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s adenosyl l-methionine

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https://www.readbyqxmd.com/read/28074264/nacl-stress-induces-cssams-gene-expression-in-cucumis-sativus-by-mediating-the-binding-of-csgt-3b-to-the-gt-1-element-within-the-cssams-promoter
#1
Li-Wei Wang, Mei-Wen He, Shi-Rong Guo, Min Zhong, Sheng Shu, Jin Sun
The CsSAMs promoter is a salt-stress-inducible promoter containing three GT-1 elements that are sufficient for the salt-stress response. The transcription factor CsGT-3b was found to bind to the GT-1 element. The S-adenosyl-L-methionine synthase (SAMs) gene is among the functional genes induced during environmental stress. However, little is known about the regulatory mechanism and upstream regulators of this salt-inducible gene in cucumber plants. Thus, it is necessary to understand the characteristics of the SAMs gene by analyzing its promoter and transcription factors...
January 10, 2017: Planta
https://www.readbyqxmd.com/read/28068060/structural-and-functional-basis-of-c-methylation-of-coumarin-scaffolds-by-novo
#2
Joanna C Sadler, Chun-Wa Chung, Julie E Mosley, Glenn A Burley, Luke D Humphreys
C-methylation of aromatic small molecules by C-methyltransferases (C-MTs) is an important biological trans-formation that involves C-C bond formation using S-adenosyl-L-methionine (SAM) as the methyl donor. Here, two advanc-es in the mechanistic understanding of C-methylation of the 8-position of coumarin substrates catalyzed by the C-MT No-vO from Streptomyces Spheroides are described. First, a crystal structure of NovO reveals the Arg116-Asn117 and His120-Arg121 motifs are essential for coumarin substrate binding...
January 9, 2017: ACS Chemical Biology
https://www.readbyqxmd.com/read/28054779/n6-adenosine-dna-methyltransferase-from-h-pylori-98-10-strain-in-complex-with-dna-and-adomet-structural-insights-from-in-silico-studies
#3
Swati Singh, Lalitha Guruprasad
Helicobacter pylori is a primitive Gram-negative bacterium that resides in the acidic environment of the human gastrointestinal tract, and some strains of this bacterium cause gastric ulcers and cancer. DNA methyltransferases (MTases) are promising drug targets for the treatment of cancer and other diseases that are also caused by epigenetic alternations of the genome. The N6-adenine-specific DNA MTase from H. pylori (M. Hpy N6mA) catalyzes the transfer of a methyl group from the cofactor S-adenosyl-l-methionine (AdoMet) to the flipped adenine of the substrate DNA...
January 5, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28045519/7-carboxy-7-deazaguanine-synthase-a-radical-s-adenosyl-l-methionine-enzyme-with-polar-tendencies
#4
Nathan A Bruender, Tsehai Aj Grell, Daniel P Dowling, Reid M McCarty, Catherine L Drennan, Vahe Bandarian
Radical S-adenosyl-L-methionine (SAM) enzymes are widely distributed and catalyze diverse reactions.  SAM binds to the unique iron atom of a site-differentiated [4Fe-4S] cluster and is reductively cleaved to generate a 5-deoxyadenosyl radical, which initiates turnover.  7-Carboxy-7-deazaguanine (CDG) synthase catalyzes a key step in the biosynthesis of 7-deazapurine containing natural products.  6-Carboxypterin (6-CP), an oxidized analog of the natural substrate 6-carboxy-5,6,7,8-tetrahydropterin (CPH4), is shown to be an alternate substrate for CDG synthase...
January 3, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28042932/novel-adomet-analogues-as-tools-for-enzymatic-transfer-of-photo-crosslinkers-and-capturing-rna-protein-interactions
#5
Fabian Muttach, Florain Mäsing, Armido Studer, Andrea Rentmeister
Elucidation of biomolecular interactions is of utmost importance in biochemistry. Photo-crosslinking offers the possibility to precisely determine RNA-protein interactions. However, despite the inherent specificity of enzymes, approaches for site-specific introduction of photo-crosslinking moieties into nucleic acids are scarce. Methyltransferases in combination with synthetic analogues of their natural cosubstrate S-adenosyl-L-methionine (AdoMet) allow for the post-synthetic site-specific modification of biomolecules...
