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https://www.readbyqxmd.com/read/28644475/post-translational-modification-of-ribosomally-synthesized-peptides-by-a-radical-sam-epimerase-in-bacillus-subtilis
#1
Alhosna Benjdia, Alain Guillot, Pauline Ruffié, Jérôme Leprince, Olivier Berteau
Ribosomally synthesized peptides are built out of L-amino acids, whereas D-amino acids are generally the hallmark of non-ribosomal synthetic processes. Here we show that the model bacterium Bacillus subtilis is able to produce a novel type of ribosomally synthesized and post-translationally modified peptide that contains D-amino acids, and which we propose to call epipeptides. We demonstrate that a two [4Fe-4S]-cluster radical S-adenosyl-L-methionine (SAM) enzyme converts L-amino acids into their D-counterparts by catalysing Cα-hydrogen-atom abstraction and using a critical cysteine residue as the hydrogen-atom donor...
July 2017: Nature Chemistry
https://www.readbyqxmd.com/read/28642436/metalloprotein-entatic-control-of-ligand-metal-bonds-quantified-by-ultrafast-x-ray-spectroscopy
#2
Michael W Mara, Ryan G Hadt, Marco Eli Reinhard, Thomas Kroll, Hyeongtaek Lim, Robert W Hartsock, Roberto Alonso-Mori, Matthieu Chollet, James M Glownia, Silke Nelson, Dimosthenis Sokaras, Kristjan Kunnus, Keith O Hodgson, Britt Hedman, Uwe Bergmann, Kelly J Gaffney, Edward I Solomon
The multifunctional protein cytochrome c (cyt c) plays key roles in electron transport and apoptosis, switching function by modulating bonding between a heme iron and the sulfur in a methionine residue. This Fe-S(Met) bond is too weak to persist in the absence of protein constraints. We ruptured the bond in ferrous cyt c using an optical laser pulse and monitored the bond reformation within the protein active site using ultrafast x-ray pulses from an x-ray free-electron laser, determining that the Fe-S(Met) bond enthalpy is ~4 kcal/mol stronger than in the absence of protein constraints...
June 23, 2017: Science
https://www.readbyqxmd.com/read/28641210/comparative-analysis-of-polyspecificity-of-the-endogenous-trna-synthetase-of-different-expression-host-towards-photocrosslinking-amino-acids-using-an-in-silico-approach
#3
Nadarajan Saravanan Prabhu, Hyungdon Yun
Photo-induced covalent crosslinking has emerged as the powerful strategy for analyzing and characterizing the protein-protein interaction and mapping protein 3D conformations. In the last decades, a number of photocrosslinking amino acids have been reported but only a few have been efficiently utilized for photocrosslinking purposes. Recently, incorporation of diazirine containing photoactivatable analogs such as photo-methionine, photo-leucine, photo-isoleucine and photo-lysine into target proteins were accomplished in live cells (Human A549cells, HEK 293) by depleting corresponding natural amino acid and supplementing these analogs in the medium...
June 8, 2017: Journal of Molecular Graphics & Modelling
https://www.readbyqxmd.com/read/28640310/spectroscopic-evidence-for-cofactor-substrate-interaction-in-the-radical-sam-enzyme-tyw1
#4
Velavan Kathirvelu, Phanélie Perche-Letuvée, Jean-Marc Latour, Mohamed Atta, Farhad Forouhar, Serge Gambarelli, Ricardo Garcia-Serres
TYW1 is a metalloenzyme involved in the modifications of guanosine 37 of Phe-tRNA of Eukaryota and Archaea. It catalyzes the second step of Wybutosine biosynthesis, which consists of the formation of the tricyclic compound imG-14 from m(1)G using pyruvate and SAM (S-adenosyl-methionine) as co-substrates. Two [4Fe-4S] clusters are needed in the catalytic process. One effects the reductive binding of SAM, which initiates the radical reaction that inserts a C-C moiety into m(1)G. The other [4Fe-4S] cluster binds the pyruvate molecule that provides the C-C motif...
