dodecil sulfato de sódio para as interações hidrofóbicas e iônicas; (iii) Triton 100X para as interações hidrofóbicas; (iv) ureia para as interações hidrofóbicas e pontes de hidrogênio; (v) ß-mercaptoetanol para as ligações dissulfeto; e (vi) ß-mercaptoetanol e ureia e (vii) dodecil sulfato de sódio e ureia, para avaliar o efeito sinérgico entre os sistemas. O ponto otimizado (caracterizado principalmente por promover maiores valores de L* e de capacidade de absorção de água, menores valores de índice de solubilidade em água, de capacidade de absorção de óleo, de desnaturação proteica e valores intermediários de textura instrumental e de energia mecânica específica) foi processado juntamente com uma amostra controle para ambos os processos com o intuito de validar os modelos matemáticos e avaliar as possíveis alterações na morfologia dos análogos de carne, na massa molecular das proteínas, na composição de aminoácidos totais e na desnaturação proteica. As melhores condições de processamento foram obtidos para os análogos de carne contendo de 12 e 5 % de glúten vital, 58 e 18 % de umidade de condicionamento e 135 e 100 °C para a temperatura de extrusão, para o processo AU e BU, respectivamente. As principais interações proteína-proteína encontradas nos análogos de carne foram as ligações dissulfeto e ligações de hidrogênio para o processo AU e as ligações dissulfeto e interações iônicas para o processo BU. A adição de glúten vital promoveu uma aparência mais lisa e melhor orientação na estrutura das fibras. Verificou-se que ocorreu aumento nas proteínas de baixa massa molecular e diminuição nas proteínas de alta massa molecular. No perfil de aminoácidos totais houve maior variação negativa para os aminoácidos essenciais (triptofano e treonina), semi essenciais (cisteína) e não essenciais (serina), indicando que houve redução no valor nutricional. As estruturas secundárias (a-hélice, ß-folha, ß-volta e a estrutura desordenada) mostraram alteração na sua conformação devido à desnaturação proteica e formação de novos agregados
Abstract: Meat analogue obtained by termoplastic extrusion of vegetable proteins are characterized by its high protein levels and structure similar to meat fibers, which comprises many types of chemical bonds and/or interactions between proteins. The aim of this work was to evaluate the technological and physico-chemical characteristics of meat analogue based on isolated soy protein obtained by thermoplastic extrusion process at high moisture (HM) and low moisture (LM) content. For each moisture condition was used a Central Rotational Composite Design with three independent variables (vital gluten, moisture content and extrusion temperature). The dependent variables evaluated were instrumental texture, instrumental color, water absorption capacity, water solubility index, oil absorption capacity, protein dispersibility index, specific mechanical energy, and the type of protein interactions. These interactions were evaluated using seven specific solvents types: (i) phosphate buffer for proteins in native state; (ii) sodium dodecil sulphate for hydrophobic and ionic interactions; (iii) Triton 100X for hydrophobic interactions; (iv) urea for hydrophobic interactions and hydrogen bonds; (v) ß-mercaptoethanol for dissulfide bonds; and (vi) ß-mercaptoethanol and urea and (vii) sodium dodecil sulphate and urea, for the synergistic effect between the systems. The optimized point (characterized mainly by promoting higher values for L* and water absorption capacity, lower values for water solubility index, oil absoption capacity and protein denaturation and intermediate values for instrumental texture and specific mechanical energy) was processed, together with a control sample for each processes, in order to validate the mathematical models and to evaluate possibles changes in the meat analogues morphology, in the protein molecular weight, in the total amino acid composition, and in the protein denaturation. The best processing conditions were obtained for the meat analogue containing 12 and 5 % of vital gluten, 58 and 18 % of moisture content and 135 and 100 °C of extrusion temperature, for the HM and LM processes, respectively. The main protein-protein interactions found in meat analogues were the dissulfide bonds and hydrogen bonds for the LM process and the dissulfide bonds and ionic interactions for the HM process. The addition of vital gluten promoted a smoother appearance and better orientation in the fiber structure. It was found that occured an increase in the protein with low molecular weight and a reduction in the protein with high molecular weight. There were a greater negative variation for the essential (tryptophan and threonine), semi-essential (cysteine) and nonessential (serine) amino acids in the total amino acid profile, indicating a reduction of the nutritional value. The secondary structure (a-helix, ß-sheet, ß-turn and disordered structure) showed alteration in its conformation due to the protein denaturation and formation of new aggregates
Doutorado
Tecnologia de Alimentos
Doutor em Tecnologia de Alimentos
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Frippiat, Steven. « Synthèses et fonctionnalisations de noyaux imidazolones : utilisations innovantes d'isonitriles et d'oxazolines ». Thesis, Normandie, 2020. http://www.theses.fr/2020NORMIR17.
Texte intégralRésumé :
A ce jour, les dérivés d’imidazolones-4-arylidènes et dialkyles-(4,4’)-imidazolones font l’objet de nombreuses convoitises pour les scientifiques tant sur le domaine des matériaux via ses propriétés de fluorescence, que sur celui du médical, en particulier pour le traitement de maladies comme les cancers, l’hypertension ou la maladie d’Alzheimer. Les chimistes n’ont eu de cesses de présenter des procédés de synthèses plus originaux les uns que les autres pour l’obtention de ces imidazolones. Cependant, ces méthodes parfois anciennes, peuvent sembler être en décalage avec les demandes d’accéder en une seule étape à un large panel de dérivés hautement fonctionnels. De plus, ces voies de synthèses ne répondent plus à enjeux actuels : être davantage économiques en terme d’étapes mais aussi d’atomes. C’est pourquoi il nous a semblé important de proposer nous-mêmes des solutions dans l’optique de répondre à ces problématiques à l’aide d’une fonction particulière : la fonction isonitrileUp until now, arylidene-4-imidazolones and dialkyl-(4,4’)-imidazolones derivatives are subject of longing for scientists both in the field of materials with fluorescence properties, and medical area, in particular for the treatment of diseases such as cancer, high blood pressure or Alzheimer's disease. Chemists have constantly presented synthetic methods, each more original than the other for the synthesis of these imidazolones. However, these old methods can appear to be out of step with the demands for one-step access to a large panel of highly functional derivatives. In addition, these synthetic routes are no longer respond to current challenges : being more economical in terms of synthetic’s step but also of atoms. This is why it seemed important to us to come up with some solutions in order to respond to these problems according to a particular function: the isocyanide function
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Nemeth, Joseph. « Design and synthesis of chemical probes for the protein kinase B PH domain ». Thesis, St Andrews, 2008. http://hdl.handle.net/10023/572.
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GANDINI, ENRICO. « MOLECULAR DYNAMICS AND CHEMINFORMATICS METHODS TO EXPLORE THE CHEMICAL REALITY ». Doctoral thesis, Università degli Studi di Milano, 2022. http://hdl.handle.net/2434/888609.
