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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
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
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
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
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
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
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
Rebecca C Gregory, Glyn R Hemsworth, Johan P Turkenburg, Samuel J Hart, Paul H Walton, Gideon J Davies
The enzymatic deconstruction of recalcitrant polysaccharide biomass is central to the conversion of these substrates for societal benefit, such as in biofuels. Traditional models for enzyme-catalysed polysaccharide degradation involved the synergistic action of endo-, exo- and processive glycoside hydrolases working in concert to hydrolyse the substrate. More recently this model has been succeeded by one featuring a newly discovered class of mononuclear copper enzymes: lytic polysaccharide monooxygenases (LPMOs; classified as Auxiliary Activity (AA) enzymes in the CAZy classification)...
September 29, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Mi-Ji Yu, Sun-Hee Yoon, Young-Wan Kim
Lytic polysaccharide monooxygenases (LPMOs) are copper ion-containing enzymes that degrade crystalline polysaccharides, such as cellulose or chitin, through an oxidative mechanism. To the best of our knowledge, there are no assay methods for the direct characterization of LPMOs that degrade substrates without coupled enzymes. As such, in this study, a coupled enzyme-free assay method for LPMOs was developed, which is based on measuring the consumption of ascorbic acid used as an external electron donor for LPMOs...
November 2016: Enzyme and Microbial Technology
Jennifer S M Loose, Zarah Forsberg, Daniel Kracher, Stefan Scheiblbrandner, Roland Ludwig, Vincent G H Eijsink, Gustav Vaaje-Kolstad
Lytic polysaccharide monooxygenases (LPMOs) represent a recent addition to the carbohydrate-active enzymes and are classified as auxiliary activity (AA) families 9, 10, 11, and 13. LPMOs are crucial for effective degradation of recalcitrant polysaccharides like cellulose or chitin. These enzymes are copper-dependent and utilize a redox mechanism to cleave glycosidic bonds that is dependent on molecular oxygen and an external electron donor. The electrons can be provided by various sources, such as chemical compounds (e...
December 2016: Protein Science: a Publication of the Protein Society
Gerdt Müller, Dayanand Chandrahas Kalyani, Svein Jarle Horn
Enzymatic catalysis plays a key role in the conversion of lignocellulosic biomass to fuels and chemicals such as lactic acid. In the last decade, the efficiency of commercial cellulase cocktails has increased significantly, in part due to the inclusion of lytic polysaccharide monooxygenases (LPMOs). However, the LPMOs' need for molecular oxygen to break down cellulose demands reinvestigations of process conditions. In this study, we evaluate the efficiency of lactic acid production from steam-exploded birch using an LPMO-containing cellulase cocktail in combination with lactic acid bacteria, investigating both separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF)...
September 6, 2016: Biotechnology and Bioengineering
Yuka Kojima, Anikó Várnai, Takuya Ishida, Naoki Sunagawa, Dejan M Petrovic, Kiyohiko Igarashi, Jody Jellison, Barry Goodell, Gry Alfredsen, Bjørge Westereng, Vincent G H Eijsink, Makoto Yoshida
: Fungi secrete a set of glycoside hydrolases and lytic polysaccharide monooxygenases (LPMOs) to degrade plant polysaccharides. Brown-rot fungi, such as Gloeophyllum trabeum, tend to have few LPMOs and information on these enzymes is scarce. The genome of G. trabeum encodes four AA9 LPMOs, whose coding sequences were amplified from cDNA. Due to alternative splicing, two variants of GtLPMO9A seem to be produced, a single domain variant, GtLPMO9A-1, and a longer variant, GtLPMO9A-2, which contains a C-terminal domain comprising approximately 55 residues without a predicted function...
September 2, 2016: Applied and Environmental Microbiology
Laura Nekiunaite, Magnus Ø Arntzen, Birte Svensson, Gustav Vaaje-Kolstad, Maher Abou Hachem
BACKGROUND: Starch is the second most abundant plant-derived biomass and a major feedstock in non-food industrial applications and first generation biofuel production. In contrast to lignocellulose, detailed insight into fungal degradation of starch is currently lacking. This study explores the secretomes of Aspergillus nidulans grown on cereal starches from wheat and high-amylose (HA) maize, as well as legume starch from pea for 5 days. RESULTS: Aspergillus nidulans grew efficiently on cereal starches, whereas growth on pea starch was poor...
2016: Biotechnology for Biofuels
Matthias Frommhagen, Martijn J Koetsier, Adrie H Westphal, Jaap Visser, Sandra W A Hinz, Jean-Paul Vincken, Willem J H van Berkel, Mirjam A Kabel, Harry Gruppen
BACKGROUND: Lytic polysaccharide monooxgygenases (LPMOs) are known to boost the hydrolytic breakdown of lignocellulosic biomass, especially cellulose, due to their oxidative mechanism. For their activity, LPMOs require an electron donor for reducing the divalent copper cofactor. LPMO activities are mainly investigated with ascorbic acid as a reducing agent, but little is known about the effect of plant-derived reducing agents on LPMOs activity. RESULTS: Here, we show that three LPMOs from the fungus Myceliophthora thermophila C1, MtLPMO9A, MtLPMO9B and MtLPMO9C, differ in their substrate preference, C1-/C4-regioselectivity and reducing agent specificity...
