scholarly journals Bis(2,4-dioxopentan-3-ido-κ2 O,O′)dioxidomolybdenum(VI): a redetermination

IUCrData ◽  
2021 ◽  
Vol 6 (8) ◽  
Author(s):  
Dean H. Johnston ◽  
Calvin King ◽  
Aileen Seitz ◽  
Mia Sethi

The title compound, [Mo(C5H7O2)2O2] or cis-[MoO2(acac)2] (acac is acetylacetonate), contains a molybdenum(VI) atom coordinated by two acetylacetonate ligands and two doubly bonded oxido ligands in a distorted octahedral shape. The molecule is chiral and the asymmetric unit contains two independent molecules (one Δ, one Λ). Extensive C—H...O contacts are present throughout the structure. Data were collected at 100 K, providing higher precision of unit-cell parameters and atomic positions than previous determinations [Kamenar et al. (1973). Cryst. Struct. Commun. 2, 41–44.; Krasochka et al. (1975). Zh. Strukt. Khim. 16, 696–698].

Author(s):  
Fang Lu ◽  
Bei Zhang ◽  
Yong Liu ◽  
Ying Song ◽  
Gangxing Guo ◽  
...  

Phytases are phosphatases that hydrolyze phytates to less phosphorylatedmyo-inositol derivatives and inorganic phosphate. β-Propeller phytases, which are very diverse phytases with improved thermostability that are active at neutral and alkaline pH and have absolute substrate specificity, are ideal substitutes for other commercial phytases. PhyH-DI, a β-propeller phytase fromBacillussp. HJB17, was found to act synergistically with other single-domain phytases and can increase their efficiency in the hydrolysis of phytate. Crystals of native and selenomethionine-substituted PhyH-DI were obtained using the vapour-diffusion method in a condition consisting of 0.2 Msodium chloride, 0.1 MTris pH 8.5, 25%(w/v) PEG 3350 at 289 K. X-ray diffraction data were collected to 3.00 and 2.70 Å resolution, respectively, at 100 K. Native PhyH-DI crystals belonged to space groupC121, with unit-cell parametersa = 156.84,b = 45.54,c = 97.64 Å, α = 90.00, β = 125.86, γ = 90.00°. The asymmetric unit contained two molecules of PhyH-DI, with a corresponding Matthews coefficient of 2.17 Å3 Da−1and a solvent content of 43.26%. Crystals of selenomethionine-substituted PhyH-DI belonged to space groupC2221, with unit-cell parametersa = 94.71,b= 97.03,c= 69.16 Å, α = β = γ = 90.00°. The asymmetric unit contained one molecule of the protein, with a corresponding Matthews coefficient of 2.44 Å3 Da−1and a solvent content of 49.64%. Initial phases for PhyH-DI were obtained from SeMet SAD data sets. These data will be useful for further studies of the structure–function relationship of PhyH-DI.


1999 ◽  
Vol 55 (2) ◽  
pp. 522-524 ◽  
Author(s):  
Randall L. Oliver ◽  
Jacqueline M. Tremblay ◽  
George M. Helmkamp ◽  
Lynwood R. Yarbrough ◽  
Natalie W. Breakfield ◽  
...  

Phosphatidylinositol-transfer protein (PITP) is a soluble, ubiquitously expressed, highly conserved protein encoded by two genes in humans, rodents and other mammals. A cDNA encoding the alpha isoform of the rat gene was expressed to high levels in Escherichia coli, the protein purified and the homogeneous protein used for crystallization studies. Crystals of rat PITP-α were obtained by vapor-diffusion techniques using the sitting-drop method. Crystals grow within two weeks by vapor-diffusion techniques in the presence of polyethylene glycol 4000. Both crystal forms pack in the monoclinic space group P21. Crystal form I has unit-cell parameters a = 44.75, b = 74.25, c = 48.32 Å and β = 114.14°. Unit-cell parameters for crystal form II are a = 47.86, b = 73.59, c = 80.49 Å and β = 98.54°. Crystal form I has a Vm of 2.295 Å3 Da−1 and an estimated solvent content of 46.4% with one molecule per asymmetric unit, while crystal form II has a Vm of 2.196 Å3 Da−1 and an estimated solvent content of 44.0%, assuming two molecules per asymmetric unit.


