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Essential amino acids

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https://www.readbyqxmd.com/read/28240595/electrostatic-anchoring-precedes-stable-membrane-attachment-of-snap25-snap23-to-the-plasma-membrane
#1
Pascal Weber, Helena Batoulis, Kerstin Rink, Stefan Dahlhoff, Kerstin Pinkwart, Thomas Söllner, Thorsten Lang
The SNAREs SNAP25 and SNAP23 are proteins that are cytosolic after translation, but then become stably attached to the cell membrane through palmitoylation of cysteine residues. For palmitoylation to occur, membrane association is a prerequisite, but it is unclear which motif may increase the affinities of the proteins to the target membrane. In experiments with rat neuroendocrine cells, we find that a few polybasic amino acids in the cysteine rich region are essential for plasma membrane targeting. Reconstitution of membrane-protein binding in a liposome assay shows that the mechanism involves protein electrostatics between polybasic amino acid residues and anionic lipids like phosphoinositides that play a primary role in these interactions...
February 27, 2017: ELife
https://www.readbyqxmd.com/read/28239982/phytochemicals-in-quinoa-and-amaranth-grains-and-their-antioxidant-anti-inflammatory-and-potential-health-beneficial-effects-a-review
#2
Yao Tang, Rong Tsao
Quinoa (Chenopodium quinoa Willd.) and amaranth (Amaranthus cruentus L.) are pseudocereal grains rich in both macronutrients and micronutrients including vitamins and minerals. The proteins are particularly of high nutritional quality due to the outstanding balance of essential amino acids. However, recent research strongly suggests that the essential nutrients such as phytochemicals of quinoa and amaranth may also with potential health beneficial effects. This review focuses on the phytochemical composition of quinoa and amaranth seeds, the antioxidant and anti-inflammatory activities of hydrophilic (e...
February 26, 2017: Molecular Nutrition & Food Research
https://www.readbyqxmd.com/read/28239971/characterization-of-n-methylated-amino-acids-by-gc-ms-after-ethyl-chloroformate-derivatization
#3
B Sudarshana Reddy, V Naresh Chary, P Pavankumar, S Prabhakar
Methylation is an essential metabolic process in the biological systems, and it is significant for several biological reactions in living organisms. Methylated compounds are known to be involved in most of the bodily functions, and some of them serve as biomarkers. Theoretically, all α-amino acids can be methylated, and it is possible to encounter them in most animal/plant samples. But the analytical data, especially the mass spectral data, are available only for a few of the methylated amino acids. Thus, it is essential to generate mass spectral data and to develop mass spectrometry methods for the identification of all possible methylated amino acids for future metabolomic studies...
August 2016: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28239779/variation-in-barley-1%C3%A2-%C3%A2-3-1%C3%A2-%C3%A2-%C3%A2-4-%C3%AE-glucan-endohydrolases-reveals-novel-allozymes-with-increased-thermostability
#4
Juanita C Lauer, Suong Cu, Rachel A Burton, Jason K Eglinton
Novel barley (1 → 3, 1 → 4)-β-glucan endohydrolases with increased thermostability. Rapid and reliable degradation of (1 → 3, 1 → 4)-β-glucan to produce low viscosity wort is an essential requirement for malting barley. The (1 → 3, 1 → 4)-β-glucan endohyrolases are responsible for the primary hydrolysis of cell wall β-glucan. The variation in β-glucanase genes HvGlb1 and HvGlb2 that encode EI and EII, respectively, were examined in elite and exotic germplasm. Six EI and 14 EII allozymes were identified, and significant variation was found in β-glucanase from Hordeum vulgare ssp...
February 26, 2017: TAG. Theoretical and Applied Genetics. Theoretische und Angewandte Genetik
https://www.readbyqxmd.com/read/28238686/expression-and-evolutionary-analyses-of-three-acetylcholinesterase-genes-mi-ace-1-mi-ace-2-mi-ace-3-in-the-root-knot-nematode-meloidogyne-incognita
#5
Ruqiang Cui, Lei Zhang, Yuyan Chen, Wenkun Huang, Chengming Fan, Qingsong Wu, Deliang Peng, Washington da Silva, Xiaotang Sun
The full cDNA of Mi-ace-3 encoding an acetylcholinesterase (AChE) in Meloidogyne incognita was cloned and characterized. Mi-ace-3 had an open reading frame of 1875 bp encoding 624 amino acid residues. Key residues essential to AChE structure and function were conserved. The deduced Mi-ACE-3 protein sequence had 72% amino acid similarity with that of Ditylenchus destructor Dd-AChE-3. Phylogenetic analyses using 41 AChEs from 24 species showed that Mi-ACE-3 formed a cluster with 4 other nematode AChEs. Our results revealed that the Mi-ace-3 cloned in this study, which is orthologous to Caenorhabditis elegans AChE, belongs to the nematode ACE-3/4 subgroup...
