Academic literature on the topic 'Glutamic acid polymers'
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Journal articles on the topic "Glutamic acid polymers"
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Thompson, Marisa, and Carmen Scholz. "Highly Branched Polymers Based on Poly(amino acid)s for Biomedical Application." Nanomaterials 11, no. 5 (2021): 1119. http://dx.doi.org/10.3390/nano11051119.
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Polymers consisting of amino acid building blocks continue to receive consideration for biomedical applications. Since poly(amino acid)s are built from natural amino acids, the same building blocks proteins are made of, they are biocompatible, biodegradable and their degradation products are metabolizable. Some amino acids display a unique asymmetrical AB2 structure, which facilitates their ability to form branched structures. This review compares the three forms of highly branched polymeric structures: structurally highly organized dendrimers, dendrigrafts and the less organized, but readily synthesizable hyperbranched polymers. Their syntheses are reviewed and compared, methods of synthesis modulations are considered and variations on their traditional syntheses are shown. The potential use of highly branched polymers in the realm of biomedical applications is discussed, specifically their applications as delivery vehicles for genes and drugs and their use as antiviral compounds. Of the twenty essential amino acids, L-lysine, L-glutamic acid, and L-aspartic acid are asymmetrical AB2 molecules, but the bulk of the research into highly branched poly(amino acid)s has focused on the polycationic poly(L-lysine) with a lesser extent on poly(L-glutamic acid). Hence, the majority of potential applications lies in delivery systems for nucleic acids and this review examines and compares how these three types of highly branched polymers function as non-viral gene delivery vectors. When considering drug delivery systems, the small size of these highly branched polymers is advantageous for the delivery of inhalable drug. Even though highly branched polymers, in particular dendrimers, have been studied for more than 40 years for the delivery of genes and drugs, they have not translated in large scale into the clinic except for promising antiviral applications that have been commercialized.
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Sanda, Fumio, Taizo Fujiyama, and Takeshi Endo. "Chemical synthesis of poly-?-glutamic acid by polycondensation of ?-glutamic acid dimer: Synthesis and reaction of poly-?-glutamic acid methyl ester." Journal of Polymer Science Part A: Polymer Chemistry 39, no. 5 (2001): 732–41. http://dx.doi.org/10.1002/1099-0518(20010301)39:5<732::aid-pola1045>3.0.co;2-p.
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Baumgartner, Ryan, Diane Kuai, and Jianjun Cheng. "Synthesis of controlled, high-molecular weight poly(l-glutamic acid) brush polymers." Biomaterials Science 5, no. 9 (2017): 1836–44. http://dx.doi.org/10.1039/c7bm00339k.
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Gao, Baojiao, Liqin Zhang, and Dandan Zhang. "Effects of structures of bidentate Schiff base type bonded-ligands derived from benzaldehyde on the photoluminescence performance of polymer–rare earth complexes." Physical Chemistry Chemical Physics 20, no. 6 (2018): 4373–85. http://dx.doi.org/10.1039/c7cp07590a.
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Two kinds of bidentate Schiff base ligands derived from benzaldehyde, benzaldehyde/m-aminophenol (BAMA) type and benzaldehyde/glutamic acid (BAGL) type ligands, were synchronously synthesized and bonded on the backbone of polysulfone (PSF) through molecular design and by polymer reactions, and two functional polymers, PSF-BAMA and PSF-BAGL, were obtained.
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Tolmachev, Dmitry, George Mamistvalov, Natalia Lukasheva, Sergey Larin, and Mikko Karttunen. "Effects of Amino Acid Side-Chain Length and Chemical Structure on Anionic Polyglutamic and Polyaspartic Acid Cellulose-Based Polyelectrolyte Brushes." Polymers 13, no. 11 (2021): 1789. http://dx.doi.org/10.3390/polym13111789.
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We used atomistic molecular dynamics (MD) simulations to study polyelectrolyte brushes based on anionic α,L-glutamic acid and α,L-aspartic acid grafted on cellulose in the presence of divalent CaCl2 salt at different concentrations. The motivation is to search for ways to control properties such as sorption capacity and the structural response of the brush to multivalent salts. For this detailed understanding of the role of side-chain length, the chemical structure and their interplay are required. It was found that in the case of glutamic acid oligomers, the longer side chains facilitate attractive interactions with the cellulose surface, which forces the grafted chains to lie down on the surface. The additional methylene group in the side chain enables side-chain rotation, enhancing this effect. On the other hand, the shorter and more restricted side chains of aspartic acid oligomers prevent attractive interactions to a large degree and push the grafted chains away from the surface. The difference in side-chain length also leads to differences in other properties of the brush in divalent salt solutions. At a low grafting density, the longer side chains of glutamic acid allow the adsorbed cations to be spatially distributed inside the brush resulting in a charge inversion. With an increase in grafting density, the difference in the total charge of the aspartic and glutamine brushes disappears, but new structural features appear. The longer sides allow for ion bridging between the grafted chains and the cellulose surface without a significant change in main-chain conformation. This leads to the brush structure being less sensitive to changes in salt concentration.