January 2, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28031456/a-novel-motif-for-s-adenosyl-l-methionine-binding-by-the-ribosomal-rna-methyltransferase-tlya-from-mycobacterium-tuberculosis
#6
Marta A Witek, Emily G Kuiper, Elizabeth Minten, Emily K Crispell, Graeme L Conn
Capreomycin is a potent ribosome-targeting antibiotic that is an essential component of current antituberculosis treatments, particularly in the case of multi-drug resistant Mycobacterium tuberculosis (Mtb). Optimal capreomycin binding and Mtb ribosome inhibition requires ribosomal RNA (rRNA) methylation in both ribosome subunits by TlyA (Rv1694), an enzyme with dual 2'-O-methytransferase and putative hemolytic activities. Despite TlyA's important role in capreomycin sensitivity and identification of inactivating mutations in the corresponding Mtb gene tylA which cause resistance to capreomycin, our current structural and mechanistic understanding of TlyA action remains limited...
December 27, 2016: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28031370/binding-of-the-methyl-donor-sam-to-mers-cov-2-o-methyltransferase-nsp16-promotes-the-recruitment-of-the-allosteric-activator-nsp10
#7
Wahiba Aouadi, Alexandre Blanjoie, Jean-Jacques Vasseur, Françoise Debart, Bruno Canard, Etienne Decroly
: The Middle East respiratory syndrome coronavirus (MERS-CoV) non-structural protein 16 (nsp16) is an S-adenosyl-L-methionine (SAM)-dependent 2' -O-methyltransferase (MTase) that is thought to methylate the ribose 2' -OH of the first transcribed nucleotide (N1) of viral RNA cap structures. This 2' -O MTase activity is regulated by nsp10. The 2' -O methylation prevents virus detection by cell innate immunity mechanisms and viral translation inhibition by the interferon-stimulated IFIT-1 protein...
December 28, 2016: Journal of Virology
https://www.readbyqxmd.com/read/28027411/dna-repair-by-the-radical-sam-enzyme-spore-photoproduct-lyase-from-biochemistry-to-structural-investigations
#8
Olivier Berteau, Alhosna Benjdia
Radical S-adenosyl-L-methionine (SAM) enzymes have emerged as one of the last superfamilies of enzymes discovered to date. Arguably, it is the most versatile group of enzymes involved in at least 85 biochemical transformations. One of the founding members of this enzyme superfamily is the Spore Photoproduct (SP) lyase, a DNA repair enzyme catalyzing the direct reversal repair of a unique DNA lesion, the so-called spore photoproduct, back into two thymidine residues. Discovered more than 20 years ago in the bacterium Bacillus subtilis, SP lyase has been shown to be widespread in the endospore-forming Firmicutes from the Bacilli and Clostridia classes and to use radical-based chemistry to perform C-C bond breakage, a chemically challenging reaction...
December 27, 2016: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28003820/feasibility-and-efficacy-of-s-adenosyl-l-methionine-in-patients-with-hbv-related-hcc-with-different-bclc-stages
#9
Tao Guo, Yukun He, Weijie Ma, Zhisu Liu, Quanyan Liu
Aims. To understand the feasibility and efficacy of treatment with SAMe in patients with hepatitis B-related HCC with different Barcelona Clinic Liver Cancer (BCLC) stages. Methods. We retrospectively enrolled 697 patients with BCLC early-stage (stages 0-A) and advanced-stage (stages B-C) HCC who underwent SAMe therapy (354 cases) or no SAMe therapy (343 cases). The baseline characteristics, postoperative recoveries, and 24-month overall survival rates of the patients in the 2 groups were compared. Cox regression model analysis was performed to confirm the independent variables influencing the survival rate...
2016: Gastroenterology Research and Practice
https://www.readbyqxmd.com/read/27998091/tryptophan-lyase-nosl-a-cornucopia-of-5-deoxyadenosyl-radical-mediated-transformations
#10
Dhananjay M Bhandari, Dmytro Fedoseyenko, Tadhg P Begley
Tryptophan lyase (NosL) is a radical S-adenosyl-l-methionine (SAM) enzyme that catalyzes the formation of 3-methyl-2-indolic acid from l-tryptophan. In this paper, we demonstrate that the 5'-deoxyadenosyl radical is considerably more versatile in its chemistry than previously anticipated: hydrogen atom abstraction from Nα-cyclopropyltryptophan occurs at Cα rather than the amino group with NosL Y90A and replacing the substrate amine with a ketone or an alkene changes the chemistry from hydrogen atom abstraction to double bond addition...
