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https://www.readbyqxmd.com/read/27915383/a-covalent-antagonist-for-the-human-adenosine-a2a-receptor
#1
Xue Yang, Guo Dong, Thomas J M Michiels, Eelke B Lenselink, Laura Heitman, Julien Louvel, Ad P IJzerman
The structure of the human A2A adenosine receptor has been elucidated by X-ray crystallography with a high affinity non-xanthine antagonist, ZM241385, bound to it. This template molecule served as a starting point for the incorporation of reactive moieties that cause the ligand to covalently bind to the receptor. In particular, we incorporated a fluorosulfonyl moiety onto ZM241385, which yielded LUF7445 (4-((3-((7-amino-2-(furan-2-yl)-[1, 2, 4]triazolo[1,5-a][1, 3, 5]triazin-5-yl)amino)propyl)carbamoyl)benzene sulfonyl fluoride)...
December 3, 2016: Purinergic Signalling
https://www.readbyqxmd.com/read/27915377/crystal-structure-and-characterization-of-esterase-est25-mutants-reveal-improved-enantioselectivity-toward-s-ketoprofen-ethyl-ester
#2
Jinyeong Kim, Seung-Hyeon Seok, Eunsoo Hong, Tae Hyeon Yoo, Min-Duk Seo, Yeonwoo Ryu
Esterases comprise a group of enzymes that catalyze the cleavage and synthesis of ester bonds. They are important in biotechnological applications owing to their enantioselectivity, regioselectivity, broad substrate specificity, and the fact that they do not require cofactors. In a previous study, we isolated the esterase Est25 from a metagenomic library. Est25 showed catalytic activity toward the (R,S)-ketoprofen ethyl ester but had low enantioselectivity toward the (S)-ketoprofen ethyl ester. Because (S)-ketoprofen has stronger anti-inflammatory effects and fewer side effects than (R)-ketoprofen, enantioselectivity of this esterase is important...
December 3, 2016: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/27915294/insightful-directed-evolution-of-escherichia-coli-quorum-sensing-promoter-region-of-the-lsracdbfg-operon-a-tool-for-synthetic-biology-systems-and-protein-expression
#3
Pricila Hauk, Kristina Stephens, Ryan Mckay, Chelsea Ryan Virgile, Hana Ueda, Marc Ostermeier, Kyoung-Seok Ryu, Herman O Sintim, William E Bentley
Quorum sensing (QS) regulates many natural phenotypes (e.q. virulence, biofilm formation, antibiotic resistance), and its components, when incorporated into synthetic genetic circuits, enable user-directed phenotypes. We created a library of Escherichia coli lsr operon promoters using error-prone PCR (ePCR) and selected for promoters that provided E. coli with higher tetracycline resistance over the native promoter when placed upstream of the tet(C) gene. Among the fourteen clones identified, we found several mutations in the binding sites of QS repressor, LsrR...
December 1, 2016: Nucleic Acids Research
https://www.readbyqxmd.com/read/27915232/quantitative-profiling-of-selective-sox-pou-pairing-on-hundreds-of-sequences-in-parallel-by-coop-seq
#4
Yiming K Chang, Yogesh Srivastava, Caizhen Hu, Adam Joyce, Xiaoxiao Yang, Zheng Zuo, James J Havranek, Gary D Stormo, Ralf Jauch
Cooperative binding of transcription factors is known to be important in the regulation of gene expression programs conferring cellular identities. However, current methods to measure cooperativity parameters have been laborious and therefore limited to studying only a few sequence variants at a time. We developed Coop-seq (cooperativity by sequencing) that is capable of efficiently and accurately determining the cooperativity parameters for hundreds of different DNA sequences in a single experiment. We apply Coop-seq to 12 dimer pairs from the Sox and POU families of transcription factors using 324 unique sequences with changed half-site orientation, altered spacing and discrete randomization within the binding elements...
