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Flavoenzyme

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https://www.readbyqxmd.com/read/29626635/on-the-origin-of-vanillyl-alcohol-oxidases
#1
Gudrun Gygli, Ronald P de Vries, Willem J H van Berkel
Vanillyl alcohol oxidase (VAO) is a fungal flavoenzyme that converts a wide range of para-substituted phenols. The products of these conversions, e.g. vanillin, coniferyl alcohol and chiral aryl alcohols, are of interest for several industries. VAO is the only known fungal member of the 4-phenol oxidising (4PO) subgroup of the VAO/PCMH flavoprotein family. While the enzyme has been biochemically characterised in great detail, little is known about its physiological role and distribution in fungi. We have identified and analysed novel, fungal candidate VAOs and found them to be mostly present in Pezizomycotina and Agaricomycotina...
April 4, 2018: Fungal Genetics and Biology: FG & B
https://www.readbyqxmd.com/read/29526505/biochemical-and-thermodynamic-comparison-of-the-selenocysteine-containing-and-non-containing-thioredoxin-glutathione-reductase-of-fasciola-gigantica
#2
Parismita Kalita, Harish Shukla, Rohit Shukla, Timir Tripathi
The thiol-disulfide redox metabolism in platyhelminth parasites depends entirely on a single selenocysteine (Sec) containing flavoenzyme, thioredoxin glutathione reductase (TGR) that links the classical thioredoxin (Trx) and glutathione (GSH) systems. In the present study, we investigated the catalytic and structural properties of different variants of Fasciola gigantica TGR to understand the role of Sec. The recombinant full-length Sec containing TGR (FgTGRsec), TGR without Sec (FgTGR) and TGRsec without the N-terminal glutaredoxin (Grx) domain (∆NTD-FgTGRsec) were purified to homogeneity...
March 8, 2018: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/29516888/identification-of-potential-inhibitors-for-mycobacterial-uridine-diphosphogalactofuranose-galactopyranose-mutase-enzyme-a-novel-drug-target-through-in-silico-approach
#3
Tapaswini Nayak, Lingaraja Jena, Pranita Waghmare, Bhaskar C Harinath
Background: The Mycobacterium tuberculosis (MTB) uridine diphosphogalactofuranose (UDP)-galactopyranose mutase (UGM) is an essential flavoenzyme for mycobacterial viability and an important component of cell wall. It catalyzes the interconversion of UDP-galactopyranose into UDP-galactofuranose, a key building block for cell wall construction, essential for linking the peptidoglycan and mycolic acid cell wall layers in MTB through a 2-keto intermediate. Further, as this enzyme is not present in humans, it is an excellent therapeutic target for MTB...
January 2018: International Journal of Mycobacteriology
https://www.readbyqxmd.com/read/29498828/protein-derived-cofactors-revisited-empowering-amino-acid-residues-with-new-functions
#4
Victor L Davidson
A protein-derived cofactor is a catalytic or redox-active site in a protein that is formed by post-translational modification of one or more amino acid residues. These post-translational modifications are irreversible and endow the modified amino acid residues with new functional properties. This Perspective focusses on the following advances in this area that have occurred during recent years. The biosynthesis of the tryptophan tryptophylquinone (TTQ) cofactor is catalyzed by a di-heme enzyme, MauG. A bis-FeIV redox state of the hemes performs three two-electron oxidations of specific Trp residues via long-range electron transfer...
March 2, 2018: Biochemistry
https://www.readbyqxmd.com/read/29496172/inhibition-of-human-monoamine-oxidase-a-and-b-by-flavonoids-isolated-from-two-algerian-medicinal-plants
#5
Farida Larit, Khaled M Elokely, Narayan D Chaurasiya, Samira Benyahia, Manal A Nael, Francisco León, Mohammad Sanad Abu-Darwish, Thomas Efferth, Yan-Hong Wang, Djamila Belouahem-Abed, Samir Benayache, Babu L Tekwani, Stephen J Cutler
BACKGROUND: Monoamine oxidases (MAOs) are outer mitochondrial membrane flavoenzymes. They catalyze the oxidative deamination of a variety of neurotransmitters. MAO-A and MAO-B may be considered as targets for inhibitors to treat neurodegenerative diseases and depression and for managing symptoms associated with Parkinson's and Alzheimer's diseases. PURPOSE: The objective was to evaluate the inhibitory effect of Hypericum afrum and Cytisus villosus against MAO-A and B and to isolate the compounds responsible for the MAO-inhibitory activity...