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Part I: Antifreeze Peptides
Organisms living in icy environments produce antifreeze proteins to control ice growth and recrystallization. It has been proposed that these molecules pin the surface of ice crystals, thus inducing the formation of a curved surface that arrests crystal growth. Such proteins are very appealing for many potential applications in food industry, material science and cryoconservation of organs and tissues. Unfortunately, their structural complexity has seriously hampered their practical use, while efficient and accessible synthetic analogues are highly desirable. In the present work, we used molecular dynamics based techniques to model the interaction of three short antifreeze synthetic peptides with an ice surface. The employed protocols succeeded in reproducing the ice pinning action of antifreeze peptides and the consequent ice growth arrest, as well as in distinguishing between antifreeze and control peptides, for which no such effect was observed. Principal components analysis of peptides trajectories in different simulation settings permitted to highlight the main structural features associated to antifreeze activity. Modeling results are highly correlated with experimentally measured properties, and insights on ice-peptide interactions and on conformational patterns favoring antifreeze activity will prompt the design of new and improved antifreeze peptides.
Part II: Molecular Similarity
Molecular similarity is an important notion in chemistry, with applications in fields such as chemical databases and drug design. Molecular similarity is also important in chemical legislation, in particular in the evaluation process for orphan drugs (i.e., drugs for rare diseases). A new molecule needs to be dissimilar from any other existing drug for a given disease to be assigned the financially advantageous status of orphan drug. Currently, there are many ways to define whether two molecules are similar or dissimilar. Thus far, the European Medicines Agency has used majority voting on discretional judgments of similarity when assessing new drugs for rare diseases. Similarity in an inherently subjective concept, which depends on individual factors such as gender, age, state of mind, and previous experiences. Automated procedures that quantitatively and objectively evaluate molecular similarity are needed. Existing automated procedures are quite effective, but only take into account 2D molecular properties. We improved upon existing similarity-prediction procedures by including calculated 3D properties in the computational models. We created a new data-set of molecular similarity assessments, that includes complex and borderline similarity scenarios. We used the new data-set to test the existing procedures, and to build new and improved computational models.
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Milner, Steven John. « The oxidative folding of insulin-like growth factor-I analogues / ». Title page, table of contents and summary only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phm65945.pdf.
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DI, LUCENTE CRISTINA. « The phytotoxin fusicoccin : a regulator of multiple 14-3-3 targets ». Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2010. http://hdl.handle.net/2108/202271.
Texte intégralRésumé :
L’identificazione della fusicoccina come metabolita responsabile degli effetti tossici di Phomopsis amygdali, dovuti alla sua capacità di attivare irreversibilmente l’H+-ATPasi di plasmalemma, ha dato impulso al chiarimento del meccanismo molecolare di azione della tossina. L’H+-ATPasi di plasmalemma è, ad oggi, l’unico bersaglio dell’azione della FC individuato. La mancata identificazione di siti di legame per la FC in batteri, lieviti, funghi e animali ha fatto ritenere che l’azione della tossina fosse quindi ristretta al regno vegetale. In questo lavoro è dimostrata la capacità della fitotossina di influenzare il processo di aggregazione piastrinica. In particolare, da un’analisi, condotta nel nostro laboratorio è stata identificato il recettore piastrinico GPIb-IX-V come possibile bersaglio dell’azione della fusicoccina. Infatti, la tossina è in grado di promuovere il legame delle proteine regolatrici 14-3-3 alla glicoproteina Ibα e di inibire l’associazione con la subunità Ibβ. Da ciò ne risulta la stimolazione dell’adesione piastrinica al fattore di von Willebrand che determina la diffusione piastrinica e l’attivazione delle integrine αIIbβ3. Tali risultati incoraggiano il proseguimento degli studi volti a stabilire se la fusicoccina possa essere utilizzata nella terapia o nella diagnosi di patologie associate alla coagulazione del sangue. Inoltre, questo lavoro pone le basi ad una futura ricerca volta a determinare la possibile applicazione della tossina ad altri complessi 14-3-3/target.
Inoltre, la disponibilità di un gran numero di derivati e analoghi della fusicoccina ha reso possibile un’analisi dettagliata della correlazione tra attività e struttura chimica. A tale scopo, è stata saggiata l’attività di questi composti correlati alla fusicoccina in saggi sia in vivo che in vitro.The fungal toxin fusicoccin induces plant wilting by affecting ion transport across the plasma membrane of plant cell. The activity of this toxin is so far unknown in humans. In this work, we show that fusicoccin is able to affect the platelet aggregation process. The toxin associates to platelet intracellular binding sites and induces aggregation in platelet-rich plasma in a dose-dependent manner. We identified the adhesion receptor glycoprotein Ib-IX-V as fusicoccin target. The toxin promotes the binding of the regulatory 14-3-3 proteins to glycoprotein Ibα and hampers that to glycoprotein Ibβ subunit. As a result, platelet adhesion to von Willebrand Factor is stimulated, leading to platelet spreading and integrin αIIbβ3 activation. We anticipate our study to be a starting point for future therapeutic use of fusicoccin in genetic bleeding diseases characterized by qualitative or quantitative abnormalities of the platelet membrane adhesion receptors. Furthermore, we demonstrated that fusicoccin action can be widen also to other 14-3-3 clients, provided that a mode III motif with an appropriate C terminal amino acid is present. Results obtained suggest also the rationale for fusicoccin inability to promote 14-3-3 binding to targets with a mode I consensus sequence. In addition, the availability of a large number of fusicoccin derivatives and analogues made possible a detailed analysis of the relationship between activity and chemical structure. The activity of these fusicoccin-related compounds has been tested either in vivo and in vitro.
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Carmona, Sylvie. « Un analogue de synthèse de la squalamine, NV669, comme nouvel inhibiteur de la protéine Tyrosine Phosphatase 1B (PTP1B) : étude de ses effets in vitro et in vivo sur la croissance des tumeurs pancréatiques et hépatiques ». Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0616.
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NV669 est un aminosterol dérivé de la squalamine qui a montré posséder des propriétés anti-cancéreuses. L'objectif de cette étude a été de rechercher les effets bénéfiques de NV669 sur des modèles de cancers humains pancréatiques et hépatiques et de comprendre les mécanismes cellulaires et moléculaires impliqués dans la diminution de la croissance tumorale par le traitement avec NV669. Les lignées cellulaires humaines pancréatiques (BxPC3 et MiaPaca-2) et hépatiques (HepG2 et Huh7) ont été traitées avec NV669 à différentes concentrations et à différents temps. Les résultats ont montré que NV669 inhibe la prolifération des cellules cancéreuses en induisant l'arrêt du cycle cellulaire en phase G2/M via le complexe cycline B1/Cdk1 et en induisant l'apoptose via le clivage de la caspase-8 et de PARP-1, et la fragmentation de l’ADN.De plus, nos recherches in vitro ont révélé que NV669 inhibe l’activité phosphatase de PTP1B et l’expression de FAK. NV669 affecte l’expression des molécules d’adhérence CDH-1, -2 et -3 dans les lignées BxPC3 et Huh7 qui forment des monocouches cellulaires. Cela suggère qu’en inhibant PTP1B, NV669 induirait l’apoptose.Par la suite, nos résultats in vivo ont montré que NV669 inhibe la croissance des xénogreffes pancréatiques et hépatiques tumorales avec une diminution significative de la prolifération cellulaire et une augmentation de l'apoptose des cellules tumorales. Par conséquent, nos recherches suggèrent que l’analogue de la squalamine, NV669, pourrait être un agent anti cancéreux, utilisé seul ou en association avec d’autres médicaments, dans le traitement de l’adénocarcinome pancréatique et du carcinome hépatocellulaireNV669 is an aminosterol derived from squalamine found to possess strong antiangiogenic and anticancer effects. The aim of this study was to investigate NV669’s beneficial effects on human pancreatic and hepatic cancer models and to understand the cellular and molecular mechanisms involved in tumor growth decrease upon treatment with NV669.Pancreatic (BxPC3, MiaPaCa-2) and hepatic (HepG2, Huh7) cancer cells were treated with NV669, and the effects on proliferation, on cell cycle and death were determined. The results showed that NV669 inhibited the viability of cancer cells, induced cell cycle arrest through the regulation of G2/M phase via a decrease in the expression of cyclin B1 and phosphorylated Cdk1 and the induction of apoptosis via cleaved caspase-8 and PARP-1 and fragmented DNA. Moreover, in vitro NV669 inhibits PTP1B activity and FAK expression. NV669 impacts on the expression of adhesion molecules CDH-1, -2 and -3 in BxPC3 and Huh7 lines that form cell monolayers. This suggests that NV669 by inhibiting PTP1B would induce apoptosis. Subsequently, our in vivo results showed that NV669 inhibited the growth of pancreatic and hepatic tumor xenografts with a significant decrease in proliferation cell and an increase of tumor cell apoptosis. Therefore, NV669 may serve as an alternative anticancer agent, used alone or in association with other medications, for the treatment of pancreatic adenocarcinoma and hepatocellular carcinoma
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Mahajan, Shikha. « Protein Profiling of Adenine Nucleoside and Nucleotide Analogs Binding Proteins Using N6-Biotinylated-8-azidoadenosine Analogs as Affinity Based Protein Profiling Probes ». Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4139.