December 2, 2016: Nucleic Acids Research
https://www.readbyqxmd.com/read/27915168/interactions-of-long-chain-homologues-of-colchicine-with-tubulin
#5
Ana Marzo-Mas, Pascale Barbier, Gilles Breuzard, Diane Allegro, Eva Falomir, Juan Murga, Miguel Carda, Vincent Peyrot, J Alberto Marco
Several colchicine analogues in which the N-acetyl residue has been replaced by aliphatic, straight-chain acyl moieties, have been synthesized. These compounds show high cytotoxic activity at the nanomolar level against the tumoral cell lines HT-29, MCF-7 and A549. Some of them exhibit activities in the picomolar range against the HT-29 line and are thus two to three orders of magnitude more cytotoxic than colchicine. In this specific cell line, the activities were found to be closely related to the length of the acyl carbon chain, an increase in the latter giving rise to an increase in the cytotoxicity with a maximum in the range of 10-12 carbon atoms, followed by a decrease in activity with still longer chains...
November 23, 2016: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/27915093/discoidin-domain-receptor-1-kinase-activity-is-required-for-regulating-collagen-iv-synthesis
#6
Corina M Borza, Yan Su, Truc-Linh Tran, Ling Yu, Nick Steyns, Kayla J Temple, Marcin J Skwark, Jens Meiler, Craig W Lindsley, Brennan R Hicks, Birgit Leitinger, Roy Zent, Ambra Pozzi
Discoidin domain receptor 1 (DDR1) is a receptor tyrosine kinase that binds to and is activated by collagens. DDR1 expression increases following kidney injury and accumulating evidence suggests that it contributes to the progression of injury. To this end, deletion of DDR1 is beneficial in ameliorating kidney injury induced by angiotensin infusion, unilateral ureteral obstruction, or nephrotoxic nephritis. Most of the beneficial effects observed in the DDR1-null mice are attributed to reduced inflammatory cell infiltration to the site of injury, suggesting that DDR1 plays a pro-inflammatory effect...
November 30, 2016: Matrix Biology: Journal of the International Society for Matrix Biology
https://www.readbyqxmd.com/read/27914892/straightforward-approach-to-produce-recombinant-scorpion-toxins-pore-blockers-of-potassium-channels
#7
Oksana Nekrasova, Ksenia Kudryashova, Arkadiy Fradkov, Sergey Yakimov, Maria Savelieva, Mikhail Kirpichnikov, Alexey Feofanov
Scorpion venom peptide blockers (KTx) of potassium channels are a valuable tool for structure-functional studies and prospective candidates for medical applications. Low yields of recombinant KTx hamper their wide application. We developed convenient and efficient bioengineering approach to a large-scale KTx production that meets increasing demands for such peptides. Maltose-binding protein was used as a carrier for cytoplasmic expression of folded disulfide-rich KTx in E. coli. TEV protease was applied for in vitro cleavage of the target peptide from the carrier...
November 30, 2016: Journal of Biotechnology
https://www.readbyqxmd.com/read/27914796/design-and-synthesis-of-new-piperidone-grafted-acetylcholinesterase-inhibitors
#8
Alireza Basiri, Michelle Xiao, Alec McCarthy, Debashis Dutta, Siddappa N Byrareddy, Martin Conda-Sheridan
Alzheimer's disease (AD) is a neurodegenerative disorder affecting 35million people worldwide. A common strategy to improve the well-being of AD patients consists on the inhibition of acetylcholinesterase with the concomitant increase of the neurotransmitter acetylcholine at cholinergic synapses. Two series of unreported N-benzylpiperidines 5(a-h) and thiazolopyrimidines 9(a-q) molecules were synthesized and evaluated in vitro for their acetylcholinesterase (AChE) inhibitory activities. Among the newly synthesized compounds, 5h, 9h, 9j, and 9p displayed higher AChE enzyme inhibitory activities than the standard drug, galantamine, with IC50 values of 0...
November 24, 2016: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/27914694/synthesis-of-novel-chromenones-linked-to-1-2-3-triazole-ring-system-investigation-of-biological-activities-against-alzheimer-s-disease
#9
Mina Saeedi, Maliheh Safavi, Elahe Karimpour-Razkenari, Mohammad Mahdavi, Najmeh Edraki, Farshad Homayouni Moghadam, Mahnaz Khanavi, Tahmineh Akbarzadeh
In this work, novel chromenones linked to 1,2,3-triazole ring system were synthesized and evaluated for their anti-ChE activity. Among them, N-((1-(2-chlorobenzyl)-1H-1,2,3-triazol-5-yl)methyl)-8-methoxy-2-oxo-2H-chromene-3-carboxamide (6m) showed good anti-acetylcholinesterase activity (IC50=15.42μM). Also, compound 6m demonstrated neuroprotective effect against H2O2-induced cell death in PC12 neurons, however, it showed no beta-secretase (BACE1) inhibitory activity. Docking and kinetic studies separately confirmed dual binding activity of compound 6m since it targeted both the catalytic active site (CAS) and the peripheral anionic site (PAS) of AChE...
