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https://www.readbyqxmd.com/read/28917797/a-rapid-and-specific-colorimetric-method-for-free-tryptophan-quantification
#1
Yinan Wu, Tianmin Wang, Chong Zhang, Xin-Hui Xing
Tryptophan is one of the eight essential amino acids and plays an important role in many biological processes. For its interaction with human health, environment and relevant commercial interest in biotechnology-based production, rapid and specific quantification method for this molecule accessible to common laboratories is badly needed. We herein reported a simple colorimetric method for free tryptophan quantification with 96-well-plate-level throughput. Our protocol firstly converted tryptophan to indole enzymatically by purified tryptophanases and then used reactivity of indole with hydroxylamine to form pink product with absorption peak at 530nm, enabling the quantification of tryptophan with simple spectrometry in just two hours...
January 1, 2018: Talanta
https://www.readbyqxmd.com/read/28917052/monitoring-of-methionine-sulfoxide-content-and-methionine-sulfoxide-reductase-activity
#2
Lionel Tarrago, Emmanuel Oheix, Zalán Péterfi, Vadim N Gladyshev
The sulfur-containing amino acid methionine (Met) plays critical roles in protein synthesis, methylation, and sulfur metabolism. Both in its free form and in the form of an amino acid residue, it can be oxidized to the R and S diastereomers of methionine sulfoxide (MetO). Organisms evolved methionine sulfoxide reductases (MSRs) to reduce MetO to Met, with the MSRs type A (MSRA) and type B (MSRB) being specific for the S and R forms of MetO, respectively. In mammals, the selenoprotein MSRB1 plays an important protein repair function, and its expression is tightly regulated by dietary selenium...
2018: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28912796/a-low-cost-imaging-method-for-the-temporal-and-spatial-colorimetric-detection-of-free-amines-on-maize-root-surfaces
#3
Truc H Doan, Tu A Doan, Michael J Kangas, AdreAnna E Ernest, Danny Tran, Christina L Wilson, Andrea E Holmes, Erin L Doyle, Tessa L Durham Brooks
Plant root exudates are important mediators in the interactions that occur between plants and microorganisms in the soil, yet much remains to be learned about spatial and temporal variation in their production. This work outlines a method utilizing a novel colorimetric paper to detect spatial and temporal changes in the production of nitrogen-containing compounds on the root surface. While existing methods have made it possible to conduct detailed analysis of root exudate composition, relatively less is known about where in the root system exudates are produced and how this localization changes as the root grows...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28912103/membrane-perturbing-activities-and-structural-properties-of-the-frog-skin-derived-peptide-esculentin-1a-1-21-nh2-and-its-diastereomer-esc-1-21-1c-correlation-with-their-antipseudomonal-and-cytotoxic-activity
#4
Maria Rosa Loffredo, Anirban Ghosh, Nicole Harmouche, Bruno Casciaro, Vincenzo Luca, Annalisa Bortolotti, Floriana Cappiello, Lorenzo Stella, Anirban Bhunia, Burkhard Bechinger, Maria Luisa Mangoni
Antimicrobial peptides (AMPs) represent new alternatives to cope with the increasing number of multi-drug resistant microbial infections. Recently, a derivative of the frog-skin AMP esculentin-1a, Esc(1-21), was found to rapidly kill both the planktonic and biofilm forms of the Gram-negative bacterium Pseudomonas aeruginosa with a membrane-perturbing activity as a plausible mode of action. Lately, its diastereomer Esc(1-21)-1c containing two d-amino acids i.e. (D)Leu14 and (D)Ser17 revealed to be less cytotoxic, more stable to proteolytic degradation and more efficient in eradicating Pseudomonas biofilm...
September 11, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28900708/apparent-activation-energies-of-protein-protein-complex-dissociation-in-the-gas-phase-determined-by-electrospray-mass-spectrometry
#5
Yelena Yefremova, F Teresa I Melder, Bright D Danquah, Kwabena F M Opuni, Cornelia Koy, Alexandra Ehrens, David Frommholz, Harald Illges, Knut Koelbel, Frank Sobott, Michael O Glocker
We have developed a method to determine apparent activation energies of dissociation for ionized protein-protein complexes in the gas phase using electrospray ionization mass spectrometry following the Rice-Ramsperger-Kassel-Marcus quasi-equilibrium theory. Protein-protein complexes were formed in solution, transferred into the gas phase, and separated from excess free protein by ion mobility filtering. Afterwards, complex disassembly was initiated by collision-induced dissociation with step-wise increasing energies...