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Identification of differential expressions of proteins in proteomic profiles of biological samples shows great potential as a valuable technique for the early diagnosis of various diseases. An important challenge in modern protein profiling approaches is to reduce the complexity of the samples by limiting the number of proteins that need to be evaluated for distinction in the expression between normal and deceased cells. In this research, an affinity based approach for the enrichment of nucleotide and nucleoside binding proteins from a complex cell proteome has been developed. To achieve this goal, new N6-biotinylated-8-azido-adenosine probes (AdoRs) have been designed and synthesized to photolabel the nucleotide and nucleoside binding proteins. These probes contain a reactive group that forms a covalent bond with the target proteins, as well as a biotin tag for affinity enrichment using avidin chromatography. Further, a mass spectrometric protein profiling approach is employed to quantitatively identify small variations in expression of nucleoside and nucleotide binding proteins in samples of interest.
Mouse neuroblastoma N18TG2 cell proteome has been used as a model system for the development of the LC-MS/MS based proteomic analysis of these affinity enriched protein fractions. Upon enrichment, the photolabeled proteome exhibited an approximately four-fold abundance of nucleoside and nucleotide binding proteins over
nonlabeled proteome. The approach was extended to compare the proteomic profiles of nucleotide and nucleoside binding proteins in cancerous (Hey) and non-cancerous (T-80) human ovarian cell proteome. Certain proteins that were not detected in cell lysate were also identified in labeled proteome, thereby demonstrating the strength of our approach in enriching low abundant proteins.
To substantiate the qualitative analysis, we have employed the Stable Isotope Labeling in Amino Acid Cell Culture (SILAC) for the quantitative study of the protein expression in cancerous and non-cancerous human ovarian cells. A modest panel of proteins with differential expressions in these cell lines was identified, a few of which have been correlated to various forms of cancer. Vimentin, stress induced phosphoprotein-1, and heat shock protein 90 that were identified to have altered expressions in these cell lines are among some of the proteins associated with ovarian cancer.
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Baldridge, Anthony Owen. « Synthesis, photophysics, and application of fluorescent protein chromophore analogs ». Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/44744.
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The green fluorescent protein chromophore exhibits remarkably different properties upon removal from the protective beta-barrel. This work focuses on the synthesis of these chromophores as wells studying the photophysics as to why they readily deactivate. Following these initial discoveries, these chromophores can be applied to many different environments providing a fluorescence "turn-on" and thus proving to be applicable in a number of different environments and fields.
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Punyamoonwongsa, Patchara. « Synthetic analogues of protein-lipid complexes ». Thesis, Aston University, 2007. http://publications.aston.ac.uk/9803/.
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Hypercoiling poly(styrene-alt-maleic anhydride) (PSMA) is known to undergo conformational transition in response to environmental stimuli. The association of PSMA with lipid 2-dilauryl-sn-glycero-3-phosphocholine (DLPC) produces polymer-lipid complex analogues to lipoprotein assemblies found in lung surfactant. These complexes represent a new bio-mimetic delivery vehicle with applications in the cosmetic and pharmaceutical industries. The primary aim of this study was to develop a better understanding of PSMA-DLPC association by using physical and spectroscopic techniques. Ternary phase diagrams were constructed to examine the effects of various factors, such as molecular weight, pH and temperature on PSMA-DLPC association. 31P-NMR spectroscopy was used to investigate the polymorphic changes of DLPC upon associating with PSMA. The Langmuir Trough technique and surface tension measurement were used to explore the association behaviour of PSMA both at the interface and in the bulk of solution, as well as its interaction with DLPC membranes. The ultimate aim of this study was to investigate the potential use of PSMA-DLPC complexes to improve the bioavailability and therapeutic efficacy of a range of drugs. Typical compounds of ophthalmic interest range from new drugs such as Pirenzepine, which has attracted clinical interest for the control of myopia progression, to the well-established family of non-steroid anti-inflammatory drugs. These drugs have widely differing structures, sizes, solubility profiles and pH-sensitivities. In order to understand the ways in which these characteristics influence incorporation and release behaviour, the marker molecules Rhodamine B and Oil Red O were chosen. PSMA-DLPC complexes, incorporated with marker molecules and Pirenzepine, were encapsulated in hydrogels of the types used for soft contact lenses. Release studies were conducted to examine if this smart drug delivery system can retain such compounds and deliver them at a slow rate over a prolonged period of time.
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Rivière, Gwladys. « Étude par RMN de la créatine kinase musculaire et d’un nouveau domaine de liaison à l’ubiquitine dans la protéine STAM2 ». Thesis, Lyon 1, 2011. http://www.theses.fr/2011LYO10285/document.
