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Marek Szczepaniak, Jerzy Moc
We present a comprehensive benchmark computational study which has explored a complete path of the anomerization reaction of bare d-erythrose involving a pair of the low-energy α- and β-furanose anomers, the former of which was observed spectroscopically (Cabezas et al., Chem. Commun. 2013, 49, 10826). We find that the ring opening of the α-anomer yields the most stable open-chain tautomer which step is followed by the rotational interconversion of the open-chain rotamers and final ring closing to form the β-anomer...
November 29, 2016: Journal of Computational Chemistry
W Wu, J Xie, H Zhang
Dietary fibers (DFs), widely used as food additives to replace fat, can benefit metabolic disorders. Soluble and highly fermentable inulin (INU) and insoluble and less fermentable microcrystalline cellulose (MCC) have hypolipidemic or cholesterol-lowering effects, respectively. The current study was aimed at identifying plasma metabolite signatures and metabolic pathways associated with inclusion of DFs with different physiochemical properties, which will lead to a better understanding of functional pathways for DFs to improve metabolic health...
October 18, 2016: Food & Function
Oskar Popik, Monika Pasternak-Suder, Sebastian Baś, Jacek Mlynarski
Herein we report a short and efficient protocol for the synthesis of naturally occurring higher-carbon sugars-sedoheptulose (d-altro-hept-2-ulose) and d-glycero-l-galacto-oct-2-ulose-from readily available sugar aldehydes and dihydroxyacetone (DHA). The key step includes a diastereoselective organocatalytic syn-selective aldol reaction of DHA with d-erythrose and d-xylose, respectively. The methodology presented can be expanded to the synthesis of various higher sugars by means of syn-selective carbon-carbon-bond-forming aldol reactions promoted by primary-based organocatalysts...
December 2015: ChemistryOpen
H Ishizuka, K Tokuoka, T Sasaki, H Taniguchi
An erythrose reductase was obtained from the cells of an Aureobasidium sp. mutant having high erythritol-producing activity. This enzyme was purified 600-fold over the cell-free extract by ammonium sulfate precipitation, ion exchange chromatography, affinity chromatography, and hydrophobic chromatography. It gave a single band on polyacrylamide gel electrophoresis, and had a molecular weight of 37,000 and an isoelectric point of 4.8. This enzyme had maximum reductive activity at 45°C and pH 6.5. The optimum pH of the oxidative reaction was 9...
January 1992: Bioscience, Biotechnology, and Biochemistry
Zhandong Li, Lifeng An, Hao Li, ShaoPeng Wang, You Zhou, Fei Yuan, Lin Li
Nasopharyngeal cancer or nasopharyngeal carcinoma (NPC) is the most common cancer originating in the nasopharynx. The factors that induce nasopharyngeal cancer are still not clear. Additional information about the chemicals or genes related to nasopharyngeal cancer will promote a better understanding of the pathogenesis of this cancer and the factors that induce it. Thus, a computational method NPC-RGCP was proposed in this study to identify the possible relevant chemicals and genes based on the presently known chemicals and genes related to nasopharyngeal cancer...
2016: Scientific Reports
Arpan Modi, Nitish Kumar, Subhash Narayanan
Stevia (Stevia rebaudiana Bertoni) is a medicinal plant having sweet, diterpenoid glycosides known as steviol glycosides which are 200-300 times sweeter than sucrose (0.4 % solution). They are synthesized mainly in the leaves via plastid localized 2-C-methyl-D-erythrose-4-phosphate pathway (MEP pathway). Fifteen genes are involved in the formation of these glycosides. In the present protocol, a method for the quantification of transcripts of these genes is shown. The work involves RNA extraction and cDNA preparation, and therefore, procedures for the confirmation of DNA-free cDNA preparation have also been illustrated...
2016: Methods in Molecular Biology
Aniek D van der Woude, Ruth Perez Gallego, Angie Vreugdenhil, Vinod Puthan Veetil, Tania Chroumpi, Klaas J Hellingwerf
BACKGROUND: Erythritol is a polyol that is used in the food and beverage industry. Due to its non-caloric and non-cariogenic properties, the popularity of this sweetener is increasing. Large scale production of erythritol is currently based on conversion of glucose by selected fungi. In this study, we describe a biotechnological process to produce erythritol from light and CO2, using engineered Synechocystis sp. PCC6803. METHODS: By functionally expressing codon-optimized genes encoding the erythrose-4-phosphate phosphatase TM1254 and the erythrose reductase Gcy1p, or GLD1, this cyanobacterium can directly convert the Calvin cycle intermediate erythrose-4-phosphate into erythritol via a two-step process and release the polyol sugar in the extracellular medium...