February 23, 2017: Experimental Parasitology
https://www.readbyqxmd.com/read/28237843/characterization-of-energy-and-neurotransmitter-metabolism-in-cortical-glutamatergic-neurons-derived-from-human-induced-pluripotent-stem-cells-a-novel-approach-to-study-metabolism-in-human-neurons
#6
Blanca I Aldana, Yu Zhang, Maria Fog Lihme, Lasse K Bak, Jørgen E Nielsen, Bjørn Holst, Poul Hyttel, Kristine K Freude, Helle S Waagepetersen
Alterations in the cellular metabolic machinery of the brain are associated with neurodegenerative disorders such as Alzheimer's disease. Novel human cellular disease models are essential in order to study underlying disease mechanisms. In the present study, we characterized major metabolic pathways in neurons derived from human induced pluripotent stem cells (hiPSC). With this aim, cultures of hiPSC-derived neurons were incubated with [U-(13)C]glucose, [U-(13)C]glutamate or [U-(13)C]glutamine. Isotopic labeling in metabolites was determined using gas chromatography coupled to mass spectrometry, and cellular amino acid content was quantified by high-performance liquid chromatography...
February 22, 2017: Neurochemistry International
https://www.readbyqxmd.com/read/28236766/oxidative-stress-metabolomics-profiling-and-mechanism-of-local-anesthetic-induced-cell-death-in-yeast
#7
Cory H T Boone, Ryan A Grove, Dana Adamcova, Javier Seravalli, Jiri Adamec
The World Health Organization designates lidocaine as an essential medicine in healthcare, greatly increasing the probability of human exposure. Its use has been associated with ROS generation and neurotoxicity. Physiological and metabolomic alterations, and genetics leading to the clinically observed adverse effects have not been temporally characterized. To study alterations that may lead to these undesirable effects, Saccharomyces cerevisiae grown on aerobic carbon sources to stationary phase was assessed over 6h...
February 3, 2017: Redox Biology
https://www.readbyqxmd.com/read/28236663/catalytic-competence-structure-and-stability-of-the-cancer-associated-r139w-variant-of-the-human-nad-p-h-quinone-oxidoreductase-1-nqo1
#8
Wolf-Dieter Lienhart, Emilia Strandback, Venugopal Gudipati, Karin Koch, Alexandra Binter, Michael K Uhl, David M Rantasa, Benjamin Bourgeois, Tobias Madl, Klaus Zangger, Karl Gruber, Peter Macheroux
The human NAD(P)H:quinone oxidoreductase 1 (NQO1; EC 1.6.99.2) is an essential enzyme in the antioxidant defence system. Furthermore, NQO1 protects tumour suppressors like p53, p33(ING)(1b) and p73 from proteasomal degradation. The activity of NQO1 is also exploited in chemotherapy for the activation of quinone-based treatments. Various single nucleotide polymorphisms are known, such as NQO1*2 and NQO1*3 yielding protein variants of NQO1 with single amino acid replacements, i.e. P187S and R139W, respectively...
February 25, 2017: FEBS Journal
https://www.readbyqxmd.com/read/28235469/role-of-the-c-terminal-basic-amino-acids-and-the-lipid-anchor-of-the-g%C3%AE-2-protein-in-membrane-interactions-and-cell-localization
#9
Maria A Noguera-Salvà, Francisca Guardiola-Serrano, M Laura Martin, Amaia Marcilla-Etxenike, Martin O Bergo, Xavier Busquets, Pablo V Escribá
Heterotrimeric G proteins are peripheral membrane proteins that frequently localize to the plasma membrane where their presence in molar excess over G protein coupled receptors permits signal amplification. Their distribution is regulated by protein-lipid interactions, which has a clear influence on their activity. Gβγ dimer drives the interaction between G protein heterotrimers with cell membranes. We focused our study on the role of the C-terminal region of the Gγ2 protein in G protein interactions with cell membranes...
