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https://www.readbyqxmd.com/read/27914283/binding-pattern-of-intermediate-udp-4-keto-xylose-to-human-udp-xylose-synthase-synthesis-and-std-nmr-of-model-keto-saccharides
#1
Claudia Puchner, Thomas Eixelsberger, Bernd Nidetzky, Lothar Brecker
Human UDP-xylose synthase (hUXS1) exclusively converts UDP-glucuronic acid to UDP-xylose via intermediate UDP-4-keto-xylose (UDP-Xyl-4O). Synthesis of model compounds like methyl-4-keto-xylose (Me-Xyl-4O) is reported to investigate the binding pattern thereof to hUXS1. Hence, selective oxidation of the desired hydroxyl function required employment of protecting group chemistry. Solution behavior of synthesized keto-saccharides was studied without enzyme via (1)H and (13)C NMR spectroscopy with respect to existent forms in deuterated potassium phosphate buffer...
November 5, 2016: Carbohydrate Research
https://www.readbyqxmd.com/read/27912177/raman-spectroscopy-and-quantum-mechanical-analysis-of-tautomeric-forms-in-cytosine-and-5-methylcytosine-on-gold-surfaces
#2
Dinh Bao Nguyen, Thanh Danh Nguyen, Sangsoo Kim, Sang-Woo Joo
Spectral differences between cytosine (Cyt) and 5-methylcytosine (5MC) were investigated by means of Raman spectroscopy with a combination of density functional theory (DFT) calculations. Surface-enhanced Raman scattering (SERS) revealed discriminating peaks of 5MC from those of Cyt upon adsorption on gold nanoparticles (AuNPs). Among the notable features, the multiple bands between 850 and 700cm(-1) for the ring-breathing modes of 5MC and Cyt could be correlated well with the simulated spectra based on the DFT calculations of the adsorbates on the gold cluster atoms...
November 9, 2016: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/27911816/rapid-emergence-and-mechanisms-of-resistance-by-u87-glioblastoma-cells-to-doxorubicin-in-an-in-vitro-tumor-microfluidic-ecology
#3
Jeonghun Han, Yukyung Jun, So Hyun Kim, Hong-Hoa Hoang, Yeonjoo Jung, Suyeon Kim, Jaesang Kim, Robert H Austin, Sanghyuk Lee, Sungsu Park
In vitro prediction of the probable rapid emergence of resistance to a drug in tumors could act to winnow out potential candidates for further costly development. We have developed a microfluidic device consisting of ∼500 hexagonal microcompartments that provides a complex ecology with wide ranges of drug and nutrient gradients and local populations. This ecology of a fragmented metapopulation induced the drug resistance in stage IV U87 glioblastoma cells to doxorubicin in 7 d. Exome and transcriptome sequencing of the resistant cells identified mutations and differentially expressed genes...
November 22, 2016: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/27906600/role-of-polysaccharide-and-lipid-in-lipopolysaccharide-induced-prion-protein-conversion
#4
Carol L Ladner-Keay, Marcia LeVatte, David S Wishart
Conversion of native cellular prion protein (PrP(c)) from an α-helical structure to a toxic and infectious β-sheet structure (PrP(Sc)) is a critical step in the development of prion disease. There are some indications that the formation of PrP(Sc) is preceded by a β-sheet rich PrP (PrP(β)) form which is non-infectious, but is an intermediate in the formation of infectious PrP(Sc). Furthermore the presence of lipid cofactors is thought to be critical in the formation of both intermediate-PrP(β) and lethal, infectious PrP(Sc)...
December 1, 2016: Prion
https://www.readbyqxmd.com/read/27904086/asymmetric-chlorination-of-%C3%AE-keto-esters-using-diaminomethylenemalononitrile-organocatalyst
#5
Takaaki Sakai, Shin-Ichi Hirashima, Kosuke Nakashima, Chie Maeda, Akihiro Yoshida, Yuji Koseki, Tsuyoshi Miura
Diaminomethylenemalononitrile organocatalysts promote the asymmetric chlorination of simple cyclic β-keto esters such as methyl, ethyl, and benzyl esters of 1-oxo-2,3-dihydro-1H-indene-2-carboxylic acid. This affords the corresponding chiral α-chlorinated carbonyl products in excellent yields with high enantioselectivities.
