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Space Group P1 (space + group_p1)
Kinds of Space Group P1 Selected AbstractsSynthesis and crystal structure determination of 6,7-dihydro-2-methoxy-4-(substituted)-5H -benzo[6,7]cyclohepta[1,2- b ]pyridine-3-carbonitrileCRYSTAL RESEARCH AND TECHNOLOGY, Issue 4 2007A. M. Moustafa Abstract The compounds 6,7-dihydro-2-methoxy-4-(4-methylphenyl)-5H -benzo[6.7]cyclohepta[1,2 -b ]pyridine-3-carbonitrile (compound IIIa) and 4-(4-chlorophenyl)-6,7-dihydro-2-methoxy-5H -benzo[6,7]cyclohepta[1,2- b ]pyridine-3-carbonitrile (compound IIIb) were synthesized and their structures have been determined from three dimensional X-ray data using direct method and refined by full matrix least squares with anisotropic thermal parameters for non-hydrogen atoms to conventional R(gt) of 0.036 and 0.038 for the two compounds respectively. For compound (IIIa) the crystals are monoclinic, space group Cc, with a=11.2909 (5) Å, b=17.7755(8) Å, c=9.1437(4) Å and ,=95.428(3)°, while the crystals of the second compound (IIIb) are triclinic, space group P1, with a=8.7465(3)Å, b=10.3958(3)Å, c=10.9011(4)Å, ,= 108.3870(10)°, ,=101.3741(12)°, ,=97.9594(12)°. The molecular structure of the two compounds have nearly the same configuration, where the cyclohepta ring takes the boat shape and the methoxy and the carbonitrile groups are attached at the same position C2 and C8. The difference occurs only at the position C4, where the substituent is methylphenyl for compound (IIIa) and chlorophenyl for the other. The bond lengths, valency angles and the hydrogen bonding were calculated and fully discussed. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Crystal structure of 2-(2'-hydroxyphenyl)-6-tributylstannyl-4-(3H )-quinazolinone and 2-(2'-hydroxyphenyl)-6-iodo-4-(3H)-quinazolinoneCRYSTAL RESEARCH AND TECHNOLOGY, Issue 6 2006Ketai Wang Abstract The structures of the title compounds C26H37N2O2Sn (I) and C14H9IN2O2 (II) were determined by single-crystal X-ray diffraction technique. Compound I crystallizes in the triclinic space group P1 with a = 9.560(3) Å, b = 16.899(6) Å, c = 17.872(5) Å, , = 65.957(7)°, , = 83.603(5)°, , ( = 75.242(5)°, V = 2549.8(13) Å3, Z = 4, and D =1.374 g/cm3. The compound consists of a quinazolinone ring with phenol and tributylstannyl moieties. Compound II crystallizes in the monoclinic space group P21/c with a = 7.6454(12) Å, b = 5.9270(9) Å, c = 27.975(4) Å; , = 90°, , = 95.081(3)°, , = 90°, V = 1262.7(3) Å3, Z = 4, and D = 1.915 g/cm3. The compound consists of a quinazolinone ring with phenol and iodine substituents. For both I and II, the short intramolecular O,H,N and two long intermolecular N,H,O hydrogen bonds are highly effective in holding the molecular system in a stable state. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Crystal structure analysis of {[,-N,N,-Bis(salicylidene)-1,3-propanediaminato]nickel(II)}dichloromercury(II)CRYSTAL RESEARCH AND TECHNOLOGY, Issue 2 2006C. Ar Abstract The title compound, a hetero-dinuclear complex with Ni(II) and Hg(II) ions, forms crystals which belong to the triclinic system, space group P1, with unit cell dimensions a = 8.9620(12), b = 9.2370(11), c = 12.0810(13) Å, , = 92.100(3)° , , = 105.317(5)°, , = 110.502(3)°, V = 894.2(2) Å3. The cell contains two molecules. The Ni,Hg distance is 3.4859(7) Å. The distance Hg...Hga (symmetry code: -x,-y,-z) between the neighbouring molecules is 4.7514(7) Å. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Synthesis, spectroscopic studies and ab-initio structure determination from X-ray powder diffraction of bis-(N-3-acetophenylsalicylaldiminato)copper(II)CRYSTAL RESEARCH AND TECHNOLOGY, Issue 8 2005S. Banerjee Abstract The synthesis, spectroscopic studies and crystal structure determination from X-ray powder diffraction have been carried out for bis-(N-3-acetophenylsalicylaldiminato)copper(II). The structure is triclinic, space group P1 with unit cell dimensions a = 11.817(1) Å, b = 12.087(1) Å, c = 9.210(1) Å, , = 102.62(1)°, , = 111.16(1)°, , = 86.15(1)°, V = 1197.0(2)Å3, Z = 2. The structure has been solved by Monte Carlo simulated annealing approach and refined by GSAS package. The final Rp value was 8.68%. The coordination geometry around the copper atom in the complex is intermediate between square-planar and tetrahedral with two salicylaldimine ligands in trans arrangement. Intermolecular C,H,O hydrogen bonds between molecules related by translation generate infinite chains along [010] direction. The molecular chains are linked via additional C,H,O hydrogen bonds to form a three-dimensional supramolecular network. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Symmetry determination following structure solution in P1JOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 6 2008L. Palatinus A new method for space-group determination is described. It is based on a symmetry analysis of the structure-factor phases resulting from a structure solution in space group P1. The output of the symmetry analysis is a list of all symmetry operations compatible with the lattice. Each symmetry operation is assigned a symmetry agreement factor that is used to select the symmetry operations that are the elements of the space group of the structure. On the basis of the list of the selected operations the complete space group of the structure is constructed. The method is independent of the number of dimensions, and can also be used in solution of aperiodic structures. A number of cases are described where this method is particularly advantageous compared with the traditional symmetry analysis. [source] Solid state characterization of mometasone furoate anhydrous and monohydrate formsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 11 2005Xiaoming (Sean) Chen Abstract Mometasone furoate is a potent glucocorticoid anti-inflammatory agent. Its anhydrous Form 1 and monohydrate form were characterized by X-ray crystallography, X-ray powder diffraction at ambient and elevated temperature, thermal analysis, FT-IR, and dynamic moisture adsorption. In Form 1, mometasone furoate molecules pack tightly with molecules interlocked in a space group of P212121. The monohydrate form crystallizes in space group P1. The unit cell of the monohydrate contains one water molecule and one mometasone furoate molecule. The water molecules form channels along the a axis and mometasone furoate molecules pack in layers in the same direction. Dehydration was observed between 60 and 100°C by thermogravimetric analysis with a heating rate of 10°C/min. It corresponds to a broad endotherm over the same temperature range in the differential scanning calorimetry with the same heating rate. Variable temperature X-ray powder diffraction reveals that a new anhydrous form (Form 2) was fully produced above 90°C. This crystalline form was converted to Form 1 after being heated above 150°C; and was totally converted to the monohydrate after 1 day at 23°C, 45% RH. © 2005 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 94:2496-2509, 2005 [source] Characterization and crystal structure of D -mannitol hemihydrateJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 11 2004Cletus Nunes Abstract The objectives of this study were (i) to isolate and characterize mannitol hydrate, and (ii) to solve its crystal structure from high-resolution synchrotron X-ray powder diffraction data. Mannitol hydrate was prepared by freeze-drying aqueous mannitol solutions (5% w/v) under controlled conditions. X-ray powder diffractometry, differential scanning calorimetry, and thermogravimetric analyses indicated that mannitol exists as a hemihydrate (C6H14O6,·,0.5H2O). Synchrotron data were collected on the X3B1 beamline at the National Synchrotron Light Source. The simulated annealing program PSSP was used to solve the structure, which was subsequently refined by Rietveld analysis using the program package GSAS. The compound crystallizes in space group P1, with a,=,9.8963 Å, b,=,10.5424 Å, c,=,4.7860 Å, ,,=,102.589°, ,,=,86.092°, and ,,=,116.079°. The unit cell contains two dissimilar D -mannitol molecules and one water molecule, forming a hydrogen bonding pattern significantly different from that seen in the anhydrous polymorphs. © 2004 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 93:2800,2809, 2004 [source] Enantiotropic phase transition and twinning in 2,2,3,3,4,4-hexafluoropentane-1,5-diolACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2009Jeong-Myeong Ha Four crystal structure determinations of 2,2,3,3,4,4-hexafluoropentane-1,5-diol (HFPD), C5H6F6O2, were conducted on a single specimen by varying the temperature. Two polymorphs of HFPD were found to be enantiotropically related as phases (I) and (II), both in the space group