December 21, 2016: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/27997103/kinetic-isotope-effects-and-transition-state-structure-for-human-phenylethanolamine-n-methyltransferase
#11
Christopher F Stratton, Myles B Poulin, Quan Du, Vern L Schramm
Phenylethanolamine N-methyltransferase (PNMT) catalyzes the S-adenosyl-l-methionine (SAM)-dependent conversion of norepinephrine to epinephrine. Epinephrine has been associated with critical processes in humans including the control of respiration and blood pressure. Additionally, PNMT activity has been suggested to play a role in hypertension and Alzheimer's disease. In the current study, labeled SAM substrates were used to measure primary methyl-(14)C and (36)S and secondary methyl-(3)H, 5'-(3)H, and 5'-(14)C intrinsic kinetic isotope effects for human PNMT...
December 28, 2016: ACS Chemical Biology
https://www.readbyqxmd.com/read/27994052/bcid-is-a-radical-sam-enzyme-that-completes-bacteriochlorophyllide-e-biosynthesis-by-oxidizing-a-methyl-group-into-a-formyl-group-at-c-7
#12
Jennifer L Thweatt, Bryan H Ferlez, John H Golbeck, Donald A Bryant
Green bacteria are chlorophotorophs that synthesize bacteriochlorophyll (BChl) c, d, or e, which assemble into supramolecular, nanotubular structures in large light-harvesting structures called chlorosomes. The biosynthetic pathways of these chlorophylls are known except for one reaction. Null mutants of bciD, which encodes a putative radical-SAM protein, are unable to synthesize BChl e but accumulate BChl c; however, it is unknown whether BciD is sufficient to convert BChl c (or its precursor, bacteriochlorophyllide (BChlide) c into BChl e (or BChlide e)...
December 19, 2016: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/27994001/stability-of-the-human-sperm-dna-methylome-to-folic-acid-fortification-and-short-term-supplementation
#13
D Chan, S McGraw, K Klein, L M Wallock, C Konermann, C Plass, P Chan, B Robaire, R A Jacob, C M T Greenwood, J M Trasler
STUDY QUESTION: Do short-term and long-term exposures to low-dose folic acid supplementation alter DNA methylation in sperm? SUMMARY ANSWER: No alterations in sperm DNA methylation patterns were found following the administration of low-dose folic acid supplements of 400 μg/day for 90 days (short-term exposure) or when pre-fortification of food with folic acid and post-fortification sperm samples (long-term exposure) were compared. WHAT IS KNOWN ALREADY: Excess dietary folate may be detrimental to health and DNA methylation profiles due to folate's role in one-carbon metabolism and the formation of S-adenosyl methionine, the universal methyl donor...
December 18, 2016: Human Reproduction
https://www.readbyqxmd.com/read/27989946/itraq-analysis-of-the-tobacco-leaf-proteome-reveals-that-rna-directed-dna-methylation-rddm-has-important-roles-in-defense-against-geminivirus-betasatellite-infection
#14
Xueting Zhong, Zhan Qi Wang, Ruyuan Xiao, Yaqin Wang, Yan Xie, Xueping Zhou
: Geminiviruses have caused serious losses in crop production. To investigate the mechanisms underlying host defenses against geminiviruses, an isobaric tags for relative and absolute quantification (iTRAQ)-based quantitative proteomic approach was used to explore the expression profiles of proteins in Nicotiana benthamiana (N. benthamiana) leaves in response to tomato yellow leaf curl China virus (TYLCCNV) with its betasatellite (TYLCCNB) at an early phase. In total, 4155 proteins were identified and 272 proteins were changed differentially in response to TYLCCNV/TYLCCNB infection...
January 30, 2017: Journal of Proteomics
https://www.readbyqxmd.com/read/27986851/activation-mode-of-the-eukaryotic-m2g10-trna-methyltransferase-trm11-by-its-partner-protein-trm112
#15
Gabrielle Bourgeois, Julien Marcoux, Jean-Michel Saliou, Sarah Cianférani, Marc Graille
Post-transcriptional and post-translational modifications of factors involved in translation are very important for the control and accuracy of protein biosynthesis. Among these factors, tRNAs harbor the largest variety of grafted chemical structures, which participate in tRNA stability or mRNA decoding. Here, we focused on Trm112 protein, which associates with four different eukaryotic methyltransferases modifying tRNAs (Trm9 and Trm11) but also 18S-rRNA (Bud23) and translation termination factor eRF1 (Mtq2)...
