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L-methyl tryptophan

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https://www.readbyqxmd.com/read/29412668/total-synthesis-of-ecumicin
#1
Paige M E Hawkins, Andrew M Giltrap, Gayathri Nagalingam, Warwick J Britton, Richard J Payne
The first total synthesis of the potent anti-mycobacterial cyclic depsipeptide natural product ecumicin is described. Synthesis was achieved via a solid-phase strategy, incorporating the synthetic non-proteinogenic amino acids N-methyl-4-methoxy-l-tryptophan and threo-β-hydroxy-l-phenylalanine into the growing linear peptide chain. The synthesis employed key on-resin esterification and dimethylation steps as well as a final macrolactamization between the unusual N-methyl-4-methoxy-l-tryptophan unit and a bulky N-methyl-l-valine residue...
February 7, 2018: Organic Letters
https://www.readbyqxmd.com/read/29301550/role-of-the-indoleamine-2-3-dioxygenase-kynurenine-pathway-of-tryptophan-metabolism-in-behavioral-alterations-in-a-hepatic-encephalopathy-rat-model
#2
Xi Jiang, Lexing Xu, Lin Tang, Fuhe Liu, Ziwei Chen, Jiajia Zhang, Lei Chen, Cong Pang, Xuefeng Yu
BACKGROUND: This study aims to explore the role of indoleamine-2,3-dioxygenase (IDO)/kynurenine (KYN) pathway of tryptophan (TRY) metabolism in behavioral alterations observed in hepatic encephalopathy (HE) rats. METHODS: Expression levels of proinflammatory cytokines were tested by QT-PCR and ELISA, levels of IDOs were tested by QT-PCR and Western blot, and levels of 5-hydroxytryptamine (5-HT), KYN, TRY, 3-hydroxykynurenine (3-HK), and kynurenic acid (KA) in different brain regions were estimated using HPLC...
January 4, 2018: Journal of Neuroinflammation
https://www.readbyqxmd.com/read/29261637/amino-acid-pet-imaging-of-the-early-metabolic-response-during-tumor-treating-fields-ttfields-therapy-in-recurrent-glioblastoma
#3
Edit Bosnyák, Geoffrey R Barger, Sharon K Michelhaugh, Natasha L Robinette, Alit Amit-Yousif, Sandeep Mittal, Csaba Juhász
Tumor-treating fields (TTFields) therapy is a relatively new treatment approach for malignant gliomas. We evaluated if amino acid PET can detect an objective metabolic response to TTFields therapy in recurrent glioblastomas. PET scanning with alpha[C-11]-methyl-L-tryptophan (AMT) before and 2 to 3 months after the start of TTFields treatment showed an interval decrease of tryptophan uptake in the whole tumor (2 patients) or in a portion of the tumor (1 patient). These data demonstrate that TTFields therapy can induce an early metabolic response in recurrent glioblastoma, and this treatment response can be detected by amino acid PET...
December 19, 2017: Clinical Nuclear Medicine
https://www.readbyqxmd.com/read/29232414/influence-of-trp-flipping-on-carbohydrate-binding-in-lectins-an-example-on-aleuria-aurantia-lectin-aal
#4
Josef Houser, Stanislav Kozmon, Deepti Mishra, Sushil K Mishra, Patrick R Romano, Michaela Wimmerová, Jaroslav Koča
Protein-carbohydrate interactions are very often mediated by the stacking CH-π interactions involving the side chains of aromatic amino acids such as tryptophan (Trp), tyrosine (Tyr) or phenylalanine (Phe). Especially suitable for stacking is the Trp residue. Analysis of the PDB database shows Trp stacking for 265 carbohydrate or carbohydrate like ligands in 5 208 Trp containing motives. An appropriate model system to study such an interaction is the AAL lectin family where the stacking interactions play a crucial role and are thought to be a driving force for carbohydrate binding...