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Kino, Kuniki, Toshinobu Arai та Yasuhiro Arimura. "Poly-α-Glutamic Acid Synthesis Using a Novel Catalytic Activity of RimK fromEscherichia coliK-12". Applied and Environmental Microbiology 77, № 6 (2011): 2019–25. http://dx.doi.org/10.1128/aem.02043-10.
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ABSTRACTPoly-l-α-amino acids have various applications because of their biodegradable properties and biocompatibility. Microorganisms contain several enzymes that catalyze the polymerization ofl-amino acids in an ATP-dependent manner, but the products from these reactions contain amide linkages at the side residues of amino acids: e.g., poly-γ-glutamic acid, poly-ε-lysine, and cyanophycin. In this study, we found a novel catalytic activity of RimK, a ribosomal protein S6-modifying enzyme derived fromEscherichia coliK-12. This enzyme catalyzed poly-α-glutamic acid synthesis from unprotectedl-glutamic acid (Glu) by hydrolyzing ATP to ADP and phosphate. RimK synthesized poly-α-glutamic acid of various lengths; matrix-assisted laser desorption ionization-time of flight-mass spectrometry showed that a 46-mer of Glu (maximum length) was synthesized at pH 9. Interestingly, the lengths of polymers changed with changing pH. RimK also exhibited 86% activity after incubation at 55°C for 15 min, thus showing thermal stability. Furthermore, peptide elongation seemed to be catalyzed at the C terminus in a stepwise manner. Although RimK showed strict substrate specificity toward Glu, it also used, to a small extent, other amino acids as C-terminal substrates and synthesized heteropeptides. In addition, RimK-catalyzed modification of ribosomal protein S6 was confirmed. The number of Glu residues added to the protein varied with pH and was largest at pH 9.5.
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Cedrati, Valeria, Aurora Pacini, Andrea Nitti та ін. "“Clickable” bacterial poly(γ-glutamic acid)". Polymer Chemistry 11, № 35 (2020): 5582–89. http://dx.doi.org/10.1039/d0py00843e.
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Bonduelle, Colin, Fatma Makni, Laura Severac, et al. "Smart metallopoly(l-glutamic acid) polymers: reversible helix-to-coil transition at neutral pH." RSC Advances 6, no. 88 (2016): 84694–97. http://dx.doi.org/10.1039/c6ra19753a.
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Yuan, Weize, Remi Casier, and Jean Duhamel. "Unfolding of Helical Poly(L-Glutamic Acid) in N,N-Dimethylformamide Probed by Pyrene Excimer Fluorescence (PEF)." Polymers 13, no. 11 (2021): 1690. http://dx.doi.org/10.3390/polym13111690.
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The denaturation undergone by α–helical poly(L-glutamic acid) (PLGA) in N,N-dimethylformamide upon addition of guanidine hydrochloride (GdHCl) was characterized by comparing the fluorescence of a series of PLGA constructs randomly labeled with the dye pyrene (Py-PLGA) to that of a series of Py-PDLGA samples prepared from a racemic mixture of D,L-glutamic acid. The process of pyrene excimer formation (PEF) was taken advantage of to probe changes in the conformation of α–helical Py-PLGA. Fluorescence Blob Model (FBM) analysis of the fluorescence decays of the Py-PLGA and Py-PDLGA constructs yielded the average number (<Nblob>) of glutamic acids located inside a blob, which represented the volume probed by an excited pyrenyl label. <Nblob> remained constant for randomly coiled Py-PDLGA but decreased from ~20 to ~10 glutamic acids for the Py-PLGA samples as GdHCl was added to the solution. The decrease in <Nblob> reflected the decrease in the local density of PLGA as the α–helix unraveled in solution. The changes in <Nblob> with GdHCl concentration was used to determine the change in Gibbs energy required to denature the PLGA α–helix in DMF. The relationship between <Nblob> and the local density of macromolecules can now be applied to characterize the conformation of macromolecules in solution.
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Nakahama, Masashi, Julien Reboul, Kenji Yoshida, Shuhei Furukawa, and Susumu Kitagawa. "l-Glutamic acid release from a series of aluminum-based isoreticular porous coordination polymers." Journal of Materials Chemistry B 3, no. 20 (2015): 4205–12. http://dx.doi.org/10.1039/c5tb00346f.
Full textDissertations / Theses on the topic "Glutamic acid polymers"
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Adebayo, Olajumoke O. "Evaluation of bacterial polymers as protective agents for sensitive probiotic bacteria." Thesis, University of Wolverhampton, 2018. http://hdl.handle.net/2436/621096.
