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المصدر: Crystallography Reports. 66:476-478
مصطلحات موضوعية: 010302 applied physics, chemistry.chemical_classification, Carboxypeptidase T, Resolution (electron density), Mutant, Synchrotron radiation, General Chemistry, 010403 inorganic & nuclear chemistry, Condensed Matter Physics, 01 natural sciences, 0104 chemical sciences, Amino acid, law.invention, Crystallography, chemistry, Beamline, law, 0103 physical sciences, X-ray crystallography, General Materials Science, Crystallization
الوصف: Crystals of mutant carboxypeptidase T from Thermoactinomyces vulgaris (CPT11QG)with amino acid substitutions L211Q, T262S, L254S, and A251S were grown by the hanging-drop vapor-diffusion method. The crystals belong to sp. gr. P6(3)22. The X-ray-diffraction-data set,suitable for the crystal-structure determination at 2.6 A resolution,was collected from the grown crystals at the ID23-1 beamline of the European Synchrotron Radiation Facility (ESRF, France).
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المصدر: Crystallography Reports. 64:910-913
مصطلحات موضوعية: 010302 applied physics, chemistry.chemical_classification, biology, Chemistry, Mutant, Wolinella succinogenes, Resolution (electron density), Active site, General Chemistry, 010403 inorganic & nuclear chemistry, Condensed Matter Physics, 01 natural sciences, Glutaminase activity, 0104 chemical sciences, law.invention, Crystallography, Enzyme, law, 0103 physical sciences, X-ray crystallography, biology.protein, General Materials Science, Crystallization
الوصف: The double mutant of Wolinella succinogenes L-asparaginase (Was72) with the V23Q and K24T substitutions in the C-terminal region of the N-terminal loop enclosing the active site was crystallized in the apo form and in complexes with L-aspartic and L-glutamic acids. This mutant exhibits glutaminase activity eight times lower compared to the wild-type enzyme. Crystals of the apo enzyme were grown in two modifications (sp. gr. P21 and sp. gr. P22121). Crystals grown in the presence of both aspartic and glutamic acids belong to the same space group (P21) but have different unit cell parameters. The X-ray diffraction data sets were collected from all types of crystals at 1.65–2.00 A resolution. All X-ray diffraction data sets are suitable for the determination of the three-dimensional structure of the enzyme.
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المؤلفون: Ilyas G. Khaliullin, Galina E. Konstantinova, Vladimir I. Timofeev, Inna P. Kuranova, V. Kh. Akparov
المصدر: Crystallography Reports. 65:900-902
مصطلحات موضوعية: 010302 applied physics, chemistry.chemical_classification, Carboxypeptidase T, biology, Chemistry, Resolution (electron density), Mutant, Active site, General Chemistry, Crystal structure, 010403 inorganic & nuclear chemistry, Condensed Matter Physics, 01 natural sciences, 0104 chemical sciences, law.invention, Crystallography, Enzyme, law, 0103 physical sciences, X-ray crystallography, biology.protein, General Materials Science, Crystallization
الوصف: Crystals of mutant carboxypeptidase T from Thermoactinomyces vulgaris (CPT11QG) with amino-acid substitutions G215S, Q249G, A251G, T257A, D260G, T262D, and L254I and with the insertion ins253T were grown in microgravity by the capillary counter-diffusion method. The crystals belong to sp. gr. P31, which differs from the space group of the wild-type enzyme (P6322). The X-ray diffraction data set was collected from the crystals at the SPring-8 synchrotron facility (Japan) and is suitable for crystal structure determination at 2.45 A resolution.