2017: PloS One
https://www.readbyqxmd.com/read/29183598/tribenuron-methyl-resistance-and-mutation-diversity-of-the-ahas-gene-in-shepherd-s-purse-capsella-bursa-pastoris-l-medik-in-henan-province-china
#5
Lele Zhang, Wenlei Guo, Qi Li, Cuixia Wu, Ning Zhao, Weitang Liu, Jinxin Wang
Shepherd's purse is a troublesome dicot weed that occurs in the major wheat-producing areas in China. Twenty-eight shepherd's purse populations were collected from winter wheat-planting areas in Henan Province and used to evaluate tribenuron-methyl resistance and acetohydroxyacid synthase (AHAS) gene-mutation diversity. The results indicate that all 28 shepherd's purse populations were resistant to tribenuron-methyl at different levels compared with the susceptible population. Mutation of the 197 codon (CCT) changed proline (Pro) into tyrosine (Tyr), histidine (His), leucine (Leu), serine (Ser), arginine (Arg), alanine (Ala) and threonine (Thr), whereas mutation of the 574 codon (TGG) changed tryptophan (Trp) into leucine (Leu)...
November 2017: Pesticide Biochemistry and Physiology
https://www.readbyqxmd.com/read/29163899/design-crystal-structure-and-atomic-force-microscopy-study-of-thioether-ligated-d-l-cyclic-antimicrobial-peptides-against-multidrug-resistant-pseudomonas-aeruginosa
#6
Runze He, Ivan Di Bonaventura, Ricardo Visini, Bee-Ha Gan, Yongchun Fu, Daniel Probst, Alexandre Lüscher, Thilo Köhler, Christian van Delden, Achim Stocker, Wenjing Hong, Tamis Darbre, Jean-Louis Reymond
Here we report a new family of cyclic antimicrobial peptides (CAMPs) targeting MDR strains of Pseudomonas aeruginosa. These CAMPs are cyclized via a xylene double thioether bridge connecting two cysteines placed at the ends of a linear amphiphilic alternating d,l-sequence composed of lysines and tryptophans. Investigations by transmission electron microscopy (TEM), dynamic light scattering and atomic force microscopy (AFM) suggest that these peptide macrocycles interact with the membrane to form lipid-peptide aggregates...
November 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/28993242/a-distinct-microrna-expression-profile-is-associated-with-%C3%AE-11-c-methyl-l-tryptophan-amt-pet-uptake-in-epileptogenic-cortical-tubers-resected-from-patients-with-tuberous-sclerosis-complex
#7
Shruti Bagla, Daniela Cukovic, Eishi Asano, Sandeep Sood, Aimee Luat, Harry T Chugani, Diane C Chugani, Alan A Dombkowski
Tuberous sclerosis complex (TSC) is characterized by hamartomatous lesions in various organs and arises due to mutations in the TSC1 or TSC2 genes. TSC mutations lead to a range of neurological manifestations including epilepsy, cognitive impairment, autism spectrum disorders (ASD), and brain lesions that include cortical tubers. There is evidence that seizures arise at or near cortical tubers, but it is unknown why some tubers are epileptogenic while others are not. We have previously reported increased tryptophan metabolism measured with α[(11)C]-methyl-l-tryptophan (AMT) positron emission tomography (PET) in epileptogenic tubers in approximately two-thirds of patients with tuberous sclerosis and intractable epilepsy...
October 7, 2017: Neurobiology of Disease
https://www.readbyqxmd.com/read/28923384/synthesis-and-structure-elucidation-of-novel-salophen-based-dioxo-uranium-vi-complexes-in-vitro-and-in-silico-studies-of-their-dna-bsa-binding-properties-and-anticancer-activity
#8
S Yousef Ebrahimipour, Maryam Mohamadi, Masoud Torkzadeh Mahani, Jim Simpson, Joel T Mague, Iran Sheikhshoaei
The synthesis and characterization of three dioxo U(VI) complexes, [UO2(L(1))(OH2)], [UO2(L(2))DMF], and [UO2(L(2))DMSO], [L(1)](2-) = 1,1'-(4-methyl-1,2-phenylenebis (nitrilomethylidyne))di-2-naphtholate: [L(2)](2-) = 1,1'-(o-phenylenebis (nitrilomethylidyne)) di-2-naphtholate, are reported. Elemental analysis, FT-IR, (1)HNMR, UV-Vis spectroscopy, molar conductivity and single crystal X-ray diffraction were used to characterize the complexes. It was found that the complexes adopt a distorted pentagonal bipyramidal coordination geometry...