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Probiotics are live microorganisms which when administered in adequate amounts confer one or more health benefits on the host. Different processing conditions, the acidic condition of the stomach and exposure to hydrolytic enzymes affect the viability and efficacy of probiotic organisms. This study investigated the protective effects of two biopolymers poly-gamma-glutamic acid (γ-PGA) and bacterial cellulose (BC) on probiotics during freeze drying and during exposure to simulated intestinal juices and bile salts. The antibacterial property of Bifidobacterium strains was also investigated against four pathogenic bacteria. γ-PGA, a naturally occurring biopolymer was produced by two bacteria (Bacillus subtilis ATCC 15245 and B. licheniformis ATCC 9945a) in GS and E media, γ-PGA yields of about 14.11g/l were achieved in shake flasks and molecular weight of up to 1620 k Da was recorded, γ-PGA production was scaled up in a fermenter with B. subtilis using GS medium. BC, an edible biopolymer was produced by Gluconacetobacter xylinus ATCC 23770 in HS medium and a modified HS (MHS) medium. A yield of about 1.37g/l was recorded and BC production with MHS medium was used for probiotic application. B. longum NCIMB 8809 B. breve NCIMB 8807 and B. animalis NCIMB 702716 showed the best antimicrobial properties against the investigated pathogens. Survival of Bifidobacterium strains was improved when protected with powdered BC (PBC) although γ-PGA offered better protection than PBC. Viability of B. longum NCIMB 8809, B. breve NCIMB 8807 and B. animalis NCIMB 702716 in simulated gastric juice (SGJ) and simulated intestinal juice with bile salts was improved when protected with 5% γ-PGA and 5% γ-PGA+PBC with a reduction of < 1 Log CFU/ml while a reduction of ≤2 Log CFU/ml was recorded in PBC protected cells. Protecting Bifidobacterium strains with γ-PGA, PBC or a novel γ-PGA + PBC combination is a promising method to deliver probiotic bacteria to the target site in order to confer their health benefits on the host.
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Souza, Viviane Costa de. "Polímeros de ß-ciclodextrina : síntese, caracterização e utilização na obtenção/estabilização de nanopartículas de prata." Pós-Graduação em Química, 2017. https://ri.ufs.br/handle/riufs/6831.
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Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPqThe development of polymers with the ability to transport and release drugs and bioactives has been growing rapidly because of their unique properties in protecting and enhancing solubilization of drugs in physiological media. In this work, polyesters derived from β-cyclodextrin were developed in two different systems: The former consisted of cyclodextrin cross-linked with citric acid and subsequently functionalized with glutamic acid. The latter was obtained from β-cyclodextrin esterified with gluthamic acid. The polyesters were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Solid-state Cross-Polarization Magic Angle Spinning Carbon-13 Nuclear Magnetic Resonance (CP/MAS 13C–NMR) and Thermogravimetric Analysis (TGA) for the confirmation of the formation of polymers and the esterification of glutamic acid with β-cyclodextrin molecules. The formation of inclusion complex of the polymers in solution with orange methyl was evaluated to verify the activation of β-cyclodextrin cavities. The polymers were used as reducer and stabilizer in the synthesis of silver nanoparticles (AgNPs). The characterization of the AgNPs was performed by UV-Vis spectroscopy, and bands between 350-500 nm evidenced of the obtainment of silver nanoparticles. Analyses by transmission electron microscopy revealed AgNPs with spherical morphology and diameter around ~ 5 to ~60 nm, corroborating with the results of UV-Vis.
O desenvolvimento de polímero com a capacidade de transportar e liberar fármacos e compostos bioativos vem crescendo rapidamente, devido suas propriedades únicas em proteger e aumentar a solubilização em meios fisiológicos. Neste trabalho, foram desenvolvidos poliésteres derivado de β-ciclodextrina em dois sistemas distintos. O primeiro sistema foi obtido a partir de β-ciclodextrina reticulado com ácido cítrico e posteriormente funcionalizado com ácido glutâmico. O segundo foi a partir de β-ciclodextrina esterificada com ácido glutâmico. Os poliésteres foram caracterizados por espectroscopia na região do infravermelho com transformada de Fourier (FTIR), ressonância magnética nuclear no estado sólido sob polarização cruzada e rotação com ângulo mágico (RMN 13C CP/MAS) e análise termogravimétrica (TG), para a confirmação da formação dos polímeros e a esterificação do ácido glutâmico com as moléculas de β-ciclodextrina. A formação de complexo de inclusão dos polímeros com o alaranjado de metila foi avaliada em solução, comprovando-se a ativação das cavidades de β-ciclodextrina. Os polímeros foram testados quanto a habilidade de promover a formação/estabilização de nanopartículas de prata (AgNPs) a partir de nitrato de prata em solução. A caracterização das AgNPs foi realizada por espectroscopia de UV-Vis, e as bandas observadas entre 350-500 nm são evidências da presença de nanopartículas de prata. As imagens de microscopia eletrônica de transmissão revelaram AgNPs de morfologia esférica com diâmetro em torno de ~5 a ~60 nm, corroborando com os resultados de UV-Vis.
São Cristóvão, SE
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Prodhomme, Emmanuel Jean-Paul Fernand. "Poly #gamma#-D-glutamic acid as a template for functionalised water-soluble biomaterials." Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.396135.
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Bhat, Aditya. "Bacterial production of poly-γ-glutamic acid and evaluation of its effect on the viability of probiotic microorganisms". Thesis, University of Wolverhampton, 2012. http://hdl.handle.net/2436/241854.