2016: Chemical & Pharmaceutical Bulletin
https://www.readbyqxmd.com/read/27901143/a-butterfly-motion-of-formic-acid-and-cyclobutanone-in-the-1%C3%A2-%C3%A2-1-hydrogen-bonded-molecular-cluster
#6
Luca Evangelisti, Lorenzo Spada, Weixing Li, Susana Blanco, Juan Carlos López, Alberto Lesarri, Jens-Uwe Grabow, Walther Caminati
Upon supersonic expansion, formic acid and cyclobutanone (CBU) form a molecular cluster in which the two constituent molecules, linked by OHO and CHO hydrogen bonds, undergo a rapid interconversion between two equivalent forms. The tunneling motion takes place through the rupture and reformation of the C-HO hydrogen bond between the carbonyl oxygen of HCOOH and one of the two hydrogen atoms of the methylenic group adjacent to the cyclobutanone keto group. From the microwave spectra, tunneling energy splittings (ΔE01) have been determined for the parent (1122...
November 30, 2016: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/27899792/nature-nurtures-the-design-of-new-semi-synthetic-macrolide-antibiotics
#7
REVIEW
Prabhavathi Fernandes, Evan Martens, David Pereira
Erythromycin and its analogs are used to treat respiratory tract and other infections. The broad use of these antibiotics during the last 5 decades has led to resistance that can range from 20% to over 70% in certain parts of the world. Efforts to find macrolides that were active against macrolide-resistant strains led to the development of erythromycin analogs with alkyl-aryl side chains that mimicked the sugar side chain of 16-membered macrolides, such as tylosin. Further modifications were made to improve the potency of these molecules by removal of the cladinose sugar to obtain a smaller molecule, a modification that was learned from an older macrolide, pikromycin...
November 30, 2016: Journal of Antibiotics
https://www.readbyqxmd.com/read/27898046/pro-and-antioxidant-activity-of-three-selected-flavan-type-flavonoids-catechin-eriodictyol-and-taxifolin
#8
Vladimir Chobot, Franz Hadacek, Gert Bachmann, Wolfram Weckwerth, Lenka Kubicova
The flavanol (±)-catechin shows an OH group but no 4-keto group on ring C (C3), and no conjugation between ring A and B. The related flavanone (+)-eriodictyol has a keto group on C4 but no 3-OH group on ring C. (+)-Taxifolin, another flavanone, has an OH on C3 and a keto group on C4 of the C ring. Deoxyribose degradation assay systems, with hydrogen peroxide and ascorbic acid either added or omitted, were performed in variants in which Fe(III) was added in a complex with ethylenediaminetetraacetic acid (EDTA)...
November 26, 2016: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/27897077/understanding-the-conformational-flexibility-and-electrostatic-properties-of-curcumin-in-the-active-site-of-rhache-via-molecular-docking-molecular-dynamics-and-charge-density-analysis
#9
Saravanan Kandasamy, Kalaiarasi Chinnasamy, Kumaradhas Poomani
Acetylcholinesterase (AChE) is an important enzyme responsible for Alzheimer disease (AD), as per report, keto-enol form of curcumin inhibits this enzyme. The present study aims to understand the binding mechanism of keto-enol curcumin with the recombinant human Acetylcholinesterase (rhAChE) from its conformational flexibility, intermolecular interactions, charge density distribution and the electrostatic properties at the active site of rhAChE. To accomplish this, a molecular docking analysis of curcumin with the rhAChE was performed, which gives the structure and conformation of curcumin in the active site of rhAChE...
November 29, 2016: Journal of Biomolecular Structure & Dynamics
https://www.readbyqxmd.com/read/27894872/synthesis-screening-and-docking-analysis-of-hispolon-analogs-as-potential-antitubercular-agents
#10
Neduri V Balaji, Bollikolla Hari Babu, Gottumukkala V Subbaraju, Kurre Purna Nagasree, Muthyala Murali Krishna Kumar
A series of 20 hispolons/dihydrohispolons were synthesized and characterized by spectral data. These compounds were subjected to in vitro antitubercular activity screening against Mycobacterium tuberculosis (H37Rv) strain. The synthesized compounds showed varied antitubercular activity ranging from 100 to 1.6μg/mL. Among the screened compounds, four compounds (H1, H2, H3 and H15) have shown moderate activity with MIC 25μg/mL. Potent activities were observed for the dihydrohispolon derivative H14 (MIC 1.6μg/mL) followed by H13 (6...
