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Flavoenzyme

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https://www.readbyqxmd.com/read/29221464/molecular-and-functional-characterization-of-ferredoxin-nadp-h-oxidoreductase-from-gracilaria-chilensis-and-its-complex-with-ferredoxin
#1
María Alejandra Vorphal, Carola Bruna, Traudy Wandersleben, Jorge Dagnino-Leone, Francisco Lobos-González, Elena Uribe, José Martínez-Oyanedel, Marta Bunster
BACKGROUD: Ferredoxin NADP(H) oxidoreductases (EC 1.18.1.2) (FNR) are flavoenzymes present in photosynthetic organisms; they are relevant for the production of reduced donors to redox reactions, i.e. in photosynthesis, the reduction of NADP+ to NADPH using the electrons provided by Ferredoxin (Fd), a small FeS soluble protein acceptor of electrons from PSI in chloroplasts. In rhodophyta no information about this system has been reported, this work is a contribution to the molecular and functional characterization of FNR from Gracilaria chilensis, also providing a structural analysis of the complex FNR/Fd...
December 8, 2017: Biological Research
https://www.readbyqxmd.com/read/29168057/-1-h-15-n-and-13-c-backbone-resonance-assignments-of-pentaerythritol-tetranitrate-reductase-from-enterobacter-cloacae-pb2
#2
Andreea I Iorgu, Nicola J Baxter, Matthew J Cliff, Jonathan P Waltho, Sam Hay, Nigel S Scrutton
Pentaerythritol tetranitrate reductase (PETNR) is a flavoenzyme possessing a broad substrate specificity and is a member of the Old Yellow Enzyme family of oxidoreductases. As well as having high potential as an industrial biocatalyst, PETNR is an excellent model system for studying hydrogen transfer reactions. Mechanistic studies performed with PETNR using stopped-flow methods have shown that tunneling contributes towards hydride transfer from the NAD(P)H coenzyme to the flavin mononucleotide (FMN) cofactor and fast protein dynamics have been inferred to facilitate this catalytic step...
November 22, 2017: Biomolecular NMR Assignments
https://www.readbyqxmd.com/read/29133410/unprecedented-pathway-of-reducing-equivalents-in-a-diflavin-linked-disulfide-oxidoreductase
#3
Rubén M Buey, Juan B Arellano, Luis López-Maury, Sergio Galindo-Trigo, Adrián Velázquez-Campoy, José L Revuelta, José M de Pereda, Francisco J Florencio, Peter Schürmann, Bob B Buchanan, Monica Balsera
Flavoproteins participate in a wide variety of physiologically relevant processes that typically involve redox reactions. Within this protein superfamily, there exists a group that is able to transfer reducing equivalents from FAD to a redox-active disulfide bridge, which further reduces disulfide bridges in target proteins to regulate their structure and function. We have identified a previously undescribed type of flavin enzyme that is exclusive to oxygenic photosynthetic prokaryotes and that is based on the primary sequence that had been assigned as an NADPH-dependent thioredoxin reductase (NTR)...
November 13, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29124817/why-the-flavin-dinucleotide-cofactor-needs-to-be-covalently-linked-to-complex-ii-of-the-electron-transport-chain-for-conversion-of-fadh2-to-fad
#4
Daniel F A R Dourado, Marcel Swart, Alexandra Teresa Pires Carvalho
A covalently bound flavin cofactor is predominant in the succinate:ubiquinone oxidoreductase (SQR, Complex II), an essential component of the aerobic electron transport, and in the menaquinol:fumarate oxidoreductase (QFR), the anaerobic counterpart, albeit being only present in ~10% of the known flavoenzymes. Here, we investigated the role of this 8α-N(3)-histidyl linkage between the flavin dinucleotide (FAD) cofactor and the respiratory Complex II. After parameterization with DFT we performed classical molecular dynamics simulations and quantum mechanics calculations of Complex II:FAD and Complex II:FADH2, covalently bound and unbound to His-A57...
November 10, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29116682/flavin-n5-covalent-intermediate-in-the-non-redox-dehalogenation-reaction-catalyzed-by-an-atypical-flavoenzyme
#5
Yumin Dai, Karina Kizjakina, Ashley C Campbell, David A Korasick, John J Tanner, Pablo Sobrado
The flavin-dependent enzyme 2-haloacrylate hydratase (2-HAH) catalyzes the conversion of 2-chloroacrylate, a major component in the manufacture of acrylic polymers, to pyruvate. The enzyme from has been expressed in Escherichia coli, purified, and characterized. 2-HAH is monomeric in solution and contains a non-covalent, yet tightly bound, FAD. Although the reaction catalyzed is redox neutral, 2-HAH is active only in the reduced state. A covalent flavin-substrate intermediate, consistent with the flavin-acrylate iminium ion, was trapped with cyanoborohydride and characterized by mass spectrometry...
