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https://www.readbyqxmd.com/read/27930319/co-synthesized-from-the-central-one-carbon-pool-as-source-for-the-iron-carbonyl-in-o2-tolerant-nife-hydrogenase
#1
Ingmar Bürstel, Elisabeth Siebert, Stefan Frielingsdorf, Ingo Zebger, Bärbel Friedrich, Oliver Lenz
Hydrogenases are nature's key catalysts involved in both microbial consumption and production of molecular hydrogen. H2 exhibits a strongly bonded, almost inert electron pair and requires transition metals for activation. Consequently, all hydrogenases are metalloenzymes that contain at least one iron atom in the catalytic center. For appropriate interaction with H2, the iron moiety demands for a sophisticated coordination environment that cannot be provided just by standard amino acids. This dilemma has been overcome by the introduction of unprecedented chemistry-that is, by ligating the iron with carbon monoxide (CO) and cyanide (or equivalent) groups...
December 5, 2016: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/27928027/five-coordinate-h64q-neuroglobin-as-a-ligand-trap-antidote-for-carbon-monoxide-poisoning
#2
Ivan Azarov, Ling Wang, Jason J Rose, Qinzi Xu, Xueyin N Huang, Andrea Belanger, Ying Wang, Lanping Guo, Chen Liu, Kamil B Ucer, Charles F McTiernan, Christopher P O'Donnell, Sruti Shiva, Jesús Tejero, Daniel B Kim-Shapiro, Mark T Gladwin
Carbon monoxide (CO) is a leading cause of poisoning deaths worldwide, with no available antidotal therapy. We introduce a potential treatment paradigm for CO poisoning, based on near-irreversible binding of CO by an engineered human neuroglobin (Ngb). Ngb is a six-coordinate hemoprotein, with the heme iron coordinated by two histidine residues. We mutated the distal histidine to glutamine (H64Q) and substituted three surface cysteines with less reactive amino acids to form a five-coordinate heme protein (Ngb-H64Q-CCC)...
December 7, 2016: Science Translational Medicine
https://www.readbyqxmd.com/read/27916887/cucumber-metallothionein-like-2-csmtl2-exhibits-metal-binding-properties
#3
Yu Pan, Yanglu Pan, Junpeng Zhai, Yan Xiong, Jinhua Li, Xiaobing Du, Chenggang Su, Xingguo Zhang
We identified a novel member of the metallothionein (MT) family, Cucumis sativus metallothionein-like 2 (CsMTL2), by screening a young cucumber fruit complementary DNA (cDNA) library. The CsMTL2 encodes a putative 77-amino acid Class II MT protein that contains two cysteine (Cys)-rich domains separated by a Cys-free spacer region. We found that CsMTL2 expression was regulated by metal stress and was specifically induced by Cd(2+) treatment. We investigated the metal-binding characteristics of CsMTL2 and its possible role in the homeostasis and/or detoxification of metals by heterologous overexpression in Escherichia coli cells...
November 30, 2016: Genes
https://www.readbyqxmd.com/read/27915018/design-and-surface-immobilization-of-short-anti-biofilm-peptides
#4
Biswajit Mishra, Tamara Lushnikova, Radha M Golla, Xiuqing Wang, Guangshun Wang
: Short antimicrobial peptides are essential to keep us healthy and their lasting potency can inspire the design of new types of antibiotics. This study reports the design of a family of eight-residue tryptophan-rich peptides (TetraF2W) obtained by converting the four phenylalanines in temporin-SHf to tryptophans. The temporin-SHf template was identified from the antimicrobial peptide database (http://aps.unmc.edu/AP). Remarkably, the double arginine variant (TetraF2W-RR) was more effective in killing methicillin-resistant Staphylococcus aureus (MRSA) USA300, but less cytotoxic to human skin HaCat and kidney HEK293 cells, than the lysine-containing dibasic combinations (KR, RK and KK)...
November 30, 2016: Acta Biomaterialia
https://www.readbyqxmd.com/read/27909777/quantitative-determination-of-the-neurotoxin-%C3%AE-n-methylamino-l-alanine-bmaa-by-capillary-electrophoresis-tandem-mass-spectrometry
#5
Elliott S Kerrin, Robert L White, Michael A Quilliam
Recent reports of the widespread occurrence of the neurotoxin β-N-methylamino-L-alanine (BMAA) in cyanobacteria and particularly seafood have raised concerns for public health. LC-MS/MS is currently the analytical method of choice for BMAA determinations but incomplete separation of isomeric and isobaric compounds, matrix suppression and conjugated forms are plausible limitations. In this study, capillary electrophoresis (CE) coupled with MS/MS has been developed as an alternative method for the quantitative determination of free BMAA...