November 18, 2016: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/27894813/salicylic-acid-retention-impairs-aspirin-reactivity-in-type-2-diabetes
#11
Haowen Zhang, Hao Xie, Xiao Zheng, Yingying Chai, Zhiyuan Tang, Hanyu Chen, Feiyan Li, Heier Christoph, Jiandong Chen, Weixin Sun, Hui Ye, Shiguang Wang, Haiping Hao, Xiaohu Chen
High on-aspirin platelet reactivity (HAPR) has been associated with compromised aspirin efficacy in patients with diabetes suffering from acute cardiovascular events, but the key mechanisms remain elusive. The objective of this study was to uncover the potential link between pathogenic accumulation of salicylic acid (SA), the major metabolite of aspirin, and HAPR in diabetic state. Aspirin failed to inhibit platelet CD62P expression and thromboxane (TX) B2/6-keto-prostaglandin(PG)F1α ratio in a type 2 diabetes mellitus (T2DM) mice model, particularly in the female, which were unanimously accompanied by significantly higher plasma SA concentrations...
November 25, 2016: European Journal of Pharmacology
https://www.readbyqxmd.com/read/27889763/inhibition-of-the-jak2-stat3-sosc1-signaling-pathway-improves-secretion-function-of-vascular-endothelial-cells-in-a-rat-model-of-pregnancy-induced-hypertension
#12
Jian-Ying Luo, Dan Fu, Ya-Qin Wu, Ying Gao
BACKGROUND/AIMS: The present study aimed to investigate the effects of the JAK2/STAT3/SOSC1 signaling pathway on the secretion function of vascular endothelial cells (VECs) in a rat model of pregnancy-induced hypertension (PIH). METHODS: A PIH rat model was established. Forty-eight pregnant Sprague-Dawley female rats were selected and assigned into four groups: the normal group (normal non-pregnant rats), the non-PIH group (pregnant rats without PIH), the PIH group (pregnant rats with PIH) and the AG490 group (pregnant rats with PIH treated with AG490)...
November 25, 2016: Cellular Physiology and Biochemistry
https://www.readbyqxmd.com/read/27888021/heightened-aggressive-behavior-in-mice-deficient-in-aldo-keto-reductase-1a-akr1a
#13
Takujiro Homma, Ryusuke Akihara, Satoshi Okano, Mototada Shichiri, Yasukazu Yoshida, Ken-Ichi Yamada, Satoshi Miyata, Osamu Nakajima, Junichi Fujii
Aldehyde reductase (Akr1a) is involved in the synthesis of ascorbic acid (AsA) which may play a role in social behavior. In the current study, we performed analyses on Akr1a-deficient (Akr1a(-/-)) mice that synthesize about 10% as much AsA as wild-type mice from the viewpoint of intermale aggression. The use of the resident-intruder test revealed that the Akr1a(-/-) mice exhibited more aggressive phenotypes than wild-type control mice. Unexpectedly, however, the oral administration of additional AsA failed to reduce the aggressive behavior of Akr1a(-/-) mice, suggesting that the heightened aggression was independent of AsA biosynthesis...
November 22, 2016: Behavioural Brain Research
https://www.readbyqxmd.com/read/27886607/preparation-of-the-tri-arabino-di-mycolate-fragment-of-mycobacterial-arabinogalactan-from-defined-synthetic-mycolic-acids
#14
Mohsin O Mohammed, Juma'a R Al Dulayymi, Mark S Baird
An efficient synthetic approach to tri-arabino di-mycolates, using structurally defined synthetic α-, keto and methoxy mycolic acids is described.
November 10, 2016: Carbohydrate Research
https://www.readbyqxmd.com/read/27885628/bcaa-metabolism-and-nh3-homeostasis
#15
M E Conway, S M Hutson
The branched chain amino acids (BCAA) are essential amino acids required not only for growth and development, but also as nutrient signals and as nitrogen donors to neurotransmitter synthesis and glutamate/glutamine cycling. Transamination and oxidative decarboxylation of the BCAAs are catalysed by the branched-chain aminotransferase proteins (BCATm, mitochondrial and BCATc, cytosolic) and the branched-chain α-keto acid dehydrogenase enzyme complex (BCKDC), respectively. These proteins show tissue, cell compartmentation, and protein-protein interactions, which call for substrate shuttling or channelling and nitrogen transfer for oxidation to occur...