November 10, 2017: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28862845/structural-and-functional-analyses-of-periplasmic-5-methylthioadenosine-s-adenosylhomocysteine-nucleosidase-from-aeromonas-hydrophila
#9
Yongbin Xu, Lulu Wang, Jinli Chen, Jing Zhao, Shengdi Fan, Yuesheng Dong, Nam-Chul Ha, Chunshan Quan
The Gram-negative, rod-shaped bacterium Aeromonas hydrophila has two multifunctional 5'-methylthioadenosine/S-adenosylhomocysteine nucleosidase (MTAN) enzymes, MtaN-1 and MtaN-2, that differ from those in other bacteria. These proteins are essential for several metabolic pathways, including biological methylation, polyamine biosynthesis, methionine recycling, and bacterial quorum sensing. To gain insight into how these two proteins function, we determined four high-resolution crystal structures of MtaN-1 in its apo form and in complex with the substrates S-adenosyl-l-homocysteine, 5'-methylthioadenosine, and 5'-deoxyadenosine...
October 10, 2017: Biochemistry
https://www.readbyqxmd.com/read/28820583/processing-2-methyl-l-tryptophan-through-tandem-transamination-and-selective-oxygenation-initiates-indole-ring-expansion-in-the-biosynthesis-of-thiostrepton
#10
Zhi Lin, Jia Ji, Shuaixiang Zhou, Fang Zhang, Jiequn Wu, Yinlong Guo, Wen Liu
Thiostrepton (TSR), an archetypal member of the family of ribosomally synthesized and post-translationally modified thiopeptide antibiotics, possesses a biologically important quinaldic acid (QA) moiety within the side-ring system of its characteristic thiopeptide framework. QA is derived from an independent l-Trp residue; however, its associated transformation process remains poorly understood. We here report that during the formation of QA, the key expansion of an indole to a quinoline relies on the activities of the pyridoxal-5'-phosphate-dependent protein TsrA and the flavoprotein TsrE...
August 23, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28782636/embryo-yolk-sac-membrane-kynurenine-formamidase-of-l-tryptophan-to-nad-pathway-as-a-primary-target-for-organophosphorus-insecticides-opi-in-opi-induced-nad-associated-avian-teratogenesis
#11
Josef Seifert
The objective of this study was to provide in ovo evidence for the proposed role of kynurenine formamidase of l-tryptophan to NAD(+) pathway in embryo yolk sac membranes as a primary target for organophosphorus insecticide (OPI) teratogens in OPI-induced NAD-associated avian teratogenesis. Slices prepared from yolk sac membranes or embryo livers of chicken eggs treated with the OPI dicrotophos and/or methyl parathion were incubated with l-tryptophan. Yolk sac membrane slices metabolized l-tryptophan in the pathway to NAD(+) before that function was established in livers...
October 2017: Toxicology in Vitro: An International Journal Published in Association with BIBRA
https://www.readbyqxmd.com/read/28771838/human-regulatory-macrophages-are-potent-in-suppression-of-the-xenoimmune-response-via-indoleamine-2-3-dioxygenase-involved-mechanism-s
#12
Fei Guo, Min Hu, Dandan Huang, Yuanfei Zhao, Benjamin Heng, Gilles Guillemin, Chai K Lim, Wayne J Hawthorne, Shounan Yi
BACKGROUND: For xenotransplantation to truly succeed, we must develop immunomodulatory strategies to suppress the xenoimmune response but by minimizing immunosuppression over the long term. Regulatory macrophages (Mreg) have been shown to suppress polyclonal T-cell proliferation in vitro and prolong allograft survival in vivo. However, the question of whether they are capable of suppressing xenoimmune responses remains unknown. This study assessed the potential of human Mreg to be used as an effective immunomodulatory method in xenotransplantation...