June 22, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28637772/tolerance-to-increased-supplemented-dietary-intakes-of-methionine-in-healthy-older-adults
#5
Nicolaas Ep Deutz, Sunday Y Simbo, Gerdien C Ligthart-Melis, Luc Cynober, Miro Smriga, Mariëlle Pkj Engelen
Background: l-Methionine (Met) is an essential amino acid for humans and is important for protein synthesis and the formation of polyamines and is involved in the synthesis of many metabolites, including homocysteine. Free-Met supplements have been claimed to have multiple positive effects; however, it remains unclear what the exact tolerance level is. With aging, Met metabolism changes, and increased plasma homocysteine is more apparent. High plasma concentrations of homocysteine are assumed to be associated with a high risk of developing atherosclerosis...
June 21, 2017: American Journal of Clinical Nutrition
https://www.readbyqxmd.com/read/28636071/the-role-of-homocysteine-in-seminal-vesicles-remodeling-in-rat
#6
Adel Ghoul, Elara Moudilou, Mohamed El Hadi Cherifi, Fouzia Zerrouk, Billel Chaouad, Anissa Moulahoum, Souhila Aouichat-Bouguerra, Khira Othmani, Jean-Marie Exbrayat, Yasmina Benazzoug
INTRODUCTION: Elevated plasma homocysteine (Hcy) levels have been associated with several tissue injuries including heart and liver fibrosis. In these diseases, hyperhomocysteinemia (Hhcy) plays a major role in modulating the alteration of the balance between matrix metalloproteinases (MMP) and tissue inhibitors of metalloproteinases (TIMPs), leading to the pathological accumulation of extracellular matrix (ECM) proteins. Since the effect of Hhcy on ECM of seminal vesicle was not studied, the aim of our research was to check if Hcy can induce a remodeling within seminal vesicles ECM...
June 21, 2017: Folia Histochemica et Cytobiologica
https://www.readbyqxmd.com/read/28635324/gliptins-suppress-inflammatory-macrophage-activation-to-mitigate-inflammation-fibrosis-oxidative-stress-and-vascular-dysfunction-in-models-of-non-alcoholic-steatohepatitis-and-liver-fibrosis
#7
Xiaoyu Wang, Michael Hausding, Shih-Yen Weng, Yong Ook Kim, Sebastian Steven, Thomas Klein, Andreas Daiber, Detlef Schuppan
AIMS: Non-alcoholic steatohepatitis (NASH) is characterized by steatosis, panlobular inflammation, liver fibrosis and increased cardiovascular mortality. Dipeptidyl peptidase-4 (DPP-4) inhibitors (gliptins) are indirect glucagon like peptide 1 (GLP-1) agonists with antidiabetic and anti-inflammatory activity, used for the treatment of type 2 diabetes. Their potential and underlying mechanisms to treat metabolic liver inflammation and fibrosis as well as the associated vascular dysfunction remain to be explored...
June 21, 2017: Antioxidants & Redox Signaling
https://www.readbyqxmd.com/read/28633643/enhancement-of-thermoalkaliphilic-xylanase-production-by-pichia-pastoris-through-novel-fed-batch-strategy-in-high-cell-density-fermentation
#8
Tingting Shang, Dayong Si, Dongyan Zhang, Xuhui Liu, Longmei Zhao, Cong Hu, Yu Fu, Rijun Zhang
BACKGROUND: Xylanase degrades xylan into monomers of various sizes by catalyzing the endohydrolysis of the 1,4-β-D-xylosidic linkage randomly, possessing potential in wide industrial applications. Most of xylanases are susceptible to be inactive when suffering high temperature and high alkaline process. Therefore, it is necessary to develop a high amount of effective thermoalkaliphilic xylanases. This study aims to enhance thermoalkaliphilic xylanase production in Pichia pastoris through fermentation parameters optimization and novel efficient fed-batch strategy in high cell-density fermentation...