P1. These structures contain closely related R44(20) sheets. A structure determination was completed on form (Ia) at 283,K. Form (Ia) was then supercooled below the phase transition temperature at 279 to 173,K to give form (Ib) for a second structure determination. Metastable form (Ib) was transformed by momentary warming and recooling to give form (II) for a third structure determination at 173,K. Form (II) transformed to form (Ic) upon warming to 283,K. Enantiotropic phase transitions between phases (I) and (II) were confirmed with X-ray powder diffraction and differential scanning calorimetry. Form (Ia) was found as a twin by nonmerohedry by a reflection in (011). This twinning persists in all phases described. Additional twinning was found after the phase (I) to phase (II) transformation. These two additional twin components are related to the first pair by a 180° rotation about the (012) plane. This latter pair of twins persisted as the specimen was warmed back to form (Ic) at 283,K. [source] A new crystal phase of barium nitroprusside trihydrate studied by neutron diffraction at 20,KACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2004G. Chevrier The crystal of barium pentacyanonitrosylferrate trihydrate {barium nitroprusside trihydrate, Ba[Fe(CN)5(NO)]·3H2O} has been studied by neutron diffraction at 20,K. The study was performed to characterize the structural phase generated by the phase transition undergone by the crystals at 80,K, at which temperature the unit-cell volume doubles. This crystal phase still exists at 20,K. The crystal structure, in space group P1, is completely ordered. The positional changes of the water molecules in the present structure with respect to those of the compound at 105,K are presented. [source] Methyl (±)-1-ethyl-2-hydroxy-4-(4-methoxybenzoyl)-5-(4-methoxyphenyl)-3-oxo-2,3-dihydro-1H -pyrrole-2-acetateACTA CRYSTALLOGRAPHICA SECTION C, Issue 10 2003Mehmet Akkurt The title compound, C24H25NO7, is a racemic mixture of 2,3-dihydro-1H -pyrrol-3-ones. It crystallizes in the triclinic system, space group P1, with Z = 2. The asymmetric unit contains two enantiomorphic molecules and the structure is stabilized by hydrogen-bond contacts. [source] Atomic resolution studies of haloalkane dehalogenases DhaA04, DhaA14 and DhaA15 with engineered access tunnelsACTA CRYSTALLOGRAPHICA SECTION D, Issue 9 2010A. Stsiapanava The haloalkane dehalogenase DhaA from Rhodococcus rhodochrous NCIMB 13064 is a bacterial enzyme that shows catalytic activity for the hydrolytic degradation of the highly toxic industrial pollutant 1,2,3-trichloropropane (TCP). Mutagenesis focused on the access tunnels of DhaA produced protein variants with significantly improved activity towards TCP. Three mutants of DhaA named DhaA04 (C176Y), DhaA14 (I135F) and DhaA15 (C176Y + I135F) were constructed in order to study the functional relevance of the tunnels connecting the buried active site of the protein with the surrounding solvent. All three protein variants were crystallized using the sitting-drop vapour-diffusion technique. The crystals of DhaA04 belonged to the orthorhombic space group P212121, while the crystals of DhaA14 and DhaA15 had triclinic symmetry in space group P1. The crystal structures of DhaA04, DhaA14 and DhaA15 with ligands present in the active site were solved and refined using diffraction data to 1.23, 0.95 and 1.22,Å, resolution, respectively. Structural comparisons of the wild type and the three mutants suggest that the tunnels play a key role in the processes of ligand exchange between the buried active site and the surrounding solvent. [source] ACORN2: new developments of the ACORN conceptACTA CRYSTALLOGRAPHICA SECTION D, Issue 9 2009E. J. Dodson The density-modification procedures incorporated in ACORN, available in the CCP4 package, have proved to be very successful in solving and refining high-resolution crystal structures from very poor starting sets. These can be calculated from a correctly positioned initial fragment containing between 1 and 8% of the scattering power of the total structure. Improvements of ACORN, reported here and incorporated in the program ACORN2, have lowered the size of the fragment required and examples are given of structures solved with only 0.25% of the scattering power in the fragment, which may be a single atom. Applications of ACORN2 to structures with