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Poly-γ-glutamic acid (γ-PGA) is a naturally occurring biopolymer made up of repeating units of glutamic acid and can be potentially used for multiple applications. This study compared the production of γ-PGA by eight bacteria (B. subtilis 23856, B. subtilis 23857, B. subtilis 23858 B. subtilis 23859, B. subtilis natto, B. licheniformis 1525, B. licheniformis 6816 and B. licheniformis 9945a) in GS and E media. B. subtilis natto and B. licheniformis 9945a have been investigated extensively for γ-PGA production, however, the remaining six have not previously been used. Using the eight bacteria, yields of up to 22.3 g/l were achieved in shake flasks. On characterization, it was observed that γ-PGA with different properties (crystallinity, acid/salt form and molecular weights ranging from 3,000 Da to 871,000 Da) was produced. Production of γ-PGA by B. subtilis natto in GS medium was scaled up using a fermenter and was tested for novel probiotic applications. The survival of probiotics during freeze drying, storage and ingestion was improved by combining them with a γ-PGA matrix. For L. paracasei, 10% γ-PGA protected the cells significantly better (P < 0.05) than 10% sucrose during freeze drying, whereas for B. longum and B. breve, it showed comparable cryoprotectant activity (P > 0.05) to 10% sucrose. This study also demonstrated the potential use of a non-dairy foodstuff (orange juice) for delivery of probiotics. Two Bifidobacteria strains protected with γ-PGA survived significantly better (P < 0.05) in orange juice for 39 days, with a log reduction in viability of less than 2.99 CFU/ml, when compared to unprotected cells, which showed complete loss in viability by day 20. In addition, γ-PGA protection improved survival of Bifidobacteria in a solution mimicking the environment of the stomach. γ-PGA-protected Bifidobacteria showed little (< 0.47 log CFU/ml) or no loss in viability when stored in simulated gastric juice (pH 2.0) for four hours, whereas unprotected cells died within two hours.
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Čangelová, Katarína. "Studium možných aplikací polymeru kyseliny glutamové." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2019. http://www.nusl.cz/ntk/nusl-401873.
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The subject of the thesis is study of possible applications of isoform of glutamic acid polymer (-PGA). The theoretical part is focused on the properties of this biopolymer and potential applications in various areas. Producers and mechanisms of biosynthesis are also mentioned. In the experimental part, the polymer was firstly characterised by following methods: FT-IR spectroscopy, TGA, DSC and SEC-MALS. Its isoelectric point, antimicrobial activity and solubility in various solvents were also determined. The biopolymer was also precipitated by divalent cations and its interaction with oppositely charged CTAB surfactant was studied. The main experimental study was researching the effect of -PGA on viability of Saccharomyces cerevisiae and Lactobacillus rhamnosus under stress conditions by flow cytometry. The performed stresses included ethanol exposure, high temperature and freezing stress, in which its effects were compared to conventional cryoprotectants. The cells of the mentioned microorganisms were also stressed osmotically and exposed to model gastrointestinal juices - gastric, pancreatic and bile. The protective effects of -PGA on the cells were recorded in ethanol stress on Lactobacillus rhamnosus. Its excellent cryoprotection properties were confirmed and its protective effect of gastric juice exposure on Saccharomyces cerevisiae cells was also observed. At the end of the experimental part, -PGA/alginate beads suitable for encapsulation of probiotic bacteria and -PGA/chitosan nanoparticles for encapsulation of biologically active substances.
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Alves, Maria José Ferreira. "Glutaminólise em astrocitomas." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/5/5138/tde-02122014-083743/.