June 21, 2017: BMC Biotechnology
https://www.readbyqxmd.com/read/28632940/characterization-of-the-i4399m-variant-of-apolipoprotein-a-implications-for-altered-prothrombotic-properties-of-lipoprotein-a
#9
Corey A Scipione, Jackson T McAiney, Daniel J Simard, Zainab A Bazzi, Matthew Gemin, Rocco Romagnuolo, Fraser L Macrae, Robert A Ariëns, Robert A Hegele, Janeen Auld, James W Gauld, Michael B Boffa, Marlys L Koschinsky
BACKGROUND: Lipoprotein(a) (Lp(a)) is a causal risk factor for a variety of cardiovascular diseases. Apolipoprotein(a) (apo(a)), the distinguishing component of Lp(a), is homologous to plasminogen, suggesting that Lp(a) can interfere with the normal fibrinolytic functions of plasminogen. This has implications for the persistence of fibrin clots in the vasculature and hence to atherothrombotic diseases. A single nucleotide polymorphism (rs3798220) in the gene encoding apo(a) has been reported that results in an Ile to Met substitution in the protease-like domain (I4399M variant)...
June 20, 2017: Journal of Thrombosis and Haemostasis: JTH
https://www.readbyqxmd.com/read/28632778/over-expressing-the-soluble-gp130-fc-does-not-ameliorate-methionine-and-choline-deficient-diet-induced-non-alcoholic-steatohepatitis-in-mice
#10
Helene L Kammoun, Tamara Louise Allen, Darren Colin Henstridge, Michael James Kraakman, Lone Peijs, Stefan Rose-John, Mark Anthony Febbraio
Non-alcoholic steatohepatitis (NASH) is a liver disease with the potential to lead to cirrhosis and hepatocellular carcinoma. Interleukin-6 (IL-6) has been implicated in the pathogenesis of NASH, with the so-called IL-6 'trans-signaling' cascade being responsible for the pro-inflammatory actions of this cytokine. We aimed to block IL-6 'trans-signaling', using a transgenic mouse that overexpresses human soluble glycoprotein130 (sgp130Fc Tg mice) fed a commonly used dietary model of inducing NASH (methionine and choline deficient-diet; MCD diet) and hypothesized that markers of NASH would be ameliorated in such mice...
2017: PloS One
https://www.readbyqxmd.com/read/28632732/fructo-oligosaccharides-and-intestinal-barrier-function-in-a-methionine-choline-deficient-mouse-model-of-nonalcoholic-steatohepatitis
#11
Kotaro Matsumoto, Mayuko Ichimura, Koichi Tsuneyama, Yuki Moritoki, Hiromichi Tsunashima, Katsuhisa Omagari, Masumi Hara, Ichiro Yasuda, Hiroshi Miyakawa, Kentaro Kikuchi
Impairments in intestinal barrier function, epithelial mucins, and tight junction proteins have been reported to be associated with nonalcoholic steatohepatitis. Prebiotic fructo-oligosaccharides restore balance in the gastrointestinal microbiome. This study was conducted to determine the effects of dietary fructo-oligosaccharides on intestinal barrier function and steatohepatitis in methionine-choline-deficient mice. Three groups of 12-week-old male C57BL/6J mice were studied for 3 weeks; specifically, mice were fed a methionine-choline-deficient diet, a methionine-choline-deficient diet plus 5% fructo-oligosaccharides in water, or a normal control diet...
2017: PloS One
https://www.readbyqxmd.com/read/28631755/construction-of-a-synthetic-metabolic-pathway-for-biosynthesis-of-the-non-natural-methionine-precursor-2-4-dihydroxybutyric-acid
#12
Thomas Walther, Christopher M Topham, Romain Irague, Clément Auriol, Audrey Baylac, Hélène Cordier, Clémentine Dressaire, Luce Lozano-Huguet, Nathalie Tarrat, Nelly Martineau, Marion Stodel, Yannick Malbert, Marc Maestracci, Robert Huet, Isabelle André, Magali Remaud-Siméon, Jean Marie François
2,4-Dihydroxybutyric acid (DHB) is a molecule with considerable potential as a versatile chemical synthon. Notably, it may serve as a precursor for chemical synthesis of the methionine analogue 2-hydroxy-4-(methylthio)butyrate, thus, targeting a considerable market in animal nutrition. However, no natural metabolic pathway exists for the biosynthesis of DHB. Here we have therefore conceived a three-step metabolic pathway for the synthesis of DHB starting from the natural metabolite malate. The pathway employs previously unreported malate kinase, malate semialdehyde dehydrogenase and malate semialdehyde reductase activities...