space group P1 have shown the remarkable property that when the starting point is a pair of equal atoms, or even a single atom placed at the origin, the refinement process breaks the centric nature of the initial phases and converges to phases corresponding to one of the two possible enantiomorphs. Examples are given of the application of ACORN2 to the solution and/or refinement of a number of known trial structures and to the refinement of structures when phases are available either from MAD or from a molecular-replacement model. [source] Crystallization and preliminary X-ray crystallographic investigations of an unusual type III polyketide synthase PKS18 from Mycobacterium tuberculosisACTA CRYSTALLOGRAPHICA SECTION D, Issue 4 2004Raju Rukmini The biosynthetic machinery of polyketide synthases involves various sequential enzymatic reactions, such as initiation, elongation and cyclization, to produce polyketides. PKS18 protein from Mycobacterium tuberculosis belongs to the type III polyketide synthase family and displays an unusual starter-unit specificity to catalyze the formation of ,-pyrones. This enzyme uses malonyl-CoA to iteratively extend long-chain aliphatic coenzyme A (C12 to C20) molecules, producing triketide and tetraketide pyrone products. In order to aid in understanding the structural basis of this long-chain specificity and to further characterize the enzymatic mechanism of PKS18, the protein has been crystallized. The crystal belongs to the triclinic space group P1, with unit-cell parameters a = 59.9, b = 80.7, c = 99.6,Å, , = 108.2, , = 93.0, , = 103.7°. [source] Structure determination of adeno-associated virus 2: three complete virus particles per asymmetric unitACTA CRYSTALLOGRAPHICA SECTION D, Issue 6 2003Qing Xie The atomic structure of adeno-associated virus 2 (AAV-2) has been determined to 3.0,Å resolution. AAV-2 crystallized in space group P1, with unit-cell parameters a = 249.7, b = 249.7, c = 644.8,Å, , = 90.0, , = 101.2, , = 120.0°. The crystals contained three full virus particles in the asymmetric unit, allowing 180-fold non-crystallographic symmetry averaging. The particle orientations were determined using the self-rotation function and found to have similar but resolvably different orientations. Approximate alignment of icosahedral and interparticle threefold screw symmetry led to a native Patterson that was interpretable in terms of approximate particle positions. Accurate positions required a Patterson correlation search that was constrained to be consistent with non-crystallographic threefold projection symmetry evident in the diffraction intensities. Initial phases to 15.0,Å resolution were calculated by molecular replacement using the known structure of a distantly related homolog (23% sequence identity). Real-space averaging was performed and phases were extended from 15.0 to 3.0,Å. An atomic model was fitted and refined using a simulated-annealing real-space procedure. [source] Purification, crystallization and preliminary characterization of an Eph-B2/ephrin-B2 complexACTA CRYSTALLOGRAPHICA SECTION D, Issue 3 2002Juha-P. Eph receptors and their ephrin ligands are involved in various aspects of cell,cell communication during development, including those of the axon pathfinding processes in the nervous system and cell,cell interactions of the vascular endothelial cells. The recognition and binding properties of the ligand-binding domain of EphB2 receptor and the extracellular domain of ephrin-B2 have been studied and two different cocrystals of their complex have been generated. One crystal form has space group C2, diffracts to 3.5,Å and has unit-cell parameters a = 128, b = 88, c = 79,Å, , = 112°. The other crystal form grows in space group P1, has unit-cell parameters a = 78, b = 78, c = 78,Å, , = 69, , = 75, , = 69° and diffracts to 2.7,Å. Structure-determination experiments using the latter form are in progress. The structure of the complex will elucidate the chemical nature of the interactions between Eph receptors and ephrins, which would create the possibility of using them as targets for structure-based anticancer-drug development. [source] P1 Shake-and-Bake: can success be guaranteed?ACTA CRYSTALLOGRAPHICA SECTION D, Issue 2 2000Hongliang Xu The multi-trial direct-methods procedure known as Shake-and-Bake has been applied to three small proteins (alpha-1 