2016: Biotechnology for Biofuels
Katja Salomon Johansen
Lytic polysaccharide monooxygenases (LPMOs) are copper-enzymes that catalyze oxidative cleavage of glycosidic bonds. These enzymes are secreted by many microorganisms to initiate infection and degradation processes. In particular, the concept of fungal degradation of lignocellulose has been revised in the light of this recent finding. LPMOs require a source of electrons for activity, and both enzymatic and plant-derived sources have been identified. Importantly, light-induced electron delivery from light-harvesting pigments can efficiently drive LPMO activity...
August 12, 2016: Trends in Plant Science
Suehiro Iwata, Dai Akase, Misako Aida, Sotiris S Xantheas
The influence of the nearest neighbor and next-nearest neighbor water molecules on the strength of the hydrogen (H) bonds was examined for the polyhedral clusters of cubic (H2O)8, dodecahedral (H2O)20 and tetrakaidecahedral (H2O)24 cages. The relative stability and the characteristics of the H bond networks are also studied. The charge-transfer (CT) and dispersion interaction terms of every pair of H bonds are evaluated using perturbation theory based on the locally-projected molecular orbitals (LPMO PT). Every water molecule and every H-bonded pair in these polyhedral clusters are classified by the types of the neighbor molecules and H bonds...
July 20, 2016: Physical Chemistry Chemical Physics: PCCP
Rohit Rai, Baljit Kaur, Surender Singh, Macros Di Falco, Adrian Tsang, B S Chadha
Penicillium sp. (Dal 5) isolated from rhizosphere of conifers from Dalhousie (Himachal Pradesh, India) was found to be an efficient cellulolytic strain. The culture under shake flask on CWR (cellulose, wheat bran and rice straw) medium produced appreciably higher levels of endoglucanase (35.69U/ml), β-glucosidase (4.20U/ml), cellobiohydrolase (2.86U/ml), FPase (1.2U/ml) and xylanase (115U/ml) compared to other Penicillium strains reported in literature. The mass spectroscopy analysis of Penicillium sp. Dal 5 secretome identified 108 proteins constituting an array of CAZymes including glycosyl hydrolases (GH) belonging to 24 different families, polysaccharide lyases (PL), carbohydrate esterases (CE), lytic polysaccharide mono-oxygenases (LPMO) in addition to swollenin and a variety of carbohydrate binding modules (CBM) indicating an elaborate genetic potential of this strain for hydrolysis of lignocellulosics...
September 2016: Bioresource Technology
Gaston Courtade, Reinhard Wimmer, Åsmund K Røhr, Marita Preims, Alfons K G Felice, Maria Dimarogona, Gustav Vaaje-Kolstad, Morten Sørlie, Mats Sandgren, Roland Ludwig, Vincent G H Eijsink, Finn Lillelund Aachmann
Lytic polysaccharide monooxygenases (LPMOs) are copper-dependent enzymes that catalyze oxidative cleavage of glycosidic bonds using molecular oxygen and an external electron donor. We have used NMR and isothermal titration calorimetry (ITC) to study the interactions of a broad-specificity fungal LPMO, NcLPMO9C, with various substrates and with cellobiose dehydrogenase (CDH), a known natural supplier of electrons. The NMR studies revealed interactions with cellohexaose that center around the copper site. NMR studies with xyloglucans, i...
May 24, 2016: Proceedings of the National Academy of Sciences of the United States of America
Gaston Courtade, Reinhard Wimmer, Maria Dimarogona, Mats Sandgren, Vincent G H Eijsink, Finn L Aachmann
The apo-form of the 23.3 kDa catalytic domain of the AA9 family lytic polysaccharide monooxygenase NcLPMO9C from Neurospora crassa has been isotopically labeled and recombinantly expressed in Pichia pastoris. In this paper, we report the (1)H, (13)C, and (15)N chemical shift assignments of this LPMO.
October 2016: Biomolecular NMR Assignments
Amanda K Chaplin, Michael T Wilson, Michael A Hough, Dimitri A Svistunenko, Glyn R Hemsworth, Paul H Walton, Erik Vijgenboom, Jonathan A R Worrall
Copper-dependent lytic polysaccharide monooxygenases (LPMOs) are enzymes that oxidatively deconstruct polysaccharides. The active site copper in LPMOs is coordinated by a histidine-brace. This utilizes the amino group and side chain of the N-terminal His residue with the side chain of a second His residue to create a T-shaped arrangement of nitrogen ligands. We report a structural, kinetic, and thermodynamic appraisal of copper binding to the histidine-brace in an auxiliary activity family 10 (AA10) LPMO from Streptomyces lividans (SliLPMO10E)...
June 10, 2016: Journal of Biological Chemistry
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