1999 ◽  
Vol 55 (8) ◽  
pp. 1459-1461 ◽  
Author(s):  
Núria Verdaguer ◽  
Thomas C. Marlovits ◽  
Jerónimo Bravo ◽  
David I. Stuart ◽  
Dieter Blaas ◽  
...  

Human rhinoviruses, the major cause of mild recurrent infections of the upper respiratory tract, are small icosahedral particles. Over 100 different serotypes have been identified. The majority (91 serotypes) use intercellular adhesion molecule 1 as the cell-attachment site; ten serotypes (the minor group) bind to members of the low-density lipoprotein receptor. Three different crystal forms of the minor-group human rhinovirus serotype 2 (HRV2) were obtained by the hanging-drop vapour-diffusion technique using ammonium sulfate and sodium/potassium phosphate as precipitants. Monoclinic crystals, space group P21, diffracted at least to 2.8 Å resolution, and two complete virus particles were located in the crystal asymmetric unit. A second type of crystals had a compact cubic like morphology and diffracted beyond 2.5 Å resolution. These crystals belong to a primitive orthorhombic space group, with unit-cell parameters a = 309.3, b = 353.5, c = 759.6 Å, and contain one virus particle in the asymmetric unit. A third type of crystals, with a prismatic shape and belonging to space group I222, was also obtained under similar crystallization conditions. These latter crystals, with unit-cell parameters a = 308.7, b = 352.2, c = 380.5 Å, diffracted to high resolution (beyond 1.8 Å) and contained 15 protomers per asymmetric unit; this requires that three perpendicular crystal twofold axes coincide with three of the viral particle's dyad axes.


2012 ◽  
Vol 68 (8) ◽  
pp. m1047-m1047 ◽  
Author(s):  
Qiu Ping Huang ◽  
Jing Jing Guo ◽  
Yi Dong Zhang ◽  
Shu Hua Zhang

The asymmetric unit of the title compound, [Co(C9H8Cl2NO)3], contains three independent molecules. In each molecule, the CoIIIion is coordinated by an O atom and an N atom from three bidentate 2,4-dichloro-6-(ethyliminomethyl)phenolate ligands in a slightly distorted octahedral environment. In the crystal, a weak C—H...Cl hydrogen bond is observed.


1999 ◽  
Vol 55 (7) ◽  
pp. 1368-1369 ◽  
Author(s):  
Nicholas C. Blackwell ◽  
Paul M. Cullis ◽  
Ronald A. Cooper ◽  
Tina Izard

2-Dehydro-3-deoxygalactarate (DDG) aldolase (E.C. 4.1.2.20) catalyzes the reversible aldol cleavage of DDG and 2-dehydro-3-deoxyglucarate to pyruvate and tartronic semialdehyde. Rhombohedral crystals of recombinant DDG aldolase from Escherichia coli K-12 were obtained. The crystals belong to space group R32 with unit-cell parameters a = 93 Å, α = 85°. The crystals diffract to beyond 1.8 Å resolution on a Cu Kα rotating-anode generator. The asymmetric unit is likely to contain two molecules, corresponding to a packing density of 1.34 Å3 Da−1.


