scholarly journals Mechanism and Structural Insights Into a Novel Esterase, E53, Isolated From Erythrobacter longus

2022 ◽  
Vol 12 ◽  
Author(s):  
Yi Ding ◽  
Laiyin Nie ◽  
Xiao-Chen Yang ◽  
Yang Li ◽  
Ying-Yi Huo ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Diffraction Method ◽  
Industrial Applications ◽  
X Ray Diffraction ◽  
Functional Studies ◽  
Detailed Structural Analysis ◽  
Alkaline Conditions ◽  
Novel Esterase ◽  
Reaction With Water ◽  
Mutagenesis Study

Esterases are a class of enzymes that split esters into an acid and an alcohol in a chemical reaction with water, having high potential in pharmaceutical, food and biofuel industrial applications. To advance the understanding of esterases, we have identified and characterized E53, an alkalophilic esterase from a marine bacterium Erythrobacter longus. The crystal structures of wild type E53 and three variants were solved successfully using the X-ray diffraction method. Phylogenetic analysis classified E53 as a member of the family IV esterase. The enzyme showed highest activity against p-nitrophenyl butyrate substrate at pH 8.5–9.5 and 40°C. Based on the structural feature, the catalytic pocket was defined as R1 (catalytic center), R2 (pocket entrance), and R3 (end area of pocket) regions. Nine variants were generated spanning R1–R3 and thorough functional studies were performed. Detailed structural analysis and the results obtained from the mutagenesis study revealed that mutations in the R1 region could regulate the catalytic reaction in both positive and negative directions; expanding the bottleneck in R2 region has improved the enzymatic activity; and R3 region was associated with the determination of the pH pattern of E53. N166A in R3 region showed reduced activity only under alkaline conditions, and structural analysis indicated the role of N166 in stabilizing the loop by forming a hydrogen bond with L193 and G233. In summary, the systematic studies on E53 performed in this work provide structural and functional insights into alkaliphilic esterases and further our knowledge of these enzymes.

scholarly journals Chemical Modification of Combusted Coal Gangue for U(VI) Adsorption: Towards a Waste Control by Waste Strategy

2021 ◽  
Vol 13 (15) ◽  
pp. 8421
Author(s):  
Yuan Gao ◽  
Jiandong Huang ◽  
Meng Li ◽  
Zhongran Dai ◽  
Rongli Jiang ◽  
...  
Keyword(s):  
Structural Analysis ◽  
High Efficiency ◽  
Low Cost ◽  
Chemical Activation ◽  
Cost Effective ◽  
Coal Gangue ◽  
Order Kinetic ◽  
Practical Applications ◽  
Detailed Structural Analysis ◽  
Alkaline Conditions

Uranium mining waste causes serious radiation-related health and environmental problems. This has encouraged efforts toward U(VI) removal with low cost and high efficiency. Typical uranium adsorbents, such as polymers, geopolymers, zeolites, and MOFs, and their associated high costs limit their practical applications. In this regard, this work found that the natural combusted coal gangue (CCG) could be a potential precursor of cheap sorbents to eliminate U(VI). The removal efficiency was modulated by chemical activation under acid and alkaline conditions, obtaining HCG (CCG activated with HCl) and KCG (CCG activated with KOH), respectively. The detailed structural analysis uncovered that those natural mineral substances, including quartz and kaolinite, were the main components in CCG and HCG. One of the key findings was that kalsilite formed in KCG under a mild synthetic condition can conspicuous enhance the affinity towards U(VI). The best equilibrium adsorption capacity with KCG was observed to be 140 mg/g under pH 6 within 120 min, following a pseudo-second-order kinetic model. To understand the improved adsorption performance, an adsorption mechanism was proposed by evaluating the pH of uranyl solutions, adsorbent dosage, as well as contact time. Combining with the structural analysis, this revealed that the uranyl adsorption process was mainly governed by chemisorption. This study gave rise to a utilization approach for CCG to obtain cost-effective adsorbents and paved a novel way towards eliminating uranium by a waste control by waste strategy.

A bis-Au(III) [28]hexaphyrin triphenylphosphine adduct

2016 ◽  
Vol 20 (08n11) ◽  
pp. 997-1001 ◽  
Author(s):  
Koji Naoda ◽  
Atsuhiro Osuka
Keyword(s):  
Solid State ◽  
Structural Analysis ◽  
Trifluoroacetic Acid ◽  
X Ray Diffraction ◽  
Nmr Spectrum ◽  
X Ray ◽  
H Nmr ◽  
Detailed Structural Analysis ◽  
Nir Absorption ◽  
Plausible Mechanism