December 15, 2016: Nucleic Acids Research
https://www.readbyqxmd.com/read/27981425/-1-h-15-n-13-c-backbone-resonance-assignments-of-human-soluble-catechol-o-methyltransferase-in-complex-with-s-adenosyl-l-methionine-and-3-5-dinitrocatechol
#16
Sylwia Czarnota, Nicola J Baxter, Matthew J Cliff, Jonathan P Waltho, Nigel S Scrutton, Sam Hay
Catechol O-methyltransferase (COMT) is an enzyme that plays a major role in catechol neurotransmitter deactivation. Inhibition of COMT can increase neurotransmitter levels, which provides a means of treatment for Parkinson's disease, schizophrenia and depression. COMT exists as two isozymes: a soluble cytoplasmic form (S-COMT), expressed in the liver and kidneys and a membrane-bound form (MB-COMT), found mostly in the brain. Here we report the backbone (1)H, (15)N and (13)C chemical shift assignments of S-COMT in complex with S-adenosyl-L-methionine, 3,5-dinitrocatechol and Mg(2+)...
December 15, 2016: Biomolecular NMR Assignments
https://www.readbyqxmd.com/read/27943567/methyltransferase-directed-labeling-of-biomolecules-and-its-applications
#17
Jochem Deen, Charlotte Vranken, Volker Leen, Robert K Neely, Kris Pieter Frans Janssen, Johan Hofkens
Methyltransferases (MTases) compose a large family of enzymes which have the ability to methylate a diverse set of targets, ranging from the three major biopolymers DNA, RNA and protein to small molecules. Most of these MTases use the cofactor S-Adenosyl-L-Methionine (AdoMet) as their methyl source. Given the important biological role of methylation, e.g. in epigenetic regulation of gene activity and the vast potential of targeted functionalization in biology, diagnostics and nanotechnology, it should come as no surprise that recent years have seen significant efforts in the development of AdoMet analogues with the aim of transferring moieties other than simple methyl groups...
December 12, 2016: Angewandte Chemie
https://www.readbyqxmd.com/read/27940912/kinetic-isotope-effects-reveal-early-transition-state-of-protein-lysine-methyltransferase-set8
#18
Joshua A Linscott, Kanishk Kapilashrami, Zhen Wang, Chamara Senevirathne, Ian R Bothwell, Gil Blum, Minkui Luo
Protein lysine methyltransferases (PKMTs) catalyze the methylation of protein substrates, and their dysregulation has been linked to many diseases, including cancer. Accumulated evidence suggests that the reaction path of PKMT-catalyzed methylation consists of the formation of a cofactor(cosubstrate)-PKMT-substrate complex, lysine deprotonation through dynamic water channels, and a nucleophilic substitution (SN2) transition state for transmethylation. However, the molecular characters of the proposed process remain to be elucidated experimentally...
December 27, 2016: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/27934872/structural-analysis-of-glycine-sarcosine-n-methyltransferase-from-methanohalophilus-portucalensis-reveals-mechanistic-insights-into-the-regulation-of-methyltransferase-activity
#19
Yi-Ru Lee, Te-Sheng Lin, Shu-Jung Lai, Mu-Sen Liu, Mei-Chin Lai, Nei-Li Chan
Methyltransferases play crucial roles in many cellular processes, and various regulatory mechanisms have evolved to control their activities. For methyltransferases involved in biosynthetic pathways, regulation via feedback inhibition is a commonly employed strategy to prevent excessive accumulation of the pathways' end products. To date, no biosynthetic methyltransferases have been characterized by X-ray crystallography in complex with their corresponding end product. Here, we report the crystal structures of the glycine sarcosine N-methyltransferase from the halophilic archaeon Methanohalophilus portucalensis (MpGSMT), which represents the first structural elucidation of the GSMT methyltransferase family...
December 9, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27934015/the-b12-radical-sam-enzyme-poyc-catalyzes-valine-c%C3%AE-methylation-during-polytheonamide-biosynthesis
#20
Aubérie Parent, Alain Guillot, Alhosna Benjdia, Gwladys Chartier, Jérôme Leprince, Olivier Berteau
Genomic and metagenomic investigations have recently led to the delineation of a novel class of natural products called ribosomally synthesized and post-translationally modified peptides (RiPPs). RiPPs are ubiquitous among living organisms and include pharmaceutically relevant compounds such as antibiotics and toxins. A prominent example is polytheonamide A, which exhibits numerous post-translational modifications, some of which were unknown in ribosomal peptides until recently. Among these post-translational modifications, C-methylations have been proposed to be catalyzed by two putative radical S-adenosylmethionine (rSAM) enzymes, PoyB and PoyC...
December 7, 2016: Journal of the American Chemical Society
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