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O metabolismo da glutamina (Gln) é alvo de atenções recentes para a compreensão da reprogramação metabólica para o suprimento energético das células tumorais em proliferação e para o desenvolvimento de novas estratégias terapêuticas em câncer. Tanto a absorção de glutamina quanto a taxa de glutaminólise, o catabolismo da Gln para gerar adenosina trifosfato (ATP) e lactato na mitocôndria estão aumentados em diferentes tumores. A Gln e glicose participam do processo da proliferação de células tumorais tanto na produção de (ATP) como no fornecimento de produtos intermediários utilizados na síntese de macromoléculas e Gln é utilizado para anaplerose do ciclo do ácido tricarboxílico. Nesse estudo, nosso objetivo foi analisar a expressão dos genes envolvidos na glutaminólise: ASCT2, LAT1, GLS, GLSISO1, GLSISO2, GLS2, GOT1, GOT2, GLUD1 e GPT2 em astrocitomas de diferentes graus de malignidade (AGI-AGIV), classificados de acordo com a Organização Mundial de Saúde (OMS), em relação às expressões em tecidos cerebrais não neoplásicos e correlacionar os níveis de expressão destes genes aos dados clínicos. PCR quantitativo em tempo real (qRT-PCR) foi realizado em 175 amostras, sendo 22 dentre estes de tecidos não neoplásicos. Observou-se tempo de sobrevida menor entre os pacientes com hiperexpressão de LAT1, na presença de hipoexpressão de ASCT2. A expressão de GLS foi comparativamente maior que a expressão de GLS2 entre os astrocitomas de diferentes graus de malignidade, corroborando descrições prévias de que GLS relaciona-se à proliferação tumoral e GLS2 à supressão do crescimento tumoral. Observou-se, adicionalmente, o aumento da associação das expressões destes genes conforme o aumento do grau de malignidade, culminando em GBM, onde estas correlações foram estatisticamente significativas. Apesar da demonstração da ativação gradativa desta via da glutaminólise com o aumento da malignidade, a hiperexpressão dos genes relacionados a esta via mostrou-se hiperexpressa em apenas um subgrupo de pacientes com GBM. Esta observação ressalta a heterogeneidade observada em GBM e a elegibilidade restrita deste subgrupo a eventuais estratégias terapêuticas que forem desenvolvidas com alvos nesta viaThe metabolism of glutamine (Gln) is the target of recent attentions to understand the metabolic reprogramming of cancer cell for the energetic needs for cell proliferation, and to develop new cancer therapeutic strategies. Glutamine absortion and glutamine conversion to ATP and lactate in the mitochondria through glutaminolysis are both increased in different cancer types. Gln and glucose participate in metabolic pathways which provide ATP and intermediate substrats for synthesis of macromolecules, and Gln is used for anaplesoris of tricyclic acid cycle. The aims of the present study were to analyze the differential mRNA expressions of genes involved in the glutaminolysis pathways: ASCT2, LAT1, GLS, GLSISO1, GLSISO2, GLS2, GOT1, GOT2, GLUD1 e GPT2 in astrocytomas of different grades of malignancy (WHO grades I to IV) compared to non-neoplastic brain tissues, and to correlate these expression data to clinical outcome. Shorter overall survival time was observed among a subset of GBM patients presenting hyperexpression of LAT1 while ASCT2 was hypoexpressed. GLS expression was comparatively higher than GLS2 expression among astrocytomas of different grades of malignancy, which corrobates previous reports relating GLS to tumor proliferation and GLS2 to suppression of tumor growth. Additionally, increased gene expression correlation was observed in parallel to the increase of malignancy, and these associated expressions were significant among GBM. Although a stepwise increase of the glutaminolysis pathway was demonstrated with the increase of malignancy in astrocytomas, the hyperexpression of genes involved in this pathway were detected only in a subset of GBM patients. This finding confirm the heterogeneity observed among GBM, and highlights the fact that any therapeutic strategy aiming this pathway will be restricted to a subset of GBM patients
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Parkhe, Ajay Dattatraya. "Nanoscale scaffolding by folding of monodisperse and sequentially precise poly((alanine-glycine)(3)glutamic acid-glycine(glycine-alanine)(3)glutamic acid-glycine): Biosynthesis and characterization by X-ray diffraction, FTIR and NMR." 1994. https://scholarworks.umass.edu/dissertations/AAI9510516.
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We have designed repetitive polypeptides which would self assemble into a unique three dimensional structure. The de novo design of these polypeptides is based on existing information on protein chain folding. As a first step to designing more complicated scaffolds, we are interested in designing repetitive polypeptides which would self assemble into lamellae of uniform, predetermined thickness. The design of the polypeptide repeating unit has been based in part on work on the structure of silk (and its analogues) and in part on the literature on reverse turns in globular proteins. The polypeptides in this work comprise alternating beta sheet forming segments and turn forming segments with exact periodicity. Repetitive alanyl-glycyl diads are known to form a beta sheet structure. It is anticipated that these would reside in the lamella and define its thickness. The stronger the thermodynamic driving force for the chains to form alternating beta sheets and turns, the more is the probability of obtaining a unique scaffold. In this thesis, DNA sequences encoding the synthesis of repetitive units of A, B, C and D have been synthesized. Polypeptides with ten repeats of A, four repeats of D and three repeats of C were successfully synthesized in E. coli.$$\eqalign{{-}(\rm AlaGly)\sb3GluGly(GlyAla)\sb3GluGly{-}&\qquad{\bf A}\cr{-}(\rm AlaGly)\sb3AspGly(GlyAla)\sb3AspGly{-}&\qquad{\bf B}\cr{-}(\rm AlaGly)\sb3GluGly(AlaGly)\sb3ValGly{-}&\qquad{\bf C}\cr{-}(\rm AlaGly)\sb3GluGly(AlaGly)\sb3MetGly{-}&\qquad{\bf D}\cr}$$ The polypeptide containing ten repeats of A (referred to as A-10 in the Abstract) has been characterized in the solid state by x-ray diffraction, FTIR and NMR. The polypeptide A-10 forms an antiparallel beta sheet structure when stirred in 70% formic acid; electron microscopy shows the morphology of the crystallites to be needle like. The unit cell deduced from the diffraction patterns is similar to those from previous diffraction patterns on silks and silk-like polypeptides. The unit cell which best explains the diffraction data for A-10 is monoclinic with a = 9.56 A, b = 10.68 A and c = 7.0 A with the angle between b and c equal to 80$\sp\circ$. FTIR spectroscopy on crystalline A-10 shows the polypeptide predominantly adopting the antiparallel beta sheet structure. The repetitive polypeptide A-10 and a $\sp{13}$C=O enriched analogue have been synthesized biologically in Escherichia coli. The two analogues have been blended in solution and co-crystallized. FTIR spectra (in the amide I region) have been studied as a function of blend composition. Solid state CPMAS NMR experiments were carried out on the amorphous and crystalline forms of A-10. The data suggests that glutamic acids are in identical environments in the crystalline and amorphous samples. The fast relaxation rates of their alpha, beta and gamma carbons suggest that glutamic acid residues are excluded from the crystalline regions in both the samples. Static solid state NMR experiments have been carried out on oriented mats of crystalline A-10. The orientation of the crystallites has been studied by the analysis of lineshapes. The lineshape analysis is consistent with the crystallites being an imperfect form of an orientation in which the crystallographic b axis (Figure 1.6) is perpendicular to the mat and there is free rotation around b. (Abstract shortened by UMI.)