September 12, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28894859/changes-in-dynamics-of-%C3%AE-chymotrypsin-due-to-covalent-inhibitors-investigated-by-elastic-incoherent-neutron-scattering
#6
C D Andersson, N Martinez, D Zeller, S H Rondahl, M M Koza, B Frick, F Ekström, J Peters, A Linusson
An essential role of enzymes is to catalyze various chemical reactions in the human body and inhibition of the enzymatic activity by small molecules is the mechanism of action of many drugs or tool compounds used to study biological processes. Here, we investigate the effect on the dynamics of the serine protease α-chymotrypsin when in complex with two different covalently bound inhibitors using elastic incoherent neutron scattering. The results show that the inhibited enzyme displays enhanced dynamics compared to the free form...
September 12, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28877444/new-tethered-phospholipid-bilayers-integrating-functional-g-protein-coupled-receptor-membrane-protein
#7
Meriem Chadli, Samuel Rebaud, Ofelia Maniti, Bruno Tillier, Sandra Cortès, Agnes Girard-Egrot
Membrane proteins exhibiting extra- and intra-cellular domains require an adequate near-native lipid platform for their functional reconstitution. With this aim, we developed a new technology enabling the formation of a peptide-tethered Bilayer Lipid Membrane (pep-tBLM), a lipid bilayer grafted onto peptide spacers, by the way of a metal-chelate interaction. To this end, we designed an original peptide spacer derived from the natural α-laminin thiopeptide (P19), possessing a cysteine residue in N-terminal extremity for grafting on gold and modified in C-terminal extremity by four histidine residues (P19-4H)...
September 6, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28846628/cytotoxicity-of-the-essential-oil-of-fennel-foeniculum-vulgare-from-tajikistan
#8
Farukh Sharopov, Abdujabbor Valiev, Prabodh Satyal, Isomiddin Gulmurodov, Salomudin Yusufi, William N Setzer, Michael Wink
The essential oil of fennel (Foeniculum vulgare) is rich in lipophilic secondary metabolites, which can easily cross cell membranes by free diffusion. Several constituents of the oil carry reactive carbonyl groups in their ring structures. Carbonyl groups can react with amino groups of amino acid residues in proteins or in nucleotides of DNA to form Schiff's bases. Fennel essential oil is rich in anise aldehyde, which should interfere with molecular targets in cells. The aim of the present study was to investigate the chemical composition of the essential oil of fennel growing in Tajikistan...
August 28, 2017: Foods (Basel, Switzerland)
https://www.readbyqxmd.com/read/28845057/a-water-stable-lanthanide-metal-organic-framework-for-fluorimetric-detection-of-ferric-ions-and-tryptophan
#9
Hani Nasser Abdelhamid, Antonio Bermejo-Gómez, Belén Martín-Matute, Xiaodong Zou
The preparation of a highly water stable and porous lanthanide metal-organic framework (MOF) nanoparticles (denoted SUMOF-7II; SU refers to Stockholm University) is described. SUMOF-7II was synthesized starting from the tritopic linker of 2,4,6-tri-p-carboxyphenyl pyridine (H3L2) and La(III) as metal clusters. SUMOF-7II forms a stable dispersion and displays high fluorescence emission with small variation over the pH range of 6 to 12. Its fluorescence is selectively quenched by Fe(III) ions compared to other metal ions...
2017: Mikrochimica Acta
https://www.readbyqxmd.com/read/28836015/role-of-protein-glutathione-contacts-in-defining-glutaredoxin-3-2fe-2s-cluster-chirality-ligand-exchange-and-transfer-chemistry
#10
Sambuddha Sen, J A Cowan
Monothiol glutaredoxins (Grx) serve as intermediate cluster carriers in iron-sulfur cluster trafficking. The [2Fe-2S]-bound holo forms of Grx proteins display cysteinyl coordination from exogenous glutathione (GSH), in addition to contact from protein-derived Cys. Herein, we report mechanistic studies that investigate the role of exogenous glutathione in defining cluster chirality, ligand exchange, and the cluster transfer chemistry of Saccharomyces cerevisiae Grx3. Systematic perturbations were introduced to the glutathione-binding site by substitution of conserved charged amino acids that form crucial electrostatic contacts with the glutathione molecule...
August 23, 2017: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/28827102/shuffle%C3%A2-t7-strain-is-capable-of-producing-high-amount-of-recombinant-human-fibroblast-growth-factor-1-rhfgf-1-with-proper-physicochemical-and-biological-properties
#11
Marzieh Nasiri, Jalal Babaie, Samira Amiri, Ebrahim Azimi, Shiva Shamshiri, Vahid Khalaj, Majid Golkar, Pezhman Fard-Esfahani
BACKGROUND: Human fibroblast growth factor-1 (FGF-1) has powerful mitogenic activities in a variety of cell types and plays significant roles in many physiological processes e.g. angiogenesis and wound healing. There is increasing demand for large scale production of recombinant human FGF-1 (rhFGF-1), in order to investigate the potential medical use. In the present study, we explored SHuffle™ T7 strain for production of rhFGF-1. METHODS: A synthetic gene encoding Met-140 amino acid form of human FGF-1 was utilized for expression of the protein in three different E...