November 8, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/29064673/intramembrane-thiol-oxidoreductases-evolutionary-convergence-and-structural-controversy
#6
Shuang Li, Guomin Shen, Weikai Li
During oxidative protein folding, disulfide bond formation is catalyzed by thiol oxidoreductases. Through dedicated relay pathways, the disulfide is generated in donor enzymes, passed to carrier enzymes, and subsequently delivered to target proteins. The eukaryotic disulfide donors are flavoenzymes, Ero1 in the endoplasmic reticulum and Erv1 in mitochondria. In prokaryotes, disulfide generation is coupled to quinone reduction, catalyzed by intramembrane donor enzymes, DsbB and VKOR. To catalyze de novo disulfide formation, these different disulfide donors show striking structural convergence at several levels...
November 7, 2017: Biochemistry
https://www.readbyqxmd.com/read/29048885/correction-to-identification-of-the-tyroh-%C3%A2-radical-cation-in-the-flavoenzyme-trmfo
#7
Lipsa Nag, Pierre Sournia, Hannu Myllykallio, Ursula Liebl, Marten H Vos
No abstract text is available yet for this article.
November 1, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28985219/the-ins-and-outs-of-vanillyl-alcohol-oxidase-identification-of-ligand-migration-paths
#8
COMPARATIVE STUDY
Gudrun Gygli, Maria Fátima Lucas, Victor Guallar, Willem J H van Berkel
Vanillyl alcohol oxidase (VAO) is a homo-octameric flavoenzyme belonging to the VAO/PCMH family. Each VAO subunit consists of two domains, the FAD-binding and the cap domain. VAO catalyses, among other reactions, the two-step conversion of p-creosol (2-methoxy-4-methylphenol) to vanillin (4-hydroxy-3-methoxybenzaldehyde). To elucidate how different ligands enter and exit the secluded active site, Monte Carlo based simulations have been performed. One entry/exit path via the subunit interface and two additional exit paths have been identified for phenolic ligands, all leading to the si side of FAD...
October 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28970893/characterization-of-the-flavoenzyme-xiak-as-an-n-hydroxylase-and-implications-in-indolosesquiterpene-diversification
#9
Qingbo Zhang, Huixian Li, Lu Yu, Yu Sun, Yiguang Zhu, Hanning Zhu, Liping Zhang, Shu-Ming Li, Yuemao Shen, Changlin Tian, Ang Li, Hung-Wen Liu, Changsheng Zhang
Flavoenzymes are ubiquitous in biological systems and catalyze a diverse range of chemical transformations. The flavoenzyme XiaK from the biosynthetic pathway of the indolosesquiterpene xiamycin A is demonstrated to mediate the in vivo biotransformation of xiamycin A into multiple products, including a chlorinated adduct as well as dimers characterized by C-N and N-N linkages that are hypothesized to form via radical-based mechanisms. Isolation and characterization of XiaK in vitro shows that it acts as a flavin-dependent N-hydroxylase that catalyzes the hydroxylation of xiamycin A at the carbazole nitrogen to form N-hydroxyxiamycin, a product which was overlooked in earlier in vivo experiments because its chemical and chromatographic properties are similar to those of oxiamycin...
July 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/28947826/neferine-ameliorates-cardiomyoblast-apoptosis-induced-by-doxorubicin-possible-role-in-modulating-nadph-oxidase-ros-mediated-nf%C3%AE%C2%BAb-redox-signaling-cascade
#10
Lohanathan Bharathi Priya, Rathinasamy Baskaran, Chih-Yang Huang, Viswanadha Vijaya Padma
Doxorubicin (DOX) mediated cardiomyopathy is a major challenge in cancer chemotherapy. Redox-cycling of doxorubicin by flavoenzymes makes the heart more vulnerable to oxidative stress leading to cardiac dysfunction. The present study evaluates the role of neferine, a bisbenzylisoquinoline alkaloid, in curbing the molecular consequences of DOX-exposure in H9c2 cardiomyoblasts. Neferine pre-treatment increased cell viability upon DOX-exposure. DOX activates NADPH oxidase subunits, (p22phox, p47phox, gp91phox) as the primary event followed by peak in [Ca(2+)]i accumulation by 2 h, ROS by 3 h and activated ERK1/2 and p38 MAPKinases, time dependently along with the activation and translocation of NFκB and up-regulated COX2 and TNF-α expressions...
