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https://www.readbyqxmd.com/read/28335986/on-the-formation-and-role-of-reactive-oxygen-species-in-light-driven-lpmo-oxidation-of-phosphoric-acid-swollen-cellulose
#1
K B Möllers, H Mikkelsen, T I Simonsen, D Cannella, K S Johansen, M J Bjerrum, C Felby
Light-driven activation of lytic polysaccharide monooxygenases (LPMOs) has been attributed to the transfer of high redox potential electrons from excited photopigments to the enzyme. However, due to the formation of reactive oxygen species (ROS) in such a system, not only electrons from the pigments but also ROS could be part of the enzyme mechanism. This work investigates the role of ROS in the oxidation of phosphoric acid swollen cellulose (PASC) by a light-driven LPMO system. Our results clearly show that the addition of superoxide dismutase or catalase to remove ROS did not attenuate the capacity of the light-driven LPMO system to oxidize PASC, as measured by formation of oxidized oligosaccharides...
March 18, 2017: Carbohydrate Research
https://www.readbyqxmd.com/read/28302276/rp-uhplc-uv-esi-ms-ms-analysis-of-lpmo-generated-c4-oxidized-gluco-oligosaccharides-after-non-reductive-labeling-with-2-aminobenzamide
#2
Matthias Frommhagen, Gijs van Erven, Mark Sanders, Willem J H van Berkel, Mirjam A Kabel, Harry Gruppen
Lytic polysaccharide monooxygenases (LPMOs) are able to cleave recalcitrant polysaccharides, such as cellulose, by oxidizing the C1 and/or C4 atoms. The analysis of the resulting products requires a variety of analytical techniques. Up to now, these techniques mainly focused on the identification of non-oxidized and C1-oxidized oligosaccharides. The analysis of C4-oxidized gluco-oligosaccharides is mostly performed by using high pressure anion exchange chromatography (HPAEC). However, the alkaline conditions used during HPAEC analysis lead to tautomerization of C4-oxidized gluco-oligosaccharides, which limits the use of this technique...
March 6, 2017: Carbohydrate Research
https://www.readbyqxmd.com/read/28293293/the-podospora-anserina-lytic-polysaccharide-monooxygenase-palpmo9h-catalyzes-oxidative-cleavage-of-diverse-plant-cell-wall-matrix-glycans
#3
Mathieu Fanuel, Sona Garajova, David Ropartz, Nicholas McGregor, Harry Brumer, Hélène Rogniaux, Jean-Guy Berrin
BACKGROUND: The enzymatic conversion of plant biomass has been recently revolutionized by the discovery of lytic polysaccharide monooxygenases (LPMO) that catalyze oxidative cleavage of polysaccharides. These powerful enzymes are secreted by a large number of fungal saprotrophs and are important components of commercial enzyme cocktails used for industrial biomass conversion. Among the 33 AA9 LPMOs encoded by the genome of Podospora anserina, the PaLPMO9H enzyme catalyzes mixed C1/C4 oxidative cleavage of cellulose and cello-oligosaccharides...
2017: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/28291519/structural-studies-of-neurospora-crassa-lpmo9d-and-redox-partner-cdhiia-using-neutron-crystallography-and-small-angle-scattering
#4
Annette M Bodenheimer, William B O'Dell, Christopher B Stanley, Flora Meilleur
Sensitivity to hydrogen/deuterium and lack of observable radiation damage makes cold neutrons an ideal probe the structural studies of proteins with highly photosensitive groups such as the copper center of lytic polysaccharide monooxygenases (LPMOs) and flavin adenine dinucleotide (FAD) and heme redox cofactors of cellobiose dehydrogenases (CDHs). Here, neutron crystallography and small-angle neutron scattering are used to investigate Neurospora crassa LPMO9D (NcLPMO9D) and CDHIIA (NcCDHIIA), respectively...
March 4, 2017: Carbohydrate Research
https://www.readbyqxmd.com/read/28291518/a-novel-expression-system-for-lytic-polysaccharide-monooxygenases
#5
Gaston Courtade, Simone Balzer Le, Gerd Inger Sætrom, Trygve Brautaset, Finn L Aachmann
Lytic polysaccharide monooxygenases (LPMOs) are key enzymatic players of lignocellulosic biomass degradation processes. As such, they have been introduced in cellulolytic cocktails for more efficient and less expensive lignocellulose saccharification. The recombinant production of LPMOs in bacteria for scientific investigations using vectors typically based on the T7 and lacUV5 promoters has been hampered by low yields. Reasons for this have been catabolite repression when producing the proteins in defined media with glucose as the sole carbon source, as well as the lack of an inducible expression system that allows controlled production of LPMOs that are correctly processed during translocation to the periplasmic space...