August 2, 2017: Xenotransplantation
https://www.readbyqxmd.com/read/28763571/enzymatic-synthesis-of-psilocybin
#13
Janis Fricke, Felix Blei, Dirk Hoffmeister
Psilocybin is the psychotropic tryptamine-derived natural product of Psilocybe carpophores, the so-called "magic mushrooms". Although its structure has been known for 60 years, the enzymatic basis of its biosynthesis has remained obscure. We characterized four psilocybin biosynthesis enzymes, namely i) PsiD, which represents a new class of fungal l-tryptophan decarboxylases, ii) PsiK, which catalyzes the phosphotransfer step, iii) the methyltransferase PsiM, catalyzing iterative N-methyl transfer as the terminal biosynthetic step, and iv) PsiH, a monooxygenase...
August 1, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28747433/efficient-methylation-of-c2-in-l-tryptophan-by-the-cobalamin-dependent-radical-s-adenosylmethionine-methylase-tsrm-requires-an-unmodified-n1-amine
#14
Anthony J Blaszczyk, Bo Wang, Alexey Silakov, Jackson V Ho, Squire J Booker
TsrM catalyzes the methylation of C2 in l-tryptophan (Trp). This reaction is the first step in the biosynthesis of the quinaldic acid moiety of the thiopeptide antibiotic thiostrepton, which exhibits potent activity against Gram-positive pathogens. TsrM is a member of the radical S-adenosylmethionine (SAM) superfamily of enzymes, but it does not catalyze the formation of 5'-deoxyadenosin-5'-yl or any other SAM-derived radical. In addition to a [4Fe-4S] cluster, TsrM contains a cobalamin cofactor that serves as an intermediate methyl carrier in its reaction...
September 15, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28732132/entrapment-of-amino-acids-in-gas-phase-surfactant-assemblies-the-case-of-tryptophan-confined-in-positively-charged-1r-2s-dodecyl-2-hydroxy-1-methyl-2-phenylethyl-dimethylammonium-bromide-aggregates
#15
David Bongiorno, Valentina Calabrese, Leopoldo Ceraulo, Serena Indelicato, Vincenzo Turco Liveri
The ability of positively charged aggregates of the surfactant (1R,2S)-dodecyl(2-hydroxy-1-methyl-2-phenylethyl)dimethylammonium bromide (DMEB) to incorporate D-tryptophan or L-tryptophan in the gas phase has been investigated by electrospray ion mobility mass spectrometry (ESI-IM-MS). Strongly impacted by the pH of the electrosprayed solutions, both protonated (T(+) ) and deprotonated (T(-) ) tryptophan are effectively included into the aggregates, whereas, tryptophan in zwitterionic (T(0) ) form is practically absent in singly charged DMEB aggregates but can be found in multiply charged ones...
October 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28688912/inhibition-of-the-kynurenine-pathway-protects-against-reactive-microglial-associated-reductions-in-the-complexity-of-primary-cortical-neurons
#16
Katherine O'Farrell, Eimear Fagan, Thomas J Connor, Andrew Harkin
Brain glia possess the rate limiting enzyme indoleamine 2, 3-dioxygenase (IDO) which catalyses the conversion of tryptophan to kynurenine. Microglia also express kynurenine monooxygenase (KMO) and kynureninase (KYNU) which lead to the production of the free radical producing metabolites, 3-hydroxykynurenine and 3-hydroxyanthranillic acid respectively and subsequently production of the NMDA receptor agonist quinolinic acid. The aim of this study was to examine the effect of IFNγ-stimulated kynurenine pathway (KP) induction in microglia on neurite outgrowth and complexity, and to determine whether alterations could be abrogated using pharmacological inhibitors of the KP...