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المؤلفون: N. P. Gorbunov, V. R. Samygina, Alexey V. Sokolov, K. M. Dubova
المصدر: Crystallography Reports. 63:951-954
مصطلحات موضوعية: 0301 basic medicine, Diffraction, Materials science, 030102 biochemistry & molecular biology, Phenyl isothiocyanate, Resolution (electron density), General Chemistry, Tartrate, Condensed Matter Physics, 03 medical and health sciences, Crystallography, chemistry.chemical_compound, chemistry, Atomic resolution, X-ray crystallography, General Materials Science, Macrophage migration inhibitory factor
الوصف: Crystals of human macrophage migration inhibitory factor in complexes with phenyl isothiocyanate and tartrate were grown by the capillary counter-diffusion method under microgravity conditions. The preliminary X-ray diffraction study of these complexes was performed at near-atomic resolution (1.16 A).
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المؤلفون: Konstantin M. Boyko, Artem Bonchuk, A. Yu. Nikolaeva, Vladimir Popov, Pavel V. Dorovatovskii, G.S. Kachalova
المصدر: Crystallography Reports. 62:912-915
مصطلحات موضوعية: 0301 basic medicine, Diffraction, Materials science, biology, Scattering, Small-angle X-ray scattering, fungi, Resolution (electron density), General Chemistry, Condensed Matter Physics, biology.organism_classification, law.invention, 03 medical and health sciences, Crystallography, 030104 developmental biology, law, X-ray crystallography, General Materials Science, Histone octamer, Crystallization, Drosophila melanogaster
الوصف: The Drosophila genome has several dozens of transcription factors (TTK group) containing ВТВ domains assembled into octamers. The LOLA protein belongs to this family. The purification, crystallization, and preliminary X-ray diffraction and small-angle X-ray scattering (SAXS) studies of the BTB domain of this protein are reported. The crystallization conditions were found by the vapor-diffusion technique. A very low diffraction resolution (8.7 A resolution) of the crystals was insufficient for the determination of the threedimensional structure of the BTB domain. The SAXS study demonstrated that the BTB domain of the LOLA protein exists as an octamer in solution.
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المؤلفون: Anton S. Orekhov, S. V. Kononova, Vera V. Klechkovskaya
المصدر: Crystallography Reports. 62:710-715
مصطلحات موضوعية: Materials science, business.industry, Polymer characterization, Scanning electron microscope, Resolution (electron density), Scanning confocal electron microscopy, 02 engineering and technology, General Chemistry, Scanning capacitance microscopy, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, 0104 chemical sciences, Scanning ion-conductance microscopy, Optoelectronics, Energy filtered transmission electron microscopy, General Materials Science, Electron beam-induced deposition, 0210 nano-technology, business
الوصف: The possibilities of low-voltage scanning electron microscopy for visualization of specific features of the microstructure in internal layers of multilayer polymer films are demonstrated by the example of “chitosan–polyelectrolyte complex–alginic acid” composite. The process of electron beam interaction with a sample at low electron energies is considered. The key parameters of low-voltage electron microscopy, which make it possible to increase the resolution of SEM images of polymer systems, are discussed.
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المؤلفون: Alexander P. Dudka
المصدر: Crystallography Reports. 62:195-204
مصطلحات موضوعية: 010302 applied physics, Diffraction, Materials science, Silicon, Resolution (electron density), chemistry.chemical_element, General Chemistry, 010403 inorganic & nuclear chemistry, Condensed Matter Physics, 01 natural sciences, Piezoelectricity, 0104 chemical sciences, Crystallography, chemistry, 0103 physical sciences, General Materials Science, Gallium, Unit (ring theory), Single crystal, Diffractometer
الوصف: Accurate X-ray diffraction study of langasite (La3Ga5SiO14) single crystal has been performed using the data obtained on a diffractometer equipped with a CCD area detector at 295 and 90.5 K. Within the known La3Ga5SiO14 model, Ga and Si cations jointly occupy the 2d site. A new model of a “multicell” consisting of two different unit cells is proposed. Gallium atoms occupy the 2d site in one of these cells, and silicon atoms occupy this site in the other cell; all other atoms correspondingly coordinate these cations. This structure implements various physical properties exhibited by langasite family crystals. The conclusions are based on processing four data sets obtained with a high resolution (sin θ/λ ≤ 1.35 A–1), the results reproduced in repeated experiments, and the high relative precision of the study (sp. gr. P321, Z = 1; at 295 K, a = 8.1652(6) A, c = 5.0958(5) A, R/wR = 0.68/0.68%, 3927 independent reflections; at 90.5 K, a = 8.1559(4) A, c = 5.0913(6) A, R/wR = 0.92/0.93%, 3928 reflections).