2015 ◽  
Vol 71 (9) ◽  
pp. 1161-1168 ◽  
Author(s):  
Christopher T. Jurgenson ◽  
Thomas D. Pollard

Co-crystals of the bovine Arp2/3 complex with the CA motif from N-WASP in two new space groups were analyzed by X-ray diffraction. The crystals in the orthorhombic space groupP212121contained one complex per asymmetric unit, with unit-cell parametersa= 105.48,b= 156.71,c= 177.84 Å, and diffracted to 3.9 Å resolution. The crystals in the tetragonal space groupP41contained two complexes per asymmetric unit, with unit-cell parametersa=b= 149.93,c = 265.91 Å, and diffracted to 5.0 Å resolution. The electron-density maps of both new crystal forms had densities for small segments of subdomains 1 and 2 of Arp2. Both maps had density at the binding site on Arp3 for the C-terminal EWE tripeptide from N-WASP and a binding site proposed for the C motif of N-WASP in the barbed-end groove of Arp2. The map from the tetragonal crystal form had density near the barbed end of Arp3 that may correspond to the C helix of N-WASP. The noise levels and the low resolution of the maps made the assignment of specific molecular structures for any of these CA peptides impossible.


Author(s):  
Julian Radtke ◽  
Hans-Wolfram Lerner ◽  
Michael Bolte

We have encountered two polymorphs of the title compound, C24H16B2OS2, both of which display almost the same unit-cell parameters. Compound (I) crystallizes in the non-centrosymmetric space group P21 with four molecules in the asymmetric unit. These molecules are related by pseudosymmetry. As a result, the space group looks like P21/c, but the structure cannot be refined successfully in that space group. Compound (II) on the other hand crystallizes in the centrosymmetric space group P21/c with only two molecules in the asymmetric unit. The crystals studied for (I) and (II) were both non-merohedral twins.


1997 ◽  
Vol 12 (1) ◽  
pp. 20-21
Author(s):  
A. Gómez ◽  
J. Guerra-López ◽  
R. González ◽  
R. Pomés

Ammonium manganese phosphate monohydrate (NH4MnPO4.H2O) has been investigated by means of X-ray powder diffraction. The title compound is orthorhombic with unit-cell parameters a=5.7289(11), b=8.8167 (12), and c=4.9098 (8) Å.


2016 ◽  
Vol 31 (3) ◽  
pp. 233-239
Author(s):  
Jose H. Quintana Mendoza ◽  
J. A. Henao ◽  
Carlos E. Rondón Flórez ◽  
Carlos E. Puerto Galvis ◽  
Vladimir V. Kouznetsov

The title compound, the 4-phenyl-6-(trifluoromethyl)-3,4-dihydroquinolin-2(1H)-one (4) with chemical formula: (C16H12F3NO), was synthesized from N-[4-(trifluoromethyl)phenyl]cinnamamide (3), chemical formula: (C16H12F3NO), through an intramolecular cyclization mediated by triflic acid. Preliminary molecular characterization of both compounds was performed by Fourier transform infrared spectroscopy, gas chromatography mass spectrometry, and nuclear magnetic resonance spectroscopy (1H, 13C); crystallographic characterization was completed by X-ray diffraction of polycrystalline samples. The title compound 4 crystallized in a monoclinic system and unit-cell parameters are reported [a = 16.002 (3), b = 5.170 (1), c = 17.733 (3) Å, β = 111.11 (2)°, unit-cell volume V = 1368.5 (3) Å3, Z = 4] P21/c (No. 14) space group; the title compound 3 crystallized in a monoclinic system and unit-cell parameters are reported [a = 12.902 (2), b = 5.144 (1), c = 20.513 (5) Å, β = 91.67 (2)°, unit-cell volume V = 1360.7 (4) Å3, Z = 4] P21/c (No. 14) space group.


1998 ◽  
Vol 13 (1) ◽  
pp. 20-21 ◽  
Author(s):  
A. Paneque Quevedo ◽  
H. Novoa de Armas ◽  
L. Xuárez Marill

2,4-dichloro-5-nitrobenzoic acid (C7H3NO4Cl2) has been investigated by means of X-ray powder diffraction. The title compound is monoclinic with unit-cell parameters a=13.761 (2), b=8.435 (1), c=7.684 (1) Å, β=99.85 (1)°, V=878.5 (1) Å3, Z=4, Dx=1.772 g/cm3, space group P21/a (14).


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