peptide, vancomycin and lysozyme) that crystallize in space group P1. Phase refinement was accomplished through parameter-shift optimization using both the cosine and exponential forms of the minimal function. By extending error-free data to sufficiently high resolution, 100% convergence of trial structures to solution could be achieved in all three cases by using the exponential minimal function and a shift angle in the range 130,150°. These results suggest optimum parameters for other P1 structures and emphasize the importance of collecting data to the highest possible resolution. [source] Crystallization of type I chloramphenicol acetyltransferase: an approach based on the concept of ionic strength reducersACTA CRYSTALLOGRAPHICA SECTION D, Issue 1 2000Antonina E. Andreeva Chloramphenicol acetyltransferase (CAT) is responsible for bacterial resistance to chloramphenicol. It catalyzes inactivation of the antibiotic by acetyl-group transfer from acetyl CoA to one or both hydroxyl groups of chloramphenicol. Type I CAT possesses some unique properties which are not observed in other CAT variants. Type I CAT overexpressed in Escherichia coli was purified and crystals with a resolution limit of 2.22,Å have been obtained using a novel procedure which is based on the concept of `ionic strength reducers'. The crystals have the symmetry of space group P1 and unit-cell parameters a = 96.46, b = 113.86, c = 114.21,Å, , = 119.9, , = 94.1, , = 98.6°. These dimensions are consistent with four to six trimers per unit cell, corresponding to a solvent fraction ranging from 65 to 47%. [source] Crystallization and preliminary X-ray crystallographic study of GenX, a lysyl-tRNA synthetase paralogue from Escherichia coli, in complex with translation elongation factor PACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 9 2010Tomomi Sumida GenX, a lysyl-tRNA synthetase paralogue from Escherichia coli, was overexpressed in E. coli, purified by three chromatographic steps and cocrystallized with a lysyl adenylate analogue (LysAMS) by the hanging-drop vapour-diffusion method using PEG 4000 as a precipitant. The GenX,LysAMS crystals belonged to the triclinic space group P1, with unit-cell parameters a = 54.80, b = 69.15, c = 94.08,Å, , = 95.47, , = 106.51, , = 90.46°, and diffracted to 1.9,Å resolution. Furthermore, GenX was cocrystallized with translation elongation factor P (EF-P), which is believed to be a putative substrate of GenX, and LysAMS using PEG 4000 and ammonium sulfate as precipitants. The GenX,EF-P,LysAMS crystals belonged to the monoclinic space group P21, with unit-cell parameters a = 105.93, b = 102.96, c = 119.94,Å, , = 99.4°, and diffracted to 2.5,Å resolution. Structure determination of the E. coli GenX,LysAMS and GenX,EF-P,LysAMS complexes by molecular replacement was successful and structure refinements are now in progress. [source] Crystallization and preliminary X-ray analysis of cecropin B from Bombyx moriACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 7 2010Zhongyuan Liu Cecropin B is a 37-residue cationic antimicrobial peptide derived from the haemolymph of Bombyx mori. The precise mechanism by which cecropins exert their antimicrobial and cytolytic activities is not well understood. Crystals of cecropin B were obtained by the hanging-drop vapour-diffusion method using polyethylene glycol as a precipitant at 289,K. The crystal diffracted to 1.43,Å resolution using X-ray radiation and belonged to the orthorhombic space group P1, with unit-cell parameters a = 15.08, b = 22.75, c = 30.20,Å, , = 96.9, , = 103.1, , = 96.5°. The asymmetric unit contained only one molecule of cecropin B, with a calculated Matthews coefficient of 2.48,Å3,Da,1 and a solvent content of 50.4%. [source] Crystallization and preliminary X-ray crystallographic analysis of the tetracycline-degrading monooxygenase TetX2 from Bacteroides thetaiotaomicronACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 5 2010Gesa Volkers The flavin-dependent monooxygenase TetX2 from Bacteroides thetaiotaomicron confers resistance against tetracyclines in aerobically grown Escherichia coli. TetX2 modifies several tetracycline antibiotics by regioselective hydroxylation of the substrates to 11a-hydroxy-tetracyclines. X-ray diffraction data were collected from a native TetX2 crystal and a TetX2 crystal with incorporated selenomethionine to resolutions of 