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Zhang, Guanghui. "Poly(alpha,L-glutamic acid): Synthesis of its monodisperse derivatives and interaction of its alkylated derivatives with phospholipid bilayer membranes." 1994. https://scholarworks.umass.edu/dissertations/AAI9510553.
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A general strategy has been developed to synthesize biologically monodisperse polypeptides with the major repeat unit 1. These polymers are derivatives of poly($\alpha$,L-glutamic acid) (PLGA).$$- \rm Glu\sb{17}Asp-\qquad{\bf 1}$$ Such polymers should adopt an $\alpha$-helical structure when the side chain carboxylate groups are protonated, since Glu has the highest helix forming propensity (P$\sb\alpha$ = 1.59) of all twenty natural amino acids. Polymer 2 was synthesized as a fusion protein with glutathione S-transferase (GST) in a bacterial host, and was liberated from the GST fragment by CNBr cleavage.$$\rm GluAsp(Glu\sb{17}Asp)\sb4GluGlu\qquad{\bf 2}$$ DNA sequencing and amino acid analysis confirmed the composition of 2. Polymer 2 undergoes a conformational transition in aqueous solution from a random coil to an $\alpha$-helix as indicated by circular dichroism measurements. The $\alpha$-helical structure persists when the solvent is removed as demonstrated by Fourier transform infrared (FTIR) spectroscopy. Electrophoresis shows that polymer 2 is much more homogeneous in terms of molecular weight than chemically synthesized PLGAs of comparable molecular weight. A method was adopted to make the monodisperse rodlike molecule 3, a derivative of poly($\gamma$-benzyl $\alpha$,L-glutamate) (PBLG), by reacting 2 with phenyl diazomethane. Quantitative conversion was indicated by nuclear magnetic resonance spectroscopy. In helicogenic solvents for PBLG, 3 also assumes an $\alpha$-helical structure and transforms into a random coil when trifluoroacetic acid is added to the solution. Polymer 3 self-assembles into $\alpha$-helical structure when cast as a film from tetrahydrofuran solution. Gel permeation chromatography shows that 3 has a much narrower molecular weight distribution than chemically synthesized PBLG of comparable molecular weight.$$\eqalign{\rm Glu(OBzl)Asp(OBzl)&\{\lbrack(\rm Glu(OBzl)\rbrack\sb{17} Asp\cr&\qquad(\rm OBzl)\}\sb4Glu(OBzl)Glu(OBzl)\qquad{\bf 3}\cr}$$where OBzl denotes a benzyl ester. High molecular weight PLGA was chemically synthesized from $\gamma$-benzyl $\alpha$,L-glutamate N-carboxy anhydride. This polymer was modified with 8 mol % or 15 mol % hexylamine. The modified polymers can disrupt dilauroylphosphatidylcholine multilamellar vesicles and egg yolk phosphatidylcholine small unilamellar vesicles in a manner which is dependent on the solution pH. Fluorescent probes, specifically pyrene and S-anilino-naphthalene-1-sulfonic acid, ammonium salt, indicate that the modified polymers associate in a pH-dependent fashion and provide hydrophobic domains to solubilize lipid membrane vesicles.
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Mohr, Benjamin Georg Robert. "Macromolecular assemblies: Human γ-crystallin protein, glutamic acid bottle brushes, and hyaluronic acid gels". 2013. https://scholarworks.umass.edu/dissertations/AAI3603124.