September 5, 2017: European Journal of Pharmacology
https://www.readbyqxmd.com/read/28656203/1-methyl-l-tryptophan-promotes-the-apoptosis-of-hepatic-stellate-cells-arrested-by-interferon-%C3%AE-by-increasing-the-expression-of-ifn-%C3%AE-r%C3%AE-irf-1-and-fas
#17
Ji Eun Oh, Kwang Yong Shim, Jong In Lee, Soo In Choi, Soon Koo Baik, Young Woo Eom
Liver fibrosis, a precursor to cirrhosis, is the result of the deposition of extracellular matrix (ECM) proteins and is mediated primarily by activated hepatic stellate cells (HSCs). In this study, we investigated the anti-fibrotic effects of interferon (IFN)-γ in activated HSCs in vitro and whether cell viability would be decreased by the inhibition of indoleamine 2,3-dioxygemase (IDO), which is responsible for cell cycle arrest. Following treatment with IFN-γ, cell signaling pathways and DNA content were analyzed to assess the inactivation of HSCs or the decrease in HSC proliferation...
June 26, 2017: International Journal of Molecular Medicine
https://www.readbyqxmd.com/read/28611277/association-of-rasgrf1-methylation-with-epileptic-seizures
#18
Xiaoni Chen, Xi Peng, Liang Wang, Xinwei Fu, Ji Xiu Zhou, Binglin Zhu, Jing Luo, Xuefeng Wang, Zheng Xiao
DNA methylation, one of the mechanisms of epigenetic regulation, has been suggested to be related with epilepsy. RASgrf1 is a paternally imprinted gene and has a differentially methylated region (DMR) at the promoter that can silence gene expression. We have previously observed the down-regulation of RASgrf1 in the temporal neocortex of epilepsy patients and in the hippocampus of epileptic animals. Here, we further explored the dynamic change (1-day acute period, 10-day latent period and 45-day chronic phase) of DNA methylation and RASgrf1 expression after acute epileptic seizures in kainic acid (KA)-treated mice, and we observed the impact of N-phthalyl-L-tryptophan (RG108), a DNA methyltransferase (DNMT) inhibitor, on an acute epileptic model by polymerase chain reaction (PCR), western blotting, and bisulfite sequencing PCR (BSP)...
July 11, 2017: Oncotarget
https://www.readbyqxmd.com/read/28529635/synthesis-of-5-18-f-fluoro-%C3%AE-methyl-tryptophan-new-trp-based-pet-agents
#19
Benjamin C Giglio, Haiyang Fei, Mengzhe Wang, Hui Wang, Liu He, Huijuan Feng, Zhanhong Wu, Hongjian Lu, Zibo Li
Indoleamine 2,3-dioxygenase (IDO1) plays a special role in the biology of various cancer types, because it breaks down the essential amino acid tryptophan for immune cell activation. Upregulation of IDO1 significantly correlates with the number of various T cell types in tumor tissues in melanoma and other cancers, suggesting that IDO expression is linked with effective and ineffective ('exhausted') immune response in cancer. Based on the reported IDO inhibitors (α-Methylated and indole-N-methylated tryptophan (Trp)), here we report the synthesis of potential IDO1 imaging agents through direct introduction of (18)F into the tryptophan aromatic ring...
2017: Theranostics
https://www.readbyqxmd.com/read/28488390/mesenchymal-stem-cells-protect-from-acute-liver-injury-by-attenuating-hepatotoxicity-of-liver-nkt-cells-in-inos-and-ido-dependent-manner
#20
Marina Gazdic, Bojana Simovic Markovic, Ljubica Vucicevic, Tamara Nikolic, Valentin Djonov, Nebojsa Arsenijevic, Vladimir Trajkovic, Miodrag L Lukic, Vladislav Volarevic
The effects of mesenchymal stem cells (MSCs) on phenotype and function of natural killer T (NKT) cells, is not understood. We used concanavalin A (ConA) - and α-galactosylceramide (α-GalCer)-induced liver injury to evaluate effects of MSCs on NKT-dependent hepatotoxicity. Mouse MSCs (mMSCs) significantly reduced Con A- and α-GalCer-mediated hepatitis in C57Bl/6 mice, as demonstrated by histopathological and biochemical analysis, attenuated influx of inflammatory (T-bet(+) TNF-α, IFN-γ producing and GATA3(+) , IL-4-producing) liver NKT cells and down-regulated TNF-α, IFN-γ and IL-4 levels in the sera...
May 9, 2017: Journal of Tissue Engineering and Regenerative Medicine
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