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Au cours de cette thèse, nous avons étudié deux protéines par RMN : la créatine kinase musculaire (CK-MM) et le domaine UIM-SH3 de la protéine STAM2, seuls ou en interaction avec leurs partenaires. La CK-MM est une enzyme active sous forme dimérique. Elle appartient à la famille des guanidino-kinases et intervient dans le processus énergétique de la cellule. Le but de l’étude était d’élucider le mode de fonctionnement de la CK-MM. Pour cela, nous avons enregistré des expériences de relaxation R1, R2 et des expériences de perturbation de déplacement chimique sur la CK-MM libre et complexée avec MgADP et sous forme TSAC. Ces expériences montrent que la boucle 320s, spécifique à la reconnaissance des substrats, possède une dynamique rapide en absence de substrats et une dynamique ralentie en présence de substrats. La fixation des substrats dans les sites actifs de la CK-MM induit des modifications conformationelles importantes. La protéine STAM2 est composée de deux UBDs : VHS, et UIM et d’un domaine SH3 connu pour interagir avec des déubiquitinases UBPY et AMSH. Cette protéine est impliquée dans la voie de dégradation lysosomale. L’objectif de cette étude est la caractérisation du complexe SH3/ubiquitine. Pour cela, nous avons enregistré des expériences de perturbation de déplacement chimique et de relaxation R1, R2 et nOes sur le complexe UIM-SH3/ubiquitine. Ces expériences mettent en évidence que les domaines UIM et SH3 sont capables d’interagir chacun avec une ubiquitine, avec une affinité de l’ordre de la centaine de micromolaire. L’interface entre les UBDs et l’ubiquitine implique majoritairement des résidus hydrophobes et conservésIn this thesis, we study two proteins by NMR: the muscular creatine kinase (CK-MM) and the SH3 domain of STAM2 protein, in the free and complexed forms. CK-MM is an active homodimeric enzyme which belongs to the guanidino-phosphagen-kinase family. This enzyme is involved in energetic process in the cell. The aim of this study is to elucidate the functional mode of the CK-MM. For this purpose, we measured R1 and R2 relaxation rates and chemical shit perturbation experiments on the substrate-free CK-MM, the CK-MM/MgADP complex, and the inhibitory ternary complex CK-MM/MgADP-creatine-nitrate. The experiments show that the loop 320s, specific recognition of the substrates, possesses a fast dynamic in absence of substrates (in the order of nano-picosecond) and a slower dynamic in presence of creatine-MgADP-nitrate ion. The binding of the substrate in the two active sites induces of significant conformational modification of the CK-MM. STAM2 protein consists in two ubiquitin binding domains (VHS and UIM) and a SH3 domain which interacts with deubiquinating enzymes AMSH and UBPY. This protein is involved in the lysosomal degradation pathway. The aim of this study is the characterization of the interaction between SH3 domain of STAM2 and ubiquitin. For this, we recorded the R1, R2, nOes relaxation experiments and chemical shift perturbation experiments on the UIM-SH3/ubiquitin complex. These experiments show that SH3 and UIM domains interact each with a single ubiquitin, with affinity of the order of hundred micromolars. The interface between these UBDs and ubiquitin, involves mainly hydrophobic and conserved amino-acids
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Bae, Jae Hyun. « Studies on tryptophan analogues in proteins ». [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=966131681.
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Kelly, Matthew. « Protein-related ripening studies in soy-cheese analogues ». Thesis, Manchester Metropolitan University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267385.
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Jamieson, Craig. « Total synthesis, structure and function of protein analogues ». Thesis, University of Edinburgh, 1999. http://hdl.handle.net/1842/12283.
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A previously unknown protein produced by an mRNA mutation has recently been identified in Alzheimer's patients. The protein, designated UbN, is composed of the first 75 residues of ubiquitin followed by an unrelated sequence of 20 residues. The synthesis of this 10.7kDa entity was carried out, as well as its purification which was based on a novel affinity support in conjunction with the tetrabenzofluoroene moiety. In vitro testing established how the protein could compromise the ubiquitin-dependent proteolytic system, hence exerting a toxic effect in Alzheimer's patients. The synthesis of an analogue of ubiquitin (76 residues, 8.5kDa), which contained the unnatural amino acid 2S, 4S-5-fluoroleucine in place of leucine at the 50 and 67 positions, has been carried out. A short purification and folding protocol was developed, and comparison of the analogue with the native structure was undertaken. A possible application of the analogue in the study of protein folding using 19F nmr has been examined.
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Reyes, Samuel Onofre J. « Expanding beta-turn analogs for mimicking protein-protein hot spots ». Thesis, [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1748.
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Fischetti, Francesca. « Meat analogues : le nuove alternative ai prodotti carnei ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2022.
Trouver le texte intégralRésumé :
Il presente elaborato affronta la tematica dei prodotti analoghi della carne, che già a partire da qualche anno si stanno affacciando sul mercato internazionale, con una domanda e offerta continuamente in espansione.
Lo scopo dello studio è stato quello di delineare un quadro generale di tali prodotti da un punto di vista delle sue caratteristiche intrinseche e analizzandone le prospettive future di mercato, effettuando un’indagine sul consumatore, riguardante la percezione, la propensione all’acquisto e i motivi di tale scelta.
La tesi si distingue in una prima sezione di tipo compilativo, basata su una ricerca bibliografica attraverso l’utilizzo di parole chiave. La seconda sezione dell’elaborato è di tipo sperimentale, basata sulla stesura e distribuzione di un questionario con l’obiettivo di ricavare informazioni sulle conoscenze e percezioni di potenziali consumatori all’acquisto di prodotti analoghi della carne.
Nel dettaglio, il primo capitolo affronta il contesto in cui i prodotti surrogati della carne si trovano; si evidenziano i principali riferimenti legislativi in Italia e nel contesto della Comunità europea sui novel food, e sulla denominazione commerciale dei prodotti analoghi di origine vegetale.
Il secondo capitolo affronta il processo tecnologico a cui vanno incontro le proteine per ottenere le medesime caratteristiche (fisiche e sensoriali) dei prodotti carnei.
Il terzo capitolo contiene un’analisi della formulazione, con particolare riferimento alle fonti proteiche di origine vegetale e alla classe degli additivi. Inoltre, delinea in parte l’aspetto nutrizionale.
Il quarto, ed ultimo, capitolo si apre delineando le prospettive di mercato future, e mettendo in evidenzia gli attori principali sul mercato che hanno optato per lanciare le proprie linee di analoghi della carne di origine vegetale e i canali distributivi in Italia. È seguita la descrizione del questionario posto agli intervistati, con relativi risultati e discussione.
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Webster, Kerri Lesley. « Synthesis of nodularin analogues as potential protein phosphatases inhibitors ». Thesis, University of St Andrews, 1998. http://hdl.handle.net/10023/14322.
Texte intégralRésumé :
Reversible phosphorylation of proteins on serine, threonine and tyrosine residues, is now widely accepted to be the principal mechanism for the control of intracellular events in eukaryotic and prokaryotic cells. The nodularins are known to be potent inhibitors of serine/threonine protein phosphatases, PPlc and PP2Ac, with sub-nanomolar inhibition constants. They have been shown to form covalent adducts with the enzymes and are known to be potent hepatotoxins and liver promoters. Nodularin has the general structure: cyclo [(R)-eryphro-beta-methyl-iso-Asp-(S)-X-Adda-(R)-iso- Glu-N-methyldehydrobutyric acid)], where (S)-X is a variable S-amino acid and Adda is the unique beta-amino acid, (2S,3S,8S,9S)-3-amiao-9-methoxy-2,6,8-trimethyl-10-phenyldeca-4,6- dienoic acid. In order to investigate the mode of inhibition and also to probe the active-site binding interactions, we decided to synthesis new analogues of nodularin. Specific inhibitors for either PP1 or PP2A are not presently available, but would be useful biochemical tools in delineating the individual physiological roles of these enzymes. We decided to syntliesise, the potential inhibitor cyclo [betaAla-(2R)-Glu-alpha-OMe-gamma-Pro-(2R)-Asp-alpha-OMe-gamma-(25)-Phe], a stripped-down nodularin macrocycle, and also an analogue which is suitable for synthetic elaboration at the "Adda position". Using solution phase peptide synthesis (LPPS), four such nodularin analogues (both (25)- and (2R)-proline) were synthesised in seventeen steps. The cyclisation between the Phe and Asp residues were carried out using DIPEA under conditions of high dilution. NMR studies (TOCSY, ROESY) have elucidated the three dimensional structures which have been shown to be similar to the natural product, nodularin. A shorter synthesis of these nodularin analogues was developed using solid phase peptide synthesis (SPPS). Two solid phase synthesise of the nodularin macrocycles, cyclo-[betaAla-(2R)- Glu-alpha-OMe-gamma-Pro-(2R)-Asp-beta-(25)-Phe]; one in which Fmoc-(2S)-Phe-betaAla-(2R)-Glu-alpha-OMe-gamma-Pro-(2R)-Asp(alphaO-Wang Resin)-beta-OAllyl is deprotected and then cyclised on the resin prior to cyclisation were found to be successful. Even though the resin-bound synthesis gave low yields for the cyclisation step, compared to the situation in solution, it offered advantages in the construction of the linear isopentapeptide precursor. Initial studies have shown that the nodualrin analogues 130 and 131 are moderate inhibitors (IC50 2.8 mmol) of PP1 when tested using the malachite green system. Studies towards the synthesis of incorporating more suitable Adda functionalities, and the development of a radiolabelled protein phosphatase assay are currently being investigated within the group.