2.5 and 3.0,Å, respectively. The native crystal belonged to the triclinic space group P1, with unit-cell parameters a = 68.55, b = 80.88, c = 87.53,Å, , = 111.09, , = 98.98, , = 93.38°, whereas the selenomethionine-labelled TetX2 crystal belonged to the monoclinic space group P21, with unit-cell parameters a = 87.34, b = 68.66, c = 152.48,Å, , = 101.08°. [source] Preliminary X-ray crystallographic analysis of 2-methylcitrate synthase from Salmonella typhimuriumACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 4 2010Sagar Chittori Analysis of the genomic sequences of Escherichia coli and Salmonella typhimurium has revealed the presence of several homologues of the well studied citrate synthase (CS). One of these homologues has been shown to code for 2-methylcitrate synthase (2-MCS) activity. 2-MCS catalyzes one of the steps in the 2-methylcitric acid cycle found in these organisms for the degradation of propionate to pyruvate and succinate. In the present work, the gene coding for 2-MCS from S. typhimurium (StPrpC) was cloned in pRSET-C vector and overexpressed in E. coli. The protein was purified to homogeneity using Ni,NTA affinity chromatography. The purified protein was crystallized using the microbatch-under-oil method. The StPrpC crystals diffracted X-rays to 2.4,Å resolution and belonged to the triclinic space group P1, with unit-cell parameters a = 92.068, b = 118.159, c = 120.659,Å, , = 60.84, , = 67.77, , = 81.92°. Computation of rotation functions using the X-ray diffraction data shows that the protein is likely to be a decamer of identical subunits, unlike CSs, which are dimers or hexamers. [source] Purification, crystallization and preliminary X-ray analysis of a deletion mutant of a major buckwheat allergenACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 12 2009Yuichiro Kezuka A 16,kDa buckwheat protein (BWp16) is a major allergen responsible for immediate hypersensitivity reactions including anaphylaxis. A deletion mutant of BWp16 (rBWp16,N) was overproduced and purified and was shown to be immunologically active. A three-wavelength MAD data set was collected from a crystal of selenomethionine-labelled rBWp16,N. The crystal belonged to the triclinic space group P1, with unit-cell parameters a = 28.39, b = 31.54, c = 32.20,Å, , = 111.92, , = 108.91, , = 98.74°. One monomer was expected to be present in the asymmetric unit based on the calculated Matthews coefficient of 1.76,Å3,Da,1. [source] Crystallization and preliminary X-ray analysis of the stress-response PPM phosphatase RsbX from Bacillus subtilisACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 11 2009Masatoshi Suganuma RsbX from Bacillus subtilis is a manganese-dependent PPM phosphatase and negatively regulates the signal transduction of the general stress response by the dephosphorylation of RsbS and RsbR, which are activators of the alternative RNA polymerase , factor SigB. In order to elucidate the structural,functional relationship of its Ser/Thr protein-phosphorylation mechanism, an X-ray crystallographic diffraction study of RsbX was performed. Recombinant RsbX was expressed in Escherichia coli, purified and crystallized. Crystals were obtained using the sitting-drop vapour-diffusion method and X-ray diffraction data were collected to 1.06,Å resolution with an Rmerge of 8.1%. The crystals belonged to the triclinic space group P1, with unit-cell parameters a = 33.3, b = 41.7, c = 68.6,Å, , = 98.8, , = 90.0, , = 108.4°. [source] Crystallization and preliminary X-ray analysis of aspartate transcarbamoylase from the parasitic protist Trypanosoma cruziACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 9 2009Kazuaki Matoba Aspartate transcarbamoylase (ATCase), the second enzyme of the de novo pyrimidine-biosynthetic pathway, catalyzes the production of carbamoyl aspartate from carbamoyl phosphate and l -aspartate. In contrast to Escherichia coli ATCase and eukaryotic CAD multifunctional fusion enzymes, Trypanosoma cruzi ATCase lacks regulatory subunits and is not part of the multifunctional fusion enzyme. Recombinant T. cruzi ATCase expressed in E. coli was purified and crystallized in a ligand-free form and in a complex with carbamoyl phosphate at 277,K by the sitting-drop vapour-diffusion technique using polyethylene glycol 3350 as a precipitant. Ligand-free crystals (space group P1, unit-cell parameters a = 78.42, b = 79.28, c = 92.02,Å, , = 69.56, , = 82.90, , = 63.25°) diffracted X-rays to 2.8,Å resolution, while those cocrystallized with carbamoyl phosphate (space group P21, unit-cell parameters a = 88.41, b = 158.38, c = 89.00,Å, , = 119.66°) diffracted to 1.6,Å resolution. The presence of two homotrimers in the asymmetric unit (38,kDa × 6) gives VM values of 2.3 and 2.5,Å3,Da,1 for the P1 and P21 crystal forms, respectively. [source] Crystallization and preliminary X-ray analysis of d -2-hydroxyacid dehydrogenase from Haloferax mediterraneiACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 4 2009J. Domenech d -2-Hydroxyacid dehydrogenase (D2-HDH) from Haloferax mediterranei has been overexpressed in Escherichia coli, solubilized in 8,M urea and refolded by rapid dilution. The protein was purified and crystallized by the hanging-drop vapour-diffusion method using ammonium sulfate or PEG 3350 as precipitant. Two crystal forms representing the free enzyme and the nonproductive ternary complex with ,-ketohexanoic acid and NAD+ grew under these conditions. Crystals of form I diffracted to beyond 3.0,Å resolution and belonged to the monoclinic space group P21, with unit-cell parameters a = 66.0, b = 119.6, c = 86.2,Å, , = 96.3°. Crystals of form II diffracted to beyond 2.0,Å resolution and belonged to the triclinic space group P1, with unit-cell parameters a = 66.5, b = 75.2, c = 77.6,Å, , = 109.1, , = 107.5, , = 95.9°. The calculated values for VM and analysis of the self-rotation and self-Patterson functions suggest that the asymmetric unit in both crystal forms contains two dimers related by pseudo-translational symmetry. [source] Escherichia coli tRNAArg acceptor-stem isoacceptors: comparative crystallization and preliminary X-ray diffraction analysisACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 2 2009André Eichert The aminoacylation of tRNA is a crucial step in cellular protein biosynthesis. Recognition of the cognate tRNA by the correct aminoacyl-tRNA synthetase is ensured by tRNA identity elements. In tRNAArg, the identity elements consist of the anticodon, parts of the D-loop and the discriminator base. The minor groove of the aminoacyl stem interacts with the arginyl-tRNA synthetase. As a consequence of the redundancy of the genetic code, six tRNAArg isoacceptors exist. In the present work, three different Escherichia coli tRNAArg acceptor-stem helices were crystallized. Two of them, the tRNAArg microhelices RR-1660 and RR-1662, were examined by X-ray diffraction analysis and diffracted to 1.7 and 1.8,Å resolution, respectively. The tRNAArg RR-1660 helix crystallized in space group P1, with unit-cell parameters a = 26.28, b = 28.92, c = 29.00,Å, , = 105.74, , = 99.01, , = 97.44°, whereas the tRNAArg RR-1662 helix crystallized in space group C2, with unit-cell parameters a = 33.18, b = 46.16, c = 26.04,Å, , = 101.50°. [source] Heterologous expression, crystallization and preliminary X-ray characterization of CcCel6C, a glycoside hydrolase family 6 enzyme from the basidiomycete Coprinopsis cinereaACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 2 2009Yuma Kurakata CcCel6C is a gene that encodes a glycoside hydrolase family 6 (GH6) enzyme in the Coprinopsis cinerea genome. In the evolutionary tree of GH6 enzymes, the encoded enzyme was closely related to Cel6B from Humicola insolens, previously called endoglucanase VI, while its amino-acid sequence revealed a region corresponding to the C-terminal active-site-enclosing loop typical of cellobiohydrolase II. Here, the crystallization of CcCel6C produced in Escherichia coli is reported. The square prismatic crystal belonged to the triclinic space group P1, with unit-cell parameters a = 44.04, b = 45.11, c = 48.90,Å, , = 77.81, , = 87.34, , = 68.79°. Diffraction data were collected to 1.6,Å resolution. [source] Cloning, overexpression, purification and preliminary crystallographic studies of a mitochondrial type II peroxiredoxin from Pisum sativumACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 7 2006Francisca Sevilla A cDNA encoding an open reading frame of 199 amino acids corresponding to a type II peroxiredoxin from Pisum sativum with its transit peptide was isolated by RT-PCR. The 171-amino-acid mature protein (estimated molecular weight 18.6,kDa) was cloned into the pET3d vector and overexpressed in Escherichia coli. The recombinant protein