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Free form amino acids

Danillo Valverde, Zélia Maria da Costa Ludwig, Célia Regina da Costa, Valdemir Ludwig, Herbert C Georg
At physiological conditions, myriads of biomolecules (e.g., amino acids, peptides, and proteins) exist predominantly in the zwitterionic structural form and their biological functions will result in these conditions. However these geometrical structures are inaccessible energetically in the gas phase, and at this point, stabilization of amino-acids in physiological conditions is still under debate. In this paper, the electronic properties of a glycine molecule in the liquid environment were studied by performing a relaxation of the glycine geometry in liquid water using the free energy gradient method combined with a sequential quantum mechanics/molecular mechanics approach...
January 14, 2018: Journal of Chemical Physics
Gabriel M Mascarin, Nilce N Kobori, Mark A Jackson, Christopher A Dunlap, Ítalo Delalibera
AIMS: Nitrogen is a critical element in industrial fermentation media. This study investigated the influence of various nitrogen sources on blastospore production, desiccation tolerance, and storage stability using two strains of the cosmopolitan insect pathogenic fungus Beauveria bassiana. METHODS AND RESULTS: Complex organic sources of nitrogen such as soy flour, autolyzed yeast and cottonseed flour induced great numbers of blastospores after 2-3 days of fermentation, which also survived drying and remained viable (32-56% survival) after 9 months storage at 4 °C, although variations were found between strains...
January 11, 2018: Journal of Applied Microbiology
Tomasz Klaus, Krystyna Stalińska, Dominik Czaplicki, Paweł Mak, Bozena Skupien-Rabian, Sylwia Kedracka-Krok, Karolina Wiatrowska, Monika Bzowska, Monika Machula, Joanna Bereta
IgM is a multivalent antibody which evolved as a first line defense of adaptive immunity. It consists of heavy and light chains assembled into a complex oligomer. In mouse serum there are two forms of IgM, a full-length and a truncated one. The latter contains μ' chain, which lacks a variable region. Although μ' chain was discovered many years ago, its origin has not yet been elucidated. Our results indicate that μ' chain is generated from a full-length heavy chain by non-enzymatic cleavage of the protein backbone...
January 11, 2018: Scientific Reports
Sasirekha Narayanasamy, Gopala Krishna Aradhyam
Calumenin (Calu) is a well-conserved multi EF-hand containing Ca2+-binding protein. In this work, we focused our attention on the alterations that calumenin has undergone during evolution. We demonstrate that vertebrate calumenin is significantly different from its invertebrate homologs with respect to its response to Ca2+-binding. Human calumenin (HsCalu1) is intrinsically unstructured in the Ca2+ free form and responds to Ca2+ with a dramatic gain in structure. Calumenin from C. elegans (CeCalu) is structured even in the apo form, with no conformational change on binding Ca2+...
January 10, 2018: Biochemistry
Irene Ling, Mohamed Taha, Nada A Al-Sharji, Osama K Abou-Zied
The ability of human serum albumin (HSA) to bind medium-sized hydrophobic molecules is important for the distribution, metabolism, and efficacy of many drugs. Herein, the interaction between pyrene, a hydrophobic fluorescent probe, and HSA was thoroughly investigated using steady-state and time-resolved fluorescence techniques, ligand docking, and molecular dynamics (MD) simulations. A slight quenching of the fluorescence signal from Trp214 (the sole tryptophan residue in the protein) in the presence of pyrene was used to determine the ligand binding site in the protein, using Förster's resonance energy transfer (FRET) theory...
January 4, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Eric T Christenson, Austin S Gallegos, Anirban Banerjee
Iron is universally important to cellular metabolism and mitoferrins-1 and -2 have been proposed to be the iron importers of mitochondria, the cell's assembly plant of heme and iron-sulfur clusters. These iron-containing prosthetic groups are critical for a host of physiological processes ranging from oxygen transport and energy consumption to maintaining protein structural integrity. Mitoferrin-1 (Mfrn1) belongs to the mitochondrial carrier (MC) family and is atypical given its putative metallic cargo; most MCs transport nucleotides, amino acids, or other small to medium-size metabolites...
January 5, 2018: Journal of Biological Chemistry
Shuhei Hashiro, Koyu Fujiuchi, Daisuke Sugimori, Hisashi Yasueda
We have identified an enzyme, galactolipase (ckGL), which hydrolyzes the acyl ester bond of galactolipids such as digalactosyldiacylglycerol (DGDG), in the microalga Chlorella kessleri. Following purification of the enzyme to electrophoretic homogeneity from cell-free extract, the maximum activity toward DGDG was observed at pH 6.5 and 37 °C. ckGL was Ca2+-dependent enzyme and displayed an apparent molecular mass of approx. 53 kDa on SDS-PAGE. The substrate specificity was in the order: DGDG (100%) > monogalactosyldiacylglycerol ≈ phosphatidylglycerol (~ 40%) > sulfoquinovosyldiacylglycerol (~ 20%); the enzyme exhibited almost no activity toward glycerides and other phospholipids...