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Hardie, Sharon Shillinglaw. « Nucleotide analogues as reagents for site-specific protein-DNA crosslinking ». Thesis, University of Glasgow, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394811.
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Ravi, Swathi. « Recombinant elastin analogues as cell-adhesive matrices for vascular tissue engineering ». Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/42728.
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Biomimetic materials that recapitulate the complex mechanical and biochemical cues in load-bearing tissues are of significant interest in regenerative medicine and tissue engineering applications. Several investigators have endeavored to not only emulate the mechanical properties of the vasculature, but to also mimic the biologic responsiveness of the blood vessel in creating vascular substitutes. Previous studies in our lab generated the elastin-like protein polymer LysB10, which was designed with the capability of physical and chemical crosslinks, and was shown to display a range of elastomeric properties that more closely matched those of the native artery. While extensive validation of the mechanical properties of elastin-mimetic polymers has demonstrated their functionality in a number of tissue engineering applications, limited cell growth on the surfaces of the polymers has motivated further optimization for biological interaction. Recent biologically-inspired surface strategies have focused on functionalizing material surfaces with extracellular matrix molecules and bioactive motifs in order to encourage integrin-mediated cellular responses that trigger precise intracellular signaling processes, while limiting nonspecific biomaterial interactions. Consequently, this dissertation addresses three approaches to modulating cellular behavior on elastin-mimetic analogs with the goal of promoting vascular wall healing and tissue regeneration: genetic engineering of elastin-like protein polymers (ELPs) with cell-binding domains, biofunctionalization of elastin-like protein polymers via chemoselective ligation of bioactive ligands, and incorporation of matrix protein fibronectin for engineering of cell-seeded multilamellar collagen-reinforced elastin-like constructs.
The synthesis of recombinant elastin-like protein polymers that integrate biologic functions of the extracellular matrix provides a novel design strategy for generating clinically durable vascular substitutes. Ultimately, the synthesis of model protein networks provides new insights into the relationship between molecular architecture, biomimetic ligand presentation, and associated cellular responses at the cell-material interface. Understanding how each of these design parameters affects cell response will contribute significantly to the rational engineering of bioactive materials. Potential applications for polymer blends with enhanced mechanical and biological properties include surface coatings on vascular grafts and stents, as well as composite materials for tissue engineered scaffolds and vascular substitutes.
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Glidden, Michael D. II. « Single-chain insulin analogs as ultra-stable therapeutics and as models of protein (mis)folding : stability, structure, dynamics, and function of novel analogs ». Case Western Reserve University School of Graduate Studies / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=case1522270994798884.
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Vasudevamurthy, Madhusudan. « Betaine analogues and related compounds for biomedical applications ». Thesis, University of Canterbury. Chemical and Process Engineering, 2006. http://hdl.handle.net/10092/1096.
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Living cells accumulate compensatory solutes for protection against the harmful effects of extreme environmental conditions such as high salinity, temperature and desiccation. Even at high concentrations these solutes do not disrupt the normal cellular functions and at times counteract by stabilizing the cellular components. These properties of compensatory solutes have been exploited for stabilizing proteins and cells in vitro. Betaines are widespread natural compensatory solutes that have also been used in other applications such as therapeutic agents and polymerase chain reaction (PCR) enhancers. Some biomedical applications of novel synthetic analogues of natural betaines were investigated. Natural compensatory solutes are either dipolar zwitterionic compounds or polyhydroxyl compounds, and the physical basis of compensation may differ between these, so one focus was on synthetic betaines with hydroxyl substituents. The majority of the synthetic solutes stabilized different model proteins against stress factors such as high and low temperatures. The presence of hydroxyl groups improved protection against desiccation. The observed stabilization effect is not just on the catalytic activity of the enzyme, but also on its structural conformation. Synthetic compensatory solutes have a potential application as protein stabilizers. Dimethylthetin was evaluated as a therapeutic agent and found to be harmful in a sheep model. However, from the study we were able to generate a large-animal continuous ambulatory peritoneal dialysis (CAPD) model and showed that glycine betaine could be added to the dialysis fluid in chronic renal failure. Some synthetic compensatory solutes reduce the melting temperatures of DNA better than most natural solutes. Synthetic solutes were identified that have potential to enhance PCR and could replace some reagents marketed by commercial suppliers. Density, viscosity and molecular model data on the solutes showed correlations with the biochemical effects of the solutes, but no physical measurements were found that reliably predicted their potential for biotechnological applications.
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Perera, Aruna B. Kane Robert R. « Modification of fresh tissue surfaces ; synthesis of labeled L-dopa analogs ; and synthesis of metoclopramide analogs / ». Waco, Tex. : Baylor University, 2005. http://hdl.handle.net/2104/2998.
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Beeg, Marten. « Tetracycline and its Analogues as Drugs against Protein Aggregation and Amyloid Formation ». Thesis, Open University, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.522305.
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Carrico, Isaac Sheridan Dougherty Dennis A. « Protein engineering through in vivo incorporation of phenylalanine analogs / ». Diss., Pasadena, Calif. : California Institute of Technology, 2004. http://resolver.caltech.edu/CaltechETD:etd-09082003-110526.
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Farnaes, Lauge Luster Lindgren. « Novel analogs and a protein target for the napyradiomycins ». Diss., [La Jolla] : University of California, San Diego, 2009. http://wwwlib.umi.com/cr/ucsd/fullcit?p3372521.
Texte intégralRésumé :
Thesis (Ph. D.)--University of California, San Diego, 2009.Title from first page of PDF file (viewed October 13, 2009). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.
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Dunand, Christophe. « Perception d'un signal xyloglucane par des protéines membranaires et mise en évidence d'activité xyloglucane endotransglycosylane induite ». Université Joseph Fourier (Grenoble ; 1971-2015), 1997. http://www.theses.fr/1997GRE10111.