September 25, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28939686/species-specific-involvement-of-aldehyde-oxidase-and-xanthine-oxidase-in-the-metabolism-of-the-pyrimidine-containing-mglu5-negative-allosteric-modulator-vu0424238-auglurant
#11
Rachel D Crouch, Anna L Blobaum, Andrew S Felts, P Jeffrey Conn, Craig W Lindsley
Aldehyde oxidase (AO) and xanthine oxidase (XO) are molybdo-flavoenzymes that catalyze oxidation of aromatic azaheterocycles. Differences in AO activity have been reported among various species including rat, human, and monkey. Herein we report a species difference in the enzymes responsible for metabolism of mGlu5 NAM VU0424238 (VU238, auglurant). Hepatic S9 incubations with AO and XO specific inhibitors hydralazine and allopurinol indicated that rat and cynomolgus monkey both oxidized VU238 to the 6-oxopyrimidine metabolite M1 via an AO-mediated pathway, whereas secondary oxidation to the 2,6-dioxopyrimidine metabolite M2 was mediated predominantly by AO in monkey and XO in rat...
September 22, 2017: Drug Metabolism and Disposition: the Biological Fate of Chemicals
https://www.readbyqxmd.com/read/28919416/identification-of-eukaryotic-udp-galactopyranose-mutase-inhibitors-using-the-thermofad-assay
#12
Julia S Martín Del Campo, Meital Eckshtain-Levi, Pablo Sobrado
Aspergillus fumigatus is a human pathogen responsible for deadly infections in immune-compromised patients. A potential strategy for treating A. fumigatus infections is by targeting the biosynthesis of cell wall components, such as galactofuranase, which is absent in humans. Galactofuranose biosynthesis is initiated by the flavoenzyme UDP-galactopyranose mutase (UGM), which converts UDP-galactopyranose (UDP-Galp) to UDP-galactofuranose (UDP-Galf). UGM requires the reduced form of the flavin for activity, which is obtained by reacting with NADPH...
November 4, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28890968/ultrafast-flavin-photoreduction-in-an-oxidized-animal-6-4-photolyase-through-an-unconventional-tryptophan-tetrad
#13
Ryan Martin, Fabien Lacombat, Agathe Espagne, Nadia Dozova, Pascal Plaza, Junpei Yamamoto, Pavel Müller, Klaus Brettel, Aurélien de la Lande
Photolyases are flavoenzymes repairing UV-induced lesions in DNA, which may be activated by a photoreduction of their FAD cofactor. In most photolyases, this photoreduction proceeds by electron transfer along a chain of three tryptophan (Trp) residues, connecting the flavin to the protein surface. Much less studied, animal (6-4) photolyases (repairing pyrimidine-pyrimidone (6-4) photoproducts) are particularly interesting as they were recently shown to have a longer electron transfer chain, counting four Trp residues...
September 20, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28802828/photolyase-dynamics-and-electron-transfer-mechanisms-of-dna-repair
#14
REVIEW
Meng Zhang, Lijuan Wang, Dongping Zhong
Photolyase, a flavoenzyme containing flavin adenine dinucleotide (FAD) molecule as a catalytic cofactor, repairs UV-induced DNA damage of cyclobutane pyrimidine dimer (CPD) and pyrimidine-pyrimidone (6-4) photoproduct using blue light. The FAD cofactor, conserved in the whole protein superfamily of photolyase/cryptochromes, adopts a unique folded configuration at the active site that plays a critical functional role in DNA repair. Here, we review our comprehensive characterization of the dynamics of flavin cofactor and its repair photocycles by different classes of photolyases on the most fundamental level...
October 15, 2017: Archives of Biochemistry and Biophysics
https://www.readbyqxmd.com/read/28796306/enzyme-activation-with-a-synthetic-catalytic-co-enzyme-intermediate-nucleotide-methylation-by-flavoenzymes
#15
Charles Bou-Nader, David Cornu, Vincent Guerineau, Thibault Fogeron, Marc Fontecave, Djemel Hamdane
To facilitate production of functional enzymes and to study their mechanisms, especially in the complex cases of coenzyme-dependent systems, activation of an inactive apoenzyme preparation with a catalytically competent coenzyme intermediate is an attractive strategy. This is illustrated with the simple chemical synthesis of a flavin-methylene iminium compound previously proposed as a key intermediate in the catalytic cycle of several important flavoenzymes involved in nucleic acid metabolism. Reconstitution of both flavin-dependent RNA methyltransferase and thymidylate synthase apoproteins with this synthetic compound led to active enzymes for the C5-uracil methylation within their respective transfer RNA and dUMP substrate...