November 24, 2016: Bioorganic Chemistry
https://www.readbyqxmd.com/read/27914621/glycolipid-crosslinking-is-required-for-cholera-toxin-to-partition-into-and-stabilize-ordered-domains
#10
Krishnan Raghunathan, Tiffany H Wong, Daniel J Chinnapen, Wayne I Lencer, Michael G Jobling, Anne K Kenworthy
Current models of lipid rafts propose that lipid domains exist as nanoscale compositional fluctuations and these fluctuations can potentially be stabilized into larger domains, consequently better compartmentalizing cellular functions. However, the mechanisms governing stabilized raft assembly and function remain unclear. Here, we test the role of glycolipid crosslinking as a raft targeting and ordering mechanism using the well-studied raft marker cholera toxin B pentamer (CTxB) that binds up to five GM1 glycosphingolipids to enter host cells...
November 30, 2016: Biophysical Journal
https://www.readbyqxmd.com/read/27914361/development-of-cxcr4-modulators-by-virtual-hts-of-a-novel-amide-sulfamide-compound-library
#11
Renren Bai, Qi Shi, Zhongxing Liang, Younghyoun Yoon, Yiran Han, Amber Feng, Shuangping Liu, Yoonhyeun Oum, C Chris Yun, Hyunsuk Shim
CXCR4 plays a crucial role in recruitment of inflammatory cells to inflammation sites at the beginning of the disease process. Modulating CXCR4 functions presents a new avenue for anti-inflammatory strategies. However, using CXCR4 antagonists for a long term usage presents potential serious side effect due to their stem cell mobilizing property. We have been developing partial CXCR4 antagonists without such property. A new computer-aided drug design program, the FRESH workflow, was used for anti-CXCR4 lead compound discovery and optimization, which coupled both compound library building and CXCR4 docking screens in one campaign...
November 24, 2016: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/27914354/3d-qsar-predictions-for-%C3%AE-cyclodextrin-binding-constants-using-quantum-mechanically-based-descriptors
#12
Lukas Linden, Kai-Uwe Goss, Satoshi Endo
Binding of organic chemicals to α-cyclodextrin (αCD) is a typical example for host-guest complexation that is influenced by the 3D-structure of both the binding site (host) and the solute (guest). Prediction of the binding constant is challenging and requires a successful representation of the binding site-solute interactions in the 3D-space. In this study, we tested if a 3D quantitative structure activity relationship (3D-QSAR) model with quantum mechanically based local sigma profiles (LSPs) derived from the COSMOsar3D method is capable of predicting αCD binding constants from the most recent literature and how the model performs in comparison to a standard comparative molecular field analysis and to a reference 2D-QSAR...
November 30, 2016: Chemosphere
https://www.readbyqxmd.com/read/27914349/effects-of-clay-minerals-hydroxides-and-timing-of-dissolved-organic-matter-addition-on-the-competitive-sorption-of-copper-nickel-and-zinc-a-column-experiment
#13
Yasser Refaey, Boris Jansen, John R Parsons, Pim de Voogt, Simone Bagnis, Adriaan Markus, Abdel-Hamid El-Shater, Abdel-Aziz El-Haddad, Karsten Kalbitz
Infiltration of heavy metal (HM) polluted wastewater can seriously compromise soil and groundwater quality. Interactions between mineral soil components (e.g. clay minerals) and dissolved organic matter (DOM) play a crucial role in determining HM mobility in soils. In this study, the influence of the timing of addition of DOM, i.e. concurrent with or prior to HMs, on HM mobility was explored in a set of continuous flow column experiments using well defined natural soil samples amended with goethite, birnessite and/or smectite...