February 21, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28235467/identification-and-characterization-of-a-novel-starch-branching-enzyme-from-the-picoalgae-ostreococcus-tauri
#10
Nicolas Hedin, Julieta Barchiesi, Diego F Gomez-Casati, Alberto A Iglesias, Miguel A Ballicora, María V Busi
Starch branching enzyme is a highly conserved protein from plants to algae. This enzyme participates in starch granule assembly by the addition of α-1,6-glucan branches to the α-1,4-polyglucans. This modification determines the structure of amylopectin thus arranging the final composition of the starch granule. Herein, we describe the function of the Ot01g03030 gene from the picoalgae Ostreococcus tauri. Although in silico analysis suggested that this gene codes for a starch debranching enzyme, our biochemical studies support that this gene encodes a branching enzyme (BE)...
February 21, 2017: Archives of Biochemistry and Biophysics
https://www.readbyqxmd.com/read/28231117/compositional-analysis-of-whole-grains-processed-grains-grain-co-products-and-other-carbohydrate-sources-with-applicability-to-pet-animal-nutrition
#11
Alison N Beloshapka, Preston R Buff, George C Fahey, Kelly S Swanson
Our objective was to measure the proximate, starch, amino acid, and mineral compositions of grains, grain co-products, and other carbohydrate sources with potential use in pet foods. Thirty-two samples from barley (barley flake, cut barley, ground pearled barley, malted barley, whole pearled barley, pearled barley flakes, and steamed rolled barley); oats (groats, ground oatmeal, ground steamed groats, instant oats, oat bran, oat fiber, oat flour, quick oats, regular rolled oats, steamed rolled oat groats, and steel cut groats); rice (brown rice, polished rice, defatted rice bran, and rice flour); and miscellaneous carbohydrate sources (canary grass seed, hulled millet, whole millet, quinoa, organic spelt hull pellets, potato flake, sorghum, whole wheat, and whole yellow corn) were analyzed...
March 25, 2016: Foods (Basel, Switzerland)
https://www.readbyqxmd.com/read/28230996/a-facile-n-mercaptoethoxyglycinamide-mega-linker-ap-proach-to-peptide-thioesterification-and-cyclization
#12
Patrick M M Shelton, Caroline E Weller, Champak Chatterjee
The C-terminal selective electrophilic activation of polypeptides is essential for site-specific peptide mod-ification and conjugation techniques such as Native Chemi-cal Ligation (NCL). Peptide C-terminal α-thioesters are par-ticularly valuable precursors for NCL, due to their hydrolytic stability in aqueous buffers and reactivity toward thiol nucle-ophiles. The synthesis of peptide α-thioesters, however, re-quires harsh acidic conditions or complex chemical manipu-lations, which ultimately limits their functional group com-patibility and broad utility...
February 23, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28229928/an-expanded-genetic-code-for-probing-the-role-of-electrostatics-in-enzyme-catalysis-by-vibrational-stark-spectroscopy
#13
REVIEW
Jan-Stefan Völler, Hernan Biava, Peter Hildebrandt, Nediljko Budisa
BACKGROUND: To find experimental validation for electrostatic interactions essential for catalytic reactions represents a challenge due to practical limitations in assessing electric fields within protein structures. SCOPE OF REVIEW: This review examines the applications of non-canonical amino acids (ncAAs) as genetically encoded probes for studying the role of electrostatic interactions in enzyme catalysis. MAJOR CONCLUSIONS: ncAAs constitute sensitive spectroscopic probes to detect local electric fields by exploiting the vibrational Stark effect (VSE) and thus have the potential to map the protein electrostatics...
February 14, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28225179/frozen-chirality-of-tertiary-aromatic-amides-access-to-enantioenriched-tertiary-%C3%AE-amino-acid-or-amino-alcohol-without-any-chiral-reagent
#14
Thi Thoa Mai, Baby Viswambharan, Didier Gori, Régis Guillot, Jean-Valère Naubron, Cyrille Kouklovsky, Valérie Alezra
One of the fundamental and intriguing aspects of life is the homochirality of the essential molecules. In this field, the absolute asymmetric synthesis of α-amino acids is a major challenge. Herein we report access, by chemical means, to tertiary α-amino acids derivatives in up to 96% ee without using any chiral reagent. In our strategy, the dynamic axial chirality of tertiary aromatic amides is frozen in a crystal and is responsible for the stereoselectivity of the subsequent steps. Furthermore, we are able to control the configuration of the final product by carefully sorting out the initial crystals...
February 22, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28224919/characteristics-and-regulatory-pathway-of-the-prupesep1-sepallata-gene-during-ripening-and-softening-in-peach-fruits
#15
Jinjin Li, Fang Li, Ming Qian, Mingyu Han, Hangkong Liu, Dong Zhang, Juanjuan Ma, Caiping Zhao
SEPALLATA genes are members of a subfamily of MADS-box transcription factors, and have essential roles in floral organ development and fruit ripening. In this study, the PrupeSEP1 gene was cloned from peach flesh. Its deduced amino acid sequence was very similar to that of MdMADS8 and MdMADS9 in apple and MADS-RIN-like in strawberry. During storage of melting flesh (MF) peach, the pattern of SEP1 expression was similar to that of ethylene biosynthesis and ethylene signal transduction-related gene expression (EIN2 and ETR2)...