December 1, 2016: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/27908546/effects-of-branched-chain-amino-acid-supplementation-after-radiofrequency-ablation-for-hepatocellular-carcinoma-a-randomized-trial
#6
Shunsuke Nojiri, Kei Fujiwara, Noboru Shinkai, Etsuko Iio, Takashi Joh
OBJECTIVE: Maintenance of liver function is important for better outcomes after radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC). The aim of this study was to examine the effects of oral branched-chain amino acid (BCAA) supplementation on liver function, intrahepatic recurrence rate, and incidence of complications after RFA for HCC. METHODS: Patients with cirrhosis who underwent RFA were enrolled between August 2009 and April 2012, randomized to oral supplementation with Aminoleban EN (BCAA group) or diet alone (control group), and followed to determine changes in serum parameters and health status...
January 2017: Nutrition
https://www.readbyqxmd.com/read/27908428/contribution-of-mammalian-selenocysteine-containing-proteins-to-carcinogenesis
#7
REVIEW
Elena Gennadyevna Varlamova, Irina Valentinovna Cheremushkina
Oxidative stress caused by a sharp growth of free radicals in the organism is a major cause underlying the occurrence of all kinds of malignant formations. Selenium is an important essential trace element found in selenoproteins in the form of selenocysteine, an amino acid differing from cysteine for the presence of selenium instead of sulfur and making such proteins highly active. To date the role of selenium has been extensively investigated through studying the functions of selenoproteins in carcinogenesis...
January 2017: Journal of Trace Elements in Medicine and Biology
https://www.readbyqxmd.com/read/27883086/an-in-silico-study-of-tio2-nanoparticles-interaction-with-twenty-standard-amino-acids-in-aqueous-solution
#8
Shengtang Liu, Xuan-Yu Meng, Jose Manuel Perez-Aguilar, Ruhong Zhou
Titanium dioxide (TiO2) is probably one of the most widely used nanomaterials, and its extensive exposure may result in potentially adverse biological effects. Yet, the underlying mechanisms of interaction involving TiO2 NPs and macromolecules, e.g., proteins, are still not well understood. Here, we perform all-atom molecular dynamics simulations to investigate the interactions between TiO2 NPs and the twenty standard amino acids in aqueous solution exploiting a newly developed TiO2 force field. We found that charged amino acids play a dominant role during the process of binding to the TiO2 surface, with both basic and acidic residues overwhelmingly preferred over the non-charged counterparts...
November 24, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27866376/reduction-in-dietary-acrylamide-exposure-impact-of-potatoes-with-low-acrylamide-potential
#9
Nga L Tran, Leila M Barraj, Susan Collinge
Acrylamide forms primarily from a reaction between reducing sugars (e.g., glucose and fructose) and an amino acid (asparagine, Asn) formed naturally in foods, including potatoes. This reaction occurs when carbohydrate-rich foods are heated at temperatures above 120 °C. Multiple potato varieties were transformed with potato genomic DNA that results in down-regulation of the expression of the asparagine synthetase-1 gene (Asn1), significantly reducing synthesis of free Asn, and consequently lowering the potential to form acrylamide during cooking...
November 20, 2016: Risk Analysis: An Official Publication of the Society for Risk Analysis
https://www.readbyqxmd.com/read/27859287/fungal-and-plant-gene-expression-in-the-tulasnella-calospora-serapias-vomeracea-symbiosis-provides-clues-about-nitrogen-pathways-in-orchid-mycorrhizas
#10
Valeria Fochi, Walter Chitarra, Annegret Kohler, Samuele Voyron, Vasanth R Singan, Erika A Lindquist, Kerrie W Barry, Mariangela Girlanda, Igor V Grigoriev, Francis Martin, Raffaella Balestrini, Silvia Perotto
Orchids are highly dependent on their mycorrhizal fungal partners for nutrient supply, especially during early developmental stages. In addition to organic carbon, nitrogen (N) is probably a major nutrient transferred to the plant because orchid tissues are highly N-enriched. We know almost nothing about the N form preferentially transferred to the plant or about the key molecular determinants required for N uptake and transfer. We identified, in the genome of the orchid mycorrhizal fungus Tulasnella calospora, two functional ammonium transporters and several amino acid transporters but found no evidence of a nitrate assimilation system, in agreement with the N preference of the free-living mycelium grown on different N sources...