June 20, 2017: Nature Communications
https://www.readbyqxmd.com/read/28631302/l-hcy-induced-cathepsin-v-mediates-the-vascular-endothelial-inflammation-in-hyperhomocysteinemia
#13
Yi-Ping Leng, Ye-Shuo Ma, Xiao-Gang Li, Rui-Fang Chen, Ping-Yu Zeng, Xiao-Hui Li, Cheng-Feng Qiu, Ya-Pei Li, Zhen Zhang, Alex F Chen
BACKGROUND AND PURPOSE: Vascular inflammation, including the expression of inflammatory cytokines in endothelial cells, plays a critical role in hyperhomocysteinemia-associated vascular diseases. Cathepsin V, specifically expressed in humans, is involved in vascular diseases through its elastolytic and collagenolytic activities. The aim of this study was to determine the effects of cathepsin V on the L-homocysteine (L-Hcy)-induced vascular inflammation. EXPERIMENTAL APPROACH: A high methionine diet-induced hyperhomocysteinemic mice model was used to assess the cathepsin V expression and vascular inflammation...
June 20, 2017: British Journal of Pharmacology
https://www.readbyqxmd.com/read/28631172/glutamine-a-major-player-in-nitrogen-catabolite-repression-in-the-yeast-dekkera-bruxellensis
#14
Danielli Batista Bezerra Cajueiro, Denise Castro Parente, Fernanda Cristina Bezerra Leite, Marcos Antonio de Morais Junior, Will de Barros Pita
In the present work we studied the expression of genes from nitrogen central metabolism in the yeast Dekkera bruxellensis and under regulation by the Nitrogen Catabolite Repression mechanism (NCR). These analyses could shed some light on the biological mechanisms involved in the adaptation and survival of this yeast in the sugarcane fermentation process for ethanol production. Nitrogen sources (N-sources) in the form of ammonium, nitrate, glutamate or glutamine were investigated with or without the addition of methionine sulfoximine, which inhibits the activity of the enzyme glutamine synthetase and releases cells from NCR...
June 19, 2017: Antonie Van Leeuwenhoek
https://www.readbyqxmd.com/read/28630431/role-of-methionine-adenosyltransferase-2a-in-bovine-preimplantation-development-and-its-associated-genomic-regions
#15
Shuntaro Ikeda, Ryouka Kawahara-Miki, Hisataka Iwata, Miki Sugimoto, Shinichi Kume
Methionine adenosyltransferase (MAT) is involved in folate-mediated one-carbon metabolism, which is essential for preimplantation embryos in terms of both short-term periconceptional development and long-term phenotypic programming beyond the periconceptional period. Here, our immunofluorescence analysis of bovine oocytes and preimplantation embryos revealed the consistent expression of MAT2A (the catalytic subunit of the ubiquitously expressed-type of MAT isozyme) during this period. Addition of the MAT2A inhibitor FIDAS to the culture media of bovine preimplantation embryos reduced their blastocyst development, revealing the particular importance of MAT2A in successful blastocyst development...
June 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28627890/improved-description-of-sulfur-charge-anisotropy-in-opls-force-fields-model-development-and-parameterization
#16
Xin Cindy Yan, Michael J Robertson, Julian Tirado-Rives, William L Jorgensen
The atomic point-charge model used in most molecular mechanics force fields does not represent well the electronic anisotropy that is featured in many directional non-covalent interactions. Sulfur participates in several types of such interactions with its lone pairs and σ-holes. The current study develops new models, via the addition of off-atom charged sites, for a variety of sulfur compounds in the OPLS-AA and OPLS/CM5 force fields to address the lack of charge anisotropy. Parameter optimization is carried out to reproduce liquid-state properties, torsional and non-covalent energetics from reliable quantum mechanical calculations, and electrostatic potentials...