February 14, 2017: Carbohydrate Research
https://www.readbyqxmd.com/read/28250814/type-dependent-action-modes-of-ttaa9e-and-taaa9a-acting-on-cellulose-and-differently-pretreated-lignocellulosic-substrates
#6
In Jung Kim, Nari Seo, Hyun Joo An, Jae-Han Kim, Paul V Harris, Kyoung Heon Kim
BACKGROUND: Lytic polysaccharide monooxygenase (LPMO) is a group of recently identified proteins that catalyze oxidative cleavage of the glycosidic linkages of cellulose and other polysaccharides. By utilizing the oxidative mode of action, LPMOs are able to enhance the efficiency of cellulase in the hydrolysis of cellulose. Particularly, auxiliary activity family 9 (AA9) is a group of fungal LPMOs that show a type-dependent regioselectivity on cellulose in which Types 1, 2, and 3 hydroxylate at C1, C4, and C1 and C4 positions, respectively...
2017: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/28222763/the-discovery-of-novel-lpmo-families-with-a-new-hidden-markov-model
#7
Gerben P Voshol, Erik Vijgenboom, Peter J Punt
BACKGROUND: Renewable biopolymers, such as cellulose, starch and chitin are highly resistance to enzymatic degradation. Therefore, there is a need to upgrade current degradation processes by including novel enzymes. Lytic polysaccharide mono-oxygenases (LPMOs) can disrupt recalcitrant biopolymers, thereby enhancing hydrolysis by conventional enzymes. However, novel LPMO families are difficult to identify using existing methods. Therefore, we developed a novel profile Hidden Markov model (HMM) and used it to mine genomes of ascomycetous fungi for novel LPMOs...
February 21, 2017: BMC Research Notes
https://www.readbyqxmd.com/read/28177316/crystallization-of-a-fungal-lytic-polysaccharide-monooxygenase-expressed-from-glycoengineered-pichia-pastoris-for-x-ray-and-neutron-diffraction
#8
William B O'Dell, Paul D Swartz, Kevin L Weiss, Flora Meilleur
Lytic polysaccharide monooxygenases (LPMOs) are carbohydrate-disrupting enzymes secreted by bacteria and fungi that break glycosidic bonds via an oxidative mechanism. Fungal LPMOs typically act on cellulose and can enhance the efficiency of cellulose-hydrolyzing enzymes that release soluble sugars for bioethanol production or other industrial uses. The enzyme PMO-2 from Neurospora crassa (NcPMO-2) was heterologously expressed in Pichia pastoris to facilitate crystallographic studies of the fungal LPMO mechanism...
February 1, 2017: Acta Crystallographica. Section F, Structural Biology Communications
https://www.readbyqxmd.com/read/28140411/charge-transport-mechanisms-in-sol-gel-grown-la0-7pb0-3mno3-laalo3-manganite-films
#9
Eesh Vaghela, M J Keshvani, Keval Gadani, Zalak Joshi, Hetal Boricha, K Asokan, D Venkateshwarlu, V Ganesan, N A Shah, P S Solanki
In this communication, structural, microstructural, transport and magnetotransport properties are reported for La0.7Pb0.3MnO3/LaAlO3 (LPMO/LAO) manganite films having different thicknesses. All the films were irradiated with 200 MeV Ag(+15) swift heavy ions (SHI). Films were grown using the sol-gel method by employing the acetate precursor route. Structural measurements were carried out using the X-ray diffraction (XRD) method at room temperature, while atomic force microscopy (AFM) was performed for the surface morphology...
January 31, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28125213/microplate-based-detection-of-lytic-polysaccharide-monooxygenase-activity-by-fluorescence-labeling-of-insoluble-oxidized-products
#10
Thu V Vuong, Bing Liu, Mats Sandgren, Emma R Master
Most existing methods for screening the activity of lytic polysaccharide mono-oxygenases (LPMOs) on polysaccharides are based on the detection of soluble oxidized sugars. This approach might underestimate the total performance of LPMOs since oxidation events that do not lead to oligosaccharide release are not detected. Using PcLPMO9D as a model enzyme, a microplate-based method has been developed to detect C1-oxidizing LPMO activity by covalently linking a water-soluble fluorophore to oxidized positions within the cellulose fiber...