November 11, 2016: New Phytologist
https://www.readbyqxmd.com/read/27836414/identification-of-the-igf-1-processing-product-human-ec-rodent-eb-peptide-in-various-tissues-evidence-for-its-differential-regulation-after-exercise-induced-muscle-damage-in-humans
#11
George Vassilakos, Anastassios Philippou, Michael Koutsilieris
OBJECTIVE: Insulin-like growth factor-1 (IGF-1) is a pleiotropic factor expressed in various tissues and plays a critical role in skeletal muscle physiology. Alternative splicing of the IGF-1 gene gives rise to different precursor polypeptides (isoforms) which could undergo post-translational cleavage, generating the common mature IGF-1 peptide and different carboxyl terminal extension (E-) peptides, with the fate of the latter being, so far, unknown. The objective if this study was to identify the IGF-1Ec forms or processing product(s), other than mature IGF-1, generated in different human and rodent tissues and particularly in human skeletal muscle after exercise-induced damage...
November 4, 2016: Growth Hormone & IGF Research
https://www.readbyqxmd.com/read/27830006/mutation-near-the-binding-interfaces-at-%C3%AE-hemoglobin-stabilizing-protein-is-highly-pathogenic
#12
Jesu Francis Borgio, Mohammed S Al-Madan, Sayed AbdulAzeez
Aggregation of free alpha-hemoglobin proteins forms harmful reactive oxygen radicals during the development of normal erythroid cell, which can be prevented by a chaperone, alpha hemoglobin stabilizing protein (AHSP). Mutations at the AHSP gene may affect its interacting ability with other globin proteins. Various state-of-the-art tools have been extensively used to identify the most deleterious nsSNPs at the AHSP and their pathogenic effect during AHSP-globin interaction. Comprehensive analysis revealed that the V56G of the AHS protein is the most pathogenic amino acid substitution, agreed consistently and significantly (P=1...
2016: American Journal of Translational Research
https://www.readbyqxmd.com/read/27808437/amino-acid-oxidation-a-combined-study-of-cysteine-oxo-forms-by-irmpd-spectroscopy-and-simulations
#13
Debora Scuderi, Enrico Bodo, Barbara Chiavarino, Simonetta Fornarini, Maria Elisa Crestoni
The redox activity of cysteine sulfur allows numerous post-translational protein modifications involved in the oxidative regulation of metabolism, in metal binding, and in signal transduction. A combined approach based on infrared multiple photon dissociation spectroscopy at the Centre Laser Infrarouge d'Orsay (CLIO) free electron laser facility, calculations of IR frequencies, and finite temperature ab initio molecular dynamics simulations has been employed to characterize the gas-phase structures of deprotonated cysteine sulfenic, sulfinic, and sulfonic acids, [cysSOx ](-) (x=1, 2, 3, representing the number of S-bound oxygen atoms), which are key intermediates in the redox-switching chemistry of proteins...
November 21, 2016: Chemistry: a European Journal
https://www.readbyqxmd.com/read/27808280/metal-coupled-folding-as-the-driving-force-for-the-extreme-stability-of-rad50-zinc-hook-dimer-assembly
#14
Tomasz Kochańczyk, Michał Nowakowski, Dominika Wojewska, Anna Kocyła, Andrzej Ejchart, Wiktor Koźmiński, Artur Krężel
The binding of metal ions at the interface of protein complexes presents a unique and poorly understood mechanism of molecular assembly. A remarkable example is the Rad50 zinc hook domain, which is highly conserved and facilitates the Zn(2+)-mediated homodimerization of Rad50 proteins. Here, we present a detailed analysis of the structural and thermodynamic effects governing the formation and stability (logK12 = 20.74) of this evolutionarily conserved protein assembly. We have dissected the determinants of the stability contributed by the small β-hairpin of the domain surrounding the zinc binding motif and the coiled-coiled regions using peptides of various lengths from 4 to 45 amino acid residues, alanine substitutions and peptide bond-to-ester perturbations...
November 3, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27802776/hydrophobic-amino-acids-grafted-onto-chitosan-a-novel-amphiphilic-chitosan-nanocarrier-for-hydrophobic-drugs
#15
Marjan Motiei, Soheila Kashanian, Avat Arman Taherpour
OBJECTIVE: To develop a novel biocompatible amphiphilic drug delivery for hydrophobic drugs, chitosan (CS) was grafted to a series of hydrophobic amino acids including L-alanine (A), L-proline (P) and L-tryptophan (W) by carbodiimide mediated coupling reaction. MATERIALS AND METHODS: Chemical characteristics of the modified polymers were determined and confirmed by FT-IR, (1)H-NMR, and UV-vis spectroscopy and the degree of substitution was quantified by elemental analysis...