Texte intégralRésumé :
Afin de relier l'activite biologique du motif actif des xyloglucanes a la reconnaissance par des proteines membranaires, nous avons adopte une approche biochimique de detection basee sur l'utilisation de tests immunoenzymatiques. Nous avons utilise le dimere -l-fuc (12), d-gal marque avec de la digoxigenine ou de la biotine et des proteines solubilisees provenant de fractions enrichies en plasmalemme isolees de protoplastes de rubus, pour modeliser les interactions ligand-recepteur. Les resultats obtenus ont montre qu'une proteine membranaire de 62 kda est capable de fixer le dimere fuc-gal et que cette fixation est saturable et reversible. Par ailleurs, le deplacement competitif de la fixation montre une inhibition de l'activite de liaison a la fois par des analogues structuraux (xxfg, fuc-gal-glc, fuc-gal-xyl) et par des phytohormones (2,4-d, kinetine, ga#3, acide abscissique). Cependant, a ce stade de nos travaux, il n'est a pas encore etabli que ces structures proteiques correspondent a des recepteurs de xyloglucane. Une technique de determination de l'activite xyloglucane endotransglycosylase par tests immunoenzymatiques a ete mise au point et a permis de mettre en evidence une activite induite par differents signaux. Le polymere de xyloglucane marque avec de la digoxigenine et l'oligomere xxlgbsa sont utilises comme substrats pour la reaction enzymatique. Les solutions enzymatiques testees sont extraites a partir de fractions microsomales provenant de protoplastes de rubus temoins ou traites. Grace a une sequence d'anticorps (primaire, secondaire et tertiaire), l'activite transferase est suivie en mesurant l'activite peroxydase. Les avantages de cette nouvelle methode sont la sensibilite de la detection et la possibilite d'analyser plusieurs echantillons simultanement.
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Tang, Yi Tirrell David A. « Protein engineering using unnatural amino acids : incorporation of leucine analogs into recombinant protein in vivo / ». Diss., Pasadena, Calif. : California Institute of Technology, 2002. http://resolver.caltech.edu/CaltechETD:etd-08152006-084149.
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Leroux, Florence. « Etude in vitro d'inhibiteurs de tyrosine kinases et de phosphodiesterases et d'un analogue du vasoactive intestinal peptide potentiellement actifs dans l'asthme ». Lille 2, 1996. http://www.theses.fr/1996LIL2P253.
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Gorni, Anita. « Meat analogues e carne artificiale : le nuove alternative alle proteine animali ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
Trouver le texte intégralRésumé :
Il crescente interesse verso temi di sostenibilità e la crescita esponenziale della popolazione mondiale hanno portato a rivalutare l'importanza di fonti proteiche vegetali che potessero sostituire validamente quelle animali. La materia prima più comune da cui vengono estratte le proteine vegetali è rappresentata dalla soia, a cui si aggiungono cereali (glutine), semi oleosi e funghi; esse possono esistere sottoforma di farine, concentrati ed isolati, disponibili anche in forma testurizzata.
Nel tempo, le proteine vegetali sono diventate il principale ingrediente utilizzato nella formulazione dei meat anaologues, alternative a base vegetale che si propongono di imitare le proprietà reologiche e chimico-fisiche del muscolo animale. I sostitutivi carnei possono contenere anche altri ingredienti come lipidi, carboidrati, esaltatori di sapidità, albume d’uovo, coloranti, etc. I meat analogues costituiscono una categoria commerciale molto ampia, che comprende sia prodotti di vecchia generazione sia le nuove proposte plant-based, indistinguibili dalla carne animale (Beyond Burger ed Impossible Burger). Attualmente, il mercato globale dei prodotti plant-based è in continua crescita, tuttavia la percezione negativa dei consumatori rappresenta ancora un ostacolo alla loro introduzione nella dieta.
Molto discussa è anche la coltivazione in vitro, con cui le cellule staminali prelevate direttamente dagli animali vengono fatte crescere all'interno di bioreattori per ottenere tessuto muscolare.
La tecnica è caratterizzata da diversi punti di forza, ma possiede altrettanti limiti che ne ostacolano l’applicazione su vasta scala.
I dati raccolti mostrano un quadro complessivamente positivo in cui i sostitutivi plant-based e la carne coltivata suscitano sempre più l’interesse del mercato, mentre parte dell’opinione pubblica manifesta dei dubbi sull’effettiva salubrità e sulla capacità concreta di risolvere problematiche che riguardano la sostenibilità del sistema alimentare.
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Likhodi, Olga. « Differential hydration of protein analogs in D¦2 and H¦2O ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0017/MQ54177.pdf.
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Adavalli, Sharat Chandra. « Extrusion and physicochemical properties of soy-whey protein meat analog ». Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/6272.
Texte intégralRésumé :
Thesis (M.S.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on January 16, 2008) Includes bibliographical references.
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Jaquillard, Lucie. « Spectrométrie de masse supramoléculaire : caractérisation de l'intéraction non-covalente entre PEBP1/RKIP humaine et des analogues de nucléotides ». Phd thesis, Université d'Orléans, 2012. http://tel.archives-ouvertes.fr/tel-00923153.
Texte intégralRésumé :
L'étude des interactions non-covalentes et des relations structure-fonction est à la base de la compréhension des systèmes biologiques. La MS supramoléculaire est une technique de choix pour l'étude des interactions protéine/protéine ou protéine/ligand. Dans le cadre d'études qualitatives ou quantitatives, pour chaque système étudié, les conditions expérimentales et les paramètres instrumentaux ont été optimisés pour conserver le complexe en phase gazeuse (1). L'objectif principal de ce travail est de caractériser le site nucléotidique de hPEBP1 et de contribuer à la découverte de molécules anti-métastases. Sur le plan fonctionnel, une activité enzymatique de hPEBP1 n'a pas pu être mise en évidence. Pour ce projet, une méthode MS de détermination de KD de complexes à faible affinité, plus précise et ne nécessitant par l'utilisation d'un ligand de référence a été développée (2). Une recherche des déterminants structuraux d'un ligand optimal de hPEBP1 a été réalisée par criblage de composés issus d'une synthèse raisonnée basée sur la structure des nucléotides FMN et GTP et par la détermination de leur KD (3). Les criblages ont montré que les critères structuraux indispensables pour la liaison sont la présence d'un groupement chargé ou donneur d'électrons, d'une structure apparentée à une base azotée et d'un cycle additionnel. Une part importante de l'affinité est liée au caractère hydrophobe du ligand. Certains ligands de synthèse ont montré une activité inhibitrice de l'invasion des lignées tumorales.
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Pichelin-Poitevin, Dominique. « Marquage differentiel de proteines membranaires par des inhibiteurs de thiols en presence de saccharose et de divers analogues ». Poitiers, 1987. http://www.theses.fr/1987POIT2260.
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Beatty, Kimberly Elizabeth Grubbs Robert H. Tirrell David A. « Imaging the proteome : metabolic tagging of newly synthesized proteins with reactive methionine analogues / ». Diss., Pasadena, Calif. : California Institute of Technology, 2008. http://resolver.caltech.edu/CaltechETD:etd-03052008-105142.
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Xu, Suxuan. « Fibrous soy protein meat analog from low moisture twin-screw extrusion ». Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/6035.
Texte intégralRésumé :
Thesis (M.S.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on April 16, 2008) Includes bibliographical references.
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Davidson, Patricia Marie L. « Langmuir films and nanoparticle applications of a spider silk protein analog ». Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100794.