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المؤلفون: Yu. A. Abramchik, Vladimir I. Timofeev, N. E. Zhukhlistova, Roman S. Esipov, T. I. Muravieva, Inna P. Kuranova
المصدر: Crystallography Reports. 61:44-54
مصطلحات موضوعية: 0301 basic medicine, chemistry.chemical_classification, 030102 biochemistry & molecular biology, biology, Stereochemistry, Phosphoribosyl pyrophosphate, Resolution (electron density), General Chemistry, Bacillus subtilis, Protein superfamily, Condensed Matter Physics, biology.organism_classification, medicine.disease_cause, 03 medical and health sciences, chemistry.chemical_compound, 030104 developmental biology, Enzyme, chemistry, Biochemistry, medicine, Molecule, General Materials Science, Escherichia coli
الوصف: Phosphoribosyl pyrophosphate synthetase from Escherichia coli was cloned, purified, and crystallized. Single crystals of the enzyme were grown under microgravity. The X-ray diffraction data set was collected at the Spring-8 synchrotron facility and used to determine the three-dimensional structure of the enzyme by the molecular-replacement method at 2.71 A resolution. The active and regulatory sites in the molecule of E. coli phosphoribosyl pyrophosphate synthetase were revealed by comparison with the homologous protein from Bacillus subtilis, the structure of which was determined in a complex with functional ligands. The conformations of polypeptide-chain fragments surrounding and composing the active and regulatory sites were shown to be identical in both proteins.
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المؤلفون: D. A. Korzhenevskii, A. Yu. Nikolaeva, A. V. Lipkin, Vladimir I. Timofeev, K. M. Boiko, Tatiana V. Rakitina, Pavel V. Dorovatovskii
المصدر: Crystallography Reports. 60:880-883
مصطلحات موضوعية: Crystallography, Chemistry, law, X-ray crystallography, Resolution (electron density), HU Protein, General Materials Science, General Chemistry, Crystallization, Condensed Matter Physics, Bacterial dna, law.invention
الوصف: HU proteins are involved in bacterial DNA and RNA repair. Since these proteins are absent in cells of higher organisms, inhibitors of HU proteins can be used as effective and safe antibiotics. The crystallization conditions for the M. gallisepticum HU protein were found and optimized by the vapor-diffusion method. The X-ray diffraction data set was collected to 2.91 A resolution from the crystals grown by the vapor-diffusion method on a synchrotron source. The crystals of the HU protein belong to sp. gr. P41212 and have the following unit-cell parameters: a = b = 97.94 A, c = 77.92 A, α = β = γ = 90°.
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المؤلفون: Marina Chukalina, V. E. Asadchikov, I. A. Schelokov
المصدر: Crystallography Reports. 60:611-619
مصطلحات موضوعية: Spectrum analyzer, Materials science, Computer simulation, business.industry, media_common.quotation_subject, Resolution (electron density), Physics::Optics, Geometry, General Chemistry, Condensed Matter Physics, law.invention, Crystal, Optics, law, Scheme (mathematics), Contrast (vision), General Materials Science, business, Monochromator, media_common
الوصف: A method of numerical simulation of X-ray optical systems is presented. This method has been used to analyze the operation of a unit of a laboratory microtomograph in which monochromator crystals in asymmetric Bragg geometry are applied as optical elements. Based on the analysis, it is concluded that this scheme provides in principle submicron resolution.
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