January 3, 2018: Applied Microbiology and Biotechnology
Xin Zhao, Kun Tian, Rong L He, Stephen S-T Yau
Prochlorococcus marinus, one of the most abundant marine cyanobacteria in the global ocean, is classified into low-light (LL) and high-light (HL) adapted ecotypes. These two adapted ecotypes differ in their ecophysiological characteristics, especially whether adapted for growth at high-light or low-light intensities. However, some evolutionary relationships of Prochlorococcus phylogeny remain to be resolved, such as whether the strains SS120 and MIT9211 form a monophyletic group. We use the Natural Vector (NV) method to represent the sequence in order to identify the phylogeny of the Prochlorococcus...
December 2017: Ecology and Evolution
Sinnathamby N Surendran, Kokila Sivabalakrishnan, Kanapathy Gajapathy, Sivasingham Arthiyan, Tibutius T P Jayadas, Kalingarajah Karvannan, Selvarajah Raveendran, S H P Parakrama Karunaratne, Ranjan Ramasamy
BACKGROUND: Anopheles stephensi, the major vector of urban malaria in India, was recently detected for the first time in Sri Lanka in Mannar Island on the northwestern coast. Since there are different biotypes of An. stephensi with different vector capacities in India, a study was undertaken to further characterise the genotype and biotype of An. stephensi in Mannar Island. METHODS: Mosquito larvae were collected in Pesalai village in Mannar and maintained in the insectary until adulthood...
January 3, 2018: Parasites & Vectors
Dechang Yao, Wenhai Chu, Tom Bond, Shunke Ding, Shenghua Chen
ClO2 is frequently used as a pre-oxidant in water treatment plants. However, the effects of ClO2 pre-oxidation on disinfection by-product (DBP) formation, especially the highly toxic nitrogenous DBPs, during subsequent chlor (am)ination have not been studied thoroughly. There is also limited information about DBP formation from combined amino acids (AAs), which are more abundant than free AAs in source waters. Many typical DBPs (including representative N-DBPs) have a similar structure of "CX3R" (X = H, Cl, Br or I)...
December 26, 2017: Chemosphere
Sylwia Stączek, Agnieszka Zdybicka-Barabas, Paweł Mak, Aneta Sowa-Jasiłek, Sylwia Kedracka-Krok, Urszula Jankowska, Piotr Suder, Jerzy Wydrych, Katarzyna Grygorczuk, Teresa Jakubowicz, Małgorzata Cytryńska
A lipid-binding protein apolipophorin III (apoLp-III), an exchangeable component of lipophorin particles, is involved in lipid transport and immune response in insects. In Galleria mellonella, apoLp-III binding to high-density lipophorins and formation of low-density lipophorin complexes upon immune challenge was reported. However, an unanswered question remains whether apoLp-III could form different complexes in a pathogen-dependent manner. Here we report on pathogen- and time-dependent alterations in the level of apoLp-III free and lipophorin-bound form that occur in the hemolymph and hemocytes shortly after immunization of G...
December 28, 2017: Journal of Insect Physiology
Colin Kleinguetl, James C Williams, Samar A Ibrahim, Michel Daudon, Erin T Bird, Marawan M El Tayeb
Background: Calcium tartrate tetrahydrate has been reported as the main mineral in urinary stones in rats that have significant tartrate in their diet, but in humans, there has been only one mention of calcium tartrate stones in the form of bladder stone, and that case was in Africa. Case Presentation: Patient is a 34-year-old Caucasian male who presented with typical symptoms of nephrolithiasis. CT abd/pelvis (renal stone protocol) revealed a 2 cm nonobstructing stone of the right renal pelvis. Patient underwent an uncomplicated right percutaneous nephrolithotomy and was noted to be stone free after surgery...
2017: Journal of Endourology Case Reports
Satoru Mimura, Yumiko Kubota, Haruhiko Takisawa
The minichromosome maintenance (MCM) complex, consisting of six subunits, Mcm2-7, is loaded onto replication origins through loading factors (origin recognition complex [ORC], Cdc6, and Cdt1) and forms an MCM double hexamer that licenses the initiation of DNA replication. Previous studies with Xenopus egg extracts showed that loading factors, especially Cdc6, dissociate from chromatin on MCM loading, but the molecular mechanism and physiological significance remain largely unknown. Using a cell-free system for MCM loading onto plasmid DNA in Xenopus egg extracts, we found that MCM loaded onto DNA prevents DNA binding of the loading factors ORC, Cdc6, and Cdt1...