April 2017: Plant Science: An International Journal of Experimental Plant Biology
https://www.readbyqxmd.com/read/28223355/glial-fibrillary-acidic-protein-exhibits-altered-turnover-kinetics-in-a-mouse-model-of-alexander-disease
#16
Laura R Moody, Gregory A Barrett-Wilt, Michael R Sussman, Albee Messing
Mutations in the astrocyte-specific intermediate filament, glial fibrillary acidic protein (GFAP), lead to the rare and fatal disorder, Alexander disease (AxD). A prominent feature of the disease is aberrant accumulation of GFAP. It has been proposed that this accumulation occurs due to an increase in gene transcription coupled with impaired proteasomal degradation, yet this hypothesis remains untested. We therefore sought to directly investigate GFAP turnover in a mouse model of AxD that is heterozygous for a disease-causing point mutation (GfapR236H/+) (and thus expresses both wild-type and mutant protein)...
February 21, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28223245/potential-of-single-cationic-amino-acid-molecule-arginine-for-stimulating-oral-absorption-of-insulin
#17
Noriyasu Kamei, El-Sayed Khafagy, Jun Hirose, Mariko Takeda-Morishita
We have reported that cell-penetrating peptides, such as oligoarginine, act as powerful absorption enhancers for the development of oral insulin delivery systems. However, the minimal essential sequence of oligoarginine that stimulates intestinal insulin absorption remains unclear. Therefore, the present study was conducted to clarify this minimum sequence of oligoarginine and to examine the effect of single cationic amino acid arginine on the intestinal and oral absorption of insulin. The results demonstrated that a remarkable enhancement of intestinal insulin absorption was observed after coadministration of insulin with l-arginine...
February 18, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/28223183/four-distinct-types-of-e-c-1-2-1-30-enzymes-can-catalyze-the-reduction-of-carboxylic-acids-to-aldehydes
#18
Holly Stolterfoht, Daniel Schwendenwein, Christoph W Sensen, Florian Rudroff, Margit Winkler
Increasing demand for chemicals from renewable resources calls for the development of new biotechnological methods for the reduction of oxidized bio-based compounds. Enzymatic carboxylate reduction is highly selective, both in terms of chemo- and product selectivity, but not many carboxylate reductase enzymes (CARs) have been identified on the sequence level to date. Thus far, their phylogeny is unexplored and very little is known about their structure-function-relationship. CARs minimally contain an adenylation domain, a phosphopantetheinylation domain and a reductase domain...
February 18, 2017: Journal of Biotechnology
https://www.readbyqxmd.com/read/28220789/stim1-activates-crac-channels-through-rotation-of-the-pore-helix-to-open-a-hydrophobic-gate
#19
Megumi Yamashita, Priscilla S-W Yeung, Christopher E Ing, Beth A McNally, Régis Pomès, Murali Prakriya
Store-operated Ca(2+) release-activated Ca(2+) (CRAC) channels constitute a major pathway for Ca(2+) influx and mediate many essential signalling functions in animal cells, yet how they open remains elusive. Here, we investigate the gating mechanism of the human CRAC channel Orai1 by its activator, stromal interacting molecule 1 (STIM1). We find that two rings of pore-lining residues, V102 and F99, work together to form a hydrophobic gate. Mutations of these residues to polar amino acids produce channels with leaky gates that conduct ions in the resting state...
February 21, 2017: Nature Communications
https://www.readbyqxmd.com/read/28220105/acth-receptor-mc2r-specificity-what-do-we-know-about-underlying-molecular-mechanisms
#20
REVIEW
Davids Fridmanis, Ance Roga, Janis Klovins
Coincidentally, the release of this Research Topic in Frontiers in Endocrinology takes place 25 years after the discovery of the adrenocorticotropic hormone receptor (ACTHR) by Mountjoy and colleagues. In subsequent years, following the discovery of other types of mammalian melanocortin receptors (MCRs), ACTHR also became known as melanocortin type 2 receptor (MC2R). At present, five types of MCRs have been reported, all of which share significant sequence similarity at the amino acid level, and all of which specifically bind melanocortins (MCs)-a group of biologically active peptides generated by proteolysis of the proopiomelanocortin precursor...
2017: Frontiers in Endocrinology
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