Texte intégralRésumé :
A synthetic analog of a spider silk protein (M4) was studied. Langmuir films were made and an inflexion in the isotherm indicated conformational changes upon compression. Deposition onto solid substrates was most successful using a hydrophobic substrate and the Langmuir-Schaeffer method. AFM was used to image the surface, which was mesh like and did not show any indication of order.Gold nanoparticles were produced in the presence of the protein and protein solutions were added to read made nanoparticles for the purpose of displacing the weak ligands present. CD measurements were performed on the protein solutions to study its conformation. Nanoparticle size information was obtained from TEM images. DLS was used to determine if the protein was affected by the addition of the gold nanoparticles. Precipitation of the protein was shown not to affect the nanoparticles.
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Qiu, Runan [Verfasser]. « Effects of nucleoside analogues on protein expression in cells of the SerW3 cell line / Runan Qiu ». Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2014. http://d-nb.info/1062536800/34.
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Frigerio, Mark. « Synthetic studies on novel bryostatin analogues and their interaction with the CRD2 of protein kinase C ». Thesis, University College London (University of London), 2004. http://discovery.ucl.ac.uk/1446848/.
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A fully stereocontrolled asymmetric synthesis of the Southern Hemisphere intermediate 426 for the bryostatin family of antitumour agents is described in this thesis. It details how the strategy evolved from (E)-1,4-hexadiene 450 including a Roush-Masamune coupling between 462 and 507, cyclisation to glycal 505, selective epoxidation and in-situ Fischer glycosidation to 503 and an aldol / dehydration sequence to establish the (E)-exocyclic olefin. We also document a rare example of slow bond rotation in the C(18)- C(19)-bond of 426 and provide an explanation of this phenomenon. In addition, the synthesis of two truncated bryostatin analogs 525 and 526 is described, and the interaction of 525 with the CRD2 of human PKC-α discussed.
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Pandit, Bulbul. « Study of structure activity relationship of analogs derived from SU-5416 and thalidomide and mechanism of antiproliferative activity ». Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1187127289.
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Lord, Andrew P. D. « IGF transfer from blood to tissue : comparison of IGF-I with analogs that bind poorly to binding proteins, using a vascular perfusion model : a thesis submitted to the University of Adelaide, South Australia, for the degree of Doctor of Philosophy / ». Title page, abstract and table of contents, 1993. http://web4.library.adelaide.edu.au/theses/09PH/09phl866.pdf.
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MacDonell, Karen Loraine. « Relationship between cyclic AMP-dependent protein kinase activation and smooth muscle relaxation by cyclic AMP and analogs ». Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/30098.
Texte intégralRésumé :
It is generally held that adenosine 3',5'-cyclic monophosphate (cAMP) mediates smooth muscle relaxation by the activation of cAMP-dependent protein kinase (PKA). This hypothesis was tested in two intact smooth muscle preparations, the rat vas deferens and the bovine coronary artery, using exogenously applied cAMP and cAMP analogs.
After 30 minutes of incubation, N⁶,2'-0-dibutyryl-cAMP (dBu-cAMP) (1 - 100 μM) inhibited phenylephrine (PE)-induced tension generation in the rat vas deferens in a dose-dependent manner. This analog (10 μM) also activated the soluble fraction of PKA but did not activate the particulate fraction kinase. In contrast, 8-bromo-cAMP (8Br-cAMP) (10 -100 μM) did not have any significant effect on inhibition of PE-induced tension after 30 minutes of incubation but, at a concentration of 10 μM, significantly activated both the soluble and particulate fractions of PKA. The time course of activation of soluble PKA activation by 8Br-cAMP (10 μM) demonstrated that the kinase was significantly activated only after 30 minutes of exposure to the analog.
In the bovine coronary artery, cAMP (10 - 100 μM) relaxed potassium-depolarized helical strips and significantly activated soluble PKA in a dose-dependent manner. dBu-cAMP (10 - 100 μM) affected neither tension nor soluble PKA activity. 8Br-cAMP (10 - 100 μM) did not affect the coronary artery tension but did activate soluble PKA.
Both smooth muscle preparations were homogenized with charcoal prior to the determination of PKA activity in order to minimize artifactual assay results. As a further precaution, extracellularly associated cAMP and analogs were also washed from bovine coronary artery strips after the incubation period. These controls allowed for a valid assessment of PKA activity in the cyclic nucleotide-treated tissues.
The results of the tension and kinase studies demonstrate a lack of correlation between activation of PKA and inhibition of rat vas deferens contraction or relaxation of bovine coronary artery. This does not support the hypothesis that the kinase is responsible for cAMP-induced relaxation of vascular and non-vascular smooth muscle. While the mechanism by which exogenous cAMP and specific analogs induce relaxation in some smooth muscle preparations remains unclear, it can be suggested that PKA activation is not necessarily required for the final functional effect.Medicine, Faculty of
Anesthesiology, Pharmacology and Therapeutics, Department of
Graduate
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Alahuhta, M. (Markus). « Protein crystallography of triosephosphate isomerases : functional and protein engineering studies ». Doctoral thesis, University of Oulu, 2008. http://urn.fi/urn:isbn:9789514287909.
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Abstract The aim of this PhD-study was to better understand the structure-function relationship of triosephosphate isomerase (TIM) and to use this expertise to change its substrate specificity. TIM is an important enzyme of the glycolytic pathway which catalyzes the interconversion of D-glyceraldehyde phosphate (D-GAP) and dihydroxyacetone phosphate (DHAP). Two main subjects are discussed: the engineering of monomeric TIM to create new substrate specificity and the structure-function relationship studies of the catalytically important mobile loop6. The starting point for the protein engineering project was the monomeric ml8bTIM, with an extended binding pocket between loop7 and loop8. Rational protein engineering efforts have resulted in a new variant called A-TIM that can competently bind wild type transition state analogues. A-TIM was also able to bind citrate, a compound that the wild type TIM does not bind. This A-TIM citrate complex structure is a good starting point for future protein engineering efforts. Based on the assumption that it would be beneficial for the monomeric forms of TIM to have loop6 closed permanently to increase the population of competent active sites, two point mutation variants, A178L and P168A were generated and characterized. The A178L-mutation was made to favor the closed conformation of loop6 through steric clashes in the open conformation. The P168A variant was made to stabilize the closed conformation of loop6 by removing strain. The A178L mutation induced some features of the closed conformation, but did not result in a closed conformation in the absence of ligands. Our structural studies also show that the P168A mutation does not favor the closed conformation either. However, the structures of the unliganded and liganded P168A variant, together with other known TIM structures show that the substrate binding first induces closure of loop7. This conformational switch subsequently forces loop6 to adopt its closed conformation. The protein engineering project was successful, but the efforts to find variants with a permanently closed loop6 did not fully succeed. In the context of this thesis a monomeric variant of TIM, with new binding properties, was