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Ilaria Galizia, Lucio Oldani, Karine Macritchie, Erica Amari, Dominic Dougall, Tessa N Jones, Raymond W Lam, Guido Jacopo Massei, Lakshmi N Yatham, Allan H Young
BACKGROUND: Depression is a recurrent illness with high rates of chronicity, treatment-resistance and significant economic impact. There is evidence in the literature that S-adenosyl methionine (SAMe), a naturally occurring compound in the human body, has antidepressant efficacy. This product may be an important addition to the armamentarium of antidepressant agents. OBJECTIVES: To assess the effects of SAMe in comparison with placebo or antidepressants for the treatment of depression in adults...
October 10, 2016: Cochrane Database of Systematic Reviews
Ezhilarasi Krishnamoorthy, Sameer Hassan, Luke Elizabeth Hanna, Indira Padmalayam, Rama Rajaram, Vijay Viswanathan
Lipoic acid synthase (LIAS) is an iron-sulfur cluster mitochondrial enzyme which catalyzes the final step in the de novo pathway for the biosynthesis of lipoic acid, a potent antioxidant. Recently there has been significant interest in its role in metabolic diseases and its deficiency in LIAS expression has been linked to conditions such as diabetes, atherosclerosis and neonatal-onset epilepsy, suggesting a strong inverse correlation between LIAS reduction and disease status. In this study we use a bioinformatics approach to predict its structure, which would be helpful to understanding its role...
October 4, 2016: Journal of Theoretical Biology
Benjamin D Horning, Radu M Suciu, Darian A Ghadiri, Olesya A Ulanovskaya, Megan L Matthews, Kenneth M Lum, Keriann M Backus, Steven J Brown, Hugh Rosen, Benjamin F Cravatt
Methylation is a fundamental mechanism used in Nature to modify the structure and function of biomolecules, including proteins, DNA, RNA, and metabolites. Methyl groups are predominantly installed into biomolecules by a large and diverse class of S-adenosyl methionine (SAM)-dependent methyltransferases (MTs), of which there are ∼200 known or putative members in the human proteome. Deregulated MT activity contributes to numerous diseases, including cancer, and several MT inhibitors are in clinical development...
October 12, 2016: Journal of the American Chemical Society
Chun-Min Shan, Jiyong Wang, Ke Xu, Huijie Chen, Jia-Xing Yue, Stuart Andrews, James J Moresco, John R Yates, Peter L Nagy, Liang Tong, Songtao Jia
Histone lysine-to-methionine (K-to-M) mutations are associated with multiple cancers, and they function in a dominant fashion to block the methylation of corresponding lysines on wild type histones. However, their mechanisms of function are controversial. Here we show that in fission yeast, introducing the K9M mutation into one of the three histone H3 genes dominantly blocks H3K9 methylation on wild type H3 across the genome. In addition, H3K9M enhances the interaction of histone H3 tail with the H3K9 methyltransferase Clr4 in a SAM (S-adenosyl-methionine)-dependent manner, and Clr4 is trapped at nucleation sites to prevent its spreading and the formation of large heterochromatin domains...
2016: ELife
Nataša Karas Kuželički
Preclinical Research S-adenosyl methionine (SAM) is a major methyl donor and as such exerts its influence on CNS function through methylation reactions, such as methylation of several catecholamine moiety-containing neurotransmitters, epigenetic changes through methylation of DNA, RNA, RNA-binding proteins and histones, and phospholipid methylation. Based on available evidence, SAM is currently recommended as a next-step (second-line) treatment option following inadequate treatment response to a first-line antidepressant...
September 4, 2016: Drug Development Research
Thomas Christian, Reiko Sakaguchi, Agata P Perlinska, Georges Lahoud, Takuhiro Ito, Erika A Taylor, Shigeyuki Yokoyama, Joanna I Sulkowska, Ya-Ming Hou
Proteins with knotted configurations, in comparison with unknotted proteins, are restricted in conformational space. Little is known regarding whether knotted proteins have sufficient dynamics to communicate between spatially separated substrate-binding sites. TrmD is a bacterial methyltransferase that uses a knotted protein fold to catalyze methyl transfer from S-adenosyl methionine (AdoMet) to G37-tRNA. The product, m(1)G37-tRNA, is essential for life and maintains protein-synthesis reading frames. Using an integrated approach of structural, kinetic, and computational analysis, we show that the structurally constrained TrmD knot is required for its catalytic activity...