February 1, 2018: Phytomedicine: International Journal of Phytotherapy and Phytopharmacology
https://www.readbyqxmd.com/read/29485859/stepwise-hydrogen-atom-and-proton-transfers-in-dioxygen-reduction-by-aryl-alcohol-oxidase
#6
Juan Carro, Patricia Ferreira, Angel T Martínez, Giovanni Gadda
The mechanism of dioxygen reduction by the flavoenzyme aryl-alcohol oxidase was investigated with kinetic isotope, viscosity, and pL (pH/pD) effects in rapid kinetics experiments by stopped-flow spectrophotometry of the oxidative half-reaction of the enzyme. Double-mixing of the enzyme in a stopped-flow spectrophotometer with [ -2H2]-p-methoxybenzyl alcohol and oxygen at varying aging times established a slow rate constant of 0.0023 s-1 for the wash-out of the D atom from the N5 atom of the reduced flavin. Thus, the deuterated substrate could be used to probe the cleavage of the N-H bond of the reduced flavin in the oxidative half-reaction...
February 27, 2018: Biochemistry
https://www.readbyqxmd.com/read/29464559/monoamine-oxidases
#7
Dale E Edmondson, Claudia Binda
Monoamine oxidases A and B (MAO A and B) are mammalian flavoenzymes bound to the outer mitochondrial membrane. They were discovered almost a century ago and they have been the subject of many biochemical, structural and pharmacological investigations due to their central role in neurotransmitter metabolism. Currently, the treatment of Parkinson's disease involves the use of selective MAO B inhibitors such as rasagiline and safinamide. MAO inhibition was shown to exert a general neuroprotective effect as a result of the reduction of oxidative stress produced by these enzymes, which seems to be relevant also in non-neuronal contexts...
2018: Sub-cellular Biochemistry
https://www.readbyqxmd.com/read/29462786/distinct-properties-underlie-flavin-based-electron-bifurcation-in-a-novel-electron-transfer-flavoprotein-fixab-from-rhodopseudomonas-palustris
#8
H Diessel Duan, Carolyn E Lubner, Monika Tokmina-Lukaszewska, George H Gauss, Brian Bothner, Paul W King, John W Peters, Anne-Frances Miller
A newly-recognized third fundamental mechanism of energy conservation in biology, electron bifurcation, uses free energy from exergonic redox reactions to drive endergonic redox reactions. Flavin-based electron bifurcation furnishes low potential electrons to demanding chemical reactions such as reduction of dinitrogen to ammonia. We employed the heterodimeric flavoenzyme FixAB from the diazotrophic bacterium Rhodopseudomonas palustris to elucidate unique properties that underpin flavin-based electron bifurcation...
February 9, 2018: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/29459772/monoamine-oxidase-dependent-endoplasmic-reticulum-mitochondria-dysfunction-and-mast-cell-degranulation-lead-to-adverse-cardiac-remodeling-in-diabetes
#9
Soni Deshwal, Marleen Forkink, Chou-Hui Hu, Guido Buonincontri, Salvatore Antonucci, Moises Di Sante, Michael P Murphy, Nazareno Paolocci, Daria Mochly-Rosen, Thomas Krieg, Fabio Di Lisa, Nina Kaludercic
Monoamine oxidase (MAO) inhibitors ameliorate contractile function in diabetic animals, but the mechanisms remain unknown. Equally elusive is the interplay between the cardiomyocyte alterations induced by hyperglycemia and the accompanying inflammation. Here we show that exposure of primary cardiomyocytes to high glucose and pro-inflammatory stimuli leads to MAO-dependent increase in reactive oxygen species that causes permeability transition pore opening and mitochondrial dysfunction. These events occur upstream of endoplasmic reticulum (ER) stress and are abolished by the MAO inhibitor pargyline, highlighting the role of these flavoenzymes in the ER/mitochondria cross-talk...
February 19, 2018: Cell Death and Differentiation
https://www.readbyqxmd.com/read/29417050/d-amino-acid-oxidase-plg72-interaction-and-d-serine-modulation
#10
REVIEW
Loredano Pollegioni, Luciano Piubelli, Gianluca Molla, Elena Rosini
pLG72 is a small, primate-specific protein of 153 amino acids. It is the product of the G72 gene, expressed in testis, spinal cord, and brain. The presence of G72 transcript and pLG72 has recurrently been called into question, however G72 mRNA and pLG72 protein levels were higher in blood and brain of patients with schizophrenia than in healthy controls. On the one hand, the SNP rs2391191 corresponding to the R30K substitution in pLG72 was genetically linked to schizophrenia, reduced thickness of the brain cortex in schizophrenia-affected individuals, and altered memory function...