August 18, 2017: Journal of Biotechnology
https://www.readbyqxmd.com/read/28822940/effects-of-airborne-ammonium-and-nitrate-pollution-strongly-differ-in-peat-bogs-but-symbiotic-nitrogen-fixation-remains-unaffected
#12
Eva van den Elzen, Leon J L van den Berg, Bas van der Weijden, Christian Fritz, Lucy J Sheppard, Leon P M Lamers
Pristine bogs, peatlands in which vegetation is exclusively fed by rainwater (ombrotrophic), typically have a low atmospheric deposition of reactive nitrogen (N) (<0.5kgha(-1)y(-1)). An important additional N source is N2 fixation by symbiotic microorganisms (diazotrophs) in peat and mosses. Although the effects of increased total airborne N by anthropogenic emissions on bog vegetation are well documented, the important question remains how different N forms (ammonium, NH4(+), versus nitrate, NO3(-)) affect N cycling, as their relative contribution to the total load strongly varies among regions globally...
August 17, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28822339/effects-of-simulated-n-deposition-on-foliar-nutrient-status-n-metabolism-and-photosynthetic-capacity-of-three-dominant-understory-plant-species-in-a-mature-tropical-forest
#13
Qinggong Mao, Xiankai Lu, Hui Mo, Per Gundersen, Jiangming Mo
Anthropogenic increase of nitrogen (N) deposition has threatened forest ecosystem health at both regional and global scales. In N-limited ecosystems, atmospheric N input is regarded as an important nutrient source for plant growth. However, it remains an open question on how elevated N deposition affects plant growth in N-rich forest ecosystems. To address this question, we used a simulated N deposition experiment in an N-rich mature tropical forest of southern China, with N addition levels as 0kgNha(-1)yr(-1) (Control), 50kgNha(-1)yr(-1) (Low-N), 100kgNha(-1)yr(-1) (Middle-N) and 150kgNha(-1)yr(-1) (High-N), respectively...
August 16, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28815819/novel-consortium-of-klebsiella-variicola-and-lactobacillus-species-enhances-the-functional-potential-of-fermented-dairy-products-by-increasing-the-availability-of-branched-chain-amino-acids-and-the-amount-of-distinctive-volatiles
#14
H Rosales-Bravo, H C Morales-Torres, J Vázquez-Martínez, J Molina-Torres, V Olalde-Portugal, L P Partida-Martínez
AIMS: Identify novel bacterial taxa that could increase the availability of branched-chain amino acids and the amount of distinctive volatiles during skim milk fermentation. METHODS AND RESULTS: We recovered 344 bacterial isolates from stool samples of healthy and breastfed infants. Five were selected based on their ability to produce branched-chain amino acids. Three strains were identified as Escherichia coli, one as Klebsiella pneumoniae and other as Klebsiella variicola by molecular and biochemical methods...
August 17, 2017: Journal of Applied Microbiology
https://www.readbyqxmd.com/read/28815215/structural-characterization-of-acidic-m17-leucine-aminopeptidases-from-the-tritryps-and-evaluation-of-their-role-in-nutrient-starvation-in-trypanosoma-brucei
#15
Jennifer Timm, Maria Valente, Daniel García-Caballero, Keith S Wilson, Dolores González-Pacanowska
Leucine aminopeptidase (LAP) is found in all kingdoms of life and catalyzes the metal-dependent hydrolysis of the N-terminal amino acid residue of peptide or amino acyl substrates. LAPs have been shown to participate in the N-terminal processing of certain proteins in mammalian cells and in homologous recombination and transcription regulation in bacteria, while in parasites, they are involved in host cell invasion and provision of essential amino acids for growth. The enzyme is essential for survival in Plasmodium falciparum, where its drug target potential has been suggested...