January 26, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28123349/metadata-analysis-of-phanerochaete-chrysosporium-gene-expression-data-identified-common-cazymes-encoding-gene-expression-profiles-involved-in-cellulose-and-hemicellulose-degradation
#11
Ayyappa Kumar Sista Kameshwar, Wensheng Qin
In literature, extensive studies have been conducted on popular wood degrading white rot fungus, Phanerochaete chrysosporium about its lignin degrading mechanisms compared to the cellulose and hemicellulose degrading abilities. This study delineates cellulose and hemicellulose degrading mechanisms through large scale metadata analysis of P. chrysosporium gene expression data (retrieved from NCBI GEO) to understand the common expression patterns of differentially expressed genes when cultured on different growth substrates...
2017: International Journal of Biological Sciences
https://www.readbyqxmd.com/read/28110665/oxidative-cleavage-and-hydrolytic-boosting-of-cellulose-in-soybean-spent-flakes-by-trichoderma-reesei-cel61a-lytic-polysaccharide-monooxygenase
#12
Brian C Pierce, Jane Wittrup Agger, Jesper Wichmann, Anne S Meyer
The auxiliary activity family 9 (AA9) copper-dependent lytic polysaccharide monooxygenase (LPMO) from Trichoderma reesei (EG4; TrCel61A) was investigated for its ability to oxidize the complex polysaccharides from soybean. The substrate specificity of the enzyme was assessed against a variety of substrates, including both soy spent flake, a by-product of the soy food industry, and soy spent flake pretreated with sodium hydroxide. Products from enzymatic treatments were analyzed using mass spectrometry and high performance anion exchange chromatography...
March 2017: Enzyme and Microbial Technology
https://www.readbyqxmd.com/read/28107425/using-an-inducible-promoter-of-a-gene-encoding-penicillium-verruculosum-glucoamylase-for-production-of-enzyme-preparations-with-enhanced-cellulase-performance
#13
Alexander G Bulakhov, Pavel V Volkov, Aleksandra M Rozhkova, Alexander V Gusakov, Vitaly A Nemashkalov, Aidar D Satrutdinov, Arkady P Sinitsyn
BACKGROUND: Penicillium verruculosum is an efficient producer of highly active cellulase multienzyme system. One of the approaches for enhancing cellulase performance in hydrolysis of cellulosic substrates is to enrich the reaction system with β -glucosidase and/or accessory enzymes, such as lytic polysaccharide monooxygenases (LPMO) displaying a synergism with cellulases. RESULTS: Genes bglI, encoding β-glucosidase from Aspergillus niger (AnBGL), and eglIV, encoding LPMO (formerly endoglucanase IV) from Trichoderma reesei (TrLPMO), were cloned and expressed by P...
2017: PloS One
https://www.readbyqxmd.com/read/28071716/lytic-polysaccharide-monooxygenases-disrupt-the-cellulose-fibers-structure
#14
Ana Villares, Céline Moreau, Chloé Bennati-Granier, Sona Garajova, Loïc Foucat, Xavier Falourd, Bodo Saake, Jean-Guy Berrin, Bernard Cathala
Lytic polysaccharide monooxygenases (LPMOs) are a class of powerful oxidative enzymes that breakdown recalcitrant polysaccharides such as cellulose. Here we investigate the action of LPMOs on cellulose fibers. After enzymatic treatment and dispersion, LPMO-treated fibers show intense fibrillation. Cellulose structure modifications visualized at different scales indicate that LPMO creates nicking points that trigger the disintegration of the cellulose fibrillar structure with rupture of chains and release of elementary nanofibrils...
January 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28066849/gold-nanorod-embedded-large-pore-mesoporous-organosilica-nanospheres-for-gene-and-photothermal-cooperative-therapy-of-triple-negative-breast-cancer
#15
Qianqian Ni, Zhaogang Teng, Meng Dang, Ying Tian, Yunlei Zhang, Peng Huang, Xiaodan Su, Nan Lu, Zhenlu Yang, Wei Tian, Shouju Wang, Wenfei Liu, Yuxia Tang, Guangming Lu, Longjiang Zhang
To date, clinicians still lack an effective strategy to treat triple negative breast cancer (TNBC). In this work, we design for the first time a gold nanorod embedded large-pore mesoporous organosilica (GNR@LPMO) nanoplatform for gene and photothermal cooperative therapy of TNBC. The synthesized GNR@LPMOs possess a uniform size (175 nm), high surface area (631 m(2) g(-1)), large pore size, excellent photothermal efficiency, and good biocompatibility. Thanks to the large-pore mesoporous organosilica layer, the GNR@LPMO nanoplatforms display much higher loading capacity of siRNA compared with traditional liposome and bare gold nanorods...