2018: Frontiers in Molecular Biosciences
https://www.readbyqxmd.com/read/29400320/structural-characterization-of-porphyromonas-gingivalis-enoyl-acp-reductase-ii-fabk
#11
Kirk E Hevener, Bernard D Santarsiero, Hyun Lee, Jesse A Jones, Teuta Boci, Michael E Johnson, Shahila Mehboob
Enoyl-acyl carrier protein (ACP) reductase II (FabK) is a critical rate-limiting enzyme in the bacterial type II fatty-acid synthesis (FAS II) pathway. FAS II pathway enzymes are markedly disparate from their mammalian analogs in the FAS I pathway in both structure and mechanism. Enzymes involved in bacterial fatty-acid synthesis represent viable drug targets for Gram-negative pathogens, and historical precedent exists for targeting them in the treatment of diseases of the oral cavity. The Gram-negative organism Porphyromonas gingivalis represents a key causative agent of the costly and highly prevalent disease known as chronic periodontitis, and exclusively expresses FabK as its enoyl reductase enzyme in the FAS-II pathway...
February 1, 2018: Acta Crystallographica. Section F, Structural Biology Communications
https://www.readbyqxmd.com/read/29372418/tyrosine-residues-232-and-401-play-a-critical-role-in-the-binding-of-the-cofactor-fad-of-acyl-coa-oxidase
#12
Senwen Deng, Ping Li, Yiping Wang, Jia Zeng
Acyl-coA oxidase (ACO) is an important flavoenzyme responsible for the first step of peroxisomal fatty acid β-oxidation. In this study, the roles of Tyr232 and Tyr401 in flavin adenine dinucleotide (FAD) binding and enzyme catalysis of ACO were explored using site-directed mutagenesis. For mutant proteins, different levels of activity loss were observed. Wavelength scanning of Y232 and Y401 mutant proteins indicated that there is no FAD binding in Y401S and Y401G mutant ACO. Structure analysis indicated that the phenolic hydroxyl and benzene ring of the side chain could stabilize FAD binding through hydrogen bonds network and hydrophobic pocket formation...
January 25, 2018: Applied Biochemistry and Biotechnology
https://www.readbyqxmd.com/read/29370288/direct-comparison-of-the-four-aldehyde-oxidase-enzymes-present-in-mouse-gives-insight-into-their-substrate-specificities
#13
Gökhan Kücükgöze, Silke Leimkühler
Mammalian aldehyde oxidases (AOXs) are molybdo-flavoenzymes which are present in many tissues in various mammalian species, including humans and rodents. Different species contain a different number of AOX isoforms. In particular, the reasons why mammals other than humans express a multiplicity of tissue-specific AOX enzymes is unknown. In mouse, the isoforms mAOX1, mAOX3, mAOX4 and mAOX2 are present. We previously established a codon-optimized heterologous expression systems for the mAOX1-4 isoforms in Escherichia coli that gives yield to sufficient amounts of active protein for kinetic characterizations and sets the basis in this study for site-directed mutagenesis and structure-function studies...
2018: PloS One
https://www.readbyqxmd.com/read/29359850/bioorthogonal-catalytic-activation-of-pt-and-ru-anticancer-complexes-by-fad-and-flavoproteins
#14
Silvia Alonso-de Castro, Aitziber Lopez Cortajarena, Fernando Lopez-Gallego, Luca Salassa
Recent advances in bioorthogonal catalysis promise to deliver new chemical tools for performing chemoselective transformations in complex biological environments. Herein we report how FAD (flavin adenine dinucleotide), FMN (flavin mononucleotide) and four flavoproteins behave as unconventional photocatalysts capable of converting PtIV and RuII complexes into potentially toxic PtII or RuII-OH2 species. Using electron donors and low doses of visible light, the flavoproteins mini Singlet Oxygen Generator (miniSOG) and NADH oxidase (NOX) catalytically activate PtIV prodrugs with bioorthogonal selectivity...
January 23, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29348404/crystal-structure-of-an-assembly-intermediate-of-respiratory-complex-ii
#15
Pankaj Sharma, Elena Maklashina, Gary Cecchini, T M Iverson
Flavin is covalently attached to the protein scaffold in ~10% of flavoenzymes. However, the mechanism of covalent modification is unclear, due in part to challenges in stabilizing assembly intermediates. Here, we capture the structure of an assembly intermediate of the Escherichia coli Complex II (quinol:fumarate reductase (FrdABCD)). The structure contains the E. coli FrdA subunit bound to covalent FAD and crosslinked with its assembly factor, SdhE. The structure contains two global conformational changes as compared to prior structures of the mature protein: the rotation of a domain within the FrdA subunit, and the destabilization of two large loops of the FrdA subunit, which may create a tunnel to the active site...