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Macromolecular assemblies constitute the world in which we live. The work contained within this thesis has studied three different types of macromolecular assemblies: human gamma-crystallin protein aggregation, the synthesis of glutamic acid bottle brushes, and cross-linked hyaluronic acid hydrogels. The in vitro study of human lens gamma-crystallin protein aggregation is the main component of this thesis. Separate projects that aid the body of this work include a description for the synthesis of glutamic acid bottle brush macromolecules and novel cross-linked networks of hyaluronic acid hydrogels. Cataract is the number one cause of blindness worldwide. Despite being a widespread disease, the epidemiology of cataract is still largely unknown. Cataracts are protein aggregates consisting of alpha-, beta-, and gamma-crystallin protein which are the major components of the lens in the human eye. In this work, in vitro investigations of protein-protein interactions were performed on dilute solutions of recombinant human alpha- and gamma-crystallin protein using dynamic light scattering technique. It was discovered that in phosphate buffered solutions, gamma-crystallin exists as two distinct populations of unaggregated and large aggregated protein. On the other hand, alpha-crystallin protein does not aggregate, but forms small oligomeric assemblies. Upon mixing alpha- and gamma-crystallin the aggregation of gamma-crystallin was removed. The impact of temperature, protein concentration, the reducing agent dithiothreitol, salt concentration, and pH on gamma-crystallin were all subsequently investigated. It was concluded that in vitro aggregation of gamma-crystallin protein arises from non-covalent electrostatic interactions. To further investigate the electrostatic hypothesis, point mutations were performed on human gamma-crystallin in an attempt to prevent protein aggregation. Using recombinant DNA technology, twelve different gammaS-crystallin protein mutants were created. The mutations were designed to change the proteins overall surface charge by substituting positively charged amino acids with neutral hydrophilic amino acids. The aggregation behavior of the mutant proteins was then studied by dynamic light scattering. It was observed that all gamma-crystallin mutants resulted in continued aggregation. The result suggests that the in vitro aggregation behavior of gamma-crystallin is likely due to electrostatic interactions between specific amino acids not probed in this work. Due to the time consuming nature of point mutations, chemical modifications of gamma-crystallin were subsequently performed in an alternative method to disrupt electrostatic interactions which are believed to cause gamma-crysatllin protein aggregation. GammaD- and GammaS-crystallin proteins were chemically modified with seven different molecules. Chemical modifications were characterized with a combination of mass spectroscopy, circular dichroism spectroscopy, and dynamic light scattering. The results demonstrated that modifying positively charged amino acids of human gamma-crystallin protein with poly(ethylene) glycol prevented in vitro protein aggregation. The chemical modification of lens crystallin protein provides a possible route by which protein aggregation and ultimately cataract can be prevented, arrested or reversed. In a separate project, glutamic acid bottle brushes were synthesized for future translocation experiments. Translocation is viewed as a potential method by which genomic DNA can be sequenced. In an attempt to understand the effect of polymer diameter on translocation kinetics, bottle brush polymers with varying thicknesses were synthesized. The complex synthesis and subsequent characterization by nuclear magnetic resonance, atomic force microscopy, capillary electrophoresis, static and dynamic light scattering are described herein. In summary, glutamic acid bottle brushes of three different thicknesses were successfully synthesized, characterized, and purified. Finally, the novel synthesis of thiol cross-linked hyaluronic acid hydrogels is described. Hyaluronic acid is a polysaccharide which is of interest for potential biomedical applications. The biopolymer was modified with cystamine and placed under reducing conditions which provides free thiol groups capable of crosslinking under oxidizing conditions. The synthesis, characterization, and gelation procedure for the cross-linked hyaluronic acid hydrogels is described in detail. The modified hyaluronic acid is a material capable of in situ gelation.
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王晢旭. "pH-responsive polymer vesicles assembled from lipid-contaning poly(γ-glutamic acid ) and their applications in drug delivery". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/88569342183263034880.
Full textAbstract:
碩士國立清華大學
生醫工程與環境科學系
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In this study, we used the biodegradable amphiphilic copolymers of lipid-modified poly(γ-glutamic acid) (Poly(γ-glutamic acid-co-distearin glutamate), γ-PGA-DSGA) prepared by modifying 1,2-distearoyl-rac-glycerol (distearin) as hydrophobic segments, onto poly(γ-glutamic acid) as the hydrophilic segments. The γ-PGA-based nanoparticles are prepared by self-assembly of amphiphilic copolymers in aqueous phase solution (pH 7.4 buffer). Combining the results of dynamic light scattering (DLS)、static light scattering (SLS) and transmission electron microscope (TEM), we strongly confirmed that the structure of assemblies is presented in vesicle-like form. Further, in stablization experiment, the vesicles with higher DSGA contents can be preserved in acqueous phase solution at 4℃ at least for 28 days. However, the vesicles with lower lipid contents are unstable either at room temperature or at 4℃. To endow the capacity in pH responsibility and effectively increase the stability of copolymer vesicle, chitosan and γ-PGA (or γ-PGA-PEG) were sequentially deposited on the surface of copolymer vesicle via electrostatic attraction. With the solution pH being decreased, the zeta potential of copolumer vesicle surface was turned to positive from negative because GA residues and chitosan segments were protonated. In vitro drug release experiment, the accumulated release of DOX increases as the solution pH was decreased. Moreover, the DOX-free vesicles are non-cytotoxicity examined by the cell survival experiment, but DOX-loaded vesicles can effectively kill HeLa cell. Nevertheless, DOX-loaded vesicles showed a low capacity in killing MCF-7 cells due to approximately 40% of P-glycoprotein（P-gp）in breast cancer cell (MCF-7) .As a result, these pH-responsive polymer vesicles have great potential in the applications of drug delivery systems.