2016: Microbial Cell Factories
Juliana Ferreira, Vera C M Duarte, Jennifer Noro, António Gil Fortes, Maria J Alves
Different electron-rich dienophiles were combined with the imine obtained from 2,4-O-benzylidene-d-erythrose and p-anisidine furnishing enantiomerically pure tetrahydroquinolines, by inverse electron-demand [4π + 2π] cycloaddition. The imine was also reacted with 2-substituted electron-rich 1,3-butadienes giving the diastereomeric pure product, resulting from the normal electron demand cycloaddition. The facial selectivity of both processes is proposed on the basis of a 1,4-relationship between the hydroxyl group and the nitrogen atom in the chiral N-(p-methoxyphenyl)imine derivative...
March 14, 2016: Organic & Biomolecular Chemistry
Penelope J Cross, Logan C Heyes, Shiwen Zhang, Ali Reza Nazmi, Emily J Parker
Neisseria meningitidis 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase (NmeDAH7PS) adopts a homotetrameric structure consisting of an extensive and a less extensive interface. Perturbation of the less extensive interface through a single mutation of a salt bridge (Arg126-Glu27) formed at the tetramer interface of all chains resulted in a dimeric DAH7PS in solution, as determined by small angle X-ray scattering, analytical ultracentrifugation and analytical size-exclusion chromatography. The dimeric NmeDAH7PSR126S variant was shown to be catalytically active in the aldol-like condensation reaction between D-erythrose 4-phosphate and phosphoenolpyruvate, and allosterically inhibited by L-phenylalanine to the same extent as the wild-type enzyme...
2016: PloS One
Tatiana Bilova, Elena Lukasheva, Dominic Brauch, Uta Greifenhagen, Gagan Paudel, Elena Tarakhovskaya, Nadezhda Frolova, Juliane Mittasch, Gerd Ulrich Balcke, Alain Tissier, Natalia Osmolovskaya, Thomas Vogt, Ludger A Wessjohann, Claudia Birkemeyer, Carsten Milkowski, Andrej Frolov
Glycation is the reaction of carbonyl compounds (reducing sugars and α-dicarbonyls) with amino acids, lipids, and proteins, yielding early and advanced glycation end products (AGEs). The AGEs can be formed via degradation of early glycation intermediates (glycoxidation) and by interaction with the products of monosaccharide autoxidation (autoxidative glycosylation). Although formation of these potentially deleterious compounds is well characterized in animal systems and thermally treated foods, only a little information about advanced glycation in plants is available...
April 1, 2016: Journal of Biological Chemistry
Martin Kaufmann, Clemens Mügge, Lothar W Kroh
Quantitative (1)H selective saturation transfer NMR spectroscopy ((1)H SST qNMR) was used to fully describe the milieu dependent dynamics of the isomeric system of d-erythrose. Thermodynamic activation parameters are calculated for acidic as well as for basic catalysis combining McConnell's modified Bloch equations for the chemical exchange solved for the constraint of saturating the non-hydrated acyclic isomer, the Eyring equation and Hudson's equation for pH dependent catalysis. A detailed mathematical examination describing the milieu dependent dynamics of sugar isomerisation is provided...
December 11, 2015: Carbohydrate Research
Salvatore Cardamone, Paul L A Popelier
The conformational flexibility of carbohydrates is challenging within the field of computational chemistry. This flexibility causes the electron density to change, which leads to fluctuating atomic multipole moments. Quantum Chemical Topology (QCT) allows for the partitioning of an "atom in a molecule," thus localizing electron density to finite atomic domains, which permits the unambiguous evaluation of atomic multipole moments. By selecting an ensemble of physically realistic conformers of a chemical system, one evaluates the various multipole moments at defined points in configuration space...
December 15, 2015: Journal of Computational Chemistry
Marek Szczepaniak, Jerzy Moc
D-Erythrose is a C4 monosaccharide with a biological and potential astrobiological relevance. We have investigated low-energy structures of d-erythrose and their interconversion in the gas phase with the highest-level calculations up-to-date. We have identified a number of structurally distinct furanose and open-chain isomers and predicted α ↔ α and β ↔ β furanose interconversion pathways involving the O-H rotamers. We have estimated relative Gibbs free energies of the erythrose species based on the CCSD(T)/aug-cc-pVTZ electronic energies and MP2/aug-cc-pVTZ vibrational frequencies...
November 5, 2015: Journal of Physical Chemistry. A
James Pittard, Ji Yang
This chapter describes in detail the genes and proteins of Escherichia coli involved in the biosynthesis and transport of the three aromatic amino acids tyrosine, phenylalanine, and tryptophan. It provides a historical perspective on the elaboration of the various reactions of the common pathway converting erythrose-4-phosphate and phosphoenolpyruvate to chorismate and those of the three terminal pathways converting chorismate to phenylalanine, tyrosine, and tryptophan. The regulation of key reactions by feedback inhibition, attenuation, repression, and activation are also discussed...