2016: Advances in Neurobiology
https://www.readbyqxmd.com/read/27885368/structural-characterization-of-eash-aspergillus-japonicus-an-oxidase-involved-in-cycloclavine-biosynthesis
#16
Dorota Jakubczyk, Lorenzo Caputi, Clare E M Stevenson, David M Lawson, Sarah E O'Connor
Aj_EasH is a non-heme iron- and α-keto-glutarate-dependent oxidase that is responsible for an unusual cyclopropyl ring formation in the biosynthesis of the fungal ergot alkaloid cycloclavine. The three dimensional structure of Aj_EasH (2.2 Å resolution) reported here provides insight into the mechanism of this unusual and complex reaction.
November 25, 2016: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/27885053/11%C3%AE-hydroxysteroid-dehydrogenase-1-deficiency-alters-the-gut-microbiome-response-to-western-diet
#17
Jethro S Johnson, Monica N Opiyo, Marian Thomson, Karim Gharbi, Jonathan R Seckl, Andreas Heger, Karen Chapman
The enzyme 11β-hydroxysteroid dehydrogenase (11β-HSD) interconverts active glucocorticoids and their intrinsically inert 11-keto forms. The type 1 isozyme, 11β-HSD1, predominantly reactivates glucocorticoids in vivo and can also metabolise bile acids. 11β-HSD1-deficient mice show altered inflammatory responses and are protected against the adverse metabolic effects of a high fat diet. However, the influence of 11β-HSD1 on the composition of the gut microbiome has not previously been investigated. We used high-throughput 16S rDNA amplicon sequencing to characterize the gut microbiome of 11β-HSD1-deficient and C57Bl/6 control mice, fed either a standard chow diet or a cholesterol and fat-enriched 'western' diet...
November 24, 2016: Journal of Endocrinology
https://www.readbyqxmd.com/read/27883019/17-oxo-dha-displays-additive-anti-inflammatory-effects-with-fluticasone-propionate-and-inhibits-the-nlrp3-inflammasome
#18
Chiara Cipollina, Serena Di Vincenzo, Liboria Siena, Caterina Di Sano, Mark Gjomarkaj, Elisabetta Pace
Chronic obstructive pulmonary disease (COPD) is characterized by reduced lung function associated with increased local and systemic inflammatory markers, such as TNFα and IL-1β. Glucocorticoids are used to treat this chronic disease, however their efficacy is low and new drugs are very much required. 17-oxo-DHA is a cyclooxygenase-2-dependent, electrophilic, α,β-unsaturated keto-derivative of docosahexaenoic acid with anti-inflammatory properties. We evaluated the action of 17-oxo-DHA alone or in combination with the steroid fluticasone propionate (FP) in peripheral blood mononuclear cells (PBMCs) from COPD patients and healthy individuals exposed to lipopolysaccharide...
November 24, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27872963/microbial-production-of-amino-acid-related-compounds
#19
Volker F Wendisch
Corynebacterium glutamicum is the workhorse of the production of proteinogenic amino acids used in food and feed biotechnology. After more than 50 years of safe amino acid production, C. glutamicum has recently also been engineered for the production of amino acid-derived compounds, which find various applications, e.g., as synthons for the chemical industry in several markets including the polymer market. The amino acid-derived compounds such as non-proteinogenic ω-amino acids, α,ω-diamines, and cyclic or hydroxylated amino acids have similar carbon backbones and functional groups as their amino acid precursors...
November 22, 2016: Advances in Biochemical Engineering/biotechnology
https://www.readbyqxmd.com/read/27871908/acetylated-deoxycholic-dca-and-cholic-ca-acids-are-potent-ligands-of-pregnane-x-pxr-receptor
#20
Alejandro Carazo, Lucie Hyrsova, Jan Dusek, Hana Chodounska, Alzbeta Horvatova, Karel Berka, Vaclav Bazgier, Hongying Gan-Schreier, Waleé Chamulitrat, Eva Kudova, Petr Pavek
The Pregnane X (PXR), Vitamin D (VDR) and Farnesoid X (FXR) nuclear receptors have been shown to be receptors of bile acids controlling their detoxification or synthesis. Chenodeoxycholic (CDCA) and lithocholic (LCA) acids are ligands of FXR and VDR, respectively, whereas 3-keto and acetylated derivates of LCA have been described as ligands for all three receptors. In this study, we hypothesized that oxidation or acetylation at position 3, 7 and 12 of bile acids DCA (deoxycholic acid), LCA, CA (cholic acid), and CDCA by detoxification enzymes or microbiome may have an effect on the interactions with bile acid nuclear receptors...
November 18, 2016: Toxicology Letters
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