Book chapters on the topic "Glutamic acid polymers"
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Giannos, Steven A., Devang Shah, Richard A. Gross, David L. Kaplan, and Jean M. Mayer. "Poly(Glutamic Acid) Produced by Bacterial Fermentation." In Novel Biodegradable Microbial Polymers. Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-2129-0_46.
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Giannos, Steven A., Devang Shah, Richard A. Gross, David Kaplan, and Jean M. Mayer. "The Biosynthesis of Unusual Polyamides Containing Glutamic Acid." In Biotechnology and Polymers. Springer US, 1991. http://dx.doi.org/10.1007/978-1-4615-3844-8_7.
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Xu, Zhinan, Huili Zhang, Hao Chen, et al. "Microbial Production of Poly-γ-Glutamic Acid." In Bioprocessing Technologies in Biorefinery for Sustainable Production of Fuels, Chemicals, and Polymers. John Wiley & Sons, Inc., 2013. http://dx.doi.org/10.1002/9781118642047.ch23.
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Wohlfarth, Ch. "Second virial coefficient of poly(N-isopropylacrylamide-b-l-glutamic acid)." In Polymer Solutions. Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-02890-8_580.
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Marsischky, G. T., M. Ikejima, H. Suzuki, et al. "Directed Mutagenesis of Glutamic Acid 988 of Poly(ADP-ribose) Polymerase." In ADP-Ribosylation Reactions. Springer New York, 1992. http://dx.doi.org/10.1007/978-1-4419-8718-1_6.
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Singer, Jack W., Brian Baker, Peter de Vries, et al. "Poly-(L)-Glutamic Acid-Paclitaxel (CT-2103) [XYOTAX™], a Biodegradable Polymeric Drug Conjugate." In Advances in Experimental Medicine and Biology. Springer US, 2004. http://dx.doi.org/10.1007/0-306-47932-x_6.
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Kunioka, Masao. "Biosynthesis of Poly(γ-glutamic acid) in Bacillus subtilis IFO3335 and Crosslinking Reaction by γ-Irradiation of Poly(γ-glutamic acid)." In Studies in Polymer Science. Elsevier, 1994. http://dx.doi.org/10.1016/b978-0-444-81708-2.50046-4.
Full textConference papers on the topic "Glutamic acid polymers"
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Yang, Ge, Li-Qun Ma та Xue-Yan Su. "Improvement on Polymer Blending with Nano-Technology: selfassembled Poly(γ-glutamic acid)/chitosan (γ-PGA/CH)/blends". У 2016 International Conference on Advanced Materials, Technology and Application (AMTA2016). WORLD SCIENTIFIC, 2016. http://dx.doi.org/10.1142/9789813200470_0034.
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Henschen, A., та E. Müller. "ON THE FACTOR XIIIa-INDUCED CROSSLINKING OF HUMAN FIBRIN α-CHAINS". У XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644649.
Full textAbstract:
Factor XIIIa catalysis the formation of isopeptide bonds Between γ-carbamoyl groups of peptide-bound glutamines and ε-amino groups of lysines or lysine analogues. During fibrin crosslinking two such bonds are rapidly formed between the C-termini of two γ-chains in adjacent molecules and then several bonds are more slowly formed between several α-chains. The crosslinking sites in the γ-chain were identified already 15 years ago, those in the α-chain are still only tentatively or partially identified,, However, by determining the incorporation of lysine analogues in the α-chain it could be shown that the glutamines in positions 328, 366 and possibly also 237 may participate in crosslinking reactions. Analyses of cyanogen bromide fragments isolated from crosslinked fibrin indicated the segments 271-776 and 518-587 to contain the primary crosslinking sites.In the present study factor XHI-containing fibrinogen was incubated over night with thrombin in presence of calcium ions and cysteine or, as a control, in presence of EDTA. The fibrin material was cleaved with cyanogen bromide, mercaptolysed, pyri-dylethylated and then subjected to Sephacryl S-300 chromatography. The early protein fractions were tested by reversed-phase high-performance liquid chromatography (HPLC) using fibrinogen fragments as reference. In the control sample Aa-chain fragment 271-776 eluted first but in the crosslinked sample it was missing and instead a heterogeneous mixture of higher-molecular weight components was observed. N-Terminal sequence analysis showed the mixture to contain not only the expected fragments 241-476 and 518-584,but in fact all glutamine- or lysine-containing Aα-chain fragments between positions 208 and 611. In the corresponding 6 fragments a total of 6 glutamines and 21 lysines as potential crosslinking sites are present. Two fragments contain only one each of these residues which therefore must be true crosslinking sites. Remaining sites and the actual linkages were identified after reversed-phase HPLC of the tryptic peptide mixture by N-terminal sequence and total amino acid analyses.The linkage pattern will provide information about the localisation and conformation of the C-terminal part of the α-chain and its contribution to the fibrin polymer structure.