July 2017: MSphere
https://www.readbyqxmd.com/read/28800624/destabilizing-polymorphism-in-cervid-prion-protein-hydrophobic-core-determines-prion-conformation-and-conversion-efficiency
#16
Samia Hannaoui, Sara Amidian, Yo Ching Cheng, Camilo Duque Velásquez, Lyudmyla Dorosh, Sampson Law, Glenn Telling, Maria Stepanova, Debbie McKenzie, Holger Wille, Sabine Gilch
Prion diseases are infectious neurodegenerative disorders of humans and animals caused by misfolded forms of the cellular prion protein PrPC. Prions cause disease by converting PrPC into aggregation-prone PrPSc. Chronic wasting disease (CWD) is the most contagious prion disease with substantial lateral transmission, affecting free-ranging and farmed cervids. Although the PrP primary structure is highly conserved among cervids, the disease phenotype can be modulated by species-specific polymorphisms in the prion protein gene...
August 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/28797801/dimeric-and-trimeric-homo-and-heteroleptic-hydroxamic-acid-macrocycles-formed-using-mixed-ligand-fe-iii-based-metal-templated-synthesis
#17
Athavan Sresutharsan, William Tieu, Tomas Richardson-Sanchez, Cho Zin Soe, Rachel Codd
Macrocyclic hydroxamic acids coordinate Fe(III) with high affinity as part of siderophore-mediated bacterial iron acquisition. Trimeric hydroxamic acid macrocycles, such as desferrioxamine E (DFOE), are prevalent in nature, with fewer dimeric macrocycles identified, including putrebactin (pbH2), avaroferrin (avH2), bisucaberin (bsH2) and alcaligin (alH2). This work used metal-templated synthesis (MTS) to pre-assemble complexes between one equivalent of Fe(III) and two equivalents of 4-((4-aminobutyl)(hydroxy)amino)-4-oxobutanoic acid (BBH) or 4-((5-aminopentyl)(hydroxy)amino)-4-oxobutanoic acid (PBH)...
August 1, 2017: Journal of Inorganic Biochemistry
https://www.readbyqxmd.com/read/28792212/the-lc8-recognition-motif-preferentially-samples-polyproline-ii-structure-in-its-free-state
#18
Jessica L Morgan, Malene Ringkjøbing Jensen, Valéry Ozenne, Martin Blackledge, Elisar Barbar
LC8 is a ubiquitous hub protein that binds intrinsically disordered proteins and promotes their assembly into higher-order complexes. A common feature among the more than 100 essential LC8 binding proteins is that in the 10-12-amino acid recognition sequence there is a conserved QT motif but variable amino acids N- and C-terminal to the QT pair. The sequence diversity among LC8 binding partners implies that structural factors also contribute to specificity. To investigate whether one such factor is the transient secondary structure favored by an LC8 binding sequence, we report here a molecular ensemble description of ICTL, a domain of the dynein intermediate chain that includes binding sites for light chains LC8 and Tctex1...
August 23, 2017: Biochemistry
https://www.readbyqxmd.com/read/28791742/a-multispecific-monoclonal-antibody-g2-recognizes-at-least-three-completely-different-epitope-sequences-with-high-affinity
#19
Md Nuruddin Mahmud, Masayuki Oda, Daiki Usui, Yasuo Inoshima, Naotaka Ishiguro, Yuji O Kamatari
A monoclonal antibody (mAb) G2 possesses an unusual characteristic of reacting with at least three proteins (ATP6V1C1, SEPT3, and C6H10orf76) other than its original antigen, chicken prion protein (ChPrP). The epitopes on ChPrP and ATP6V1C1 have been identified previously. In this study, we identified the epitope in the third protein, SEPT3. Interestingly, there was no amino acid sequence similarity among the epitopes on the three proteins. These epitopes had high binding affinities to G2 (KD = ∼10(-7) M for monovalent binding and KD = ∼10(-9) M for divalent binding), as determined using a SPR biosensor...
August 9, 2017: Protein Science: a Publication of the Protein Society
https://www.readbyqxmd.com/read/28751905/monoterpenyl-glycosyltransferases-differentially-contribute-to-production-of-monoterpenyl-glycosides-in-two-aromatic-vitis-vinifera-varieties
#20
Xiang-Yi Li, Ya-Qin Wen, Nan Meng, Xu Qian, Qiu-Hong Pan
HIGHLIGHTS A similar trend on accumulation of glycosidically bound monoterpenes was observed in both varietiesTwo VvGT7 alleles mutations occurred at key sites in Muscat blanc à PetitVvGT14 exerted a major role in production of monoterpenyl glycosides in both varieties Terpenoids are the major aroma components and generally exist as both free and glycosidically-bound forms, of which nonvolatile glycosides account for a large fraction in grape berries. Our previous study has indicated that differential accumulation of monoterpenyl glycosides in Vitis vinifera "Muscat blanc à Petit" between two regions is closely correlated to monoterpenyl glucosyltransferase (VvGT14, XM_002285734...
2017: Frontiers in Plant Science
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