October 2016: Nature Structural & Molecular Biology
Madeline C Weiss, Filipa L Sousa, Natalia Mrnjavac, Sinje Neukirchen, Mayo Roettger, Shijulal Nelson-Sathi, William F Martin
The concept of a last universal common ancestor of all cells (LUCA, or the progenote) is central to the study of early evolution and life's origin, yet information about how and where LUCA lived is lacking. We investigated all clusters and phylogenetic trees for 6.1 million protein coding genes from sequenced prokaryotic genomes in order to reconstruct the microbial ecology of LUCA. Among 286,514 protein clusters, we identified 355 protein families (∼0.1%) that trace to LUCA by phylogenetic criteria. Because these proteins are not universally distributed, they can shed light on LUCA's physiology...
2016: Nature Microbiology
Peter McPhie, Patrick Brown, Bin Chen, Theodore K Dayie, Allen P Minton
The dependence of the conformation of the S-adenosylmethionine (SAM) II riboswitch on the concentration of added Mg(2+) ions and SAM, individually and in mixtures, was monitored by circular dichroism (CD) spectroscopy and by measurement of the diffusion coefficient. The results are analyzed in the context of two complementary quantitative models, both of which are consistent with a single underlying physical model. Magnesium binding sites in the open state have an affinity on average higher than the affinity of those in the compact state, but formation of the compact state is accompanied by an increase in the number of binding sites...
September 13, 2016: Biochemistry
Alexander M Walker, Steven A Sattler, Matt Regner, Jeffrey P Jones, John Ralph, Wilfred Vermerris, Scott E Sattler, ChulHee Kang
Caffeoyl-coenzyme A 3-O-methyltransferase (CCoAOMT) is an S-adenosyl methionine (SAM)-dependent O-methyltransferase responsible for methylation of the meta-hydroxyl group of caffeoyl-coenzyme A (CoA) on the pathway to monolignols, with their ring methoxylation status characteristic of guaiacyl or syringyl units in lignin. In order to better understand the unique class of type 2 O-methyltransferases from monocots, we have characterized CCoAOMT from sorghum (Sorghum bicolor; SbCCoAOMT), including the SAM binary complex crystal structure and steady-state enzyme kinetics...
September 2016: Plant Physiology
Sebastian Glatt, Rene Zabel, Olga Kolaj-Robin, Osita F Onuma, Florence Baudin, Andrea Graziadei, Valerio Taverniti, Ting-Yu Lin, Frauke Baymann, Bertrand Séraphin, Karin D Breunig, Christoph W Müller
During translation elongation, decoding is based on the recognition of codons by corresponding tRNA anticodon triplets. Molecular mechanisms that regulate global protein synthesis via specific base modifications in tRNA anticodons are receiving increasing attention. The conserved eukaryotic Elongator complex specifically modifies uridines located in the wobble base position of tRNAs. Mutations in Elongator subunits are associated with certain neurodegenerative diseases and cancer. Here we present the crystal structure of D...
September 2016: Nature Structural & Molecular Biology
Ying Zhang, Sabrina Mühlen, Clare V Oates, Jaclyn S Pearson, Elizabeth L Hartland
The type III secretion system effector protein NleE from enteropathogenic Escherichia coli plays a key role in the inhibition of NF-κB activation during infection. NleE inactivates the ubiquitin chain binding activity of host proteins TAK1-binding proteins 2 and 3 (TAB2 and TAB3) by modifying the Npl4 zinc finger domain through S-adenosyl methionine-dependent cysteine methylation. Using yeast two-hybrid protein interaction studies, we found that a conserved region between amino acids 34 and 52 of NleE, in particular the motif (49)GITR(52), was critical for TAB2 and TAB3 binding...
September 16, 2016: Journal of Biological Chemistry
Dhaval Varshney, Alain-Pierre Petit, Juan A Bueren-Calabuig, Chimed Jansen, Dan A Fletcher, Mark Peggie, Simone Weidlich, Paul Scullion, Andrei V Pisliakov, Victoria H Cowling
Maturation and translation of mRNA in eukaryotes requires the addition of the 7-methylguanosine cap. In vertebrates, the cap methyltransferase, RNA guanine-7 methyltransferase (RNMT), has an activating subunit, RNMT-Activating Miniprotein (RAM). Here we report the first crystal structure of the human RNMT in complex with the activation domain of RAM. A relatively unstructured and negatively charged RAM binds to a positively charged surface groove on RNMT, distal to the active site. This results in stabilisation of a RNMT lobe structure which co-evolved with RAM and is required for RAM binding...
July 15, 2016: Nucleic Acids Research
Habib A Shojaei Saadi, Dominic Gagné, Éric Fournier, Luis Manuel Baldoceda Baldeon, Marc-André Sirard, Claude Robert
AIM: There is a growing concern about the potential adverse effects of high dose folic acid (FA) supplementation before and during pregnancy. FA metabolism generates S-adenosyl methionine (SAM) which is an important cofactor of epigenetic programming. We sought to assess the impact of a large dose of SAM on early embryo development. MATERIALS & METHODS: In vitro cultured bovine embryos were treated with SAM from the eight-cell stage to the blastocyst stage. In addition to the phenotype, the genome-wide epigenetic and transcription profiles were analyzed...