January 18, 2018: Nature Communications
https://www.readbyqxmd.com/read/29341594/designing-flavoprotein-gfp-fusion-probes-for-analyte-specific-ratiometric-fluorescence-imaging
#16
Devin A Hudson, Jeffrey L Caplan, Colin Thorpe
The development of genetically encoded fluorescent probes for analyte-specific imaging has revolutionized our understanding of intracellular processes. Current classes of intracellular probes depend on the selection of binding domains that either undergo conformational changes on analyte binding or can be linked to thiol redox chemistry. Here we have designed novel probes by fusing a flavoenzyme, whose fluorescence is quenched on reduction by the analyte of interest, with a GFP domain to allow for rapid and specific ratiometric sensing...
January 17, 2018: Biochemistry
https://www.readbyqxmd.com/read/29337919/functional-impact-of-the-n-terminal-arm-of-proline-dehydrogenase-from-thermus-thermophilus
#17
Mieke M E Huijbers, Ilona van Alen, Jenny W Wu, Arjan Barendregt, Albert J R Heck, Willem J H van Berkel
Proline dehydrogenase (ProDH) is a ubiquitous flavoenzyme that catalyzes the oxidation of proline to Δ¹-pyrroline-5-carboxylate. Thermus thermophilus ProDH (TtProDH) contains in addition to its flavin-binding domain an N -terminal arm, consisting of helices αA, αB, and αC. Here, we report the biochemical properties of the helical arm truncated TtProDH variants ΔA, ΔAB, and ΔABC, produced with maltose-binding protein as solubility tag. All three truncated variants show similar spectral properties as TtProDH, indicative of a conserved flavin-binding pocket...
January 16, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29332274/callitriche-cophocarpa-water-starwort-proteome-under-chromate-stress-evidence-for-induction-of-a-quinone-reductase
#18
Paweł Kaszycki, Aleksandra Dubicka-Lisowska, Joanna Augustynowicz, Barbara Piwowarczyk, Wojciech Wesołowski
Chromate-induced physiological stress in a water-submerged macrophyte Callitriche cophocarpa Sendtn. (water starwort) was tested at the proteomic level. The oxidative stress status of the plant treated with 1 mM Cr(VI) for 3 days revealed stimulation of peroxidases whereas catalase and superoxide dismutase activities were similar to the control levels. Employing two-dimensional electrophoresis, comparative proteomics enabled to detect five differentiating proteins subjected to identification with mass spectrometry followed by an NCBI database search...
March 2018: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/29325897/an-improved-cell-permeable-fluorogenic-substrate-as-the-basis-for-a-highly-sensitive-test-for-nad-p-h-quinone-oxidoreductase-1-nqo1-in-living-cells
#19
Simone Cuff, Ruth D Lewis, Edwin Chinje, Mohammed Jaffar, Richard Knox, Ian Weeks
NAD(P)H:quinone oxidoreductase 1 (NQO1) is a flavoenzyme upregulated in response to oxidative stress and in some cancers. Its upregulation by compounds has been used as an indicator of their potential anti-cancer properties. In this study we have designed, produced and tested a fluorogenic coumarin conjugate which selectively releases highly fluorescent 4-methylumbelliferone (4-MU) in the presence of NQO1. It was found that measuring 4-MU release rapidly and specifically quantitated NQO1 levels in vitro and in live cells...
February 20, 2018: Free Radical Biology & Medicine
https://www.readbyqxmd.com/read/29323892/same-substrate-many-reactions-oxygen-activation-in-flavoenzymes
#20
Elvira Romero, J Rubén Gómez Castellanos, Giovanni Gadda, Marco W Fraaije, Andrea Mattevi
Over time, organisms have evolved strategies to cope with the abundance of dioxygen on Earth. Oxygen-utilizing enzymes tightly control the reactions involving O2 mostly by modulating the reactivity of their cofactors. Flavins are extremely versatile cofactors that are capable of undergoing redox reactions by accepting either one electron or two electrons, alternating between the oxidized and the reduced states. The physical and chemical principles of flavin-based chemistry have been investigated widely. In the following pages we summarize the state of the art on a key area of research in flavin enzymology: the molecular basis for the activation of O2 by flavin-dependent oxidases and monooxygenases...
February 28, 2018: Chemical Reviews
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