Triphenylphosphine was added regioselectively at the C(3) position of bis-Au(III) complex of [26]hexaphyrin 5 in the presence of trifluoroacetic acid to produce [28]hexaphyrin triphenylphosphine adduct 6 in 62% yield, which has been fully characterized by NMR, UV-vis/NIR absorption, and MS spectroscopies, and X-ray diffraction analysis. The rigid planar structure forces 6 to take Hückel antiaromaticity, which has been supported by its 1H NMR spectrum. Curiously, the detailed structural analysis elucidated that the triphenylphosphine moiety exists as a phosphorane form in the solid state. A plausible mechanism via a double protonated 5 is proposed, which can explain the observed regioselectivity.

scholarly journals Molecular Characterization of Novel Family IV and VIII Esterases from a Compost Metagenomic Library

2021 ◽  
Vol 9 (8) ◽  
pp. 1614
Author(s):  
Jong-Eun Park ◽  
Geum-Seok Jeong ◽  
Hyun-Woo Lee ◽  
Hoon Kim
Keyword(s):  
Metagenomic Library ◽  
Industrial Applications ◽  
Native Form ◽  
Metagenome Library ◽  
The Family ◽  
Alkaline Conditions ◽  
Molecular Masses ◽  
Novel Esterase ◽  
Family Iv

Two novel esterase genes, est8L and est13L, were isolated and identified from a compost metagenomic library. The encoded Est8L and Est13L had molecular masses of 33,181 and 44,913 Da consisting of 314 and 411 amino acids, respectively, without signal peptides. Est8L showed the highest identity (32.9%) to a hyper-thermophilic carboxylesterase AFEST from Archaeoglobus fulgidus compared to other esterases reported and was classified to be a novel member of family IV esterases with conserved regions such as HGGG, DY, GXSXG, DPL, and GXIH. Est13L showed the highest identity (98.5%) to the family VIII esterase Est7K from the metagenome library. Est8L and Est13L had the highest activities for p-nitrophenyl butyrate (C4) and p-nitrophenyl caproate (C6), respectively, and Est13L showed a broad substrate specificity for p-nitrophenyl substrates. Est8L and Est13L effectively hydrolyzed glyceryl tributyrate. The optimum temperatures for activities of Est8L and Est13L were identical (40 °C), and the optimum pH values were 9.0 and 10.0, respectively. Est13L showed higher thermostability than Est8L. Sephacryl S-200 HR chromatography showed that the native form of Est8L was a dimer. Interestingly, Est13L was found to be a tetramer, contrary to other family VIII esterases reported. Est8L was inhibited by 30% isopropanol, methanol, and acetonitrile; however, Est13L was activated to 182.9% and 356.1%, respectively, by 30% isopropanol and methanol. Est8L showed enantioselectivity for the S-form, but Est13L showed no enantioselectivity. These results show that intracellular Est8L and/or Est13L are oligomeric in terms of native forms and can be used for pharmaceutical and industrial applications with organic solvents under alkaline conditions.

Crystallization and preliminary X-ray diffraction studies of 6-phosphogluconate dehydrogenase from Lactococcus lactis

1998 ◽  
Vol 54 (6) ◽  
pp. 1422-1424 ◽  
Author(s):  
E. Tetaud ◽  
D. R. Hall ◽  
D. G. Gourley ◽  
G. A. Leonard ◽  
S. Arkison ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Lactococcus Lactis ◽  
Biochemical Characterization ◽  
Pentose Phosphate ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Phosphogluconate Dehydrogenase ◽  
Detailed Structural Analysis ◽  
Structure Activity

6-Phosphogluconate dehydrogenase is one of the seven enzymes involved in the pentose phosphate pathway. Crystals of a mammalian and a protozoan enzyme have been obtained previously and structures determined. It is reported here that a bacterial 6-phosphogluconate dehydrogenase, from Lactococcus lactis, has been purified and used in crystallization trials. Large prisms suitable for a detailed structural analysis have been obtained and characterized as orthorhombic, space group F222, with a = 70.4, b = 105.7, c = 474.6 Å. Diffraction has been observed to 2.2 Å resolution using synchrotron radiation. Structural analysis, in combination with ongoing biochemical characterization, will assist the elucidation of the structure–activity relationships of this enzyme.