January 9, 2017: Nanoscale
https://www.readbyqxmd.com/read/28045386/learning-from-oligosaccharide-soaks-of-crystals-of-an-aa13-lytic-polysaccharide-monooxygenase-crystal-packing-ligand-binding-and-active-site-disorder
#16
Kristian E H Frandsen, Jens Christian Navarro Poulsen, Morten Tovborg, Katja S Johansen, Leila Lo Leggio
Lytic polysaccharide monooxygenases (LPMOs) are a class of copper-dependent enzymes discovered within the last ten years. They oxidatively cleave polysaccharides (chitin, lignocellulose, hemicellulose and starch-derived), presumably making recalcitrant substrates accessible to glycoside hydrolases. Recently, the first crystal structure of an LPMO-substrate complex was reported, giving insights into the interaction of LPMOs with β-linked substrates (Frandsen et al., 2016). The LPMOs acting on α-linked glycosidic bonds (family AA13) display binding surfaces that are quite different from those of LPMOs that act on β-linked glycosidic bonds (families AA9-AA11), as revealed from the first determined structure (Lo Leggio et al...
January 1, 2017: Acta Crystallographica. Section D, Structural Biology
https://www.readbyqxmd.com/read/27933913/dft-study-on-the-interaction-of-tris-benzene-1-2-dithiolato-molybdenum-complex-with-water-a-hydrolysis-mechanism-involving-a-feasible-seven-coordinate-aquomolybdenum-intermediate
#17
Lorenzo Fernández, Francisco F Pérez-Pla, Iñaki Tuñón, Elisa Llopis
In the present work, the reactivity of the tris(benzene-1,2-dithiolato)molybdenum complex ([Mo(bdt)3]) toward water is studied by means of the density functional theory (DFT). DFT calculations were performed using the M06, B3P86, and B3PW91 hybrid functionals for comparison purposes. The M06 method was employed to elucidate the reaction pathway, relative stability of the intermediate products, nature of the Mo-S bond cleavage, and electronic structure of the involved molybdenum species. This functional was also used to study the transference of electrons from the molybdenum center toward the ligands...
December 8, 2016: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/27836848/inactivation-of-cellobiose-dehydrogenases-modifies-the-cellulose-degradation-mechanism-of-podospora-anserina
#18
Narumon Tangthirasunun, David Navarro, Sona Garajova, Didier Chevret, Laetitia Chan Ho Tong, Valérie Gautier, Kevin D Hyde, Philippe Silar, Jean-Guy Berrin
Conversion of biomass into high-value products, including biofuels, is of great interest to developing sustainable biorefineries. Fungi are an inexhaustible source of enzymes to degrade plant biomass. Cellobiose dehydrogenases (CDHs) play an important role in the breakdown through synergistic action with fungal lytic polysaccharide monooxygenases (LPMOs). The three CDH genes of the model fungus Podospora anserina were inactivated, resulting in single and multiple CDH mutants. We detected almost no difference in growth and fertility of the mutants on various lignocellulose sources, except on crystalline cellulose, on which a 2-fold decrease in fertility of the mutants lacking P...
January 15, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/27833654/bioinformatic-characterization-of-type-specific-sequence-and-structural-features-in-auxiliary-activity-family-9-proteins
#19
Vuyani Moses, Rowan Hatherley, Özlem Tastan Bishop
BACKGROUND: Due to the impending depletion of fossil fuels, it has become important to identify alternative energy sources. The biofuel industry has proven to be a promising alternative. However, owing to the complex nature of plant biomass, hence the degradation, biofuel production remains a challenge. The copper-dependent Auxiliary Activity family 9 (AA9) proteins have been found to act synergistically with other cellulose-degrading enzymes resulting in an increased rate of cellulose breakdown...
2016: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/27729944/expression-and-chromatin-structures-of-cellulolytic-enzyme-gene-regulated-by-heterochromatin-protein-1
#20
Xiujun Zhang, Yinbo Qu, Yuqi Qin
BACKGROUND: Heterochromatin protein 1 (HP1, homologue HepA in Penicillium oxalicum) binding is associated with a highly compact chromatin state accompanied by gene silencing or repression. HP1 loss leads to the derepression of gene expression. We investigated HepA roles in regulating cellulolytic enzyme gene expression, as an increasingly number of studies have suggested that cellulolytic enzyme gene expression is not only regulated by transcription factors, but is also affected by the chromatin status...
2016: Biotechnology for Biofuels
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