November 30, 2016: Journal of Environmental Management
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
#14
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/27914200/assembling-the-tat-protein-translocase
#15
Felicity Alcock, Phillip J Stansfeld, Hajra Basit, Johann Habersetzer, Matthew Ab Baker, Tracy Palmer, Mark I Wallace, Ben C Berks
The twin-arginine protein translocation system (Tat) transports folded proteins across the bacterial cytoplasmic membrane and the thylakoid membranes of plant chloroplasts. The Tat transporter is assembled from multiple copies of the membrane proteins TatA, TatB, and TatC. We combine sequence co-evolution analysis, molecular simulations, and experimentation to define the interactions between the Tat proteins of Escherichia coli at molecular-level resolution. In the TatBC receptor complex the transmembrane helix of each TatB molecule is sandwiched between two TatC molecules, with one of the inter-subunit interfaces incorporating a functionally important cluster of interacting polar residues...
December 3, 2016: ELife
https://www.readbyqxmd.com/read/27914066/computational-tools-for-allosteric-drug-discovery-site-identification-and-focus-library-design
#16
Wenkang Huang, Ruth Nussinov, Jian Zhang
Allostery is an intrinsic phenomenon of biological macromolecules involving regulation and/or signal transduction induced by a ligand binding to an allosteric site distinct from a molecule's active site. Allosteric drugs are currently receiving increased attention in drug discovery because drugs that target allosteric sites can provide important advantages over the corresponding orthosteric drugs including specific subtype selectivity within receptor families. Consequently, targeting allosteric sites, instead of orthosteric sites, can reduce drug-related side effects and toxicity...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/27914062/computational-design-of-ligand-binding-proteins
#17
Christine E Tinberg, Sagar D Khare
The ability to design novel small-molecule binding sites in proteins is a stringent test of our understanding of the principles of molecular recognition, and would have many practical applications, in synthetic biology and medicine. Here, we describe a computational method in the context of the macromolecular modeling suite Rosetta to designing proteins with sites featuring predetermined interactions to ligands of choice. The required inputs for the method are a model of the small molecule and the desired interactions (e...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/27914058/osprey-predicts-resistance-mutations-using-positive-and-negative-computational-protein-design
#18
Adegoke Ojewole, Anna Lowegard, Pablo Gainza, Stephanie M Reeve, Ivelin Georgiev, Amy C Anderson, Bruce R Donald
Drug resistance in protein targets is an increasingly common phenomenon that reduces the efficacy of both existing and new antibiotics. However, knowledge of future resistance mutations during pre-clinical phases of drug development would enable the design of novel antibiotics that are robust against not only known resistant mutants, but also against those that have not yet been clinically observed. Computational structure-based protein design (CSPD) is a transformative field that enables the prediction of protein sequences with desired biochemical properties such as binding affinity and specificity to a target...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/27914004/hybrid-receptor-bound-mm-gbsa-per-residue-energy-based-pharmacophore-modelling-enhanced-approach-for-identification-of-selective-lta4h-inhibitors-as-potential-anti-inflammatory-drugs
#19
Patrick Appiah-Kubi, Mahmoud Soliman
Leukotriene A4 hydrolase has been identified as an enzyme with dual anti- and pro-inflammatory role, thus, the conversion of leukotriene to leukotriene B4 in the initiation stage of inflammation and the removal of the chemotactic Pro-Gly-Pro tripeptide. These findings make leukotriene A4 hydrolase an attractive drug target: suggesting an innovative approach towards the identification and design of novel class of compounds that can selectively inhibit leukotriene B4 synthesis while sparing the aminopeptidase activity...
December 2, 2016: Cell Biochemistry and Biophysics
https://www.readbyqxmd.com/read/27913823/mathematical-models-suggest-facilitated-fatty-acids-crossing-of-the-luminal-membrane-in-the-cardiac-muscle
#20
Efrath Barta
Long-chain fatty acids cross a few membranes on their way from the capillary blood to the cardiomyocyte cytosol, where they are utilized as an essential source of energy. Details of the transport mechanism across those membranes remained elusive despite decades of laboratory and theoretical work. Here we inspect several optional scenarios for the crossing of the luminal membrane of the endothelial cell, the first barrier that should be crossed: a passive diffusion, facilitation by receptors for albumin and facilitation by fatty acids transporters...
December 3, 2016: Journal of Membrane Biology
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