September 2008: EcoSal Plus
Alejandra Vargas-Tah, Guillermo Gosset
The aromatic compounds cinnamic and p-hydroxycinnamic acids (pHCAs) are phenylpropanoids having applications as precursors for the synthesis of thermoplastics, flavoring, cosmetic, and health products. These two aromatic acids can be obtained by chemical synthesis or extraction from plant tissues. However, both manufacturing processes have shortcomings, such as the generation of toxic subproducts or a low concentration in plant material. Alternative production methods are being developed to enable the biotechnological production of cinnamic and (pHCAs) by genetically engineering various microbial hosts, including Escherichia coli, Saccharomyces cerevisiae, Pseudomonas putida, and Streptomyces lividans...
2015: Frontiers in Bioengineering and Biotechnology
Jitao Li, Jiangang Yang, Yan Men, Yan Zeng, Yueming Zhu, Caixia Dong, Yuanxia Sun, Yanhe Ma
2-Deoxy-D-ribose 5-phosphate aldolase (DERA) accepts a wide variety of aldehydes and is used in de novo synthesis of 2-deoxysugars, which have important applications in drug manufacturing. However, DERA has low preference for non-phosphorylated substrates. In this study, DERA from Klebsiella pneumoniae (KDERA) was mutated to increase its enzyme activity and substrate tolerance towards non-phosphorylated polyhydroxy aldehyde. Mutant KDERA(K12) (S238D/F200I/ΔY259) showed a 3.15-fold improvement in enzyme activity and a 1...
October 2015: Applied Microbiology and Biotechnology
Nicholas D Gold, Christopher M Gowen, Francois-Xavier Lussier, Sarat C Cautha, Radhakrishnan Mahadevan, Vincent J J Martin
BACKGROUND: L-tyrosine is a common precursor for a wide range of valuable secondary metabolites, including benzylisoquinoline alkaloids (BIAs) and many polyketides. An industrially tractable yeast strain optimized for production of L-tyrosine could serve as a platform for the development of BIA and polyketide cell factories. This study applied a targeted metabolomics approach to evaluate metabolic engineering strategies to increase the availability of intracellular L-tyrosine in the yeast Saccharomyces cerevisiae CEN...
2015: Microbial Cell Factories
Bo Tan, Sucai Dong, Robert L Shepard, Lisa Kays, Kenneth D Roth, Sandaruwan Geeganage, Ming-Shang Kuo, Genshi Zhao
Nicotinamide phosphoribosyltransferase (NAMPT) has been extensively studied due to its essential role in NAD(+) biosynthesis in cancer cells and the prospect of developing novel therapeutics. To understand how NAMPT regulates cellular metabolism, we have shown that the treatment with FK866, a specific NAMPT inhibitor, leads to attenuation of glycolysis by blocking the glyceraldehyde 3-phosphate dehydrogenase step (Tan, B., Young, D. A., Lu, Z. H., Wang, T., Meier, T. I., Shepard, R. L., Roth, K., Zhai, Y., Huss, K...
June 19, 2015: Journal of Biological Chemistry
G R Ghezelbash, I Nahvi, A Malekpour
In order to enhance erythritol production, mutants of Candida magnoliae DSM70638 were generated by ultraviolet and chemical mutagenesis. Erythritol productivity of samples was analyzed by TLC and HPLC with the refractive index detector. One of the mutants named mutant 12-2 gave a 2.4-fold increase in erythritol (20.32 g/L) and a 5.5-fold decrease in glycerol production compared to the wild strain. A sequence-based map of erythrose reductase gene in this mutant showed a replacement of the A321 by G321 that did not cause any amino acid exchange in protein structure...
May 2014: Prikladnaia Biokhimiia i Mikrobiologiia
Masanobu Kojima, Ninako Kimura, Ryuhei Miura
Shikimic acid is a key intermediate in the aromatic amino acid pathway as well as an important starting material for the synthesis of Tamiflu, a potent and selective inhibitor of the neuraminidase enzyme of influenza viruses A and B. Here we report that in oyster mushroom (Pleurotus ostreatus) mycelia cultivated in the dark, stimulation with blue light-emitting diodes induces the accumulation of shikimic acid. An integrated analysis of primary metabolites, gene expression and protein expression suggests that the accumulation of shikimic acid caused by blue light stimulation is due to an increase in 3-deoxy-D-arabinoheptulosonate 7-phosphate synthase (DAHPS, EC2...
2015: Scientific Reports
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