October 2, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28782586/breaking-the-mirror-l-amino-acid-deaminase-a-novel-stereoselective-biocatalyst
#16
REVIEW
Gianluca Molla, Roberta Melis, Loredano Pollegioni
Enantiomerically pure amino acids are of increasing interest for the fine chemical, agrochemicals and pharmaceutical industries. During past years l-amino acids have been produced from deracemization of dl-solution employing the stereoselective flavoenzyme d-amino acid oxidase. On the other hand, the isolation of corresponding d-isomer was hampered by the scarce availability of a suitable l-amino acid oxidase activity. On this side, l-amino acid deaminase (LAAD), only present in the Proteus bacteria, represents a suitable alternative...
November 1, 2017: Biotechnology Advances
https://www.readbyqxmd.com/read/28750088/a-single-nucleotide-polymorphism-causes-enhanced-radical-oxygen-species-production-by-human-aldehyde-oxidase
#17
Alessandro Foti, Frank Dorendorf, Silke Leimkühler
Aldehyde oxidases (AOXs) are molybdo-flavoenzymes characterized by broad substrate specificity, oxidizing aromatic/aliphatic aldehydes into the corresponding carboxylic acids and hydroxylating various heteroaromatic rings. The enzymes use oxygen as the terminal electron acceptor and produce reduced oxygen species during turnover. The physiological function of mammalian AOX isoenzymes is still unclear, however, human AOX (hAOX1) is an emerging enzyme in phase-I drug metabolism. Indeed, the number of xenobiotics acting as hAOX1 substrates is increasing...
2017: PloS One
https://www.readbyqxmd.com/read/28745052/identification-of-the-tyroh-%C3%A2-radical-cation-in-the-flavoenzyme-trmfo
#18
Lipsa Nag, Pierre Sournia, Hannu Myllykallio, Ursula Liebl, Marten H Vos
Tyrosine (TyrOH) and tryptophan radicals play important roles as intermediates in biochemical charge-transfer reactions. Tryptophanyl radicals have been observed both in their protonated cation form and in their unprotonated neutral form, but to date, tyrosyl radicals have only been observed in their unprotonated form. With a genetically modified form of the flavoenzyme TrmFO as a suitable model system and using ultrafast fluorescence and absorption spectroscopy, we characterize its protonated precursor TyrOH(•+), and we show this species to have a distinct visible absorption band and a transition moment that we suggest to lie close to the phenol symmetry axis...
August 23, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28712849/structure-function-and-mechanism-of-proline-utilization-a-puta
#19
REVIEW
Li-Kai Liu, Donald F Becker, John J Tanner
Proline has important roles in multiple biological processes such as cellular bioenergetics, cell growth, oxidative and osmotic stress response, protein folding and stability, and redox signaling. The proline catabolic pathway, which forms glutamate, enables organisms to utilize proline as a carbon, nitrogen, and energy source. FAD-dependent proline dehydrogenase (PRODH) and NAD(+)-dependent glutamate semialdehyde dehydrogenase (GSALDH) convert proline to glutamate in two sequential oxidative steps. Depletion of PRODH and GSALDH in humans leads to hyperprolinemia, which is associated with mental disorders such as schizophrenia...
October 15, 2017: Archives of Biochemistry and Biophysics
https://www.readbyqxmd.com/read/28694766/flavoenzyme-mediated-reduction-reactions-and-antitumor-activity-of-nitrogen-containing-tetracyclic-ortho-quinone-compounds-and-their-nitrated-derivatives
#20
Milda Peciukaityte-Alksne, Jonas Šarlauskas, Lina Miseviciene, Audrone Maroziene, Narimantas Cenas, Kastis Krikštopaitis, Zita Staniulyte, Žilvinas Anusevicius
Nitrogen-based tetracyclic ortho-quinones (naphtho[1'2':4.5]imidazo[1,2-a]pyridine-5,6-diones, NPDOs) and their nitro-substituted derivatives (nitro-(P)NPDOs) were obtained by condensation of substituted 2,3-dichloro-1,4-naphthoquinones with 2-amino-pyridine and -pyrimidine and nitration at an elevated temperature. The structural features of the compounds as well as their global and regional electrophilic potency were characterized by means of DFT computation. The compounds were highly reactive substrates of single- and two-electron (hydride) - transferring P-450R (CPR; EC 1...
2017: EXCLI Journal
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