August 2016: Epigenomics
Robert J Hart, Atif Ghaffar, Shaymaa Abdalal, Benjamin Perrin, Ahmed S I Aly
Polyamines are positively-charged organic molecules that are important for cellular growth and division. Polyamines and their synthesizing enzymes are particularly abundant in rapidly proliferating eukaryotic cells such as parasitic protozoa and cancer cells. Polyamine biosynthesis inhibitors, such as Elfornithine, are now being considered for cancer prevention and have been used effectively against Trypanosoma brucei Inhibitors of polyamine biosynthesis have caused growth arrest of Plasmodium falciparum blood stages in vitro, but in P...
2016: Biology Open
James Kuo, Stephen R Lynch, Corey W Liu, Xirui Xiao, Chaitan Khosla
Although a few well-characterized polyketide synthases (PKSs) have been functionally reconstituted in vitro from purified protein components, the use of this strategy to decode "orphan" assembly line PKSs has not been described. To begin investigating a PKS found only in Nocardia strains associated with clinical cases of nocardiosis, we reconstituted in vitro its five terminal catalytic modules. In the presence of octanoyl-CoA, malonyl-CoA, NADPH, and S-adenosyl methionine, this pentamodular PKS system yielded unprecedented octaketide and heptaketide products whose structures were partially elucidated using mass spectrometry and NMR spectroscopy...
September 16, 2016: ACS Chemical Biology
Anna-Lisa Fuchs, Ancilla Neu, Remco Sprangers
The eukaryotic mRNA 5' cap structure is indispensible for pre-mRNA processing, mRNA export, translation initiation, and mRNA stability. Despite this importance, structural and biophysical studies that involve capped RNA are challenging and rare due to the lack of a general method to prepare mRNA in sufficient quantities. Here, we show that the vaccinia capping enzyme can be used to produce capped RNA in the amounts that are required for large-scale structural studies. We have therefore designed an efficient expression and purification protocol for the vaccinia capping enzyme...
September 2016: RNA
Peiheng He, Ziji Zhang, Weiming Liao, Dongliang Xu, Ming Fu, Yan Kang
The current study aimed to identify gene signatures during rheumatoid arthritis (RA) and osteoarthritis (OA), and used these to elucidate the underlying modular mechanisms. Using the Gene Expression Omnibus database, the present study obtained the GSE7669 mRNA expression microarray data from RA and OA synovial fibroblasts (n=6 each). The differentially expressed genes (DEGs) in RA synovial samples compared with OA samples were identified using the Linear Models for Microarray Analysis package. The Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed using the Database for Annotation Visualization and Integrated Discovery...
August 2016: Molecular Medicine Reports
Rajnish M Dhediya, Shirish S Joshi, Snehalata V Gajbhiye, Sharmila V Jalgaonkar, Mansij Biswas
BACKGROUND: Epilepsy is the third most common cause of neurological disability worldwide. Despite the introduction of antiepileptic drugs (AEDs) in the past 20years, the seizures of around 30% of patients with epilepsy remain refractory to available treatment. Also, available AEDs and the disease itself have the potential to exert detrimental effects on cognitive function and therefore compromise patient wellbeing. S-adenosyl methionine has potential antiepileptic and memory-enhancing properties because of its involvement in the transmethylation reaction...
August 2016: Epilepsy & Behavior: E&B
Moonjung Hyun, Jeongho Kim, Catherine Dumur, Frank C Schroeder, Young-Jai You
Environmental stress triggers multilevel adaptations in animal development that depend in part on epigenetic mechanisms. In response to harsh environmental conditions and pheromone signals, Caenorhabditis elegans larvae become the highly stress-resistant and long-lived dauer. Despite extensive studies of dauer formation pathways that integrate specific environmental cues and appear to depend on transcriptional reprogramming, the role of epigenetic regulation in dauer development has remained unclear. Here we report that BLMP-1, the BLIMP-1 ortholog, regulates dauer formation via epigenetic pathways; in the absence of TGF-β signaling (in daf-7 mutants), lack of blmp-1 caused lethality...
August 2016: Genetics
Shanna Anderson, Jacob Panka, Robin Rakobitsch, Kaitlin Tyre, Kerry Pulliam
This case report highlights challenges faced in the clinical management of patients with methylenetetrahydrofolate reductase (MTHFR) gene mutations and the importance of precise dosage when recommending methylated B vitamins to compensate for deficiencies caused by the polymorphism or symptoms related to the polymorphism. It also underscores the importance of obtaining ongoing objective assessments of anxiety (eg, Patient Reported Outcomes Measurement Information System, or PROMIS) to help gauge patient response...
April 2016: Integrative Medicine
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