Crystal and molecular structure of carbonylcyanide-4-chlorophenylhydrazone(4-chlorophenylhydrazonopropanedinitrile)

1984 ◽  
Vol 49 (10) ◽  
pp. 2363-2370
Author(s):  
Viktor Vrábel ◽  
Ernest Šturdík ◽  
Michal Dunaj-Jurčo ◽  
Jan Lokaj ◽  
Ján Garaj
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Structural Analysis ◽  
Least Squares Method ◽  
Crystal And Molecular Structure ◽  
Heavy Atom ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heavy Atom Method

The crystal structure of carbonylcyanide-4-chlorophenylhydrazone was solved by the single crystal X-ray diffraction method and interpreted by the heavy atom method. The compound crystallizes in the P21/c monoclinic group with 4 molecules per unit cell and with lattice parameters: a = 1.1843(3), b = 0.5944(1), c = 1.4922(3) nm and β = 117.92(2)°. The structure was refined by the least squares method for 1 078 observed reflections to a final value of R = 4.9%. The crystal structure consists of monomeric units, where hydrogen bonds were observed between atoms N3...H5 0.2193 nm and N3...H3 0.2404 nm between two molecules transformable through centre of symmetry -x, -y, -z. The name 4-chlorophenylhydrazonopropanedinitrile is recommended for the studied compound on the basis of this X-ray structural analysis.

scholarly journals SYNTHESIS, CHARACTERIZATION, AND ANTIBACTERIAL STUDY OF ZINC OXIDE-GRAPHENE NANOCOMPOSITES

2017 ◽  
Vol 10 (9) ◽  
pp. 206
Author(s):  
Harish Kumar ◽  
Manisha Kumari
Keyword(s):  
Zinc Oxide ◽  
Graphene Oxide ◽  
Diffraction Method ◽  
Industrial Applications ◽  
X Ray Diffraction ◽  
Zno Nps ◽  
Graphene Nanocomposites ◽  
Viable Solution ◽  
Reduced Graphene ◽  
Therapeutic Needs

Objectives: A novel facile synthesis of zinc oxide (ZnO) and zinc-graphene oxide nanocomposites (ZnGONC) was achieved by modified sol-geltechnique for their pharmaceutical and therapeutic use.Materials and Methods: Spherical, crystalline, defect-free Zinc oxide nanoparticles (ZnO NPs) with diameter 70-90 nm were synthesized by modifiedsol-gel technique. Reduced graphene oxide was synthesized by modified Hummers method. ZnGONC were synthesized by in situ method. The crystallinenature, size, shape, and dimensions of the NPs, graphene oxide, and nanocomposites were studied by X-ray diffraction method. Transmission electronmicroscopy analysis was carried out to examine the morphology of NPs and nanocomposites.Results: Fourier transform infrared spectroscopy analysis confirms that the ZnO NPs are surrounded by oxygen and silicon atoms. Antibacterialactivity of ZnO NPs and ZnGONC was investigated against Gram-positive and Gram-negative bacteria. Zone of inhibition shown by ZnO NPs andZnGONC was found to be higher than six investigated standard antibiotics.Conclusion: Synthesized ZnO NPs and nanocomposites can be used as antibacterial agents. This eco-friendly method of synthesis of ZnO NPs andZnGONC could be a viable solution for industrial applications in the future and therapeutic needs.

X-ray Structural Analysis of Molten LiF — LiCl System

1987 ◽  
Vol 42 (9) ◽  
pp. 1005-1008
Author(s):  
Yoshihiro Okamoto ◽  
Kazuo Igarashi ◽  
Junichi Mochinaga
Keyword(s):  
Structural Analysis ◽  
Alkali Halide ◽  
Short Range ◽  
Nearest Neighbor ◽  
Ion Pairs ◽  
Diffraction Method ◽  
The Other ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Common

The short range structures of molten LiF - LiCl ( 1 : 2 ) and ( 1 :1 ) mixtures with the common cation were investigated by an X -ray diffraction method and compared with those found in the pure melts and the molten alkali halide mixtures with the common anions. In both the mixtures, the nearest neighbor arrangements of the unlike ion pairs were similar to those in the pure melts. On the other hand, the nearest distances between like ions changed by mixing.

Structural analysis of Na2OGa2O3SiO2 glasses by the X-ray diffraction method

1985 ◽  
Vol 70 (1) ◽  
pp. 177-185 ◽  
Author(s):  
Nobuya Iwamoto ◽  
Norimasa Umesaki ◽  
Shigeru Goto ◽  
Teiichi Hanada ◽  
Naohiro Soga
Keyword(s):  
Structural Analysis ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
X Ray

Structural investigation of co-evaporated methyl ammonium lead halide perovskite films during growth and thermal decomposition using different PbX2 (X = I, Cl) precursors

2015 ◽  
Vol 3 (39) ◽  
pp. 19842-19849 ◽  
Author(s):  
Juliane Borchert ◽  
Heidi Boht ◽  
Wolfgang Fränzel ◽  
René Csuk ◽  
Roland Scheer ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Structural Analysis ◽  
Structural Investigation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Detailed Structural Analysis ◽  
Halide Perovskite ◽  
Lead Halide

Here we present a detailed structural analysis of methylammonium lead halide (I, Cl) films by in situ X-ray diffraction during their growth and thermal recrystallization up to their decomposition.

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