December 20, 2017: Cell Cycle
Muhammad Altaf, Helen Stoeckli-Evans
Tranexamic acid [systematic name: trans-4-(amino-meth-yl)cyclo-hexane-1-carb-oxy-lic acid], is an anti-fibrinolytic amino acid that exists as a zwitterion [trans-4-(ammonio-meth-yl)cyclo-hexane-1-carboxyl-ate] in the solid state. Its reaction with copper chloride leads to the formation of a compound with a copper(II) paddle-wheel structure that crystallizes as a hexa-hydrate, [Cu2Cl2(C8H15NO2)4]2+·2Cl-·6H2O. The asymmetric unit is composed of a copper(II) cation, two zwitterionic tranexamic acid units, a coordinating Cl- anion and a free Cl- anion, together with three water mol-ecules of crystallization...
October 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
Tarek Aboul-Fadl, Soliman S Al-Hamad, Ehab A Fouad
Naproxen (nap) is belonging to Non-steriodal anti-inflammatory drugs (NSAIDs) group of drugs that characterized by their free carboxylic group. The therapeutic activity of nap is usually accompanied by GI untoward side effects. Recently synthesized naproxen amides of some amino acid esters prodrugs to mask the free carboxylic group were reported. Those prodrugs showed a promising colorectal cancer chemopreventive activity. The current study aims to investigate the fate and hydrolysis of the prodrugs kinetically in different pH conditions, simulated gastric and intestinal fluids with pHs of 1...
December 2, 2017: Bioorganic Chemistry
T Sedlačík, O K Acar, H Studenovská, I Kotelnikov, J Kučka, Z Konečná, T Zikmund, J Kaiser, G T Kose, F Rypáček
In this study, the potential of highly porous hydrogels based on biodegradable synthetic poly(α-amino acids) to support proliferation and chondrogenesis of human dental pulp stem cells (hDPSCs) was investigated. Covalently crosslinked gels with permanent pores were formed under cryogenic conditions by free-radical copolymerization of poly[N5-(2-hydroxyethyl)-l-glutamine-stat-N5-(2-methacryloyl-oxy-ethyl)-l-glutamine] (PHEG-MA) with 2-hydroxyethyl methacrylate (HEMA) and N-propargyl methacrylamide (PrMAAm) as minor co-monomers...
December 11, 2017: Soft Matter
Imogen M Bermingham, Keith J Chappell, Daniel Watterson, Paul R Young
Respiratory syncytial virus (RSV) mediates host cell entry through the fusion (F) protein, which undergoes a conformational change to facilitate the merger of viral and host lipid membrane envelopes. RSV F comprises a trimer of disulfide bonded F1 and F2 subunits that is present on the virion surface in a 'metastable' pre-fusion state. This pre-fusion form is readily triggered to undergo refolding to bring two heptad repeats (HRA and HRB) into close proximity to form a six-helix bundle that stabilizes the post-fusion form and provides the free energy required for membrane fusion...
December 6, 2017: Journal of Virology
C D Hickey, B W K Diehl, M Nuzzo, A Millqvist-Feurby, M G Wilkinson, J J Sheehan
The effect of buttermilk powder addition post-curd formation or buttermilk addition to cheese milk on total and individual phospholipid content, chemical composition, enzyme activity, microbial populations and microstructure within Cheddar-style cheese was investigated. Buttermilk or buttermilk powder addition resulted in significant increases in total phospholipid content and their distribution throughout the cheese matrix. Addition of 10% buttermilk powder resulted in higher phospholipid content, moisture, pH and salt in moisture levels, and lower fat, fat in dry matter, L...
December 2017: Food Research International
Kun Zang, Fuhua Li, Qingjun Ma
dUTPases are essential enzymes for maintaining genome integrity and have recently been shown to play moonlighting roles when containing extra sequences. Interestingly, the trimeric dUTPase of white spot syndrome virus (wDUT) harbors a sequence insert at the position preceding the C-terminal catalytic motif V (pre-V insert), rarely seen in other dUTPases. However, whether this extra sequence endows wDUT with additional properties is unknown. Herein, we present the crystal structures of wDUT in both ligand-free and ligand-bound forms...
November 29, 2017: Journal of Biological Chemistry
Yelena Yefremova, Bright D Danquah, Kwabena Fm Opuni, Reham El-Kased, Cornelia Koy, Michael O Glocker
Proteins are essential for almost all physiological processes of life. They serve a myriad of functions which are as varied as their unique amino acid sequences and their corresponding three-dimensional structures. To fulfill their tasks, most proteins depend on stable physical associations, in the form of protein complexes that evolved between themselves and other proteins. In solution (condensed phase), proteins and/or protein complexes are in constant energy exchange with the surrounding solvent. Albeit methods to describe in-solution thermodynamic properties of proteins and of protein complexes are well established and broadly applied, they do not provide a broad enough access to life-science experimentalists to study all their proteins' properties at leisure...
December 2017: European Journal of Mass Spectrometry
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