June 19, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28627630/gene-expression-profiling-of-human-blastocysts-from-in%C3%A2-vivo-and-rescue-ivm-with-or-without-melatonin-treatment
#17
Yan Hao, Zhiguo Zhang, Dan Han, Yunxia Cao, Ping Zhou, Zhaolian Wei, Mingrong Lv, Dawei Chen
To evaluate the effect of melatonin supplementation in maturation medium for human 'rescue IVM' and investigate differences in transcriptomic profile of blastocysts developed from oocytes matured in vitro with/without melatonin treatment and in vivo, a total of 314 GV oocytes and 320 MI oocytes were collected from 200 patients younger than 35 years old undergoing ICSI cycle. The oocytes were randomly distributed in the control group (no melatonin) and four other groups of varying melatonin concentrations (10‑11, 10‑9, 10‑7, 10‑5 mol/l)...
June 9, 2017: Molecular Medicine Reports
https://www.readbyqxmd.com/read/28626453/zinc-oxide-nanoparticles-influence-microflora-in-ileal-digesta-and-correlate-well-with-blood-metabolites
#18
Yanni Feng, Lingjiang Min, Weidong Zhang, Jing Liu, Zhumei Hou, Meiqiang Chu, Lan Li, Wei Shen, Yong Zhao, Hongfu Zhang
Zinc oxide nanoparticles (ZnO NPs) are used widely in consumer and industrial products, however, their influence on gut microbiota and metabolism and their mutual interactions are not fully understood. In this study, the effects of ZnO NPs on ileal bacterial communities, plasma metabolites, and correlations between them were investigated. Hens were fed with different concentrations of ZnO NPs [based on Zn; 0 mg/kg (control), 25 mg/kg, 50 mg/kg, and 100 mg/kg] for 9 weeks. Subsequently, ileal digesta and blood plasma were collected for analysis of microflora and metabolites, respectively...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28625678/rapid-protein-production-from-stable-cho-cell-pools-using-plasmid-vector-and-the-cumate-gene-switch
#19
Adeline Poulain, Sylvie Perret, Félix Malenfant, Alaka Mullick, Bernard Massie, Yves Durocher
To rapidly produce large amounts of recombinant proteins, the generation of stable Chinese Hamster Ovary (CHO) cell pools represents a useful alternative to large-scale transient gene expression (TGE). We have developed a cell line (CHO(BRI/rcTA)) allowing the inducible expression of recombinant proteins, based on the cumate gene switch. After the identification of optimal plasmid DNA topology (supercoiled vs linearized plasmid) for PEIpro™ mediated transfection and of optimal conditions for methionine sulfoximine (MSX) selection, we were able to generate CHO(BRI/rcTA) pools producing high levels of recombinant proteins...
June 15, 2017: Journal of Biotechnology
https://www.readbyqxmd.com/read/28624493/expression-of-the-c-terminal-domain-of-human-apolipoprotein-a-i-using-a-chimeric-apolipoprotein
#20
Daniel E Sallee, James V C Horn, Lukas A Fuentes, Paul M M Weers
Human apolipoprotein A-I (apoA-I) is the most abundant protein in high-density lipoprotein, an anti-atherogenic lipid-protein complex responsible for reverse cholesterol transport. The protein is composed of an N-terminal helix bundle domain, and a small C-terminal (CT) domain. To facilitate study of CT-apoA-I, a novel strategy was employed to produce this small domain in a bacterial expression system. A protein construct was designed of insect apolipophorin III (apoLp-III) and residues 179-243 of apoA-I, with a unique a methionine residue positioned between the two proteins and an N-terminal His-tag to facilitate purification...
June 14, 2017: Protein Expression and Purification
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