created. Nevertheless, A-TIM still competently binds the inhibitors and transition state analogues of wild type TIM. Also, when combined, results discussed in the context of this thesis indicate that in wild type TIM the closure of loop7 after ligand binding is the initial step in the series of conformational changes that lead to the formation of the competent active siteTiivistelmä Tämän väitöskirjatyön tarkoituksena oli oppia paremmin ymmärtämään trioosifosfaatti-isomeraasin (TIM) toimintamekanismeja sen rakenteen perusteella ja käyttää tätä tietämystä samaisen proteiinin muokkaamiseen uusiin tarkoituksiin. TIM on keskeinen entsyymi solun energian tuotannossa ja sen toiminta on välttämätöntä kaikille eliöille. Tämän vuoksi on tärkeää oppia ymmärtämään miten se saavuttaa tehokkaan reaktionopeutensa ja miksi se katalysoi vain D-glyseraldehydi-3-fosfaattia (D-GAP) ja dihydroksiasetonifosfaattia (DHAP). TIM:n toiminta mekanismien ymmärtämiseksi sen aminohapposekvenssiä muokattiin kahdesta kohtaa (P168A ja A178L) ja seuraukset todettiin mittaamalla tuotettujen proteiinien stabiilisuutta optisesti eri lämpötiloissa ja selvittämällä niiden kolmiulotteinen rakenne käyttäen röntgensädekristallografiaa. Mutaatioita tehtiin dimeeriseen villityypin TIM:in (wtTIM) ja jo aikaisemmin muokattuun monomeeriseen TIM:in (ml1TIM). Näiden mutaatioiden tarkoituksena oli suosia entsyymin aktiivista konformaatiota, jossa reaktion kannalta välttämätön vapaasti liikkuva peptidisilmukka numero 6 on suljetussa konformaatiossa. Monomeerisissä TIM:ssa peptidisilmukka numero 6:n ei ole välttämätöntä aueta. Tulokset mutaatiokokeista olivat osittain lupaavia. P168A-mutaatio lisäsi D-GAP:in sitoutumista, mutta rikkoi tärkeän mekanismin suljetussa, ligandia sitovassa, konformaatiossa. A178L-mutaatio aiheutti muutoksia avoimeen konformaatioon ja teki siitä suljettua konformaatiota muistuttavan jopa ilman ligandia, mutta samalla koko proteiini muuttui epävakaammaksi. Näistä kahdesta mutaatiosta A178L voisi olla hyödyllinen muokattujen TIM-versioiden ominaisuuksien parantamiseksi. Lisäksi yhdessä jo aikaisemmin julkaistujen yksityiskohtien kanssa nämä tulokset tekevät mahdolliseksi esittää tarkennusta siihen miten TIM toimii kun ligandi saapuu sen lähettyville. Tämän väitöskirjatyön yksi tavoite oli myös muokata edelleen monomeeristä TIM versiota (ml8bTIM), joka on suunniteltu siten, että se voi mahdollisesti sitoa uudenlaisia ligandeja. Tämä projekti vaati onnistuakseen 20 eri versiota ml8bTIM:n sekvenssistä ja noin 30 rakennetta. Uusia ligandeja sitova muoto (A-TIM) sitoi onnistuneesti sitraattia ja villityypin TIM:n inhibiittoreita. Erityisen lupaavaa oli, että A-TIM sitoi myös bromohydroksiasetonifosfaattia (BHAP), joka sitoutuu ainoastaan toimivaan aktiiviseen kohtaan. Nämä tulokset osoittavat, että A-TIM kykenee tarvittaessa katalysoimaan isomerisaatio reaktion uudenlaisille molekyyleille. Esimerkiksi katalysoimaan isomerisointireaktiota sokerianalogien tuotannossa
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Lugo-Mas, Priscilla. « Synthetic analogues of cysteinate-ligated non-heme iron enzymes : understanding the structure-function relationship of nitrile hydratase (NHase) and superoxide reductase (SOR) / ». Thesis, Connect to this title online ; UW restricted, 2007. http://hdl.handle.net/1773/8635.
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Guyony, Valerie. « Caractérisation et optimisation du procédé de cuisson extrusion humide de matières protéiques végétales pour ’obtention d’une texture fibreuse ». Thesis, Nantes, Ecole nationale vétérinaire, 2020. http://www.theses.fr/2020ONIR149F.
Texte intégralRésumé :
Dans un contexte d’essor de la consommation des protéines végétales, de nouveaux produits végétariens élaborés qui cherchent à imiter l’aspect, la texture et le goût des produits carnés ou analogues de viande ont vu le jour depuis les années 2000. Le procédé de transformation et de texturation utilisé pour ces protéines végétales est la cuisson extrusion. Cette thèse porte sur la texturation des protéines végétales par cuisson extrusion humide, et plus précisément sur l’optimisation de la fibration en vue d’imiter au plus près la texture fibreuse caractéristique de la viande. Les objectifs de la thèse sont la compréhension des phénomènes de transformation qui interviennent pendant le procédé de cuisson extrusion humide et l’étude des paramètres procédés et matières premières sur l’intensité de la fibration. Parmi les paramètres procédés, l’attention s’est particulièrement portée sur deux paramètres principaux : les dimensions de la filière et la température de refroidissement de l’extrudat dans la filière. L’étude des paramètres matières premières a été menée en analysant d’une part l’impact des propriétés physico-chimiques et fonctionnelles de deux concentrats de soja différents et, d’autre part, l’impact de l’addition de gluten de blé, d’isolat de pois et/ou de fibres sur les propriétés et la fibration de l’extrudat obtenu. Enfin, les extrudats ont été transformés en maquettes produits finis sur la base d’un steak végétal. Le procédé de fabrication et la recette de référence, basés sur l’utilisation de protéines texturées déshydratées, ont été adaptés pour permettre leur substitution par des extrudats humidesAs vegetarian trends are growing, meat analogues, trying to mimic the appearance, texture and taste of meat, have emerged since the 2000s. Texturization process used is generally extrusion cooking. This thesis focuses on the texturization of plant proteins by wet extrusion cooking, and more specifically on the optimization of fibration in order to imitate as closely as possible the fibrous texture characteristic of meat. The objectives of the thesis are the understanding of the physical and chemical phenomena occurring during the wet extrusion cooking process and the optimization of process and raw material parameters to maximize the intensity of fibration. Among the process parameters, particular attention was paid to two main parameters: the dimensions of the die and the cooling temperature of the extrudat in the die. The study of raw material parameters was carried out by analyzing, on the one hand, the impact of the physico-chemical and functional properties of two different soy concentrates and, on the other, the impact of the addition of wheat gluten and/or pea isolate or fiber on the textural properties and fibration of the extrudate obtained. Finally, extrudate were transformed into meat analog steaks. The manufacturing process and reference recipe, based on the use of dehydrated textured proteins, have been adapted to allow their substitution by wet extrudates
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Laricheva, Elena N. « Turning on Fluorescence in Silico : From Radical Cations to 11-cis Locked Rhodopsin Analogues ». Bowling Green State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1339787341.
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Gajanandana, Oraprapai. « Studies of complexes formed in blood in vivo between an insulin-like growth factor analog and binding proteins ». Title page, contents and abstract only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09phg145.pdf.
Texte intégralRésumé :
Includes bibliographical references (43 leaves) This study shows that when LR3IGF-I is administered to animals in pharmacologically active doses, it may be present in either the free form or bound to IGF-binding protein(s) in the circulation. Age and nutrition which are factors that regulate synthesis of endogenous IGF-I and IGF-binding proteins, affect the in vivo formation of complexes between the analog and IGFBP(s). This study also suggests that IGFBP-1 inhibits the pharmacological activity of circulating LR3IGF-I on thymus whereas it appears to stimulate the pharmacological activity of LR3IGF-I in kidneys.
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Murphy, Anastasia V. « Preparation of structurally diverse C-linked antifreeze glycoprotein analogs and assessment for antifreeze protein-specific activity ». Diss., Online access via UMI:, 2005. http://wwwlib.umi.com/dissertations/fullcit/3159276.
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