November 2, 2016: Drug Development and Industrial Pharmacy
https://www.readbyqxmd.com/read/27795411/importance-of-highly-conserved-peptide-sites-of-hcmv-go-for-the-formation-of-the-gh-gl-go-complex
#16
Cora Stegmann, Mohamed E A Abdellatif, Kerstin Laib Sampaio, Paul Walther, Christian Sinzger
: The glycoprotein O (gO) is betaherpesvirus-specific. Together with the viral glycoproteins H and L, gO forms a covalent trimeric complex that is part of the viral envelope. This trimer is crucial for cell-free infectivity of human cytomegalovirus (HCMV) but dispensable for cell-associated spread. We hypothesized that the amino acids (aa) that are conserved among gOs of different cytomegaloviruses are important for the formation of the trimeric complex and hence for efficient virus spread...
October 19, 2016: Journal of Virology
https://www.readbyqxmd.com/read/27789296/drought-stress-in-tomato-increases-the-performance-of-adapted-and-non-adapted-strains-of-tetranychus-urticae
#17
Miguel G Ximénez-Embún, Pedro Castañera, Félix Ortego
The performance of the two-spotted spider mite, Tetranychus urticae Koch, on plants depends on the rate of adaptation of mite populations to each particular host and can be influenced by environmental conditions. We have tested the effects of drought stress, caused by water deficiency, in the interaction of tomato plants with tomato adapted (TA) and tomato non-adapted (TNA) strains of T. urticae. Our data revealed that mite performance was enhanced for the TA strain when reared on drought-stressed tomato plants, rising population growth and leaf damage...
October 24, 2016: Journal of Insect Physiology
https://www.readbyqxmd.com/read/27775340/chemical-etching-of-bovine-serum-albumin-protected-au25-nanoclusters-for-label-free-and-separation-free-ratiometric-fluorescent-detection-of-tris-2-carboxyethyl-phosphine
#18
Tong Shu, Jianxing Wang, Lei Su, Xueji Zhang
This study describes a novel ratiometric fluorescent sensor based on chemical etching of gold nanocluster (GNCs) for label-free, separation-free determination of tris(2-carboxyethyl)phosphine (TCEP). TCEP was discovered to exhibit unusual chemical behavior toward fluorescent gold nanoclusters: it quenched the red fluorescent emission of the bovine serum album (BSA)-protected GNCs (GNCs@BSA) and simultaneously restored the blue fluorescent emission of the dityrosine (diTyr) residues of the BSA ligand. The TCEP-induced quenching of the fluorescent GNCs@BSA was investigated with the UV-vis adsorption spectrum, the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), inductively coupled plasma-mass spectrometry (ICP-MS) and X-ray photoelectron spectroscopy (XPS), revealing the chemical etching of the gold(0) core of the GNCs@BSA by TCEP...
November 2, 2016: Analytical Chemistry
https://www.readbyqxmd.com/read/27765983/characterization-of-nutrients-amino-acids-polyphenols-and-antioxidant-activity-of-ridge-gourd-luffa-acutangula-peel
#19
M P Swetha, S P Muthukumar
Ridge gourd (Luffa acutangula) is consumed as a vegetable after peeling off the skin which is a domestic waste. Luffa acutangula peel (LAP) was observed to be a good source of fiber (20.6 %) and minerals (7.7 %). Amino acid analysis revealed presence of the highest content of Carnosine followed by aspartic acid and aminoadipic acid. Antioxidant activity of different extracts showed that ethyl acetate extract was more potent when compared to other solvent extractions. It exhibited a significant amount of phenolic acids like p-coumaric acid (68...
July 2016: Journal of Food Science and Technology
https://www.readbyqxmd.com/read/27765342/systematic-review-and-meta-analyses-of-the-effect-of%C3%A2-lipid-emulsion-on-microbial-growth-in-parenteral-nutrition
#20
REVIEW
P D Austin, K S Hand, M Elia
BACKGROUND: As lipid in parenteral nutrition (PN) purportedly enhances microbial growth, recommendations limit infusion of lipid PN (or lipid emulsion) from a single container to 24h (48h for lipid-free PN). However, the associated evidence base is ambiguous. AIM: To examine factors affecting microbial growth in PN. METHODS: A systematic review with meta-analyses examined effects of nutrients on microbial growth in PN infusates over a 48-h period using the growth ratio {GR=log10[colony-forming units (cfu)/mL at 48h/cfu/mL at time zero]}...
December 2016: Journal of Hospital Infection
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