was purified and crystallized by the hanging-drop vapour-diffusion technique. A full data set (98.2% completeness) was collected using a rotating-anode generator to a resolution of 2.8,Å from a single crystal flash-cooled at 100,K. X-ray data revealed that the protein crystallizes in space group P1, with unit-cell parameters a = 61.88, b = 66.40, c = 77.23,Å, , = 102.90, , = 104.40, , = 99.07°, and molecular replacement using a theoretical model predicted from the primary structure as a search model confirmed the presence of six molecules in the unit cell as expected from the Matthews coefficient. Refinement of the structure is in progress. [source] Inclusion Behavior of ,-Cyclodextrin with Bipyridine Molecules: Factors Governing Host-Guest Inclusion GeometriesCHEMISTRY - AN ASIAN JOURNAL, Issue 3 2009Yan-Li Zhao Dr. Abstract Guest Effect: The differences of nitrogen atom positions and the bridge bonds linked to two pyridine rings of some bipyridine guests can significantly affect the binding abilities and inclusion geometries of ,-cyclodextrin with the guests in both the solution and solid states. The 1:1 complexation of ,-cyclodextrin (,-CD) with structurally similar bipyridine guests which lead to the formation of six inclusion complexes (1,6) of ,-CD with 4,4,-vinylenedipyridine, 2,2,-vinylenedipyridine, 1-(2-pyridyl)-2-(4-pyridyl)ethylene, 4,4,-ethylene-dipyridine, 4,4,-dithiodipyridine, and 2,2,-dithiodipyridine has been investigated comprehensively by X-ray crystallography in the solid state and by 1H,NMR spectroscopy and microcalorimetric titration in aqueous solution. The complex formation constants (KS) for the stoichiometric 1:1 host,guest inclusion complexation of ,-CD with the bipyridine derivatives were determined in aqueous solution by microcalorimetry and the host,guest inclusion geometries of the complexes were deduced from 1H ROESY NMR spectroscopy. It transpires that the guest bipyridine molecules are included in the ,-CD cavity with a range of different inclusion geometries. In the solid state, the crystal superstructures for the ,-CD complexes 1, 4, and 5 are characterized by the triclinic crystal system (space group P1) commensurate with AAAA type supramolecular aggregation. By contrast, the ,-CD complexes 2, 3, and 6 display either monoclinic (space group P21) or orthorhombic (space group C2221) crystal systems, characteristic of ABAB type supramolecular aggregation. The results demonstrate that the relative locations of the nitrogen atom positions and the bridge-bond links between the two pyridine rings in these bipyridine guests, not only lead to distinct crystal systems and space groups, but also to different binding geometries and thermodynamical parameters on complexation of the bipyridines with ,-CD. The knowledge obtained from this research improves our understanding of the molecular recognition and self-assembly processes exhibited by ,-CD, both in the solid state and in aqueous solution. [source] Preparation, Structural Characterization and Luminescent Property of Binuclear Silver (I) Complex Formed by Benzotriazole and 1-Hydroxymethyl BenzotriazoleCHINESE JOURNAL OF CHEMISTRY, Issue 9 2002Qing-Xiang Liu Abstract Dinuclear silver (I) six-membered ring complex [Ag2 (bta)2 -(hmbta)2] (ClO4)2 (3) has been synthesized by the reaction of benzotriazole (bta) (1) and 1-hydroxymethyl benzotriazole (hmbta) (2) with Ag (CH3CN)4ClO4. The structures of compound 2 and Complex 3 have been studied by single crystal X-ray diffraction analysis. The change of luminescent intensity of 1, 2 and 3 was reported. Compound 2 crystallizes in the monoclinic system with space group P2 (1)/c, a = 0.7655 (10) nm, b = 1.0126 (14) nm, c =0.9502 (13) nm, , = 95.07 (2)°, V = 0.7337 (17) nm3 and Z = 4. Complex 3 crystallizes in the triclinic system with space group P1, a = 0.73611 (18) nm, b = 0.9152 (2) nm, c = 1.2277 (3) nm, , = 87.170 (5)°, V = 0.8221 (3) nm3 and Z = 1. The main structural feature of complex 3 is a symmetric dinuclear six-membered ring formed by two silver (I) atoms and four N-atoms from two benzotriazoles. The second structural feature of complex 3 is the ,-, stacking interaction between two adjacent molecular planes, which forms the two-dimentional layer structure. Besides, compared with 2, the luminescent intensity of complex 3 shows a remarkable enhancement. [source] | ||||||||||||||||||||||